I have a 85 TPI 305 IROC that over heats the funny thing is that the temp gauge dont work anymore and when u start the car i dont feel any pressure in the top hose but when u look in side the radiator cap u do see the antifreeze being sucked down and the fan wont turn on. what could be the problem i think it might be a water pump or a clogged radiator

 

More specifics would be helpful here, but I'll try to be as general as possible.

First, when you first have your cur on, the upper radiator hose isn't going to have any water going through it; the thermostat is going to be closed.

Now, to discuss heating problems...

Does it cool fine driving around in traffic, but overheat on the highway? That probably means your air dam (read: curb scraper) isn't in place. Look underneath the front of your car, you should see a black plastic flap sticking straight down below the radiator. That scoops up air as you're driving. They cost about 20 bucks, new from the dealer.

Does it overheat all the time? That would probably be caused by faulty cooling system components.. Corroded radiator, REALLY bad antifreeze, bad water pump, etc.

Does it overheat while driving around in the city but cools just fine on the highway? That's probably the radiator fan not working. There's a couple of ways to diagnose this...

First, turn the AC on max, and wait a bit.. The fan SHOULD turn on with the AC system on. If it doesn't, your fan might be dead. Look for the green wire running off the fan, and ground it. That should turn the fan on. If it doesn't, your fan's probably dead, or some weird fuse somewhere has broke. If the AC thing does work, it's probably something as simple as a fan switch. (Few bucks at most parts stores.)

------------------
89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

the car overheats all the time, its just that the fan dont work and the temp gauge

i had a newer engine put in it and a new transmission. but the old engine i had in it overheated to but when i got the new engine put in it didn't over heat at all and the fan and temp gauge worked then the tranny went bad so i went and got a new one put in at a shop, then when i got it back the temp gauge didn't work,then fan didn't work and it started to over heat. today i put in a new coolant temperature sensor in today and that made no different.

I dont know what else it could be,

 

After you made sure your fuses were good I would check the fan relay and the guage sensor. Your guage doesn't operate from the coolant temp sensor.

 

what operates the temp gauage and where is it located and what operates the fan

 

duke, keep it simple man...listen to mike above your last post.That fan isnt supposed to come on untill 225 degrees. also, if you noticed that the water was filtering through your radiator that means your pump is good.

------------------

click below to check out....
www.formula350.com

or click below to email me
webmaster@formula350.com

 

well today i got the fan to work, and soon after i took it to get gas. when i got done pumping gas i started the ROC back up and i opened the hood to see if everything was ok well it wasn't the wire that goes from the battery to a black connector which i think is the ECM wire was on fire, so i turned the car off and looked at it. (it burnt all the way through) so i had to drive it back home but when i got home it was overheating again and now when i test the fan to see if it works it dont so now what could the problem be sense that wire is burnt through

 

The temperature sender for the temp gauge is actually what triggers the fan to go on. Their is a way to ground out the fan relay so that it stays on all the time, but your best bet is to replace the temperature sensor under the passenger side exhaust manifold. Also, trace the harness and wire back as far as you can to make sure you didn't burn through the wire for the temp. sender, this could also be the problem..

 

Can I make my fan come on at 160 degrees rather than 225?

 

Hey 92fire-audio, you said thiers another temp sensor by the exhaust manifold. Is it the same part number (same part) as the one on top of the engine or different? I just changed mine on the top part but my gauge still doesn't register.


------------------
88 White Formula 305 TBI With A New CD Stereo and Abolutly Nothing Else Done To It!