Thread: Coolant in the exhaust manifold?

Hey guys, first time here. I posted this in a different forum, but this looks like it has a little more activity. My car is actually a Buick Riviera, hope that's ok

I'm going to do this cliff-notes style, because it's easier to read. If you want more details, just ask and I'll provide.


-My brother-in-law is a 3rd-party mechanic of 25+ years and has done all the major work on this car detailed here.
-The car is 1996 Riviera with a 3800 SII SC L67 engine.
-I bought the car in summer of 2007 w/135k miles.
-No major engine work until we did the U/L IMG in June, 2010 @165k miles (bought aluminums from zzp: ZZ Performance)
-Ran "fine" except high load, low RPM conditions (ran like this prior to IMG replacement)
-Changed one coil pack in fall of 2010 and above was fixed
-Seemed to lose some coolant but not alot since I've owned it, before and after the IMG change
-I had never seen oil in coolant

-Sold Rivi in January @175k miles to a family member, who drives a lots of very short trips, about 1-2 miles to work and back.
-Ran the gas tank really low one time in March (upstate NY, very cold winters), and the next morning, the car started running VERY rough. Lots of white smoke
-Tech 2 says cylinder #4 (I think) was misfiring. Only one cylinder was misfiring consistently
-Changed spark plug on that one cylinder
-Put dry gas and 5 gallons of fuel into fuel tank, ran a little better, but not much
-Still lots of white smoke coming from exhaust
-No trace of oil in coolant
-I believe there was coolant in oil. Oil level was checked and was "overfilled" by a quart or two, suspected to be coolant
-Head gasket suspected to be the problem
-Life gets busy and the car sits for a couple months.

-Tow the car to my bro-in-laws on Friday
-Wanted to do compression check on all cylinders, but the starter seized today and it wouldn't turn over, so we didn't.
-Today (06/26/2011), we stripped engine down to the block, found the 5 other spark plugs are really nasty
-Coolant (hard to quantify, maybe a pint or a quart? No small amount...) found in the front exaust manifold, didn't see any in the back manifold
-Both heads appear to be in good shape
-No coolant in the cylinders themselves
-Head gaskets are coming apart a little bit on the outter edge, but no big rips or tears around the cylinder portion

-My brother-in-law wants me to buy another head & U/L MG set (Fel-Pro for $200), new headbolts ($20) and get the heads milled ($150).

Your expert thoughts about any and all of this? How can coolant be in the oil and exhaust manifold but the heads/head gasket be ok? I need to do this for as cheap as possible on parts, labor isn't a big concern. Want to see pictures of anything?

Thanks!
jaydee

That sounds like a leaking LIM gasket to me. The head gaskets on these motors almost NEVER go. In fact, it would be the very last thing on my list. That's the only way I could see getting coolant in the oil and also getting it into the exhaust (by burning it).

But if coolant was leaking through the LIMG, how did it get into the exhaust? Through the combustion chamber? We did not see any coolant in the cylinders themselves, just the exhaust manifold.

Originally Posted by BillBoost37

I'm with him.. ^^ even though he has Ford in his SN.

Hey, at least they circled the problem. With my Pontiacs all GM did is point to it


jaydee, don't forget to get new head bolts when you reassemble as they are torque-to-yield bolts and not reuseable.

Thanks for all the constructive input guys, I appreciate it.

Ok, so pretty sure it's the LIM then. But since the heads are already out, should I see about getting them re-milled, or just throw them back on with new head gaskets?

Also, should I have any service done to the parts that are already out, clean them up with carb cleaner or something?


Still having a tough time understanding how those aluminum IMG's could only last 6-7 months. If it was an installation problem, shouldn't it have acted up immediately?

As a rule of thumb I always clean everything that I take off to do a job, whether its a bracket or a head. Nothing goes back onto my engines dirty. Now I don't hot tank everything, but I do scrub them down w/ some brake cleaner or simple green to knock as much off as possible. This especially holds true for any areas that use o-rings to seal (like the coolant elbows on these cars).

The only part I don't disturb is anything w/ burnt on oil (like inside the LIM or piston tops) as I don't want something coming loose later on and getting where it doesn't belong.

Since both heads are already off it may be worth the extra $$ to have a machine shop check them for cracks and warpage. Not trying to make you spend extra $$ you may not have through so that's up to you.

And I've seen install issues w/ gaskets creep up after some time has passed, its not totally uncommon. Don't forget your dab of RTV at all 4 corners where the LIM/heads/block all meet.

Oh, and before I forget. Before you reassemble the LIM dump at least a quart of cheap oil into the lifter valley to flush any coolant out of there, and then drain the oil before starting the car. Fill the car up w/ some cheap oil and use a cheap filter, then run it for a few minutes. Then re-drail that oil and change filter to a good one and refill w/ a good quality oil of your choice. Your rod and main bearings will thank you

Just talked to an engine shop about the heads to check for cracks/warpage. They suggested that whenever you take the heads off, you need to remill them, they'll never remain flat after you take them off. Which they charge $175 for. Is this necessarily true or are they just going after my money?


Thanks!

$75 a surface seems to be the rate around here.

If you're having that done, i'd suggest a "rebuild".

No point in doing half the job.

But find a good machine shop first.