I have a Pontiac Bonneville 1999 that is leaking coolant. I think it is leaking only when running. I checked it a couple weeks ago (just routine check on level) & it was low. It had not been running hot though. I filled it to cold-line and assumed it was fine. It ran a bit hot the other day (not on red, but higher temp. gauge than usual) and I checked it later in the day after engine cooled & coolant was gone/extremely low. I refilled it to line and my friend (who knows a bit about cars) checked radiator and said it was 'dry' and also poured coolant into it. It ran great on my way home & way to pick up my child. Temp gauge was low again and all seemed fine. But I checked the level this evening when it had cooled and nearly all coolant was gone again. There was no leak anywhere under car in any place it was parked today. What causes it to leak when running and is it safe to temporarily drive it (until I get it fixed) as long as I keep filling it w/coolant? Should I be putting water alone into it? Someone suggested I keep the radiator cap loose, is that right? Is this an expensive problem? The car has a lot of miles (around 187,000) but it has been running great (I've only had it a few months). The A/C doesn't work, but otherwise it runs good and has been fine.
More Info: I have been driving a lot more than usual this week & it has been very hot outside last couple days. I don't know if that has anything to do with it, but maybe its relevant. Also, my friend suggested that if the car did overheat (the other morning when it did run hotter though wasn't in the red zone) then maybe the temp. gauge isn't accurate anymore if it was damaged. It wasn't smoking though and drove well after it was re-filled..it just keeps losing coolant.
ok, the price of the upper intake is around -$ 129.00 at auto zone ,it may be more at other auto parts stores ,139-169,and the labor calls for around 2.6 hours,,so if someone is charging $60 per hour it may be as little as $300 to fix ,it depends what someone would charge for labor and if they bought the part they may charge you list which could be as high as 250.00 or so ,you could get the part and then see what they would charge you to install it also ,
as far as driving it ,as long as you keep a very close eye on the coolant level and the oil and the teperature you could drive it ,but if it leaks a lot suddenly you may hurt the motor ,dont let it overheat and look at the oil before you drive it (everytime),oh yeah sometimes the coolant will look like a lt green in the right light ....guy...