Rep Power: 0

I have been having an overheating issue for a few months now. i drive nearly 90 miles total to and from work each day. Almost all of those miles are highway driving, and as long as i dont hit any traffic, i dont have any issues. But when i hit traffic and i am going less than 20 mph for more than a few minutes, the car starts to heat up. it will heat up and most of the time it will go back to normal. while it heats up, the heater will blow cool air. Once traffic starts to move again and i get going faster the car will return to normal temp. Of course this problem is not consistent and i have not been able to pinpoint a direct action that causes the overheating. I had just taken it to respectable shop and they had it for almost a week and did every test imaginable to it and they couldnt find anything wrong with anything mechanical. no leaks, no pressure loss, head and gasket are good, fans worked no problem. what is weird is that while they had my car, they could not get it to heat up at all, even after a 15 mile drive and then they let it sit in the bay for almost 3 hours and it never heated up. So i picked it up after everything was said and done. The next day my wife and her sister drove to vegas and on the way back they encountered a lot of traffic and the problem is still there. i am at a complete loss as far as what to do. any help would be greatly appreciated

 
Rep Power: 313

A lot of shops misdiagnose a head gasket problem. You might also have air in your cooling system, try bleeding it out. I had a head gasket go bad and Honda said it was a thermostat and they changed it. A few days later, my problem came back. Is your overflow full to the top? I'd start by changing the thermostat because it's cheap. Check those few things and get back to here and we will try again

 
Rep Power: 256

this happened in my old car it was air in the cooling system when the car slows down so does the water pump and if there is air pockets it will not flow properly i would drain and fill with new fluid and let the air out of the system im certain there is a diy floating around somwere online.

 
Rep Power: 313

Jack up the front of the car, take off your rad cap. Start the car with the heat on full blast. Watch the coolant in the rad and you should start seeing it going down. Refill as it goes along, this is generally how you bleed the air out of the cooling system. Another option is, remove the rad cap overnight and check the coolant in the morning. It might be low. Try it and see if it works.

 
Rep Power: 0

i replaced the thermostat months ago and when it just came out of the shop the other week they replaced the timing belt and water pump. would it still be an air bubble if it has been months and months of this going on.

 
Rep Power: 313

It's possible Bleed the system and find out.