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94 Ford Explorer 4.0L V6
I removed my lower intake manifold to diagnose the source of oil leaking into my #5 cylinder. (found the problem: that the lower intake mani bolt nearest the offending cylinder was loose, letting oil leak past the gasket)
even tho i found the problem i was looking for, i inadvertently created another. I didnt drain enuf coolant before removing the lower IM and I was not familiar with the design of this motor. tons of coolant leaked out, primarily onto the floor, but there is surely some in the oil pan now. and probably even in some of the cylinders, as i can see some sitting on at least one of the intake valves that happened to be closed.
So here’s my plan:
1) sop up as much as i can see on the valve train with paper towels.
2) use air compressor to blow all over the valve train, trying to clear out coolant and flush it downward.
3) crack the oil drain plug and drain until i stop seeing green.
4) reassemble engine. disable ignition/fuel and crank the motor for a bit to stir things up. let sit a while. repeat step 3, draining any more coolant that has sank to bottom.
5) run truck until warm. drain oil. change oil and filter (I’m due anyway).
6) change again in 3k miles and pray that any coolant that remained doesnt sludge up too bad in the wrong spot and wreck my motor.in the photo you can see how the lower IM (not shown) sits between valve trains and have coolant passages at the front and back. for anyone who was curious, i put an arrow to show where the oil was leaking past the lower IM gasket into the intake tract. I didnt understand how a faulty IM gasket could leak oil into the cylinder but now i get it. the gasket was even slightly discolored just in that one spot. the oil was fouling out my spark plug, causing a slight miss and a pretty decent knock that I’ve treated by running higher octane gas until getting to around to tearing into the motor to figure it out.
anyway, will my truck survive this coolant mistake?
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You are okay man, you can relax.
I do that almost every time I do a headgasket job, just pull the drain plug and drain everything in the pan. Put the plug back in and refill with fresh oil and filter and thats that.
Trace amounts of coolant work hurt a thing and will be gone after you run the engine up to temperature.
Thanks for the reassurance man! I was paricuparly worried about whatever coolant got into the cylinders but I’m sure much more could gets into a cylinder when pulling a head.
Actually did that one also like an idiot when i was even far less equipped and knowledgeable. Thought I’d check the torque on the head bolts on cressida that was running like ass, smoking, and maybe had a head gasket leak. It had some work done by some other back yard mechanics who forgot to torque the valve cover bolts. Thought I’d back off the head bolts to retorque em in case they were loose also and maybe get lucky and fix the problem. I didn’t even relieve the cooling system pressure. Needless to say I made a mess. But the car wouldnt stay running anyway and my buddy ended up selling it shortly afterward anyway to some kids that just wanted the motor, running or not.
So the sad thing is I kinda already knew better and could have avoided this. So even tho my truck will be fine, will the automotive gods forgive me?
You are forgiven. I’ve not seen a shop yet that takes the time to drain the cooling system before pulling an intake manifold. They pull the manifold, let the coolant leak into the oil pan, then drain the oil and replace it when they are done.
No harm done, no need for saying Hail Mary 372 times tonight, all is good 🙂
[quote=”Tomh” post=79041]You are forgiven. I’ve not seen a shop yet that takes the time to drain the cooling system before pulling an intake manifold. They pull the manifold, let the coolant leak into the oil pan, then drain the oil and replace it when they are done.
No harm done, no need for saying Hail Mary 372 times tonight, all is good :)[/quote]
😆 Penance is postponed until a greater sin 👿
Sadly, I have seen flat rate techs that don’t drain the coolant at all. They drain the oil, leave the plug out and remove the intake and heads and let it run all over the floor and down the drain. Whatever goes into the engine runs out the oil drain hole.
Before they reassemble they blow out what they can see with compressed air, fill er up with oil and out the door.
I can’t say that I ever saw a job done like that come back with a problem related to coolant in the oil.
[quote=”Raistian77″ post=79073]
😆 Penance is postponed until a greater sin :evil:[/quote]lol
[quote=”wysetech” post=79072]
I can’t say that I ever saw a job done like that come back with a problem related to coolant in the oil. [/quote]that’s good news. I’m thinking that as a rule it would be best not to let any coolant into the crankcase because it’s impossible not to leave some coolant in there that will probly sludge up. but i guess the chances are that your pretty unlikely to do any serious damage. of course i’d hate to think i was responsible for sludging up a hydraulic lifter.
and i sure hope the small amount in the cylinder isnt too detrimental to the cylinder wall or something. then again, the amount of fuel that has likely been washing oil off my cyl wall/rings due to the misfire from my fouled plug probly hasnt been good either.
