Thread: Antifreeze in Oil - How to determine the source.

Just as some history to this post:

I have a 1997 Grand Prix GT.

In December 2007 (@215,000KM), the GM dealership I typically take my car to advised me that I had an antifreeze leak, and that it was the intake gaskets that were leaking. (Needless to say - in reading some of the posts at this site I'm surprised that at the time there was likely a class action law suite going for this very problem). I knew I was leaking coolant, because I had to add coolant every few months.

I've had numerous repairs done on this car and in 2007, it was starting to cost me more to keep the car running that what it was really worth. I declined getting the intake manifold gaskets replaced, since the antifreeze was leaking externally, not internally into the oil. I was of the opinion that my money would be better spent towards another vehicle.

Fast forward to March of this year, and after more than a year without having to perform any major repairs, I decided it was time to do the leaking intake gaskets. I did some online reading, picked up a chilton - and after spending some time deciding if I could tackle the job myself - I opted to take it to the dealership and let the "professionals" do the job. It's our only vehicle, and I had some significant doubts in my abilities to get this done without causing me a major problem.

This work was performed at 235,000 KM.

On May 8th while driving on the highway and going up a valley, my speed started to drop. I thought it was pretty odd since I've made the trip frequently in the past and the car has never had a problem climbing the hill. I put my foot on the gas and noticed it was all the way to the floor. At the top of the hill I tapped the brake to disengage the cruise and the engine died. Once I coasted the side of the road and came to a stop I tried to start the car, and although it would run, it had a significant knock and would not idle on it's own.

Checking the oil revealed a very dark/muddy looking oil with a lot of metalic in it. I had the car towed home.

I've sent an oil sample off for analysis and received my results today.

Here's the comments from the results:

Suggest inspecting this unit for EXCESSIVE WEAR; Suggest inspecting cooling system (head gasket, heads, seals etc for leaks. Coolant indicators

(Sodium, Potassium) are at a SEVERE LEVEL; Suggest flushing system; Cylinder region metals (pistons, rings, liners etc.) are at a SEVERE LEVEL;
Bearing metal is at a SEVERE LEVEL; Water is at a MODERATE LEVEL; FUEL DILUTION is at a MINOR LEVEL; Viscosity invalid due to water

contamination;

I suspect that it's the intake that I had fixed which is leaking antifreeze into the oil. I've put about 3,000km on since the intake was done.

Oddly enough the dealership called me a couple weeks ago to have me bring my car in for a "spark plug wire recall". I told the service advisor at that time the problems I had, what I suspected was the problem and that I was waiting for an oil analysis to come back to confirm my suspicions. They told me to let them know what the results are.

I know it's also possible that the heads/head gasket could also be causing this, and I'm wondering if there's an easy way to determine if it's one or the other (heads vs intake) without investing a lot of money into this vehicle. I'm hesitant in taking the vehicle back to the dealership for them to determine that because I suspect that they will be doing what's in their best interests, not mine in trying to determine the root cause.

Any suggestions? I'm a little choked over this whole experience. I put $1200 (also had the brakes done -with ceramic pads no less- ) into this car in March, and get 3000km for it. I suspect that had I not taken it in to get "repaired" that I'd still be driving it.

It's the LIM gaskets.

Originally Posted by TDCRacing

It's the LIM gaskets.

Is it possible to determine that with 100% certainty without taking it apart? When I go to the dealership with the report, I suspect they're going to blame the heads. Would a compression test help in determining if it's the heads? Given the Cylinder region metals (pistons, rings, liners etc.) are at a SEVERE LEVEL would a compression test be inconclusive?

I'm leaning towards towing the car to another garage with a j/m mechanic taking it appart to determine the source and going through small claims court.

I'm not expecting a new motor out of this. I would like my money back and would settle for fair market value on the car.

a cylinder leakdown test would be better for that, check conditon of rings and valves and headgaskets. i doubt its that, probally the lim gaskets most common cause.

if you pull the front knock sensor and let the coolant drain, you shouldnt have a drop of coolant to deal with when you pull the lim.

Originally Posted by bluegtp91

Well...question...did you change the oil after you had the LIM gaskets changed? If not then there is issue #1. Issue #2 would be in my book that if you take off the UIM and inspect the lower intake manifold to see if there is anything in there, metal wise...that would tell you which piston took a crap or chipped or might even have some remnants of the bearing that could have failed. #3...I'd contact Ed Morad if you plan on keeping the car at all. He can get you a solid motor for a good price, especially a short block, no heads or anything...if yours aren't damaged, you can have the car up and running again and all you would have to do pay is labor if you have all of the parts...and get the use out of those brakes

Hope you get it figured out man, good luck!!

An engine flush is part of the work that the dealership said was required as part of the job. I trust that they would have done it. If they didn't do the flush, then I'm waisting my time looking for a leak, because the antifreeze could have been introduced into the oil as part of work performed.

I'll know next week when I go into the dealership if they're willing to stand behind their work.

So I've taken my car to the dealership. They've done a cylinder leakdown test and the results came back as "3%". So from what I've read previously, this is good. They've also done a coolant pressure test (15lbs I think they said) and the pressure stays up for about 20 minutes.

The leakdown test (I believe) would indicate that there's no problem with the heads or head gasket. They said the coolant pressure test is fine, so it wouldn't be a problem with the intake manifold. However, reading online I hear about people leaving the pressure tester on for hours or overnight to prove that there's no leak. Their 20 minutes hass me puzzled.

They want to drop the oil pan to inspect for actual damage and take off the upper plenum to see if it's leaking there. From reading on the internet, there seems to be a problem with an "EGR" valve causing the upper intake to crack/melt/leak. Is it possible that could be causing me to get coolant in the oil?

Any other thoughts?