GM W body cars, 3100 3400 SFI, 3800 engines

[dan]

GM 3100-3400-3800 and W body car pattern failures
GM cars of W body type have been around for YEARS! and are EXTREMELY common in the US and in Canada, Buick Century, Buick Regal, Buick Lacrosse, Chevy impala, Chevy Malibu, Chevy montie carlo, Pontiac grand am, Pontiac Grand Prix, Oldsmobile Alero, Oldsmobile Cutlass are just a few too name that used this “structural” body style and shared similar drive lines many of them used 3100SFI 3400SFI and 3800 series I series II and Series III V6 engines, as well as 4T60E and 4T65E and as for cars equipped with supercharged 3800s or the 5.3L LS-4 the 4T65EHD transmission though some cars of later vintage beyond years of 2004 now use the 3.5L 3.6L DOHC, and 3.9L V-6 engines too. many of them share the same pattern failures or problems, and most of them start too appear as early as 80,000 miles or as late as 220,000 miles… the life expectancy of these cars can sometimes exceed 500,000 miles or more depending on how much the owner loves there car enough too take care of it, but neglect of car washing and lack of maintenance will end the life of any car… even the bulletproof 3800 bolted too a robust W body!

WARNING!
pattern failures like eric said can be sneaky little things, my suggestion too you is before you make a assumption and replace parts that you do a good diagnosis, dont bust your butt and spend $200 on parts and gaskets only too find the issue was deeper in and then find out you are spending an additional $300 and have to do the work again!

[color=#ff4400]it is also important too note that there may be more tips in the comments section below this thread as many of the viewers have contributed too this post.
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3100-3400 SFI pattern failures

lower intake manifold gasket failure (leaks coolant on ground from engine, coolant in oil.)
probably one of the most noted failure of the 60 degree V6 of earlier years is the lower intake manifold gaskets, they are know mostly for leaking externally, usually you will see a puddle of coolant and the coolant level will drop, the coolant should be leaking from what looks like where the lower intake manifold is joined too the inside bank of the heads… stop leak is not a permanent fix, it is advised too replace the junky factory lower intake manifold gaskets with the replacement Felpro metal framed gaskets with rubber seals. sometimes the coolant can leak into the oil, this is bad because this washes out the rod and main bearings and pits them, if the driver continues too drive under these conditions the engine crank case will over fill with a sludgy mixture of coolant and oil that at first looks like diarrhea, sometimes like a white baby poop color as commonly described.
[color=#ff4400][b]

leaky camshaft seal (burning oil smell sometimes noted.)[/b][/color]
earlier 60 degree V6 engines used to have a distributor ignition rather than the well know 3 coil system, the old area where the distributor shaft used to run through is plugged off with a plate, sometimes the gasket leaks.

Piston slap (a ticking noise is heard that goes away as the engine warms up.)
a ticking or almost knocking noise is heard as the engine is cold, but as the engine warms up and oil begins too flow more the ticking noise quiets, do not be alarmed this is a common issue with 3100s called piston slap and 3400 SFI engines typically with miles exceeding 140,000 or so, this is caused buy odd wear on the pistons and they develop excessive clearences slapping in the cylinder bores on typically the ignition stroke as the piston is forced down buy combustion… higher mileage engines exceeding 200,000 miles may begin too burn oil slightly but as long as you are easy on the engine while it is cold the engine usually continues too run despite the tick tick tick tick tick.

here is what it may sound like

[video]http://https://www.youtube.com/watch?v=pHBAT4KyjHg[/video]

Blown head gaskets (exibits blown head gasket symptoms)
typically only if the engine has been over heated, the heads are aluminum and the blocks are cast iron, if the engine is ever over heated the expansion rate of the heads are different than the block and the heads can warp, the gaskets will no longer seal correctly and they will blow sometimes leaking coolant causing all the common symptoms of head gasket failure, you will have to do the head gaskets and probably get the heads machined.

heater core bypass pipe failure (leaking coolant)
hoses leading from the water pump too the heater core sometimes rust and start too leak, they rust badly at times and when they spring a leak they can sometimes sprey everywhere, bad news is this is a dealership part if it needs replaced!

rockers come loose off heads (clattering noise while engine runs.)
i have noticed that sometimes the rockers will come stripped from the heads on the 3400s, its a rare instance but it happens, it will commonly make a sort of a racket under the rockers.

what it may sound like, and skip too about 5:30 this guy talks alot.

