Overheated while at idle...

[Clied]

Earlier today my dad and I went to get my car smogged. When we got there I told my dad to shut the motor off but he insisted to keep it on cause thats what you do when you go get you'r car smogged. Anyways 10 minutes later and my dad points out that the temp guage is in the red zone or close to it. I tell him to shut the car off. I then turn the heaters on full blast and open the hood. My car never overheated on me before, this was the first time. it was 85 degrees outside or it felt like it. My car does not smoke but only a little in the morning. I have a perfect idle at 650 and 750 rpms. Stock everthing except for a K&N air filter(wich the smog guy said was ilegal even though I showed his the sticker). I am thinking a replacing the radiator with a PWR and replace the stock fans with electric flexalite I think there called...

 

[oscolivar1]

Well for one thing if you want to keep everything stock and your getting the PWR I'd stick with the stock fan. IMO it cools well for the stock system.

I'd check the stock radiator if it is clogged. Go flush it out. Then i would check the Thermostat if its bad I'd replace everything.

Just wondering if you've changed you HG?
Is so give us specs. If not I'd change it now and if you don't know what that is SEARCH.

 

[Clied]

I can't believe myself but I honestly forgot to ask the previous owner about the head gasket, I know thats one of the first things to ask too. So I dont know if the head gasket has been replaced or not. I'm not trying to keep my car stock, I'm actually aiming for 400WHP. So maybe those eclecrtic fans would be a good buy.

My stock radiator looks like crap too. I dont know what it is but it looks like there is corrosion on the outer surfaces. It's like a bluish green color. Think of rust thats bluish/green colored and thats what I have on my radiator.

 

[oscolivar1]

I can't believe myself but I honestly forgot to ask the previous owner about the head gasket, I know thats one of the first things to ask too. So I dont know if the head gasket has been replaced or not. I'm not trying to keep my car stock, I'm actually aiming for 400WHP. So maybe those eclecrtic fans would be a good buy.

My stock radiator looks like crap too. I dont know what it is but it looks like there is corrosion on the outer surfaces. It's like a bluish green color. Think of rust thats bluish/green colored and thats what I have on my radiator.

Well just to give you heads up the stock fan can easily cool the motor that goes up to 400HP+, might wanna check/replace the fan clutch if you go this route. I've heard bad things about electric fans so i dont wanna try em. People have luck with them and otherw don't; if you wanna go this route go ahead im just giving you my opinion and what ive researched on this forum.

Check the sensors on the thermostat...I would probably just flush out the whole system and fill her back up including the radiator.

If I were you I'd spend a good weekend(or day don't know how experienced you are) and check if the HG has been replaced or blown. If it's blown or not replaced then get ARP blots/studs and pick a MHG.

Good Luck

 

[Clied]

Yea I did here some bad things about the electic fans but also some good things about it too. Actually I think I'm sticking with the stock fan It works great and most 400+HP Supras I see use the stock fan so it must be good. I think I should replace the thermostat and radiator cap maybe some hoses too, flush the coolant and if it still overheats I'll replace the radiator. It does not over heat while driving or on the freeway. Just when I was at idle.

Thanks appreciate the tips.:icon_bigg

 

[mmarkk]

the blue/green corrosion is coolant
so your rad is leaking

 

[Dunckel]

for what it's worth, i have an electric fan. never had any problems. i'm not saying you won't, just saying i haven't.

 

[TobyCat]

85 outside and it over heated...I'd just check the easy things first

-Thermostat (check w/ a pot of near boiling water and thermometer. Should open at 88 deg C)
- Rad cap I'm not sure how to check, but it was only 15 bucks from Toyota
- Flush your coolant a few times w/ the heater set to max until it drains out clear. Fill with new coolant 50/50
- You do have a fan shroud right? This could also be a very big reason why you overheated. The fan isn't nearly as efficient without the shroud.

Hope this helps

 

[oscolivar1]

One more thing check the fan. If it moves freely then that might be the reason you overheating. There should be some resistance when you move it.

 

[Bishop92t]

Electric fans do not work as well as the stock clutch fan. They may be sufficient for some people's cars, but for maximum cooling performance you should use a clutch fan setup (and make sure it's working properly).

 

[Clied]

Yes I do have the fan shroud on still. But I don't really have a clue about the fan clutch, I meen it seems to be operating well. Fan spins freely when the motor is running. There is no resistance when I try to spin it though by hand. Is that a bad thing?

 

[oscolivar1]

There should be some resistance....
When you spin it, it should not spin easily.

Try it again. If you spin it and is able to do a full spin or even if it can go half way that is probably why you car is overheating @ idle.

 

[oscolivar1]

Read this

http://www.supramania.com/forums/showthread.php?t=1097

Read # 3 especially as that is what i think is the problem, but you have to drive around for 15-30 min, but im sure your Fan is not suppose to spin freely.

 

[Burntz]

Regarding Your Fan Clutch


With the motor off, spin the fan with a decent amount of force. It shouldnt spin more then twice, and if it spins over a full rotation, but not twice, then you're looking at replacing it soon.

Basically, a good fan clutch = that you spin it, and it stops almost immediately. A bad one = you spin it, and it spins very easily

I dont know about a Supra, but on my friends El Camino, his was bad and it ran hot, but didnt overheat. Make sure you have coolant as well. My supra has a BHG at the moment, but it doesnt over heat until it burns enough coolant to make it run low and overheat. Hence the reason I dont drive it lol.

 

[jetjock]

On a cold start you should hear the fan for a few seconds and then it'll drop off. On a hot engine the fan should run at about 45% of water pump speed at idle. When the rpm is brought up to 2500-3000 you should both see and hear the fan speed drop off. If you're not sure you can use a timing light to look at it. The fan clutch can be repaired or tested using this process:

http://tinyurl.com/2hx4ev

Coolant may remove heat from the engine but it's airflow that removes heat from the system. Generally speaking temperature problems that occur when the car is above 30 mph are caused by liquid issues. Below 30 or at idle they're caused by airflow issues ie; fan, clog radiator or condenser exterior, etc. For interior restrictions feel the radiator for cold spots or scan it with an IR gun.

As an aside if running the heater has an effect on coolant temperature it proves the water pump is working. You should look elsewhere.

 

[Jaguar_5]

Without really reading your post, and just glancing over the rest of the posts here, heres what I have to say

First, what JetJock says! Rebuild your fan clutch if needed, make sure your radiator is good, and not clogged, burp your system! If you have to replace your thermostat or radiator cap, get a Toyota one! If you have no leaks or air anywhere in your coolant system, and the radiator, fan, etc are all healthy, and the problem still persists, you might have a ::bhg::