Ive been having a problem with my car overheating after I drive it home after work. It stays right around the 210 mark constantly, moving or stopped with the engine running. As soon as I stop to get gas or Ive finally gotten home, it overheats, the temp rises and I can hear the coolant boiling. Ive bled the system several times but nothing. Any ideas? One thing I will mention is the bottom bleeder screw snapped off the last time I was bleeding it last year so Ive only been bleeding it through the top one? Is this wrong or just more time consuming?

 

With the engine off it boils? Does it boil around 210*? It almost sounds like the system is not under pressure. Have you tried a new radiator cap?

 

X2 get a new radiator cap and see what that does for you.

 

yes it starts to boil after i turn it off, with the key in the on position I watch the temp rise and then i can hear it start to boil!

 

It's not unusual for the temperature to climb when the engine is turned off. Without circulation, the water will continue to accept heat energy from the block but won't be able to dissipate it as fast. The problem is the boiling-over issue. A 50-50 antifreeze-water solution boils at about 225F at atmospheric pressurel. Increase the pressure in the system to 18 psi (the rated pressure in our cooling systems) and that temperature is well over 260F.

I think the other posters are correct in suggesting a new cap but I'd suggest having the cooling system pressure tested to make sure there isn't another minor leak somewhere. It's easy to check the cooling system and you can probably rent the tools from Autozone....

 

I drove the car to the junk yard in south Phoenix today in 111* heat w/o the a/c on and it didnt even get hot or even boil after I shut it down. I got the lower bleeder valve and i'll put that on as soon as it cools tonight. Does it seem weird that it dindnt even come close to getting hot or even overheating when I dont use the air? BTW it is a 160* Tstat and PCM4less reprogrammed the computer for the fans to kick on early, today it hovered right above 1/4 mark. I guess I'll pick up a new cap tomorrow also.

 

I've been having the same problems. The car gets hot randomely and air seems to be building up in the lines. When it starts to get hot, I can bleed the air out and then continue driving at normal temps for about 5-10 miles, then the temp starts to rise and rise. Then I can bleed air out again and make it home. My car also gets hotter when the car is shut off then turned back on. I can be driving and have the the temp needle at about 1/4, pull in somewhere and shut the car off, then when I start the car again, it heats up very rapidly. I just took it into the shop today to get my front seal replaced and a couple other things tweaked. I'm having them look at the cooling system as well so I'll let you know what the problem was.

 

have you checked to make sure your cooling fans are turning on? If they have been reprogrammed for your 160 degree stat, there is no reason you should even be seeing 210 degree temps in town

 

The thermostat only sets the lowest temperature the coolant will see....it is quite possible to run at higher temperatures, especially in Arizona in the summertime....

 

I installed new lower bleeder on the Tstat today and got a new radiator cap. I also verified that both fans are turning on properly. I bled the system per Shoeboxs site, got a good steady stream from the lower bleeder screw but not so much as consistent from the one on the heater line, even after 10-15 minutes of leaving it open and expecting a good solid stream. Is this normal? If not how long do I need it to run to get the air out?

 

whenever i bled the air out of mine i always had a lil bit in the thermostat hose when i followed shoebox's site i poured the coolant thru the water pump less air pockets that way. id open the screw and after i just saw water coming out like a stream, ill close the screw and wait a few more minutes and check again. people/moderators on this site have told others thatthe bleeding procedure takes patience and time,i know i didnt have a lot of it but i bit the bullet and delt with it now i know how to bleed it perfectly

 

After the engine is cold, check the coolant level in the radiator, not the overflow. Top off if necessary. Check daily until radiator stays full.

 

i know how thermostats work thank you very much.

The OP stated that when he was running on the highway (read: adequate airflow) and the engine stayed cool and he couldn't hear it boiling after he turned it off

This to me sounds like an airflow issue, if the fans aren't working correctly it will get too hot in town

If it were an issue with the cooling system not being bled well enough it would more than likely still get hot on the highway

 

My point was simply that 210F is possible with a 160 thermostat...especially in a 110F ambient environment. He has what appears to be an intermittant problem as it'll run hot and boil sometimes, run cool and not boil others...

 

I replaced the cap and bled the system again a few days ago. It seems to have solved the boiling issue and the temp hasn't passed 210*, but its only been about 105* outside. I'll post back again when it hits 112* or more outside, that will be the true test! Thanks everyone.