I had a Mazda CX-7 Grand Touring AWD.
I bought it with a damage cylinder head, I replaced plus new rings and bearings and star overheating right away.
I replace radiator cap, radiator, water pump, thermostat and still overheating.
I took it to a mechanic, he tested and he told me the head gasket was blow and I had compression going to the cooling system, therefore the head gasket have to be replaced again.
I give him the ok, and after the job is done, the car keep doing the same and he doesn’t know what’s wrong and me neither.
Is somebody over there with a fresh new idea to share about this ?
Thank you.
What (I think) I understand is that you bought a vehicle with a known mechanical problem.
What I definitely do not understand is whether the cylinder head(s) were ever checked to see if there is warping. If you are simply replacing a head gasket w/o making sure that the cylinder head is “true”, then you are only doing half of the repair job.
Yes the head was replaced and checked the first time, it was an used cylinder head in good condition.
Thank you for your comment
@norberoca
Did anybody lay a straightedge on the block, to make sure it’s not also warped?
Are you absolutely sure the shop installed the new head gasket correctly? Sometimes it’s possible to install it incorrectly, believe it or not
I don’t know if they did with the block.
I agree with your comments about the gasket.
but it was installed twice, I don’t know.
The estrange thing is the engine overheat only if you drive the car over 55 mph and if you slow down, the temperature decrease again and the fan kick in, if you drive below this speed like for example in the city, runs normal but after maybe 1/2 hour the fan start.
Does this car have an airdam on it? Airdams are plastic and usually mounted underneath the lower radiator support. Their function is to basically pile up air in front of the radiator at highway speeds.
A missing airdam can cause an engine to overheat at highway speeds while allowing it to run at perfectly normal temperatures in city driving and at idle.
Sometimes they’re removed and never reinstalled (say body work for instance) or missing because of a critter strike on the highway.
No it doest’t