[video]http://https://www.youtube.com/watch?v=6afkMb6KGWI[/video]

3800 Series III Series II and some 3800 Series I

Upper plenum coolant leak (burning coolant, hydrolocked engine, coolant in oil)
N/A Versions of certian series I and series II have plastic upper plenums, series IIIs have a aluminum upper plenum, and the supercharged engines like the L-67 and L-32 SC 3800 engines obviously have aluminom supercharger housings, but upper gasket may still fail on supercharged models possibly on series III N/A L-26 engines as the gasket is still plastic, the passage for the EGR goes right through the Upper plenum as well as the coolant passages, as the coolant gets hot and cold it makes the upper plenum brittle, as time goes on the EGR passage melts and cracks, the coolant passages then crack themselves and start to leak into the intake, sometimes into the oil possibly through PCV, if they leak into the intake, the engine can suck in coolant and hydro lock the engine, if the coolant leaks into the oil it washes out the bearings pitting or even scoring them, and over fills the crank case with a sludgy mixture of coolant and oil, the fix too this is a new gasket and a metal insert you put into the new plenum and a new plenum itself, and while you have the upper plenum off you might as well do the coolant elbows and lower plenum too as you are only a few bolts away.

lower intake manifold gasket failure (coolant leaking on ground from engine or coolant leaking in oil.)
like the 60 degree V6 the gaskets are known for failure, they are made of plastic and the seals crack after many heat cycles and leak coolant up in the vallys between the lower and upper plenum through the bolts holding down the lower intake manifold. or they can leak coolant into the oil and wash out the rod and main bearings pit and score them. i have personally seen the effects of this, i have seen crank cases more than twice over filled with coolant and oil mixture which looks like a diareah color or a milky color. in many cases the engine will run roughly but it will still run. the fix is too replace the lower intake manifold gaskets with the felpro metal framed ones, the plastic ones cannot be trusted, this is why they failed initially!

Coolant elbow failure (coolant leaks only at high revs full throttle.)
a suspicions coolant leak is found from the front end of the engine, it only shows up when doing a full throttle freeway pass and all of a sudden your belt is squeaking and the low coolant light comes on, otherwise its near impossible too replicate the coolant leak buy just letting the engine run or even reving the engine with the car in park because the Rev limiter limits rev to 4,000RPM with the car in park… there are a set of coolant elbows one of them im particular joins the belt tensioner/coolant heater hoses bypass too the lower intake manifold. one of them is a 90 degree bend and is made of plastic… thats right plastic, these get hot and cold and eventually crack usually inside of the belt tensioner or mostly inside of the intake manifold and spray coolant at WOT. this leak can be found with a cooling system pressure test. the fix too the issue is too replace the crappy plastic coolant elbows with the aluminum units you can get at your auto parts store. NOTE, some belt tensioner assemblies only require one single coolant elbow as some of the belt tensioner assemblies come with the lower elbow that connects essentially to the timing cover cast solid into the assembly.

rocker cover gasket failure (burning oil smell, some smoke, engine wet with oil, my car just caught on fire.)
the plastic rocker covers on the 3800 are know for leaking oil after high miles, so badly that they have been known too cause under hood fires! too remedy the issue just get new gaskets… symptoms are a burning oil smell, under engine smoke, and the engine appears too be wet down the sides from leaky rocker cover gaskets… replace before a fire spreads.

fuel pressure regulator leak (car runs rough and rich, my upper plenum just exploded)
the fuel pressure regulators have been known for leaking on these engines, the diaphram will break and leak gas… the gas vapors will go into the plastic upper plenum. at this point your car may be running rough and may smell faintly of gas, remove the hose from the fuel regulator and have a sniff, if it smells badly of gas replace the fuel regulator, they have been known for causing upper plenums too explode on the 3800 series II from the trapped rich fuel vapors in the upper plenum and when a back fire accures it causes the plenum too burst.

