I have a 89 RS 305 TBI and mine runs cool all day on the highway but as soon as it hit stop and go its heats up to 230-240 It has the single stock electric fan with new fan motor but its not sufficient in stop and go...Also the air damn is in place but it was cut before i had the car to the same length maybe even shorter than the half barrel thing infront of it due to scrapping on dips....Does that make a big Difference?? Also It runs this hot with the A/C back when I didnt have A/C It didnt do that itll only get up to about 185-190.....Parts New Stock Radi. and Water Pump New Rad Cap new Fan Motor

 

bump

 

a 180 degree t-stat should help dramatically.

My RS used to get pretty hot (around 220) in traffic until i got the 180* tstat then it never really gave me a problem.

 

I had the same problems you have until I did the following, changed thermostat to 180 with 3-3/16 bypass holes(Summit EMP-301), Jet fan switch, turns on at 200 off at 185 (also Summit) 1 bottle water wetter and my temps stay down unless going uphill, then maybe 220 until I level out. To get the temps down a little more, I am changing the thermostat to a GM 170 and drilled 4 1/4" holes around the perimeter, changing to a Painless fan switch on at 185 off at 170 and of course 1 bottle of water wetter. Changing the fan switch and stat is a must to reduce temps. Your air dams work at speeds over 30 or 40 mph and should be intact and correct to run cool at freeway speeds. Also, put the trans in neutral when stopped if you have an auto trans. GM engineered these cars to run hot, I think the stock fan switch comes on at 234 degrees so if you want temps down, you have to change the switch.

 

Good Ideas guys but the thing is I already have a 160 Degree thermastat in it...Also My fan Is wired to always run when ignition is on....GM'S design as far as the single electric fan sux it has like no shroud to tunnel all the air...Any Ideas? Like i said my air damn is actually shorter or the sam size as the barrely thing in front of it...can i buy a higher cfm fan? If so from were and what cfm age?
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OOO Also One detail On a typical summer day here outside can Hit 110 degrees today it was 107 so yeah

 

That air dam might not do much in slow traffic but you should definetley fix it. The dealer sells the part for around $35 last time I checked and it should stick out below the half barrel thing, that way it can actually catch incomming air.

 

You are not using a remanufactured water pump are you if so throw it in the trash. Remanufactured pumps are POS. I had one once and it did the same thing. Buy a new pump always. Definitely use Water Wetter.

 

Brand New Water Pump non reman...Is there any way to push more air through the nose? Or what kinda fan can I buy as far as CFM and Brand And were?

 

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BUMP! Guys I need help here!

 

If everything is working correctly the stock fan should be more than adequate.

Did this start when you changed water pumps? There are two rotations, one for v-belt one for serpentine.

Replace your air dam. It is THAT important.

You've replaced the radiator? Did you check the A/C condenser coil for cleanliness?

Running A/C will make your engine temps higher. It's an additional load on the engine and the condenser raises air temps going into the radiator slightly. Has it actually over heated, ie boiled over?

 

Ok Ill change the air damn..No this started before I changed everything as a matter of fact that is why I changed everything...Also the condensor iis clean....It is serpentine...Im running out of things to do..if the air damn doesnt fix it then I dont know what will....Any other ideas?