2006 Chevy Malibu Hemorrhaging Coolant

My husband and I have a 2006 Chevy Malibu LS, 4-cylinder, automatic transmission, and it has about 137,000 miles on it. We’ve owned the car since 2008 and have had very little trouble with the car, except this one issue. Since the fall of 2012, the car has been leaking coolant. It’s not leaking to the ground and it’s not leaking into the engine (oil is clean). No less than 5 mechanic shops have looked at the car (including a Chevy dealership), and all shops informed us that they are unable to find a leak. So it’s magically loosing coolant?!?!?! I find this hard to believe.

Sure, they’ve all done their pressure tests, but the car passes and therefore they can’t tell where the leak is located. A few of the car shops speculated that leak could be so small that the coolant was burning off right away. And since it’s not leaking into the engine, it’s not a huge problem so they suggest we leave it alone. One or two mechanics have uttered the words “head gasket” as a potential culprit but no one wants to pull the trigger since it’s so expensive to fix. Six months ago we did add a sealant product into the radiator tank and that seemed to resolve the issue temporarily, but after a few months the coolant reservoir was clogged and coolant wasn’t passing through the car and it was starting to overheat.

It’s been a year since the problem started, and within the last couple of weeks the car has started to HEMORRHAGE coolant. And by hemorrhage I mean my husband will fill the reservoir tank up and by the end of the day the car is indicating “low coolant” again and sure enough he’ll pop the hood and the tank is nearly empty. The problem is so bad that in the last couple of days we’ve gone through a gallon of coolant. We use DEXCOOL which is recommended for that car, not the 50/50 stuff. We have noticed the hemorrhaging may have coincided with the drop in temperature, we live in Minnesota. At the rate we are putting coolant into the car, it will quickly become very expensive. We would rather figure out the real issue and fix that problem, despite the cost. We are tired of hearing that mechanics can’t find the leak. We would greatly appreciate any advice or suggestions you may have for us! Thank you in advance!

At this rate of loss, the leak should be easy to find. Either it is actively dropping on the ground or out of the tailpipe in large, white clouds. The mevhanic will mot have any problem giving you a proper diagnosis.

I had a slow leak that was hard to find. I added some UV dye to the coolant, and found a slight timing cover leak within a day.

You need to use 50/50. Straight coolant will boil off at a low temp. It also freezes at a higher temp than 50/50.

Do not BUY 50/50. It’s like paying $3 for a half gallon of water. It’s considerably cheaper from the tap. Buy the strong stuff and add water to the system in equal proportions. As soon as the engine reaches operating temperature it will mix itself.

As to your problem, I’d have another shop take a look at it now. It is surely bad enough now to be either visible, or detectable with a gizmo that sniffs the coolant in the system to see if there is any combustion gasses in it. The tool is available on loan at my local Autozone, but you may have to buy the liquid it uses.

First if you have air and dexcool mixing it can be a problem, ie dexcool sludge. It is time for a coolant change and flush, and go to a universal coolant, peak global for example. Get a new radiator cap, and a thermal scan of the radiator. You may have sludge causing problems.

In my professional experience, Dexcool is fine if changed every 5 years, as you’re supposed to

If your 10 or 15 year old Dexcool is causing problems . . . you can’t blame problems caused by lack of maintenance on the coolant

Does this car have a radiator cap. If it does, look into it and you may see bubbles. If so you have a head gasket leak. A combustion gas test will verify it. A compression test should also show the head gasket is breached.

I rarely disagree with MG McAnick, but I will in your case. First, if you have been adding straight Dexcool at full strength, I’m not sure you are capable of understanding how to mix your own coolant, so I stand by my recommendation of buying the premix in your case.

Don’t take this the wrong way, but mixing your own is more than measuring water to coolant and mixing them together. MG McAnick can probably do it in his sleep, almost an instinct and may have forgotten that there are people who do not have an in depth knowledge of cooling systems that can get it right.

Full strength antifreeze actually boils off at a rather low temperature. I heated up some once to mix with a Sodium Borate solution for treating wood and at 180F or so, it was producing a lot of steam, glad I did it outdoors on a camp stove.

I don’t think GM has used a radiator cap for some time now. Most likely you have an external cooling system reservoir with a pressure cap on it. It is a self bleeding system. First, get a 50/50 mix of either Dexcool or universal long life coolant in your system, and this will have to be done at a shop now that you have messed up the coolant/water ratio.

Then you can check the reservoir for bubbles from a blown head gasket. If you have a leak, by now it should be easy to find as Dexcool leaves a very visible trail for any leaks. I used it in my Nissan truck to find one of those “cup a month” leaks that are very hard to find. That a leak that looses a cup of coolant every month or so, mine was a cup every two months.