FUEL REGULATORS DO VERY ON THE 3800S

False low coolant light
sometimes the coolant level sensor will act up in these cars, they will get gummed up inside and cause a fake low coolant light too come on even when the coolant level is full, replacing this unit should fix the issue

supercharger coupler (supercharger knock and clatter L-67/L-32 engines only)
people say the whole supercharger is going bad, not nessisarily, in fact there is a coupler in the supercharger that often wears out, this is the most common cause of the clattering noise heard, and should fix the issue.

this is the sound of a clattering supercharger coupler

[video]http://https://www.youtube.com/watch?v=5seKcuH1kas[/video]

Throttle body failure (3800 series III L-26 and L-32 only)
engine randomly shuts off and display sometimes says “starting disabled due too electronic throttle control.” sometimes car may seem too accelerate out of control, replacing throttle usually fixes issue

PCM failure (3800 Series III and later W bod cars only)
engine may randomly shut off telling you the same thing as a electronic throttle control failure, the newer PCMs which are faster and much smaller than the bigger Aluminom PCM boxes are known for being a little more prone too failure TSBs are out for the PCMS.) keep in mind the old PCM is not reprogrammable which means you will have to get a new one and have it programmed for your car, it may be a $700 day!

Crankshaft position sensor failure (engine randomly shuts off going down the road and car wont start unless it sits for a while.)
a crank shaft position sensor is a common failure for the 3800, it is located behind the harmonic balancer, once you have the balancer off it is easy too replace, removing the balancer is the “fun part.”

4T60E-4T65E transmission issues

P-1811 Max adapt long shift (car upshifts hard)
a very common code for these transmissions, what happens is as the transmission wears out its clutch plates and it begins too slip the transmission begins compensating buy shifting with max pressure on the clutch plates, so a warn out transmission or a bad pressure control solenoid sometimes only showing when the transmission is warmed up

shift solonoid issues (erratic shifts)
sometimes in these transmissions the shift solenoids are known for having issues which can cause erratic shifting sometimes only showing up when the transmission is warmed up

pressure control solenoid issues (car upshifts hard, P1811 code sometimes just shifting erratically seeming too go into neutral in some gears at times causing engine too rev when it should shift down or up)
sometimes the pressure control solenoid can fail or wear out causing a P-1811 code max adapt long shift, or even cause erratic shifting behavior such as the feeling of false neutrals or other weird things sometimes only showing when the transmission is warmed up

Torque coverter clutch issues (car seems too shift up and down a gear sort of shutters)
sometimes the torque converter clutch can act up, when cruising at highway speeds sometimes it feels like the car is going up and down from a higher too a lower gear or feels like its sort of shuttering, this is the torque converter clutch acting up, it engages and disengages on and off at times with earlier transmissions it would actually get stuck on and stall the engine at stop lights

Overdrive spline strip (overdrive wont work)
sometimes it feels like the car will not shift into over drive, earlier transmissions of the 4T60E and 4T65E had issues with the transmission overdrive spline stripping, when the transmission goes too shift into overdrive, the overdrive gear set simply slips on the overdrive spline because it is stripped and you loose over drive.

good video here on this

[video]http://https://www.youtube.com/watch?v=csmTm94qC_M[/video]

VSS vehicle speed sensor (shifts weird or wont shift stuck in 2nd gear limp in mode, no speedometer or speedo acts funny)
located on the transaxle passenger side next too the Differential held on i believe buy a single 10MM nut, these commonly get metal shavings on the magnet, or they just go out, more commonly the wires too them corrode and fall off breaking connection, before you replace the sensor CHECK THE WIRING! common symptoms, weird shifting, and the speedometer will not work or will be all over the place.

power steering

power steering pump wearing out (whining noise changes with RPM steering feels hard when car is not moving.)
as the power steering pumps wear out in these cars they make a very destinct whine sound that many mechanics know by heart because its a very common failure, the steering may feel hard with the engine at idle and the car is parked, but once you bring the revs up a little bit or the car is moving the steering feels fine… the common solution is too replace the power steering pump.

power steering leaks (leaking power steering fluid.)
a common place for the 3800 engine W body cars too leak power steering fluid somewhere from the lines leading from the power steering pump too the rack, look at the lines top too bottom and inspect for leaks.

W body common issues

Rust
where the A frame meets the body is where it typically rusts and structurally fails, where the trailing arms bolt too the frame is another pattern spot for failure, as well as rust where the lateral links/lower control arms for the rear also are bolted up too the car is often know for rusting out and falling apart. constant washing during the winter months should slow these rustings, and weather proofing should insure the life of the car… these failures are common in vehicles with high miles and abuse that hardly see a car wash

Bent trailing arms
sometimes you hit a pot hole or a rock, or someone tries jacking up the car, and the stamped steel trailing arms get bent… not too fear you can replace them really easy, and ZZP makes chrome Molly steel tubular replacements that are much more robust.

