Overheating problem, thought i fixed it monthes ago
 

Well my 87 is runnin hot again, this time, im stuck. I dont know wat to check on this thing, i feel like i missed something when i replaced the coolant temperature sensor, the thermostat, the water pump, and then flushed the system, maybe its a bad radiator? if any of you have any tips, it is very much appreciated, and if you have a tip on how to get a dent out of the driver side door, that would be helpful too! thanks guys

could you elaborate on the overheating please?

do you have the front air dam that attaches under the car to deflect air over the radiator? i can't see it in your avatar.

yea, this morning wen i went to start it up and let it idle, it was at an idle for almost 20 minutes, not even, and the coolant temp guage turns on and i see steam commin up out of the overflow tank and the anti-freeze is bubblin. im thinking that it could be afew things now, bad/clogged radiator, maybe a blown head gasket or the electric radiator fan isnt kickin on. and yes, it is under the car.

well, check if the fans are coming on at 180*
What are the guages saying?
Is the upper hose getting hot when its overheating?
Is the lower hose colapsed when the engine is on?
Which engine do you have in it?

do you know for sure that it is overheating? I mean are you using a laser thermometer to check the temp at the radiator? I had an issue with my 86 where the guage said it was HOT but it was perfectly fine. I replaced everything that you just mentioned, including the radiator and it turned out to be the guage... :-x

well i didnt bother opening up the hood cuz i had to go somewhere, i was just letting it run, the coolant temperature guage isnt necessarily a guage, it has the little lines like a real one, but its just a red light that comes on. I have the 305 5.0 liter sb.

im sure its overheating, steam was commin from the overflow tank, and wen i shut it off, i heard the anti-freeze bubblin. again, its not really a guage, its just a red light. however i heard that wen they built this car, the electric fan wasnt built with the switch to automaticly turn it the fan on, so wat u had to do was manually turn it on by using the ac/heat, im not too sure how true that is but it seemed to work for afew monthes

if the a/c is on, the fan should come on automatically. if it doesn't, we can go from there.

like al said, check to see if the upper rad hose is hot when its overheating. don't hold it too long though :lol:

check your water/antifreeze mix with the .. oh hell i don't know what they are called. Something meter.

Antifreeze could be frozen in your hoses and such.

Oh, it was steaming you said. Ok, check you mix still ... could still have too much water and have a low boiling point

I say either you have air in the system or a bad/clogged radiator. When I took my motor apart to swap head gaskets because of overheating issues it sat for months causing the radiator to get all nice and dry inside and out. I tapped it, banged it, rattled it around in my hands with the holes facing down and long behold a TON of crud just kept coming out including a BUNCH of old rubber rings that use to seal the thermostat. they got sucked into the system and over years clogged the radiator more and more their was a good 6 silicone rings which use to be thermostat gaskets made from hi temp rtv. Now along with the new water pump no problems.

ill check everything wen i get it in the shop on monday

Too much water won't cause this unless there's a blockage and the hose testing will show some of it.

How old is the radiator ? And your 'flushing'....how did you go about it ?

Could be a bad rad cap too. Its happened similar to yours.

report back with your findings and we can go from here....

i just started to have the exact same problem, i let it idle for about 20 mins then the antifreeze in the overflow tank would start steaming and boiling. But i also notice that the fan did not kick on even when i put the heater on.... could the fan be causing this issue?

yeah the fan would play a big part. one time i was driving and my fan went out i guess the wiring was crappy....jumped to 200 pretty quickly. now it overheats and i still cant figure out why

the cooling fan doesn't kick on with the heater. the blower motor does. only if your car is equipped with a/c should it come on, as long as there aren't certain issues there. also, our cars pull air from underneath via the air dam. its a large plastic black piece that you will scrape over steep driveways and speed bumps.

As far as clogged radiator... just start the car and let it get to normal working temp. use laser thermometer or just your hand to check if rad have cold spots. If it does then most likely you have clogged rad. If it have same temp across the whole surface then mots likely its not clogged.

Definitely need to verify the fans are coming on.

I'd suggest removing the thermostat and then run the car with the rad cap off to verify the coolant is flowing. If not you should have the radiator cleaned (cored). As the engine heats up pay close attention to the hoses, sometimes when hoses get old or are defective they will collaps when hot, stopping the flow.

If you're seeing bubbles in the radiator before the engine gets real hot then you have something seriously wrong.

Be careful, if the engine is overheating that badly it can spew boiling coolant out!

ok, well i replaced the radiator afew weeks ago, it cost me $60, so i decided wat the hell, the old one was original 22yrs old. but since the i replaced it, havent had any trouble with and she runs pretty smooth