low coolant problem

[amyers17350]

I have a 06 Chevy Malibu lt. 4 cylinder engine. I drive 100 miles round trip to work and home everyday. About once a week I get a low coolant light on. I have to add about 1 cup then. Took it to the shop last week, They did a pressure Check and block test. Everything was ok. Still having the problem. Any advise would be greatly Appriciated. It has 137,000. Added about 1.5gallons in the past month and a half.

[RalphP]

How old is the pressure cap on the surge tank? Those can spring a slow leak, which would cause it to vent when the motor got warm.

I'd also check ALL hoses - I had a slow leak a few years back on the smaller hoses to the surge tank (why I replaced my first one).

Past that, I got nothing.

RwP

[amyers17350]

Pressure cap is original one 2006. Will replace to see if it helps. Didn't have any visible leaks in hoses. Is it possible to have a small hole and only leak when it gets hot. Hoses are original too. Also would it be a good idea to put Stop Leak in. It's really frustrating trying to figure out where the coolant is going. Thanks for your info.

[RalphP]

My leak was where the hose went on the surge tank.

Yes, replace the pressure cap and see if that helps.

NO! NO STOP LEAK! Unless you just WANT to replace the radiator also! And possibly the motor when it plugs up the smaller coolant passages! Doesn't happen all the time, but it's better to fix the leak than to compound the problem.

Let's see - another possibility. Do you smell antifreeze or does the window fog up when you start the car? May have a very slow leak in the heater core.

That should have shown up with the pressure test, though.

Past that - it could still be any of a number of other problems. I'd bet the pressure cap is not holding pressure, though, so try that first.

RwP

[amyers17350]

Got the pressure cap today and put it on. See what happens. I do not smell coolant nor does the window fog up when I start it.

[amyers17350]

***update*** replaced the cap and still had the problem. Took it back to the shop they drove it around and did another pressure test and finally discovered a bad head gasket, which was gonna cost $1600. The car is only worth $3000. I got rid of the car and got a new one. Thanks so much for the info and advise though.

[denley]

I hate to bring up an old thread but I too have an 06 malibu 2.2l and have the exact same symptoms. I have replaced the reservoir cap and checked hoses. I fear my problem will also be a bad head gasket but I would also like to check the water pump before having a shop start working on it. I know there is a weep hole on the pump but I can't seem to find it. No coolant seems to be leaking on the ground, but I also know this pump has an access panel to get to it. Will the weep hole be noticeable if leaking or will I need to take off the access panel to inspect it? Thanks for any help guys!