Oil in Coolant

[Russ51]

97 GTP 3.8 Series II Supercharged, 70,000kms.

Recently had car serviced and oil was discovered in coolant reseviour and rad but no oil in collant. No significant oil loss between oil changes.

Mechanic feels it is a cracked block but I have doubts as if cracked oil would get into coolant while running due to higher oil pressure but collant would also seep into oil when shut down due to pressurized collant system.......right?

Anyone familiar with this problem or suggestions

[bmwgolfguy]

Sounds like you have the Dex Cool problem GM is getting sued over in two class action lawsuits. One in San Fran and the other St. Louis federal district courts.

The 3800 Series II engine has the very problem you describe. It is not a cracked block. It is fried plenum which was made out of plastic. When it overheats it eventually melts. That's what causes the oil and antifreeze to mix. To fix properly usually entails upper and lower head gasket replacement along with a new plenum, which now is made of metal btw. Not all 3800 II's have or ever get the problem.

The parts don't cost didly. The fix is very labor intense. I have 3 LeSabre's, a 96, 01 and 02. The 96 cost me $1,200.00 to get fixed. Call around, but that price seems to be the going rate. Any mechanic familiar with that engine knows about it. If you let it go, eventually the engine will seize if not fixed.

GM is well aware of the problem and chose to fight it rather than fix it. A Toronto newspaper did an expose' on it a few years ago.

Good luck!

[richtazz]

First, the GTP isn't affected by the plenum issues, as it doens't have one. Are you sure it's oil, and not just Dex-Cool sludge?

Second, Dexcool is not the cause of the plenum issues, it's a faulty gasket on the late 99-up Vin-K and an EGR stovepipe heat issue on early 99-back versions.

If it is oil, I would suspect the lower intake gasket on your GTP. GM has come out with a revised metal/rubber version to address the issue with the OEM plastic/rubber design.

[GaryFenza]

its a classic with these cars, get the lower Intake manifold gaskets changed

[BNaylor]

I agree with Rich. Most likely Dex-Cool sludge since the reservoir is not sealed therefore not air tight. Air and Dex-Cool do not get along and that is the effect seen. And it was simply sucked back into the radiator.

Another issue is the Dex-Cool becomes worthless just like regular anti-freeze at a certain time interval. It is recommended to replace the Dex-Cool at 5 years or 150K miles, whichever comes first.

I would suspect this '97 GTP with only 70K kms falls into that category if it has never had the cooling system serviced and/or the Dex-Cool replaced. It should have been replaced back in 2002-2003 based on the 5 year condition or even sooner.

Now if you have an unexplained coolant loss or high consumption then I would suspect gaskets such as the LIM or even supercharger which has two o-ring seals that could go bad.

[BNaylor]

Originally Posted by bmwgolfguy

Sounds like you have the Dex Cool problem GM is getting sued over in two class action lawsuits. One in San Fran and the other St. Louis federal district courts.

A lawsuit doesn't mean anything and doesn't establish any factual outcome or legally acceptable evidence to make a claim it is the Dex-Cool.

Are you sure about that? The first one in St Louis was dealt a major setback. To date GM has technically prevailed in the litigation brought against it.

February 24, 2007

ST. LOUIS -- The push for a national class action lawsuit against GM for problems related to their Dex-Cool coolant suffered a setback Friday, when a U.S. federal judge ruled that national class action status would be too complicated.

A number of statewide class action lawsuits have been filed, although two of those have been rejected already in Michigan and California. Another class action goes to trial in Missouri in November 2007.

http://www.carcomplaints.com/news/20...-lawsuit.shtml

[Russ51]

Thanks for the input.

I don't think it is a dex-cool issue as there is no sludge showing in the reseviour or rad. The coolant system was just flushed and oil was found in the system and continues to show up. Also, all the coolant hoses (rad, heater hoses, etc) are shiney on top and I'm told this is due to the oil breaking down the rubber and as such this problem has been going on for awhile. The system was flushed 4 or 5 years ago with new dex-cool.

Does this sound like lower intake manifold gasket as some have suggested or o rings in supercharger?

Does that help to narrow it down?

[longlacryan]

i agree with you having done more gm intake gaskets than i care to count.
99% of the time the oil in the anifreeze is caused by the intake gaskets.
change the lower intake gaskets. this will also require you to change the gaskets and o rings under the s/c.

[BNaylor]

On L67 SII 3800 engines concerning LIM gaskets the two prevalent symptoms I've seen and had is coolant in the motor oil not oil in the coolant, although it is possble. Also, no oil in coolant or coolant in oil just a noticable coolant loss and driveability issues. Another possibility would be head gaskets - a leak between a coolant passage and an oil passage within the defective head gasket. Plus unless confirmed through an analysis it could be combustion by-products.

If there is a sufficient quantity of oil going into the cooling system then you may see that by seeing lower oil levels than normal. So accurately check the oil level and condition of the oil for a milky substance and coagulation.

Another scenario I've seen is ATF in the cooling system caused by a bad radiator and not motor oil at all.

These LIM gaskets were replaced due to coolant loss found to be coolant in the oil.



If you decide to replace the LIM gaskets be sure to use the new GM aluminum framed ones. See link below.

Click here

[Russ51]

Getting really confused here. Makes sense that if it were the LIM gasket there would be coolant in the oil. There isn't. Oil level seems consistant and is clean with no milkey substance. Don't think it's oil from the supercharger as the oil found in coolant reseviour doesn't have that rank supercharger oil smell. There is no sludge at all in the collant system, just oil so not likely to be a dex-cool issue.

Could it be the front cover is cracked internally or......?

[BNaylor]

Are you 100% sure it is motor oil contamination?

There are different types of Dex-Cool sludge or residue. Dex-Cool supposedly has a defoamer additive. On many reports the sludge or an oily film seen is from the defoamer that wears out prematurely from lack of sufficient cooling system pressure and then the defoamer deposits that black oily looking stuff where air is present.

Has the cooling system been pressure tested?

[Russ51]

No, I haven't had the coolant system pressure tested yet. Something I hadn't even thought about. The contamination in the coolant system is just oily, not black or sludgey but about the same color as the clean engine oil. I'm told that the fact that the heater and rad hoses are shiney on top indicates oil in the coolant system (for some time) and slowly breaking down the hoses.

[richtazz]

If there were enough oil in your coolant to seep all the way through 1/8" of rubber to cause the outside of the hoses to be shiny, your hoses would be like sponge and mush. I agree you should get the cooling system pressure checked.

[BNaylor]

This is a weird one Rich but I would like at other possibilties before tearing the engine down. Another suggestion would be to replace all heater hoses and upper and lower radiator hoses. Maybe they are the cause.

[Russ51]

Yup, it's weird alright. A real mystery for me. I have removed the thermostat and sent it to the rad shop to have the coolant system flushed again, this time properly. Because I just can't seem to figure out where the oil is getting into the coolant I'll start from square one and trying to elliminate each possibility.

What else can I do?