Rusty rocker panels
very common with cars like the Buick Century Custom and Buick Century Limited where there rocker pannels are not hidden buy fancy plastic trim, road salt and water and crap gather on the rocker pannels and in the rocker pannels they begin too rust from the inside out, and then sadly the only fix is body work.

Bent lateral links/rear control arms (just hit a big pothole and my steering wheel is angled at 30 degrees too the left, but i am going straght.)
the small thin lateral links in the rear that act as control arms are known for bending in accidents or if you hit deep rough pot holes, these can be a pain too replace, you may also discover the structural unit they bolt too the body may be badly rusted and falling apart.

Broken sway bars (a clunking noise is heard when coming into a corner or out of a corner.)
where the sway bar meets the sway bar links they are known for rusting and breaking, replacement units are solid metal and not hollow, some are thicker, this will not only fix the breakage issue in the future, but means a stiffer sway bar which means better cornering.

engine light for evaprative missions leak/check gas cap
there are several common fixes too this one, first is too replace the gas cap, sometimes the gas cap is no good because it simply will not seal because it wont tighten down enough or the seal that goes around the gas filler neck is cracked and rotted and leaks. sometimes the filler neck rusts out and developes small pinholes and causes slight leaks, and later W body cars seem too have a issue with the canister vent solenoid that bolts too the frame, sometimes they go bad and need replaced and they can really turn that engine light on.

Electrical and other

gas gauge does not read fuel level, seems too wave up and down very innacurate
this is very commonly caused buy the fuel sending units “fuel level indicatior.” i guess you could call it, they tend too have issues after a while and they become very inaccurate and the fuel gauge will tend too wave everywhere at times from full too half full too near empty too everywhere… replacing the fuel sending unit may fix this issue and usually this is a indicator that the fuel pump will fail soon, so replacing is a good idea before you end up stranded somewhere because you ran out of gas or because the fuel pump called it quits next.

here is another video too give sort of a demo

[video]http://https://www.youtube.com/watch?v=cIdbPllQA4Y[/video]

fuel pump failure (car will turn over but wont fire under its own power, car misses and stumbles.)
car wont start, it will turn over rapidly just wont fire, you have no fuel pressure, the result is typically the legondary GM fuel pump failure, and its not just with W body cars its with the H body cars as well, replacing the fuel pump usually fixes the issue and fuel pressure will be restored, sometimes giving a sharp tap on the gas tank a few times may get it too work again just too get you home but don’t count on it as a permanent fix.

Battery terminal issues, old and new (car seems too cut out when driving, i loose power when i hit a bump or wiggle the battery cables, car wont start no crank no start condition, my battery terminals broke on my 2004 or newer GM Vehcile.)
the batter terminals on the older GM Vehicles, mostly in the years between mid 90s too mid late 2000s where the side post type that bolted onto the the side of the battery rather than clamp on, these terminals had a tendency too wear out over time and even after tightened too the maximum had issues with wearing out and causing connection issues, even with them tightened down tight wiggling them would cause a connection problem, the solution is too clean connections first, then if that does not work replace the terminal components, for the newer vehicles most of the ones beyond 2004 they went back too a top post set up but rather than use a lead battery connector they used a cheep stamped steel one, and eventually get brittle and corrode VERY badly, there cheep and very bad design causes them too break and not tighten down too the battery properly causing connection issues, replace these with the good old fashioned lead connectors, so cheep and easy i did one in a parking lot on a black Friday.

window regulator issue (window wont go up or down.)
your windows not going up or down, GM window regulators are natorious for failure, too prevent this try avoiding the window regulators as much as possible during the winter after you just got done scraping the windows off, this is what commonly kills the regulators, when they are killed replace them usually the motor burns out or gears get stripped, and replacing them should fix the issue…

PRNDL mielage indicator burnt out
very common thing on 1997-2005 Buick Centurys and 1997-2004 Regals, right below the speedo tells what your gear you have slected and your mileage, these commonly burn out, some people replace some resistors and stuff and make it work again, others buy a instrument cluster.

VATS system failure (car wont start, SECURITY light on)
sometimes the security system acts up, either the chip in the kea goes wonky or more commonly the entire system needs replaced and its a expensive day. VATS security system disables the fuel pump and starter and all that too prevent theft, after the car gets quite old these are common failures and then turns on the car owner.

