interesting temp problem

GREATWHITE666

Registered User
i knew it, of course after all the work, gotta have the problems. Well here it is, another temp thing... just installed a180 t stat and flushed and refilled radiator. the temp problem i have is ONLY on the highway, around town it's beautiful, i can tell the 180 lowered the temp at least a letter. so on the highway... when im going to school i have the max Ac on low.. and it's fine... it hovers in the middle of "norm" moving just a little, which is fine. but on the way home for some reason, it's all different. this is the second time it happened... i was driving back on the highway, NO AC on, and the temp gauge just kept rising over the "m", no boost, and temp was only about 5 degrees warmer than going to school,.. it got eventually to where i had to put the heater on high so i wouldnt have to shut the car off, this kept it under control,, this has happened 2 times now, only on highway, going to school with AC on, fine, then coming home.. no AC, normal driving... i need to put heater on so i dont have to pull over..... i suspected a bubble in the system,, maybe i didnt flush the radiator right? i remember that i closed the screw/plug on the radiator and then filled it back.. could that air that got in there when it was emptied cause this? the stock t stat was always fine without AC on, and no the 180 i put in is not backwards... lol sorry so long guys... but i really hate having to look at my temp gauge more than the road! thanks for any help.
-damon
 
Sometimes it does take awhile to get all the air out.
There is a vent plug that you need to loosen before you add the coolant. I usually take it right out and add fluid until it starts to flow out of the hole. I then put the plug in and tighten it while I squeeze on one of the hoses to make sure I get as much air out of the system as possible. I then fill up the rad. Every so often after that I will crack the vent plug until coolant leaks out and then retighten. I have also noticed that the thermostat that came with our cars had a hole in it with a ball bearing that acts as a valve. This hole helps to purge excess air that gets trapped behind it, without it the air remains trapped until the thermostat opens up. Some people have just drilled a 1/16" dia. hole in the thermostat if it did not come with this.

Also. The lower radiator hoses on our cars came equipped with a spring inside it to prevent it from collapsing when the water pump sucks coolant out of the rad. (When the hose collapses, no coolant will flow through it and the car will overheat). I'll bet that yours is missing because new ones do not come with it. I just keep taking the old one out of mine and transfering it to the new hose when I replace it.

Just a few possibilities.
 
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ok

damn,, it must be some air then... guess ill try to unscrew that plug a squeezing the hose to see what i can get. i hope that's it,, thanks
damon
 
GreatWhite,
Do you have a aftermarket hood? (Cobra Hood)
I've been hearing probs about overheating only on highway with those aftermarket hoods. Just a thought..
 
dont think so

no i dont have one of those hoods, it is stock. and the air dam seems to be fine. The car was normal before i did the radiator flush and t stat change. after doing a search and reading forever, ive come to the answer of probably some air in the system. my step dad keep telling me that should never happen because it should be pushed out through the overflow reservior, but then i read someone on here say that no matter what anyone says, it can happen. like i said, the car was fine, before, i just wanted it to run cooler,, also, today it got hotter than normal just driving around,, went up to the "M" just casual driving... anyone agree on this? air? ive read soem posts on getting it out, i liked the funnel idea of placing one in the radiator cap hole and filling the funnel up then squeezing the upper hose... with the cap off of that thing next to the t stat... sound like a good place? again i want to stress that the car was running "normal" before all this, thanks for help guys, keep it coming,
-damon
 
the temp problem i have is ONLY on the highway, around town it's beautiful, i can tell the 180 lowered the temp at least a letter. so on the highway... when im going to school i have the max Ac on low.. and it's fine...
i was driving back on the highway, NO AC on, and the temp gauge just kept rising over the "m"

Sure sounds like your fan isnt turning on when it should. When running the AC, the low speed fan turns on automatically and stays on while the AC is running.

Paul
 
even more interesting

i dont think that's it, i believe the fan is fine because when the AC is on around town, that's the only time the car seems to stay by the "n"... now it's gotten more interesting,, seems like anytime now when the ac is not on (fan not on) it gets hotter than it has before. im checking for air tomorrow, thanks for the idea BT Motorsports, but i think the fan is fine.
-damon
 
You misunderstood my post. It seems as though your fan is not turning on when it should be without the AC causing it to do so. Your problem may be as simple as a bad ECT switch.

Paul
 
It seems you have air in the system. Burping the system can be a big pain.

I am pretty sure the highest point in the system is the heater line on the passengers side of the engine where it goes into the intake crossover near the thermostat housing. This is also where the ECT sensor is. If you have a bubble at that sensor the computer will not know the engine temp and will not turn on the fan.

You might be able to loosen the sensor and pour coolant into the vent tube until it comes out of the sensor location. I will try to verify the levels tonight at home.

Aaron
 
what difference would the fan make during highway driving. doesn't the fan shut of at 45 mph anyway.
 
1badsc.........what difference would the fan make during highway driving. doesn't the fan shut of at 45 mph anyway....

I beleive that is correct cause the fan cannot push air faster than 45mph so it is just wasting the fan if not hurting air flow with drag from the fan.

Blue tounge....more info on the ECT SWITCH please. I assume the ECT and the ECT SWITCH are two different things??? I know where the ECT is, but my bird runs hot too and I'd like to test my ECT Switch. My fan only turns on with A/C on. But shuts off at 45mph.

(Who tested this theory?? Somebody lay on hood while ex wife drove down a empty freeway to see if fan turns off??):D
 
lol

ok update here, i just vented out all i could, i put a funnel in the rad top, and unscrewed vent plug, started car, squeezed upper rad hose, all fine, no bubbles coming up, replaced cap and vent plug, let run for a few min. Ive never actually looked at this so i dont know how it should be but, after about 5 minutes of running, the upper rad hose was expanded and the radiator was hot, i don tknow how long it hsould take to heat up.. maybe it's normal.. but i wasnt sure because of the new t stat i just put in.. ive read that the opening could not be big enough? i just got it at a local parts shop... there's no leaks anywhere, and no bubbles in coolant when i rev it. think it could be tstat?
 
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