I’m with the group. I don’t think you have anything to worry about. And I will also say that you’ve probably put more care and attention into the job than most professional techs I’m sad to say. If you’re worried about the coolant in the cylinders you can always remove the plugs, pull the fuel pump fuse, and crank the engine before you try and start it. This will help ‘blow out’ any coolant that might have gotten into the cylinders before you try and start the engine. Once you’ve done that, put everything back together and fire it up. Good luck and keep us posted.
Thanks so much Eric. Here’s the final results:
1) Upon cracking the oil drain plug there was only ~1 ounce of green coolant before the oil came out black.
2) Pulling the plugs and cranking the motor was not even necessary. Nothing came out. Anything that did get in there (which would have been very little) likely woulda leaked past the rings into the oil pan while the truck sat for a couple days (after i cracked the drain plug of course, but I’m due for an oil change anyway so i don’t think another tiny amount of coolant in my oil will kill me for a few more miles.)
3) After reassembling everything, I forgot to put the serpentine belt back on. Who else looks over a car ten times before starting it back up and still always forgets something? :whistle:
Everything was just fine like you guys said it would be when i started it up. didn’t even smoke.
As far as solving the initial problem (originally posted here: http://www.ericthecarguy.com/kunena/8-Service-and-Repair-Questions-Answered-Here/45477-what-causes-spark-plug-to-look-like-this?start=10#79874)4) I probably only needed to re-torque my lower intake manifold bolts to stop the oil leak into my number 5 (middle left) cylinder. but i was already in there and i couldnt return the gasket set anyway so i went ahead and replaced the lower intake manifold gasket (with the revised 2 piece design that allegedly is better designed to seal the coolant ports). plus other gaskets got destroyed during the dis-assembly (like the upper intake mani gasket, and the valve cover gaskets get all bent)
5) I’ll pull my spark plugs in a week or so just to be super certain there’s no more oil on them. im sure there wont be so i wont bother to report back unless there’s something unusual.
6) Got everything bac together with no external leaks. but I’ll keep an eye to make sure theres no internal leak of coolant into the oil (since the lower intake manifold has coolant ports as seen in the picture). the manual says to look for pitting in the casting of the head or lower intake mani. sure enuf there was some very minor pitting (under the super hard crud i had to scrape at for a while). manual recommends resurfacing (yeah right) or mentions that some techs fill with epoxy. i think i’m good tho. will update if not.
7) In my short test drive i caught a hint of a rattle going up a steep hill just like the detonation (knocking) I’ve been having. I had attributed this knock (confirmed by running higher octane fuel to nearly eliminate the knock) to the fouled spark plug. now with new plugs/wires and no internal oil leak it should not be knocking. i still have high octane gas in the tank so more attention/driving is needed to see if A ) The truck is, in fact, still knocking (or ever was I’m only moderately competent to diagnose noises)and B ) What else might be causing it.
8 ) I was really hoping for a bit more power. Alas I believe I’ve overestimated how much power 94 Explorers have. My compression is great, no discernible exhaust back pressure using vac gauge at IM, etc etc. I ruled out a bunch more potential causes of low power at the end of the other thread. It idles the same, real smooth (but not as perfect as, say, a newer car). honestly would probably just benefit from newer motor mounts.
All-in-all this has been another educational adventure. I’m quite pleased that my truck is essential in great shape again and I plan to get another 140k out of it. With help from ETCG forum of course! Thanks for the patience with the dumb questions. My automotive knowledge far outpaces my automotive experience. Hopefully someone else finds some part of this useful sometime. total cost was $85 for the gasket set that included valve cover gaskets, and $13 for coolant (plus a dollar for a gallon of distilled water cuz i’m that awesome). If i had to do it again I would just spend $10 on the plenum gasket and retorque the damn bolt
Glad you got her back together and running. Excellent job.
Power on that platform was never very great, the Explorers are very heavy for their size and that drive train has lots of loss.
