Over heat

An email I received from a friend.



was wondering if you could give me a thought as to what is wrong with my car.



95 honda was overheating, going into the red on the guage driving around the city. took it in, they replaced the thermostat. worked fine for a little over 3 months. then we had a night -20 and next day it was overheating but this time it was overheating fast, and boiling over. decided to take it in to a dealership. they said the radiator froze. replaced the radiator and the thermostat again (they said it got damaged) worked fine for about 1.5 months. then it started smoking and over heating (it hadnt smoked before) they said the head gasket was cracked (probably from overheating the last time) I just had that replaced (and some other stuff while they were at it like the timing belt and water pump) i got it back 2 days ago. its about 32 degrees here. it started heating up fast when i got on the freeway (about 2/3rds up on the guage) and in about 15 min of freeway driving it was in the red. it was in the red for about 2 mins (i was looking for an exit) and it suddenly dropped down to the middle. it stayed there for awhile (10–15 min) then rose back up to just under the red where it stayed for the rest of the way (about 5 more min). at destination it sat off max 10 min before i had to head home. for the first 30 min or so it wasnt heating up to much at all, it was in the middle almsot the whole way, sometimes under the middle on the gauge. after about 30 min it started to climb and went all the way into the red. it was there about 2 min again where it dropped to just below the line and stayed there the rest of the way home (about 10 min)

i was driving on the freeway 45 mile each direction, both directions are hilly. I was going about 3.5 each way on the guage that shows how fast you accelerate or w/e. and speed wise I was going anywhere from 65-85 (i was going 85 most of the way home cause it wasn’t running hot) slowing down didnt seem to have a noticable effect (though I didn’t try sitting with it idle)

is the thermostat blown again or is it more likely something else because Ive had so much replaced and its still running hot, but it doesnt do it all the time., but it seems that it has been overheating multiple times Im wondering maybe if there is something else behind it (the mechanics all seem to think the fan works fine)



I know its hard to judge not driving it but meh im sick of paing mechanics and still having the same problem. they replace the parts and dont test it out on the freeway to see if that was the issue.

This was my response:

You have a large air bubble in in your cooling system. Take it back to who ever worked on it last and tell them your symptoms and that a friend told you he thought it was that. It also could be that the goofed up the head gasket job, but I think this is more likely.

If you want to bleed it yourself I can post directions for you, but they should do it at no charge.

P.S. I’m gonna re-post this at cartalk.com and see what others have to say. I’ll send the link and you can see if anyone else has a suggestion.

I just wanted to get a second opinion.

If anyone has any questions I’ll do my best to get the info for you.

Thanks.

I’m voting for air in the cooling system.

Someone needs to measure the actual coolant temperature to make sure it’s not just a faulty temperature sender.

Thanks,

She’s going to take it back. i’ll let you know what she finds out.

Thanks

Could the temp sensor also be malfunctioning? I know it actually overheated a couple times, but it is 16 years old…just because you are paranoid doesn’t mean they aren’t out to get you. Even if the temp gauge is wigging out, doesn’t mean it wasn’t sometimes right.

If the radiator froze at -22F, then the dealer who put in the thermostat did not replace the coolant and did not check the old coolant for the freeze point. A 50:50 mix of antifreeze and water is good to -34. In your climate, you might want to go a little richer on the antifreeze, up to 2:1 antifreeze to water ratio.

Anyway, I’d say the dealer had some explaining to do. The head gasket could have been damaged from the freeze just as much as the overheating.