My heat(engine temp) keeps going to the red zone. I replaced the thermostat yesterday to no avail.

The only thing I could do to get it to cool off a little (back down to 220) is turn the A/C on.

I put in a 160' thermo, so it definatley should not be getting that hot. So why does it cool down only when the A/c is on?

Aggg. I'm gonna blow this pos up....

 

check to see if hoses are collapsing, take car to radiator shop & have them do a leakdown test to see if radiator is clogged up.

 

i had the same problem. turns out i was missing this air dam that bolts up under the radiator and pushes air up into it. I had already replaced thermostat, fan, and everything else, but it didnt work properly until i got that air dam. make sure you have it. it looks like a big mud flap under the radiator.
Jason

 

Is is smoking any when it gets in the red ? If not , it could be your temp sending unit .

What about your radiator cap ? Whens the last time you changed it ? Or have you ever replaced it with a new one ?

Ever flushed your radiator ? Get some Zerex radiator flush (small white bottle with green label -does great job) Used this stuff in Mom's car recently !

Is your fan coming on ? If not , it could be the switch , or fan motor .

With the car off and keys out of the ignition , check your fan blades for cracks . Belive it or not , a crack in your fan blade or blades can cause a car to overheat . My car , last summer was overheating , I could not find out what was wrong with it for anything . It was going way up in the red like you are and it was a cracked fan blade !

If your ever in your car and you start to overheat real bad , turn on your heater full blast . Sure you will sweat your *** off and have sweat running down your buttcrack (buttcrack -is this one word or two words guys ? butt crack ? but ; it will cool the car down ! Just roll down the windows !

 

Wayne is 100% correct on the heater call.
I think alternator is shot.
Don't knock the idea.
Car sluggish?
overheating?
Poor idle?
Yep alternator.
While ya at it, check water level in battery also. Bet it's low.

 

At least your temp gauge works. Mine is pinned to the top all the time, although on days when i hit the boneyards threatening to replace it with an IROC gauge panel (brainfart, can't think of the right words) and new sending unit, it reads right. Damn what $850 can get you...

 

Actually cutting on the heater when the car is overheated will only drop the temperature 2-3 degrees. Or so my mechanic says.

 

Well yeah, it won't make a huge difference in the engine temp, but Wayne's right, every little bit counts! When I used to speed around on the streets, I would kick on the heater (in the summer) and roll up the windows to keep the engine a bit cooler and to make the car more aerodynamic. But I didn't do that often!

Wayne, you have the electric fan, right? A fan blade cracked on it? I didn't think that could happen to plastic! I'll have to check mine out for cracks; I don't have an overheating problem, but that fan did survive my accident.

The A/c will kick the fan on if the pressure in the a/c hard lines gets too high; caused by the condensor (unit in front of your radiator, same length/height as your engine radiator, so unless you look at the side of your radiator by the fill cap, you'd never know it was there) running too warm. The a/c kicks the fan on to increase airflow over the condensor to keep the a/c cool. And if that fan kicks on right away, you know there's something wrong with airflow over the radiator. I agree w/camaro89dude, look for that air dam! If you have one, and it looks beat, you might want to replace it with a new one. I think GM wants $40? Those things take a beating, and yours might be bent/cracked, and hurting airflow over the radiator.

 

Turning on the heater IF your car is too warm or overheating
CAN HELP SAVE THE ENGINE.
Super quick last chance fix before you melt the piston!
Lowers temp WAY MORE than 2-3 degrees......
Try it next time going up a long incline, see what happens!

 

I would sy Flush your radiator, check to see when and if your fan is kicking in, replace the hoses then if the problem still occurs looks to see if it is the air dam then

 

I had the same problem with my 2.8 and idiot lights. It turned out to be my NEW temp. sending unit was tripping the light after 5 mins. I thought I was overheating too, after checking out the engine, I replaced the NEW unit with another one and problem solved. I NEVER was overheating.

