My 1990 Bonneville has been using coolant for about the last 15,000 miles. About half a gallon every 2-3 thousand miles. When I park it in the garage it does not leave a puddle, no coolant on the floor from the heater core, no oil in the coolant or coolant in the oil... where is it going? I should have been concerned long before now, but I tried convincing myself that I was just working air out of the system for a while. But now that I have added over 2 gallons in the last 15,000 miles I am thinking something may be wrong. Is there any other kind of internal leak that could be happening that these engines are known for?
Thanks
Tom

MINE TOO!!! prolly leaking on top of the block, right by a manifold, or even a blown head gasket. let us know when you figure it out.

Perhaps on the tstat housing? Cold start the car, rev a little with the hood popped.. you see anything leaking?


-justin

I have searched for a leak at all the possible locations.. nothing found. Is it possible the car is somehow burning off the coolant without contaminating the oil or the coolant? Maybe it only leaks in driving conditions, like anything over 3k rpm or something. I really don't know, it still runs fine so I havn't been to worried; although this cold weather makes it a lot of fun to start when I leave it out for the night

What trim level do you have? LE, SE, SSE?


-justin

5 oz per tank ? Water injection maybe ?

Got any white smoke coming out?
As said before, start the engine and check for leeks under the hood and under the car...

This is an LE. There is plenty of steam coming out of the exhaust, but it is around 15 degrees F here right now, so thats not unusual, and it still runs great. Next time I have the garage warmed up I'll just have to do a taste test of any wet areas on the engine and see if I find anything sweet. At least one person has the same problem I do.

if there is nothing external it must be an internal leak.
Bars leaks?

A flush and fill with some Bar'* sounds great. BTW: Stuff works wonders.. broken radiator was fixed in 10seconds of idling with that stuff. If I had a coolant leak.. i'd use that stuff. All their products are good stuff, btw.


-justin