Coolant leaking into oil

[Grand Prix Andy]

Hi there, I am new to this forum, I have read alot of complaints that people are having with thier Grand Prix Generation II 3.8L Upper intake manifold gaskets, My car is losing Coolant, which i believe is going into the oil there are signs that the coolant is leaking into the oil and I keep topping up the coolant and I keep losing coolant again, the car drives like a dream and sometimes I notice as im going up a hill the car Rpms go up and down and you can feel the loss of power, I can see that the car is burning coolant also from the tailpipe but I cannot smell it burning only notice once in a while white smoke as im driving but that could also be from the cold weather, the car does not have any missfires or shakes, I was wondering if these are the signs of a upper intake manifold gasket or blown head gasket???? I am stumpped I love this car but am dumbfounded as to what It could be and what I should do or check for!!! has anyone had this problem.

Thanks this is a great forum and I hope that i can get some good help.

[wlkjr]

Check under the oil fill cap and if it is milky looking that is a sure sign you have coolant getting into the oil. Coolant in the oil is not good at all and you could lose the engine if you keep driving it. It is not a good lubricant. Get to the source of the leak asap which is probably the intake gaskets. An oil analysis will also tell if you have a problem.

[Grand Prix Andy]

Originally Posted by wlkjr

Check under the oil fill cap and if it is milky looking that is a sure sign you have coolant getting into the oil. Coolant in the oil is not good at all and you could lose the engine if you keep driving it. It is not a good lubricant. Get to the source of the leak asap which is probably the intake gaskets. An oil analysis will also tell if you have a problem.

Thanks I have checked under the oil cap and I can see that the coolant is leaking into the oil, I have heard that the upper intake gaskets are a common problem? in the gen II 3.8L engines, Should i just change the upper gaskets only or would you recommend that I change upper and lower intake gaskets??

Once again thanks

[richtazz]

If your car is a pre-99, you need to change the whole upper plenum (not just the gasket) and the lower intake gaskets while you're in there. If your car is mid-99 or later, GM revised the upper plenum to stop the EGR stovepipe issue, but continued using the same junk gaskets. SO basiclly, if the the car is early 99 or older, buy the Dorman aftermarket upper plenum, and the revised GM lower intake gasket set ( it's made of metal instead of the OEM plastic, FEl-Pro hasn't come out with a metal version for the 3800-K yet). If it's mid 99-newer, you may just need the upper and lower gaskets, but an inspection of the plenum would still be a good idea to be sure it's not eroded or deformed from EGR heat. I've seen a few newer models with the redesigned plenum that still have deformation around the throttle body area from the EGR tube.

[snupytcb]

yes intake gaskets are a very common problem on the 3.8. check the oil on the dipstick because the fill cap holds the condensation. also check compression. a quick and easy test is to run engine at idle w/ coolant cap off, if it blowes coolant out like ol' faithfull you have a head gasket problem.

[Grand Prix Andy]

Originally Posted by richtazz

If your car is a pre-99, you need to change the whole upper plenum (not just the gasket) and the lower intake gaskets while you're in there. If your car is mid-99 or later, GM revised the upper plenum to stop the EGR stovepipe issue, but continued using the same junk gaskets. SO basiclly, if the the car is early 99 or older, buy the Dorman aftermarket upper plenum, and the revised GM lower intake gasket set ( it's made of metal instead of the OEM plastic, FEl-Pro hasn't come out with a metal version for the 3800-K yet). If it's mid 99-newer, you may just need the upper and lower gaskets, but an inspection of the plenum would still be a good idea to be sure it's not eroded or deformed from EGR heat. I've seen a few newer models with the redesigned plenum that still have deformation around the throttle body area from the EGR tube.

Hi there thanks alot for this information it really helped I am going to get the entire plenum,gaskets and lower intake gaskets changed once again I thank you very much for this info

[Grand Prix Andy]

Originally Posted by snupytcb

yes intake gaskets are a very common problem on the 3.8. check the oil on the dipstick because the fill cap holds the condensation. also check compression. a quick and easy test is to run engine at idle w/ coolant cap off, if it blowes coolant out like ol' faithfull you have a head gasket problem.

Thanks alot for that info I did do that and its not blowing any coolant or anything like that I would like to thank all the people who have responded to my concern, once again thanks alot