Moisture in headlights (water in my headlights and water droplets, foggy from the inside.)
too me this seems to be a pattern failure, and seems too be more common with pontiacs, in fact i seem too be experiencing this issue myself. sometimes the assembly for the headlights don’t seal properly and after a humid day or after washing your car moisture accumulates inside and its not good for your light bulbs… picture included this time!
[URL=http://s49.photobucket.com/user/13aceofspades13/media/moistureinheadlight-Edited.jpg.html][IMG]http://i49.photobucket.com/albums/f261/13aceofspades13/moistureinheadlight-Edited.jpg[/IMG][/URL]

Topic

[Rip Tides]

[quote=”13aceofspades13″ post=95342]
window regulator issue (window wont go up or down.)
your windows not going up or down, GM window regulators are natorious for failure, too prevent this try avoiding the window regulators as much as possible during the winter after you just got done scraping the windows off, this is what commonly kills the regulators, when they are killed replace them usually the motor burns out or gears get stripped, and replacing them should fix the issue…
[/quote]

Great write-up, but wanted to add something to this part.

This all relates to the 4-Door versions of the cars mentioned in the write up.

On the front windows small white clips that hook onto the cables controlled by the regulators will break. One breaking will cause the window to cant (go crooked) when operated. If both break the window will fall into the door itself. Replacement clips are much more inexpensive than a regulator replacement and can be found at most auto parts places.

Here is an example of these clips:

The rear windows on these same 4-door style will fail in a similar fashion, except it’s the cable guides that will break first. With the design being different than the front this means they will require total regulator system replacement.

Here is an example of the rear regulator with all 3 possible fail points marked:

Almost all the regulators for these cars come with tracks, cables, mountings, ie: the works as seen in the pic above. If your regulator still operates but doesn’t move the windows some of these systems can be rigged or repaired to work depending on the type of failure without needing an all new regulator system.

[dan]

awesome man, thanks!

all suggestions are welcome, please feel free too add pictures if you happen too know what parts fail.

and as he said four door cars, some of the cars where coups as well as sedans and Oldsmobile offered a convertible i believe…

[dan]

made some modifiactions added some things here and there and some links too some parts for examples but keep in mind parts may very for your W body vehicle and 3100 3400 and 3800 engine… not all are the same many are different such as fuel regulators, the 1998 buick regal and a 1996 Oldsmobile Delta Eight Eight both have the 3800 series II but the Buick Regal has a different fuel regulator.

[Steven Cummings]

I just want to add regarding your 4T65E tranny for anyone who has to drop it:

There is a bolt that holds the bellhousing for the tranny to the engine that has the head under the cylinder head. The passenger tire and splash shield can be removed allowing access. THe bolt can be accessed using three 1 foot extensions under the cylinder head and above the engine block.

I spent a day trying to figure out why my transmission wasn’t dropping the first time…

Other than that, outstanding writeup!

[dan]

thank you, yea when i swapped the engine in my regal i had one heck of a time with that… its hiding right in there and it takes some patience too get to it! a couple of long extensions and i thing a 15MM socket gets that one… and a lot of patinece!

[Richard Cook]

I admire your data compilation and its accuracy. I recently lost the best car I ever owned in a roll-over when I fell asleep at the wheel coming home from work. Aside from almost choping my left pinky off, I emerged virtually unscathed, which was lucky for me because I wasn’t wearing a seat belt. Back to topic, this car was a ’99 Pontiac grand Prix coupe 3800 Series II. The engine was magnificent and matched well with the body. That said, there were quite a few plugs of info in your post that I personally experienced. unfortunatly, I didn’t get to fix them as soon as I was aware. Money is far and few between in this household for that weren’t right in your face. They were resolved nontheless. Most recent was problems with it starting and dying while driving. after about 700 bucks worth of parts and labor, it turned out to be the crankshaft position sensor. Needless to I was livid to see that $35 part costed hundreds to resolve, but hay, you learn more in failure than in success…. or something like that. Thanks again for off loading the info for people to troubleshoot and anticipate.

