Milky engine oil cap but not dipstick, also smoking from exhaust

KAY JORD

MEMBER
1997 PONTIAC FIREBIRD
3.4L
6 CYL
AUTOMATIC
180,000 MILES

I know I have a coolant leak somewhere, so I constantly put water in the engine, putting coolant leaks too fast, stalled on way home twice, was over heating slightly. Let car cool down and put water in, got it to start up it was shaking, and when I revved the engine it started to smoke out of the exhaust. I checked the dipstick, looks perfectly normal but when I check the engine oil cap it does look spotty and not usual.

1 Reply

STEVE W.

MECHANIC
13,465 POSTS

Welcome to 2CarPros. What you are describing sounds like a coolant leak in the upper intake manifold. However I would ask you to verify the year and engine. The 1993-1995 Firebirds had the 3.4 the late 1995-2002's had the 3.8.

Different repairs for each engine. On the 3.8 the issue is with the plastic upper intake manifold 90% of the time. They fail in the area of the EGR valve and draw coolant into the engine. The coolant will pool up in the top of the lower intake and cause problems there as well.
On the 3.4 it would be the lower intake manifold gasket.
Once we're sure which engine it is we can go farther. That should be on the emissions sticker under the hood. Looking forward to your reply.