Air keeps getting into coolant

[Dzdimi14]

About a month ago my car was overheating so I decided to bleed the cooling system, after I got all the air out the car was running perfect, a little bit cold in fact, but now the car started overheating again so I decided to check if there was Air in the coolant again. Lo and behold there was. How is this air getting into my cooling system?

[manuel325i]

Do a pressure test, you could possible have a small leak somewhere. You can rent a pressure testing machine from your local Autozone (however you will need the adapter that fits onto your expansion tank). Are you losing any coolant?

[jeffnhiscars]

You can buy a test kit to detect exhaust gas in your coolant which will confirm that you have a blown head gasket

[e30onBBSs]

definitely pressure test it. If it's full of coolant and excess air is getting in that means that the coolant is going somewhere. Put the tester on it pump it to the spec PSI then wait and see if the pressure drops significantly after maybe 15 mins come back to see the reading. 5 mins is probably fine but may as well be thorough

[jeffnhiscars]

Exhaust gas getting in to coolant can let itself out the reservoir cap and theoretically not lower the coolant level if you don't overheat it. Pressure testing is a good idea but keep in mind they are not high pressure testers compared to combustion gas being forced past a blown head gasket.

You can do compressio and leak down tests....but I still say it's a blown head gasket....unless it's a cracked head. I'm not aware of any other way for air to get in to the cooling system once it's been properly bled.I'd get the test kit for exhaust gas in the coolant before I did anything else.

[Kershaw]

I had a similar issue. I struggled with diagnosing it for 2 years until it got really bad and I had coolant in my oil. Very small crack in the cylinder head through the thermostat housing bolt.

Pressure test first though. Start with the simple stuff.

[e30onBBSs]

Exhaust gas getting in to coolant can let itself out the reservoir cap and theoretically not lower the coolant level if you don't overheat it. Pressure testing is a good idea but keep in mind they are not high pressure testers compared to combustion gas being forced past a blown head gasket.

You can do compressio and leak down tests....but I still say it's a blown head gasket....unless it's a cracked head. I'm not aware of any other way for air to get in to the cooling system once it's been properly bled.I'd get the test kit for exhaust gas in the coolant before I did anything else.

+1 on comp and leak down. We did those in school today really will help narrow down the problem.

And OP what are the symptoms besides overheating? Smoke coming out the exhaust? Smoke coming out the hood? Steam, anything? Is coolant missing? Are you sure your rad hoses aren't leaking etc?

[frankenbeemer]

Exhaust gas getting in to coolant can let itself out the reservoir cap and theoretically not lower the coolant level if you don't overheat it. Pressure testing is a good idea but keep in mind they are not high pressure testers compared to combustion gas being forced past a blown head gasket.

You can do compressio and leak down tests....but I still say it's a blown head gasket....unless it's a cracked head. I'm not aware of any other way for air to get in to the cooling system once it's been properly bled.I'd get the test kit for exhaust gas in the coolant before I did anything else.

Same problem here, not to hijack the thread. :devil: Do the hydrocarbon test OP.

[Dzdimi14]

Do a pressure test, you could possible have a small leak somewhere. You can rent a pressure testing machine from your local Autozone (however you will need the adapter that fits onto your expansion tank). Are you losing any coolant?

Not that I can tell, It actually looks like my coolant is over filled

[Dzdimi14]

+1 on comp and leak down. We did those in school today really will help narrow down the problem.

And OP what are the symptoms besides overheating? Smoke coming out the exhaust? Smoke coming out the hood? Steam, anything? Is coolant missing? Are you sure your rad hoses aren't leaking etc?

Nothing at all, the only other problem with the car is a little exhaust leak where the exhaust manifold meets the cat. Plus its a little over due for a valve adjustment.

[Dzdimi14]

Exhaust gas getting in to coolant can let itself out the reservoir cap and theoretically not lower the coolant level if you don't overheat it. Pressure testing is a good idea but keep in mind they are not high pressure testers compared to combustion gas being forced past a blown head gasket.

You can do compressio and leak down tests....but I still say it's a blown head gasket....unless it's a cracked head. I'm not aware of any other way for air to get in to the cooling system once it's been properly bled.I'd get the test kit for exhaust gas in the coolant before I did anything else.

If it is a blown head gasket, do you think that I would be competent enough to do it my self. I have some experience under the hood, replaced fan clutch, whole exhaust, brakes, change my own oil etc, but I am not a mechanic in any means of the word. Im only 17 so money is a little tight haha.

[5Toes]

you can def. do a head gasket with your experience level and a friend to help. you will need a set of etorx sockets though and a torque wrench. make sure to get the head checked out by a machine shop before re-assembly. ive had good luck using elring gasket sets and the elring headgasket without the copper coating

[Dzdimi14]

you can def. do a head gasket with your experience level and a friend to help. you will need a set of etorx sockets though and a torque wrench. make sure to get the head checked out by a machine shop before re-assembly. ive had good luck using elring gasket sets and the elring headgasket without the copper coating

Cool, I already have a torque wrench, How long do you think it will take me, keep in mind im going to have to do it in my apartment buildings parking lot haha.

[Dzdimi14]

you can def. do a head gasket with your experience level and a friend to help. you will need a set of etorx sockets though and a torque wrench. make sure to get the head checked out by a machine shop before re-assembly. ive had good luck using elring gasket sets and the elring headgasket without the copper coating

Also do you have any idea how much it will cost in total?

[jeffnhiscars]

Also do you have any idea how much it will cost in total?

Pressure testing, decking & valves (seats and faces) figure $250-350 at the machine shop. I just bought an elring HG set for $65. Add some misc for new coolant, oil, a hose or 2, timing belt etc etc and you'll spend $500 if no surprises