 

Yeah , its the electric fan . I wouldn't think it would be able to crack either , but it did .

 

I do have an airdam, it's not too beat up.
I need to check on my fan blades I guess.

It's weird cause it only really heats up when I am sitting still, at a traffic light or sumpting.

It cools down when I'm driving, which would lead me to believe that my airdam is working correctly.

I guess I need to do a flush, and make sure it's not the radiator, and also check the hoses...

Anything I missed?

 

I BET your radiator just needs flushing ! My Mom's car was doing the same exact thing not to long ago . Running cool when driving then when she would sit at a redlight it would heat up !

 

IMO, your radiator is working fine. I think your fan's just not turning on early enough if at all. See, you said it cools down when you're moving. So your fan doesn't have to work when your moving due to the fact air is being forced up into the radiator with your airdam. Which leads me to believe that your radiator and airdam ARE working. When you stop, your air dam doesn't do jack. And if your fan isn't turning (or has cracks in the fins, or just isn't spinning fast enough) then your radiator isn't getting some cool air in there to cool down the coolant. Which means, hotter and hotter coolant while staying at a light. But once you start moving your airdam throws air into it and it starts to cool again. So, I think it's your fan. It's doing the exact same thing mine does. The only way I get around town here in HOT 110 degree Tucson is having the A/C on the whole time so my fan will turn on. I'm just too lazy to fix it! So, these are the things you can do,

1. Get a new Fan Temp sensor (Which I bet is your problem)

2. Rig your fan to turn on with a flick of a toggle switch or rig it to turn on whenever you turn on your car. If you search the archives here you can find a diagram from a while ago, or ask the guys on the cooling board.

3. Get a jet fan switch from like jegs or somewhere. This will make your fan turn on at a cooler temp.

4. Fix your fan or get a new one. It might have a crack in a couple of blades or the motor might be dead. So pick one up from a junkyard or something.

5. Good Luck! Cooling problems SUCK!!

 

Cooling probs definately suck.

It seems like there are 20 different things I can do. I need to start wit hte most obvious. Check to see if the fan is cracked or broken.

Next Fan sensor.
1. Where is it located?
2. Part number?
3. How much does it cost?

I guess a flush can't hurt either....

 

I agree with elevario.
Thermo fan switch is bad. Your fan automatically comes on with the a/c. But with the a/c off the thermo fan switch controls the fan.

 

I don't know the part number and it's located on the passenger side head. The part doesn't cost more than 20 dollars.

 

Does the fan turn on at all without turning on the AC? Then I would get a new fan switch, or you could do what I have done do a new Hot Rod mod to my fan. I got this little box with a **** and a thermometer(spelling?) that you put into your radiator hose. I can set my fan to come on when ever I want it too, currently I have it set to 175 degrees. I had to use a heat gun(or whatever its really called) to get the fan to come on when the radiator water got to 175*. Then I had to coustom wire up my ac to turn the fan on as well but that only took a few hours to get it right.From now on I will always put this onto any of my vehicles. This pic has the set up without AC control.

 

I just wired my fan to a relay on the power attenea wire on my radio. Comes on when ever Radio is on. So in effect, when ever the car is on. A/C override not hooked up, just the relay. Have not gone ove 185 yet. Total in parts... $20? most expensive being the relay. 5 bucks in wires and 3 in connectors.

 

Where should I get the relay from. What the name/part?

Thanks for all the help so far.


Yes the fan comes on when I start the car.

 

I know you can get the relays from all the chain auto stores; I got mine from advance. Like 5 or 10 bucks I think??? Cant really remember. My relay was inside the engine bay on the firewall of the drivers side, thats proabably where yours is....takes 30 seconds to change.

 

What does the relay look like?

 

I am not too sure on the specifics, but as far as i remember it looked like a black rectangular box. Reminded me of something you might see on a video game hook up. I'll try to check this afternoon, but one of the other smarter guys on here will probably beat me to it.

 

Does anyone recomend a relay kit for me?