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Hi All,
As some of you may know, I have been working on my 1997 Saturn SC2 toward solving performance issues. It’s been coming along very well. Every time I address a system, I have been gaining power, improving gas mileage or turning off the CEL. BUT I still have a pesky vacuum leak. I tested for vac leaks (traditional method, carb cleaner), but found none. I have been inspecting vac hoses periodically hoping that a new idea (of where to look next) will hit me…it hasn’t happened yet. So, I have this valve cover gasket replacement planned for Friday and I got to thinking:
What are the chances my vacuum leak is due to my worn valve cover gasket? I mean, it is leaking oil there, why not vac/air, too?
Any thoughts, comments or suggestions would be greatly appreciated.
PS-I will be running a power balance test maybe Saturday and then a compression test (after I replace my muffler). Damn, I just remembered, I also have suspension parts (lower control arm, RF and rear stabilizer links) that need replaced and a tire rotation to do. And later, a complete timing chain replacement. Whew this car is keeping me busy!
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Hi Everyone,
It took a while but my valve cover gasket replacement done. There was a lot of cleaning to do so I ended up working into the wee hours of this morning. Just a few additional notes: I saw a video by someone who used acetone to clean a composite cover (like mine). However, I would not recommend this. Acetone does, to an extent, damage plastic. I used dish soap (degreasing action) and a small scrub brush to clean my cover inside and out (rinsed and dried thoroughly). I also used rubbing alcohol to clean all mating surfaces (x3) wiped them dry (x2). I also used a razor blade sparingly (only for tough spots of baked on oil).
Well guys,
I cleaned up the old oil stains so I could easily identify new ones, if applicable. It looked pretty good (pics below). Took it for a 7 mi. test drive and checked it. It was holding well, no leaks. Drove home, checked it again and found a leak on the intake side, near the power steering pump (pic). Once it is cool, I will double check the torques (Probably should have done this before I went for the test drive). If my torques are accurate (pretty sure they are), I may be able to conclude that the cover is, in fact, warped (a common problem with composite valve covers) or my 2 beads of Permatex-Black RTV at the timing cover-head interface (intake and exhaust side) were not large/thick enough (but I followed the directions to the letter).
Although I am a little disappointed, I need to remember that my repair improved it significantly as it only leaks in one spot rather than several. My Saturn is happier now.
If anyone has any comments or suggestions please feel free to share. Thanks so much for reading/responding.
check the tightness. Let the gasket due its job. No rtv
since everything is fresh. Try removing the rtv and put the
cover back on and tighten.see if the leak goes away.My fasteners were tight (spec. 89 in-lbs)
ok, will remove the small vertical bead of RTV from that interface that I refer to. That seems to be the exact location of the leak, too. 🙁
I will also dab the gasket with an absorbent cloth/papertowel to remove the oil residue and clean the mating surfaces again (but with acetone this time, just in case the alcohol was not as effective as I thought it would be).
Thanks, college man!
Ok, so Round 2:
I still have a leak BUT I do have a plan and some good news to report.
The good news is that I no longer have a high idle condition (1200 rpm) at start-up. It started and stayed at 900 rpm. Happy about that. But still have a vac leak. Since I have no loose vac lines/connections (that I have come across yet), I want to guess that I might have an intake gasket leak but will wait for more evidence.My plan for the valve cover issue is to keep an eye out for a new one. I have occasionally seen them on eBay new, I guess leftover stock after Saturn went under. Also, I think I may torque my fasteners a little tighter than spec to account for the torque wrench +/- 4% accuracy. If anyone has any comments, feel free. Thanks.
Need to move on to my power balance test.
P.S.- I am learning a lesson about “come-backs” LOL :huh:
I don’t think a 1/4 to 1/2 turn more on the fasteners is going to hurt anything. I must say I’m impressed with your work though. Very clean.
You can use the methods outlined in this video to check for vacuum leaks.
The power balance test is more if you have a misfire and you’re trying to track down the problem cylinder. More info on performance diagnosis here.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Good luck and please continue with the updates.
[quote=”EricTheCarGuy” post=93065]I don’t think a 1/4 to 1/2 turn more on the fasteners is going to hurt anything. I must say I’m impressed with your work though. Very clean.
You can use the methods outlined in this video to check for vacuum leaks.
The power balance test is more if you have a misfire and you’re trying to track down the problem cylinder. More info on performance diagnosis here.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Good luck and please continue with the updates.[/quote]
Thank you, Eric, for the compliment on my clean-up work.
Will start with 1/4 on all and possibly and additional 1/4 turn, if needed.
The very first item I addressed, if I remember correctly (will check my notes, kept detailed records) was the vac leak check, as per the attached video. I may have been timid with the carb spray the first time so I will repeat.
The reason I am doing the power balance test is per your video, “Solving Engine Performance Issues, part 1”. I have that “machine gun” noise in the exhaust as I am coasting (at idle/deceleration) at 2200 rpm. I recently had codes (O2 sensor-upstream, coolant level sensor, crankshaft position sensor, multiple random misfire), but CEL turned off after I replaced a few parts (O2 sensor, upper radiator hose/and system bleed/fluid top-off, upper motor mount, plugs, wires and air filter). Not sure if any of the codes are still stored, though. However, I am treating this vehicle as if it does still have a misfire, and I am assessing engine health. 🙂
Will continue to update.
PS-I found something very surpising last month while I was changing the plugs-the order of one of the plug wires at the coil towers was installed improperly by the previous owner (wire 3, tower 3 should be wire 3, tower 4). Now that could explain a lot!
If it’s a DIS ignition system it may not matter where the wires are placed. Both leads on the same coil fire at the same time on those systems. I don’t know if that’s what you have on your car, but it’s a common GM set up.
That said, don’t ever rule out engine mechanical. A worn valve or piston ring can cause a miss the same as a spark or fuel problem.
Good luck and keep us posted.
[quote=”EricTheCarGuy” post=93169]If it’s a DIS ignition system it may not matter where the wires are placed. Both leads on the same coil fire at the same time on those systems. I don’t know if that’s what you have on your car, but it’s a common GM set up.
That said, don’t ever rule out engine mechanical. A worn valve or piston ring can cause a miss the same as a spark or fuel problem.
Good luck and keep us posted.[/quote]
Yes, it is DIS. So you are saying that there is no wire to tower specificity? 😳
But yes engine mechanical is where I am headed. Ran FI 1-3 power balance test today (RPMs dropped) and have been investigating more of my vac leak (been a beautiful day to be wrenching!). PCV grommet looked worn but tested-carb cleaner-ok. Checking break booster hose then see if I can get a more directed spray at intake.
Spark test/Compression test is next.
Thanks for all your help so far, Eric. I have learned soooo much.
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