2007 Chevy Malibu coolent leaking

Mysterious coolent leak, I have filled the overflow resivior (the only access I can see to the radiator) several times and evertime I drive then stop and check it…it’s at the bottom again, just hardly visible. I have filled with water and coolent. I have had it checked for a leak and it passed their pressure test. But I am still having the same issue. A couple weeks after that shop visit it actually over heated. Since then I have added and added as if the radiator was empty! I have filled it running and not running. HELP. I still have 5 years left to pay, I finally bought American and feel let down.

Check the oil and make sure that the oil you see on the dip stick is not or turns a creamy color when you rub it between your fingers. If it does this is an indication that the coolant is leaking into you oil.

My brother-in-law made me drive over last night to check. He checked the oil…for that same reason and other things, he was puzzled as well. Another idea from someone was check the passenger side floorboard to see if it was wet. It was not. The only “Leaking” I have ever actually seen was on the passenger side just inside near the front tire…but I pointed that out at the “shop” and they then did the pressure check and found no leak. They replaced the cap, in case that could be an issue. the leak is not constant, but only after I drive it a ways and it doesn’t start right away. The day I discovered it, a co-worker taking a break saw the leak (tiny puddle) about 30 minutes after I had arrived. At some point it stopped, because a few hours later I checked and…no puddle.

update…I think we finally “filled” the radiator. Could it be possible for all the coolent or rather the water to have “evaporated?” The level seems to have leveled off, and is running right in the middle of cold/hot. My husband thinks maybe there was not enough in the radiator to leak out when they did the pressure test. I am just wondering if I should take it back in to be tested again or just watch it ourselves?

A Pressure Test Not Only Checks For Leaking Coolant, But It Is Actually Performed To Check The Integrity Of The System And Its Ability To Hold Pressure Over Time, Even Air Pressure.
"My husband thinks maybe there was not enough in the radiator to leak out when they did the pressure test. "

Whether the system was low on coolant or not the system should have lost pressure during the time the test was run if there was a leak. Do you know how long the pressure held?

I’m thinking that:
[list]The leak could be temperature related, leaking when “cold”, for instance.[/list]
[list]Properly diagnosing this problem shouldn’t be “rocket science”.[/list]
[list]The people doing the work may not be up to the task.[/list]
[list]You should consider going to a different dealer or shop.[/list]

You don’t say whether the car is in warranty or out of warranty.

Is the car still under warranty?
Approximately how many miles on it?
Is this a dealer or independent shop doing the work?

Please provide more information as requested.


Your cooling system should be filled with Dexcool. It’s a pink color and it leaves a nice trail where ever it leaks. You’ve been adding coolant, are you using the right type. It has to be dexcool or a compatible coolant.

Has anyone done anything to the coolant system? It’s possible that the system wasn’t bled correctly and you’ve been working out a large air bubble.

If you haven’t been using the correct coolant, you will need to do a complete drain and refill. BTW, you don’t fill the overflow to the top. The fill line maybe about halfway up the tank, in some systems, the fill line is at the bottom.

Someone is going to have to get a little dirty. Keep checking for puddles and the next time you see it, get underneath and check to see where the wetness is coming from. It could always be the resevoir itself that has a crack in it. Car heats up and pushes coolant to the resevoir under pressure. Coolant leaks out of the resevoir so nothing to pull back into the radiator when it cools again, eventually resulting in dry radiator. A pressure test may not have included the resevoir.