As for the knock? Found this that might help you out
Engine – Carbon Knock On Acceleration
Article No:
01-19-710/01/01
^ ENGINE – 4.0L OHV – CARBON KNOCK ON ACCELERATION
^ NOISE – CARBON KNOCK ON ACCELERATION – VEHICLES EQUIPPED WITH 4.0L OHV ENGINE ONLY
FORD:
1990-1997 AEROSTAR
1990-2000 EXPLORER, RANGERISSUE
Some vehicles equipped with the 4.0L OHV engine may exhibit an engine noise which may be perceived by the customer as a piston/connecting rod bearing knock. This carbon knock is heard only under load during the drive cycle. Carbon knock is a customer drive duty-cycle phenomenon that cannot be repaired with an engine exchange. This may be caused by carbon build-up within the combustion chamber.ACTION
Verify condition. If normal diagnostics fail to correct the condition, de-carbon the combustion chamber to help quiet the carbon knock noise. Refer to the following Service Procedure for details.SERVICE PROCEDURE
1. Use Motorcraft Carburetor Tune-up Cleaner PM-3.
2. Carbon removal:
a. Disconnect canister purge line from throttle body.
b. Attach a vacuum line to the canister purge port.
c. At hot engine idle, allow the engine to ingest 1/2 to 2/3 of a can of Motorcraft Carburetor Tune-up Cleaner. Use caution not to ingest too quickly due to potential hydro-lock issues.
d Shut engine off and allow it to soak for one hour.
e. Start engine, allow engine to ingest the remainder of the Motorcraft Carburetor Tune-up Cleaner.
f. Remove vacuum line and re-install canister purge line.
g. Road test vehicle at 3500 RPM for 2-3 miles.
h. Repeat above procedure two times for a total of three times.
i. Change oil and filter.3. Review the customers’ driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.
4. Use regular unleaded fuel, 87 Octane. Mid-grade and Premium fuels may increase the probability of carbon buildup, leading to a knock noise.
This was great info.! I was taught in school that a blown head gasket, ie: coolant in cylinder was a ticking time bomb for the engine. Apart feom a compkete overhaul, it was just a matter of time before the end of the engine. I often wondered about pulling pan, draining and flushing oil after coolant was introduced. Anyone know the burning temps between the two?
[quote=”bbryan1″ post=79960]This was great info.! I was taught in school that a blown head gasket, ie: coolant in cylinder was a ticking time bomb for the engine. Apart feom a compkete overhaul, it was just a matter of time before the end of the engine. I often wondered about pulling pan, draining and flushing oil after coolant was introduced. Anyone know the burning temps between the two?[/quote]
That is more for continuing to drive with a internal leak, leaving a decent amount of coolant in the oil and driving with the “chocolate shake” muck in the pan or parking the vehicle long term with antifreeze in the oil.
That makes good sense. “How long have you been driving with this leaking head gasket sir?” Would be a good question then when assesing the severity of potential problems. It would be completely different than a manifold leak into the cylinder I can see. I would still take all precautions to avoid it but I can see how the tm qould be alright in this instance. Thanks guys.
This forum is a great forum that’s for sure. Thanks very much for getting back with us on the update. Look us up if you have any trouble in the future.
carbon knock! of course. initially i just thought the knock (detonation) could be related to the misfire from the oil soaked plug.
but it seems the knock and oil fouled plug were just two different symptoms of the oil leak.
So once upon a time, oil starts leaking into the intake track and into the cylinder. it starts fouling the plug right away. only after a while does carbon start to build up. the carbon build up causes a knock. i start running premium gas that reduces the knock (knowing that this is just a band aid for the cause of the knock. And i even know that running premium can cause additional carbon buildup.) some months later i finally solve the leak and put new plugs in but i still have carbon build-up and so i still have a knock.
i will add tho that now that the leak is fixed and i’m back to running regular gas, the knock is not nearly as bad as it had gotten just before i started running premium.
Evidence of carbon knock:
known issue as evidenced by the TSB (technical service bulletin),
had oil leak (sounds to be coming from same side),
occurs only under load (going up hills in particular),
worse when thoroughly warmed up after long drive
reduced by running higher octane fuel
has only gotten slightly worse in 10k miles (engine hasn’t blown up / spun a bearing / thrown a rod / etc)I’ll run Seafoam thru the intake per the TSB and report back in the future. hopefully solves the knock! thanks guys, hope this is helpful or interesting to someone
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