Topic: my 1990 runs above 230 degrees
in Forum: C4 Cooling and Heating Systems
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Thanks so much for this info i will check it out but from what ive seen this is great info and the location will help me a great deal also....thanks again and i will be posting pics of the car hopefully soon have a great and safe day

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As Stated clean your radiator, check all relays and fuses. During the summer I run straight water and wetter water, I changed stat to 160 and had ecm reflashed to turn fans on early, never get above 175/180 sitting in traffic.
Vette2100
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Vette2100
I wouldn't get too concerned about running 230-240 at red lights if the A/C is running. However if its running that hot while the car is moving there is a problem that can be solved and it won't cost you a fortune. I live in Mesa AZ and it is VERY HOT. The only time I get that hot is at lights with the A/C on. On Corvette Forum I was beat up by its members telling me how stupid I am. If you want to learn from my experience get on ebay and buy a American Eagle 2 row radiator all aluminum 1" rows. Delivered to your door less than $200. Made in China yes but a quality product. The Dewitt radiator costs $550+ shipping. Your choice. If you do this job replace all the hoses while you are right there and prevent any BS. Run 50/50 and enjoy the ride. I ended up replacing every single part from the water pump to the radiator. I spent over $700 in parts and labor. However I won't have anymore issues with it at least not anytime soon. My fan comes on at 190 degrees. The auxiliary comes on at 230+ or when the A/C is turned on.
Like helpos (Paul) and Vette2100 said:
Check for debris on your radiator. I have read a while ago that a make-shift vac attachment can be made by gluing a 3/4" PVC elbow to a length (?) of 3/4" PVC pipe. Glue adaptors to increase the diameter of the pipe so that it can be attached, or at least duct-taped to your shop vac.
Work the tool up from below the radiator and vacuum away.
Adams' Apple said: Bill, I sent you some troubleshooting info, and the cooling fan wiring diagrams....hope those help.

If you would send me that trouble shooting info I'd much appreciate it Adams' Apple.....
I'm having much the same problems as Bill is.
Thanks
Colin.
hwatkins said:
Like helpos (Paul) and Vette2100 said:
Check for debris on your radiator. I have read a while ago that a make-shift vac attachment can be made by gluing a 3/4" PVC elbow to a length (?) of 3/4" PVC pipe. Glue adaptors to increase the diameter of the pipe so that it can be attached, or at least duct-taped to your shop vac.
Work the tool up from below the radiator and vacuum away.
Good tip, HW -- I'll give it a try too.
C.
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Vette(s): 1985 Coupe-L98/Auto,Bright Red/Carmine.
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cco said:
If you would send me that trouble shooting info I'd much appreciate it Adams' Apple.....
I'm having much the same problems as Bill is.
Thanks
Colin.
Adams' Apple said: Bill, I sent you some troubleshooting info, and the cooling fan wiring diagrams....hope those help.

If you would send me that trouble shooting info I'd much appreciate it Adams' Apple.....
I'm having much the same problems as Bill is.
Thanks
Colin.
The info I sent was specific for the '90, but I'll send it your way...most of it might be the same as yours. If not, lemmie know, and I'll get the "correct" info for your year.

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The 90 and 94 cooling fan systems are different.
The 90 has an ECM controlled single fan, single speed main fan, and the switch controlled B4P boost fan in front of the condenser.
The 94 has dual main fans, no B4P boost fan. The main fans are arranged in a Lo-Hi speed configuration using 3 relays, both controlled by the ECM.
The circuits are very different.
The 90 has an ECM controlled single fan, single speed main fan, and the switch controlled B4P boost fan in front of the condenser.
The 94 has dual main fans, no B4P boost fan. The main fans are arranged in a Lo-Hi speed configuration using 3 relays, both controlled by the ECM.
The circuits are very different.
Adams' Apple said:
The info I sent was specific for the '90, but I'll send it your way...most of it might be the same as yours. If not, lemmie know, and I'll get the "correct" info for your year.
cco said:
If you would send me that trouble shooting info I'd much appreciate it Adams' Apple.....
I'm having much the same problems as Bill is.
Thanks
Colin.
Adams' Apple said: Bill, I sent you some troubleshooting info, and the cooling fan wiring diagrams....hope those help.

If you would send me that trouble shooting info I'd much appreciate it Adams' Apple.....
I'm having much the same problems as Bill is.
Thanks
Colin.
The info I sent was specific for the '90, but I'll send it your way...most of it might be the same as yours. If not, lemmie know, and I'll get the "correct" info for your year.

Got it this morning and thank you AA ...... Lots of good info here -- cheers for taking the time.
Colin.
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Posts: 90
Vette(s): 87 Red Coupe, not as pretty, had 213G miles, great running engine; got 20-21 around town, 27-28 on hwy; I got to drive a Vette, every day for 6 yrs. It was my first; so now I know what the fuss is all about. (Sold it 2015 for $3000, still ran great.)
C4 were designed to run over 200, even 215-220 isn't really "hot" for them, but a normal system will run 195-205 on the road, 10-20 higher in stop+go traffic (or Arizona summer, or in Death Valley, same difference...). It looks scary, but it seems to be OK, within those limits. Unfortunately, our air dams suck leaves, dead birds and chipmunks, and other road kill/debris, along with air, which assaults the front fan, dents the fins in the radiator, and gets between the radiator and condenser, so they can't breath (or cool your engine).
After you get both fans working, or replaced, plus relays, then make sure the leaves and feathers and crud between the radiator and condenser are cleaned out, or replaced, as mine had to be, then you should put a screen between the road and your fans+radiators to keep the road kill from killing your cooling system, again. There is at least one cheap solution to this problem, which is a problem common to all C4s, which is to go to Home Depot or Lows or 84 Lumber and get a piece of leaf guard gutter screen and screw+zip tie it across the opening, so the air dam can still suction air, without the damaging debris.
Just saying....
in Forum: C4 Cooling and Heating Systems
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