It all started about 3 weeks ago while i was waiting at a drive thru at kfc when suddenly i noticed my needle going up to H close to the red line so i immediately turned it off to cool down. I checked for leaks and obviously couldn't find one. checked the bolt under the motor fan if there were any leaks to indicate a bad waterpump. but no signs at all so i figured maybe its thermostat.

So I made a quick stop at autozone to get a thermostat. It fixed it for a couple of weeks and then yesterday while waiting at BANK OF AMERICA I noticed my needle going up again. Now I'm pissed because I thought I had fixed the damn problem.


So heres my dilemma... I can't find one good reason why my car is overheating. my waterpump is pretty much new. my radiator is pretty clean
and the rest of the hoses are still in good condtion

is there a solution out here?

 

ill tell u this much its not ur waterpump. maybe air in the system or ur fans not working or a bad thermostat....but its not ur waterpump

 

does your heater work? is the coolant moving thru the system, or just your motor getting hot? check it out, let us know..

 

what is coolant level / type?

 

maybe you have air in the system, maybe your radiator's fins are clogged by road debris.

 

I'd put money on air in the system, so just try a coolant flush/bleed and see where that gets you. Either that or your water pump pulley could be seized or something like that.

 

Always a solution my man. Especially when doing things yourself.

At any rate, I get the impression that you aren't sure the problem was even the thermostat to start with. Perhaps you replaced the thermostat and the system worked again *not* as a result of a different stat in place?

Doesn't much matter,.. a cheap thermostat can EASILY go bad on you in a few days/weeks and start sticking closed. So as others have indicated do the basic checks on the system..

With your coolant system you can have the car running and feel on the outgoing and return hoses on the radiator and around the engine where-ever you can spot coolant hose. It is fairly easy to determine where the coolant is coming from... that is,.. "Is this outflow from my pump to engine? Is this inflow to be recycled and cooled from the engine, is this before or after my thermostat?.. and so on."

This is important because you can determine the status of your thermostat simply by feeling the temperature of the coolant in the line before and after it.. if stuck it will be hot on one end and no so much on the other. If a stat is stuck open you won't really overheat to start with... though pressure will be effected as the thermostat is there for a reason.

There isn't much to a cooling system -- Waterpump, attaching pulling and belt,... thermostat, and hoses. If you can rule out your waterpump having any problems (IE: No leaks, and the propeller is turning as it should and moving water along fine) -- then you are well into the game. Now you only have a few things left to inspect.

If the levels remain high (no leaks) ,.. the pump is good, and you don't find any obvious "cold" spots.. then it has to be air or another malfunctioning t-stat. Both of which are easily fixed.

Flushing the entire system is less than an hour job.. and that is taking your time. I would go ahead and flush it regardless of what you do just as good maintenance. I might even run some of the flushing cleaner through it just because a cleaner Rad is a more efficient Rad.. but that isn't absolutely necessary.

If you need help on the exact flow and what to look for in the cooling system we can help -- there are plenty of other posts from the past on your issue as well .. I would also comb through those.

I'm less inclined to think this is air, and more inclined to think it is your T-stat malfunctioning or some other random blockage.. might be the water pump after all. They can stop working yet not leak.. not nearly as common, but the internal prop can stop thus blocking flow while the body is sealed well .. (Though usually the pressure buildup will show some slight leaking through the access.. not always).

You will get it figured out,.. just don't let it run hot for any length of time. A broken coolant system can easily be fixed.. an overheated engine that burns up a headgasket, or worse is a great deal harder.

 

sounds ike a nice fat bubble of air stuck in your system. bleed and enjoy.

 

Is your radiator fan turning properly? You were stopped both times when the temps started to go up. When you are driving on the highway, the natural airflow from the motion of the vehicle can help cool the radiator. When you are stopped, not so much. That is why radiator fans exist.

 

Have you checked between the radiator and A/C condenser for debris?

 

gotta love the follow up by the op

 

He never mentioned bleeding air out after the thermostat swap, plus as others have mentioned - I have seen many DOA parts stores thermostats. I usually test them before install.

Lastly, buy one of these: http://www.thetoolwarehouse.net/p-3029-lisle-24610.aspx They make bleeding coolant super easy.

 

if its a mechanical fan, i bet the fan clutch is bad. since like others have said, you were stopped both times it happened. if the clutch doesnt engage, the car will over heat. youll know if it is engaging or not with the hood up. itll catch and make a hell of a whirring noise, and airflow will be dramatically increased. i remember first time i ever heard one engage on my supra back in hs. freaked me out at first. lol. i dont know what year they went away from mechanical fans, if they ever did, but my 1st gen has a mechanical fan on it.

 

IIRC they retired the mechanical fan in '98.

 

where did you get that from?
98 still has a clutch fan as well as 99 and 2000 after that I cannot confirm as I have not looked.

With the issue above it is the fan clutch as well as the secondary a/c fan not being triggered as back up. Also a rad cap to keep the pressure high would help . A bubble alone should not cause overheating unless it is massive .