My car overheats all the time and after repeatedly filling up the radiator, I took it to a shop. $70 and a cooling system diagnostic later, I was told that exhaust gas is in the coolant.

So what caused this and where do I go from here?

 

Cracked head or blown head gasket...take off the head and take it to the machine shop and have it magnafluxed. This is a test to see if the head is cracked. If it is, congratulations you are going to get to purchase a new head. If it isn't, just get a gasket kit and reinstall it. Make sure to get the helms manual and torque the bolts EXACTLY as specified.

 

Will the head still need to be milled or whatever they call it even though there's no cracks?

 

first off
what type of car, and engine preferably if you know that much

secondly, good chance you can buy a goddamn used head and have some1 strap it on there 4 ya, check ebay.

first tho i need to know #1

~boomer

 

For $70, they should tell you what was causing it. Any idiot (no insult intended) can tell if combustion chamber gasses are leaking into the cooling system.

My guess would be the head gasket. Remove head, replace gasket, reinstall head. Easier said then done, but it is by no means hard.

 

D16Z6 in a Civic. 187,000 miles on it.

 

yes the head will need to be milled to get rid of any minor warpage and get a good mating surface for the gasket. How much you want to mill is up to you.