[dan]

[quote=”RichLeeCook” post=96499]I admire your data compilation and its accuracy. I recently lost the best car I ever owned in a roll-over when I fell asleep at the wheel coming home from work. Aside from almost choping my left pinky off, I emerged virtually unscathed, which was lucky for me because I wasn’t wearing a seat belt. Back to topic, this car was a ’99 Pontiac grand Prix coupe 3800 Series II. The engine was magnificent and matched well with the body. That said, there were quite a few plugs of info in your post that I personally experienced. unfortunatly, I didn’t get to fix them as soon as I was aware. Money is far and few between in this household for that weren’t right in your face. They were resolved nontheless. Most recent was problems with it starting and dying while driving. after about 700 bucks worth of parts and labor, it turned out to be the crankshaft position sensor. Needless to I was livid to see that $35 part costed hundreds to resolve, but hay, you learn more in failure than in success…. or something like that. Thanks again for off loading the info for people to troubleshoot and anticipate.[/quote]

thank you i am glad you like the post.

the crank shaft position sensors turned out too be one of the biggest WTF IS WRONG WITH MY CAR pattern failures of the 3800, it was easy too diagnose the lower intake manifold gasket failure and the upper as well, as well as a leaky coolant elbow with a simple cooling system pressure test could easy be found as you apply pressure air and coolant would sprey from that general area… the crank shaft position sensor was one of those parts not many knew about and not many would think of, and because of its location (behind the harmonic balancer) its not easily seen unless you really get a look down in. most people would go with the tride and true “it must be something with needing a tune up.” and eventually throwing parts at the car only too find a some $40 dollar part would fix the issue in many cases after spending hundreds. then replacing the part only the brave soul who would dare remove the harmonic balancer could make it a DIY and also requiring special tools… but once the harmonic balancer is off its a easy breazy job.

the W body cars are known for being safe and rubust cars, my grandpa hit at least 2 deer with his 2000 Buick Century custom, it took a silver SUV with a driver too ignorant too drive defensively too total the car, but even after having its fender wrinkled like aluminom foil and its tire shoved into the fender the car still ran like a champ and i could still almost drive it, and best of all my brother who was so close too being buy the door that almost got smashed was compleetly un scaved. these cars last so long and are so reliabe that often there owners almost fall in love with there W body cars… and when a sad fateful day comes that a accedent bad enough too total the car it can be depressing, but hey… you survived and are alive today too tell the tale, and you probably learned too wear that seat belt 😉

thanks for your input and i am glad you like the post.

[dan]

made a few modifications added a few videos for sound diagnosis assistance.

[dan]

added a common failure with battery terminals, something i forgot.

[angelo paloumbis]

Also do not overlook the engine oil pan. It depends on the area of the country you live in. The area I am in (Chicago) I see alot of rust perferating through causing oil leaks/seepeage.It is about a 5-6 hr job (can be done in 3hrs) to replace the pan working on a lift.(I would not attempt to do this on the ground with jack stands).
By the way i am a professional auto tech.

[dan]

yes the 3800s that had the steel pan where known for rusting out really bad and leaking, but now the new series III engines have aluminum pans which remedied that issues, the gaskets are also known for starting to leak at high miles sometimes.

[Erin]

Skimming the list, I had plenty of those problems on a 94 grand prix with the 3.4 DOHC (LQ1) engine. It was falling apart faster than I could fix it. It was the second worst car I ever owned.

Anyways sticking to the facts – what about radiator leaks? Mine had a leak and I tried TWO different ones from a junk yard from W-bodies and they leaked in the same spot.

Also on W body with the LQ1, what about the distributor shaft leak (where it was just a plug in there)

[fordranger]

3100’s 34oo’s and breaking camshafts after intake manifold gasket replacement…. what a nightmare

[Vincent]

excellent write up but also so should not with the high feature V6 engines about oil consumption higher than tolerances.

[dan]

@framedforlife
yes as the pistons start to slap they do start to consume oil, this is well known, if I haven’t written that down I will add.

@fordranger
I have heard of 3100s and 3400s breaking camshafts before, though its not as common as the lower intake manifold gasket leak, I think it is caused in fact buy that as the bearings in the crankshaft mostly such as the mains and rods pit, I would imagine it pits and scores the cam bearings also.

@Summer_Night
that is a good point about the radiator leaks… however I have noted this is a general issue with all plastic tanked radiators, I have seen it in Fords, GM cars, even dodges and foreign makes, after a while the plastic gets hot and cold so many times and it cracks and the radiator starts to leak and eventually needs replaced. as for the distributor shaft, that will be added, earlier 3100s had that issue.

[Author]

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