I have a 91' RS 305 V8. My car overheats in the hot weather. I ghetto rigged my fan to stay on indefinetly, and i have a low 165 temp thermastat in. My car gets hot slowly and if i keep driving will get into the red everytime. I changed my thermastat from a 195, and i flushed my coolant. I got my fan going forever, so that isn't a problem.
I also figured if 165 is to low, then the coolant keeps going round and roung, and the temp never goes down, the coolant will not work anymore, so i figure put a 195 in, same problem. ANY ideas?

 

i'm stumped, oh hy, maybe you need a new radiator.

to tst your radiator remove a hose from the verry botom. all the fluid should come right out (as long as cap is off) if not, theres your expensive problem. keep us posted!!

also, if you just changed your coolent you may want to put a bucket down to catch all that coolnt, stuff is spendy.

 

Is your air deflector there? Without it it will do exactly what you say.

 

I was having the same problem. First check for the rubber air dam under your bumper. If it is in place then you only have one option left. It cant be the Ecm sending units because the fan it already on all the time. If the air dam is in place try cleaning out the front of the radiatior with a garden hose or compressed air. If that dosent help, take out your radiator and have it cleaned and pressure tested (cost around 30 bucks). They will disassemble the radiatior and give it an acid bath, repaint it and it should only take a day if you drop it off in the morning. Also keep the 195 thermostat because the car was made to run hot and the 165 will not help a stock 305 anyway...
p.s. when you go to the radiator place ask the guy who will be cleaning it if this radiator is the right size for the car. Sometimes people have it changed and do not put the right size back in.

 

"to tst your radiator remove a hose from the verry botom. all the fluid should come right out (as long as cap is off) if not, theres your expensive problem. keep us posted!!

also, if you just changed your coolent you may want to put a bucket down to catch all that coolnt, stuff is spendy." -Xophertony

Yes, when i remove the hose, then all of the fluid does pour right out. I did this a few times with water to clean out my radiator and hoses.


"I was having the same problem. First check for the rubber air dam under your bumper."
"Also keep the 195 thermostat because the car was made to run hot and the 165 will not help a stock 305 anyway... "
- 84H.O.Trans Am

This is a good idea. I do have that black plastic curve under my engine, and its been a problem latley. It keeps coming off and scraping the ground. I actually tied it to the bumber perty close, closing the pocket, so after hearing all this i will lossen the rope to have more of a gap between the ground effect and the dam.
And you guys think i should really keep the 195?, i do understand the logic, but my car will be a little hotter, i was thinking about doing this, and i think i will. These suggestions are good thank you.
Also, a side problem, as soon as i start my car, i opened my radiator cap, and i saw the fluids swirling, isn't that a sign that the thermastat is open allready? My car is almost cold that ain't right ... Ok, i'll keep you all posted. Thank you.

 

OK...so your fans are on.

The air dam in intact. Mine was falling off too so I had to pull it off and make some new holes to keep it on right.

When was the last time you did a coolant drain and refill. Sometimes if the ratio of glycol/water is not right it will cause a problem.

Also, leaks anywhere in the system will increase your coolant temp by a certain number of degrees. You'll know by the smell of coolant when the engine gets hot. Also after you park it, look underneathe to spot any leaks.


Your water pump may have pooped on you. On the underside is a hole designated the "weep hole". If you see any fluid stains around it from a leak, its a likely bet that your pump is out. I pulled mine off and installed a Edelbrock hi-flo aluminum water pump and am very pleased. The reason your temp keeps rising could be because the pump is crap and can't keep up.


So to conclude, keep your 195 stat. Check all hoses and gasket surfaces (incl the intake gasket) for any leaks or bubbling when the engine is running. Once you have fixed those, go to the pump and replace it.