[Ice D]

Ok similar situation as my other coolant thread. But now my car will overheat if I don't have the heater on full blast. Work that I have done on the car in order from most recent. coolant flush, oil change, thermostat, head gasket, in the past two months. Timing belt and water pump last spring. I am really at a loss as to what the problem could be. All I can think of is bad thermostat, water pump, head gasket, clogged radiator or cooling system, and trapped air.

 

[Ice D]

My lower coolant hose is still cold during driving but now it's overheating.

 

[pimpindistress]

maybe you put the thermostat in backwards, or maybe you need to bleed the coolant system. could have just got a bad thermostat too , it happen to me one time before

 

[Ice D]

Tomorrow I will check the thermostat to see if I installed it the right way and also if it works. I don't think I put the tstat in backwards. Spring toward engine, correct?

 

[pimpindistress]

yeah thats correct

 

[crx1.8]

your probably still have air traped in the system. When you bleed your system make sure your heater valve is turn fully open.

You could also have a clogged radiator. Or your thermostat switch or fan switch isn't working.

 

[sharkytm]

It could also be an air blockage in the heater core or radiator.

Step 1, if I were working on it: Drain the coolant. Pop the lower hose, and drain the radiator.
Step 2: Button it all back up, checking the tstat's orientation, and dunking it in boiling water on the stove to make sure the tstat wasn't DOA.
Step 3: Refill the radiator, following the instructions in the Helms manual. Basically, pour coolant into the radiator with the heater valve open and the bleeder cracked. Do this until coolant (with no bubbles) comes out of the bleeder. Then fill the overflow tank, and start the car. Let it run for a few minutes, adding coolant as needed to the overflow tank.

That should ensure that there are no airblocks in either core or radiator, and that everything's working.

 

[Ice D]

Last night I drained coolant, checked tstat, refilled, bled and still car overheats. When I tested the tstat it wouldn't start opening until 195-200 deg. I am going to buy a new one (there cheap) today. Also I bled the car for about half an hour with heat on and revving to burp it and got a lot of air out. Now the fan does't come on or lower hose warm up.

 

[Ice D]

I just spent all my money putting on snow tires so I guess I am not getting another thermostat.

 

[inh]

sounds liek a clog then. if the tstat works... then yea, im gonna say clogged radiator.. i thappens

 

[Ice D]

Funny thing is when I just pour water into the radiator with the plug open the water drains out at the same rate I am pourin it. Also when I flushed a month ago I took the tstat out so it would flush better. After I started the car the lower hose warmed up within a couple minutes.

 

[bassist1088]

when you changed the head gasket did you have the head milled because if it is warped the exaust could be slipping into the water channel through a small hole thus overheating as for the circulating if it is warped it could be going intot he combustion chamber before it circulates, do you have to keep puttin water in it every few days?

 

[Ice D]

I did not mill the head. I didn't have time and took a chance. But I haven't had to add coolant since I changed it.

 

[Ice D]

When I flushed it last night the coolant looked clean. So I'm assuming hg is still good.

 

[inh]

run it without the tstat and see if it starts circulating coolant. if it does then you knwo its a bad tstat

 

[crx1.8]

Last night I drained coolant, checked tstat, refilled, bled and still car overheats. When I tested the tstat it wouldn't start opening until 195-200 deg. I am going to buy a new one (there cheap) today. Also I bled the car for about half an hour with heat on and revving to burp it and got a lot of air out. Now the fan does't come on or lower hose warm up.

well after burping the system you probably lost some coolant. If the fan was working fine before your fluid is just low. Your fan will not come on if your coolant level is low enough.

 

[Ice D]

I'll run it with out the tstat and see what happens.

 

[Ice D]

Changed thermostat this past weekend and now coolant is circulating and not overheating anymore.