Losing coolant?

Hello! I have a 2005 Chevy Cobalt, 2.2L engine and am having a few problems. I believe I am losing coolant somewhere, but cannot ever see any leaks or anything on the ground where I park. I am having to top off the reservoir a couple times a month with water/coolant to keep the temperature from going up above normal (which I’ve found is around 190 degrees). I first noticed this when the temperature had reached 230 degrees! I also hear a sound like sloshing water in the front end when I first start and drive the vehicle. The sloshing usually subsides after I’ve been driving for several minutes. To top it all off I now have a bit of foam on the oil cap and the oil looks a tad bit cloudy. Any help would be much appreciated. Thank you!

Yikes. Well, the sloshing sound could mean that you have air in the radiator. This will block the coolant from circulating effectively. I believe the fix for this is to start the car with the radiator cap off, get it to operating temp, and monitor the level, filling it as needed until it is full, then cap it and top off the overflow bottle.

The foam in the oil is a bad sign, you are probably leaking coolant into the oil. Could also be the cause for air in the radiator if the engine is forcing combustion gases past the gasket and into the cooling system. A shop can test this by running the car with the radiator cap off and using their emissions tester probe to test for hydrocarbons in the radiator. A leaking head gasket is the main reason I can think of for combustion gas leaking into the coolant and coolant leaking into the oil, but there might be other reasons, too.

Yikes is right! Thanks for the info! I’m hoping it is possibly a bad head gasket and not a cracked engine block, as has been suggested to me.

Cracked engine blocks on stock engines are extremely rare. Blown headgaskets, unfortunately, are not. And they’re a common manifestation of a repeatedly overheating engine left uncorrected.

I’ll bet you also have bubbles coming out of the raditor fill lhole when you run the engine with the cap off? Those would be the combustion gasses being blown through the headgasket breech into the water jacket and migrating up to the highest point, the fill hole.

Do a pressure leakdown test if you’d like to confirm. It’s a test wherein you trun the crankshaft until the cylinder under test has both valves closed, put a fixture in the spark plug hole, push in some air, shut the pressure line off, and monitor a pressure gage. If the cylinder won’t hold air, your headgasket is blown. I guarantee there’ll be one or two that won’t. The kit is pretty inexpensuve at any parts store and the test easy to run.

At this point you probably also have a warped head, and perhaps even a channel eroded into the metal of the head.

And coolant makes a lousy lubricant. That foam in the oil is a really bad sign.

Honestly, as aminimum you’ll be pulling the head. Middle case, the head will need machining. Worst case, you’ll have channels eroded into the top of the block that’ll make everything else wasted money.

Honestly, I’d start looking for either a boneyard motor or a rebuilt longblock.

Sincere best.

Thank you for the very helpful post. This may be a stupid question, but how do I check to see if the head is warped?

Someone has to take it off and measure it, probably at a shop that specializes in machining heads.

To find out if the head is warped, you remove it. So something tells me that you won’t be doing the checking.

with the head off take a straight edge and lay against the surface of the block side of the head and see if the edge is touching all the way across or you can take the head to any mechine shop and most of the time they will tell you for free if it is warped but the head should be magnafluxed to check for cracks if it is cast iron if it is alum. you wont need that done.

Thanks people!

If you’re going to try and check it yourself, you should enlist a friend to assist.

have your friend hold an extremely straight edge (which you also probalby won’t have - a regular ruler just won’t do). Using a feeler guage at .008 check to make sure you’re clearance between the edge and the head is less. Check in the middle, and both ends.

Check diagonally across the head (corner to corner), both ways.
Check lengthwise, on both sides.
Check the ends, width-wise.

However, as the others have said, you can’t really do it without special tools/materials. The first step is to remove it. Once it’s off, putting it in the trunk and taking it to a machine shop is a minor deal. However, give Autozone (or O’Reilly’s, or…) a call, too. They will often sell a preassembled head for ~$500.

Good luck.

A shop would put it on a “flat plate”, which is a ground granite table (usually from Barre Vt.) with a surface measured with a laser and certified to be extremely flat. Then they’d measure any space between the reference surface and the head.

Or, one with a Coordinate Measuring Machine could also use it to measure the surface with extreme accuracy.

But, if you take a regular steel rule, set it against the head’s surface, and it shows warpage, than there’s no need to measure it…it’s warped.