: 2000 Catera Mixing Oil in Coolant

06-17-04, 11:36 PM
I hope someone can shed some light on this problem. My son has a well-maintained 2000 Catera which is mixing oil into the coolant. From what little information I've been able to gather from google searches, this engine uses an oil/water heat exchanger located under the intake manifold. It seems that this heat exchanger is frequently the cause of this mixing. Can anyone here offer details on this problem, or the repair? I will probably fix this problem myself but I have no shop manual for this car and need to have some idea what I'm getting into before I start. I am an experienced home mechanic.

Thanks in advance for any help.

06-18-04, 02:01 PM
Yes, its an Oil to coolant oil cooler located under the air intake manifold....

What happens is over time they develop cracks in them and spew oil into the coolant running around it. This can damage the engine.

The cost of the cooler is around 400 dollars and takes a bit to install it .. luckily it doesnt require taking the engine out. Go to http://www.cadillac-parts-dealer.com/parts.htm enter in your car, and then on the left side bar of the catalog, go to Engine> Lubrication> Oil Cooler...

In some cases, the leak can be fixed by adding sealant around the cooler and the mounting plate: http://www.jasperengines.com/tech/Catera_TB.pdf but that might not solve the problem.

Heres a photo of the cooler itself:

To get to the cooler: http://autos.groups.yahoo.com/group/CateraOwners/files/Cadillac%20Catera%20TSB%20%26%20Service%20Files/%20Replace%20Oil%20Cooler/

*May need a yahoo account and membership to the group?*

08-02-04, 02:56 PM
The new and improved oil heat exchanger is finally here and supposed to fix the troubles with the cracking and leaking. I just got one from my cadillac dealer and the price is cheaper than the original. It is around $180.00 from the cadillac dealer. Let me tell you it is a lot more bulletproof than the old one. It took me the better part of the day to do the job myself. Now I am not getting red oil and brown coolant.

11-23-05, 07:46 PM

12-28-06, 10:31 AM
Catera10, did you change the oil cooler yet? I see that you said you're a mechanic. If you want to do it yourself, check out www.vauxhallownersnetwork.co.uk/showthread.php?t=63566 for a detailed description complete with photos. The dude that posted it is a Brit and you know their English is a bit different from ours but you can generally get what he's saying. Best of luck amigo.

Marks DTM Calib
01-12-07, 09:09 AM
And try UK ebay for an oil cooler.....might be cheaper....

10-11-07, 08:22 PM
I have A 1997 Catera and also have oil mixing with the water, causing a whitish brown sludge in surge tank and coolant system, I removed the oil cooler and the top side where lines connect showed no signs of leakage , however underside of cover showed the whitish brown sludge, not red like someone had mentioned,however I pressure checked the cooler and no leaks were found to the cooler itself(could the seals have failed) if so wouldnt I have seen oil to the top of cooler cover?)after some investigating I found out my son's mom had someone replace the heater bypass and I found they hooked up a vaccumn line that runs drivers side down by trans area to the plheumn ontop the intake, this hose is a vent and the heater bypass vac. line should have gone on this port( could this have caused the problem ?) I also pulled the radiator and pressure checked the trans cooler, thinking trans fluid was mixing with coolant, however no leaks found. I'm going to replace the t-stat. since it's right there, and do a cylinder leak down test(hopeing it's not a head gasket)anyone out there with similar problem and now corrected, please let me know,because I dont have a manual that shows belt timming, this is my only fear of removing the heads for inspection.