The car is a 2007 Accord with four banger, 200k+ miles. Last year I had the AC compressor and evaporator replaced. A new thermostat was also installed. Shortly after that, the car overhead, producing a white powder and melting the plastic reserve. The radiator was determined to have corroded around the cap causing a radiator leak which in turn causes the car to overhead. We then had the head checked, it was fine, replaced the thermostat, radiator & reserve. Additionally, the engine was flushed, and fresh coolant added. The car ran fine for a while, then started to overhead. We had the heater core checked out, the mechanic flushed and again the car ran for a while then started to overheat. We took it to another garage, replaced the water pump, flushed the coolant, replaced the thermostat. The car overheated. Took to another place and the guy said it had some particulant in the coolant(possible stop leak from a previous owner), he again did a head check, checked out fine, flushed for an extended period, replaced the coolant and the car ran fine for a while then started overheating. DOES ANYBODY HAVE ANY IDEA OF WHAT IS GOING ON!

 

With the engine cool, check the coolant level in the radiator. Is the coolant level low in the radiator and reservoir?

When the car overheats, does the fans on the radiator spin?

 

Fan works and the coolant levels are where they should be. The car is my son's. Since the first time it overheated, he has been very careful. If the guage gets up 3/4's he pulls it over and calls.

 

Why are you going to different shops? Do you not trust their advice or do they simply have no other answers?

I dont know how these shops are "checking" the head-gasket, but modern MLS gaskets rarely produce easily tangible results when checking for failure, particularly with conventional methods(ie. block checker fluids)

The only way to detect a small leak on an MLS equipped engine is by utilizing a gas analyzer to detect for the presence of hydrocarbons in the cooling system. There should be under 5ppm. Anything more is a failure.

Of course it could be a matter as simple as properly bleeding the cooling system. You really need to find a quality repair facility.

 

Two of the shops are considered by many in the Cincinnati area to be the best or of the better foreign car shops. They aren't small and they have more than 5 mechanics & bays, all with many certifications. I myself am a mechanical engineer & and car hobbyist. The shops seem to think that some stop leak stuff used in the past accumulates in the coolant, causing the car to eventually overheat, which made sense to me for a while, but after multiple flushes I'm really having my doubts.

 

That is plausible, but flushing will typically take care of that.

I dont know that anyone online can really help you with out intrusive testing.

The shops that are associated with this forum are typically considered quality shops. If you haven't tried one of these, maybe do so:
https://iatn.net/repair/?action=sear...0196&show_all=