2000 Chevrolet Malibu coolant system

TIA31

MEMBER
2000 CHEVROLET MALIBU
3.1L
6 CYL
FWD
AUTOMATIC
100,000 MILES

I have had a coolant leak for a while and I wouldn't have even noticed except every week I wouldn't have heat so I would add coolant, I seen some leaking from under the car on the drivers and passenger near the radiator, so I figured I needed a radiator, I decided to buy the stop leak pellets to buy me some time and I followed the directions and I don't have a leak anymore it seems, but the car is running hot, not overheating but hotter than it ever had and its making me nervous so I brought it to one of my "friends" who is a mechanic and without even looking into it says u need an intake manifold gasket. Whoa that's really serious I don't really see any other issues car runs good, engine has small knock but always kinda has theres no oil coolant mixture no crazy white smoke no overheating so do you think it could really be something that serious, im hre asking cause there is no way I can afford to fix a problem likethat im jut curious what I might be working with im hoping I could of clogged the system, if you could give me your opinion I would greatly appreciate it, thank you

1 Reply

CARADIODOC

MECHANIC
33,916 POSTS

Your friend is basing his guess on past experience. GM has had some problems with intake manifold gaskets, but that isn't really a serious repair. It should only take a couple of hours.

Before I would trust that kind of diagnosis, I'd want to verify that's really what's leaking. One method is to use a pressure tester to pressurize the cooling system, then you look for where the coolant is leaking out. If it really is leaking from the radiator, for a car as new as yours, that is commonly caused by not replacing the antifreeze often enough. GM uses the red "Dex-Cool" antifreeze. They advertised it as "lifetime" antifreeze to make their cost of maintenance appear to be lower than that of their competitors, then on the sticker on the car they said to replace it every three years. Even the Dex-Cool company says to replace it every two years because that's when the additives, like corrosion inhibitors and water pump lubricant, wear out. If you follow either of GM's printed recommendations, you'll have acids build up in the system that lead to corroded and leaking radiators and heater cores.

If the leak is too slow to see with a pressure test, you can add a small bottle of dark purple dye, then search later with a black light. The dye will show up as a yellow stain that you can follow back to the source. Auto parts stores will have the dye, and those that rent or borrow tools will have the black light.