Ok....

'92 RS 305 TBI

Single Fan Cooling System...

I recently replaced the radiator...Before then, I had no problem with overheating...the car never reached 220F, unless in traffic, even then it didn't pass the 220 mark...No aftermarket mods whatsoever...after changing the rad...the car started overheating...The fan won't kick in at all!! I've already changed the CTS (2ice), Fan Relay and the Fan Switch...Nothing has helped! I was getting a code (15 I think?) when the CTS went bad...this time I get no codes...I ran the fan direct and it comes on...If I turn the A/C on...it will kick in..but it won't kick in by itself...Another thing...after it gets hot, it wont cool down even at highway speeds! I think the solution to that would be to put in a new rad. My dad insisted on a junkyard one so I let him get one from his buddy ...(bad choice in my opinion)...could that be why it wont cool down at high speeds?? Remember, before changing the rad...I had no problems w/overheating...What could be the cause of the fan not kicking in??? Right now, I've got it wired with a switch, but I want it to work the way it is supposed to...the fan fuse is still good...is there anything else...sensors, fusable links...or something else I should check?? Please help me out...I dont know what else to do! I haven't had any luck in the archives so far (by the way, air dam is in place & good)

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"WARNING: Objects in mirror are about to disappear VERY quickly!"

 

What is stopping you from reinstalling your original radiator if you had no probs?

Since you installed one that may have been sitting around did you have it cleaned? It may have blockage.

Otherwise you may have waterpump problems, or even something as simple as your radiator cap losing pressure. Bottom hose collapsing. Thermostat probs.

 

Did you ever change your thermistat????? Sounds like that could be a problem at higher speeds????

Code 15, isn't that "Coolent Temputure sensor voltage to LOW" Meaning that when you put in a fan "switch", it's not a thermistor but rather a switch, a thermistor changes resistence vs. temp so that the voltage going through it will change so that the computer knows coolent temp and when to kick in the fan.

I think your car does not have a fan switch if it's like my 1992 RS with single fan, the computer controls the fan, and the fan will not kick in till temp reaches 230F, yep no kidding 230F sucks but thats GM for you, if you want to change this you have to get after market chip with a lower temp setting. No way around it, also check both relays, the A/C relay is the black round one and the engine fan relay is the one that looks like the fuel pump relay.

I would also get the radiator cleaned at a shop to make sure there is no blockage. or corrison or soder bloom.

 

I changed the radiator because the plastic tank broke...it leaked water as soon as it got pressurized...that's why i changed it...i changed the t-stat...i still cant figure the electric prob out!

 

Try replacing your radiator cap, they are cheap, also check to make sure your thermostat housing isn't leaking, this will cause a loss in pressure causing your car to overheat.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat
2:73 GEARS
Rebuilt 700R4, with manual valve body
B&M Megashifter
Soon to be installed
Exhaust Cut-Out and different gears, either 3:73 or 3:42
"There is nothing more addicting than speed"

 

Get a cowl hood to let out a lot of hot air.