My 1990 runs above 230 at a stop light has went as high as 250 and this concerns me but back on the hihgway its runs at 160 thats a big difference.Im thinking of installing a extra fan but its very tight in the engine compartment,has anyone installed a cooloing fan and if so did it help and where did you put it? Thanks for any info

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'90 should already have two cooling fans ??...one behind the radiator and a aux. fan in front of the radiator/ condenser. 230* (which IMO is hot) is NORMAL for these cars to run in the summer heat, sitting idling. However 250* is NOT normal and not good....be certain both fans are running. If the fans are both there and running..check for debri (leaves,paper/plastic bags etc.) in front of the condenser and between the condenser and the radiator. Any sort of blockage of the fins on the condenser or radiator can cause overheating. The opening at the front of these cars doesn't let much air in...but it does work well as a vacuum cleaner for sucking up road debri..

|UPDATED|8/21/2012 5:10:41 AM (AZT)|/UPDATED|

WOW!!! I agree...250* is TOO hot! 230 is fairly normal in town/traffic/stopped, but seeing 250 would scare the bejezzus outta me.
If it cools back down once you get moving, I'd also agree that you may have a cooling fan problem. You should be able to hear the fan(s) come on if you're siting in traffic, or at a light. The main fan should come on around 228 or so, but should definitely be on by 240.
The fan relays have been a problem on some year cars. If you fan does not run at all, even with the A/C on, I'd start with fuses, then relays, then check to see if the fans will run if hot-wired.


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Joel Adams  
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

My '90 was doing the same thing.  Per comments on this forum I pulled the radiator cover and found fur, bags, grease etc all over the radiator.  I got that all cleaned up (driveway was nasty!).  It was running much better at speed, but still when stopped the gauge climbed and I even had the "check gauges" light come on the dash.  I wasn't able to ever hear the main fan come on, and am not able to with my schedule to see if the relay/fuses/fan were okay.  I took it to my local dealership and they found the main fan shorted out along with the fusible link.  I had them check the radiator fluid and it wasn't very good so they did a drain and fill.  They also noted the thermostat wasn't working to well so they swapped that too.  Bit expensive of a job, but much better than a major breakdown due to overheating!

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Thanks to all for the info and i have checked alot thats been suggested except the hot wiring  of a particular fan could you tell me exactly how thats done?I have noticed that the driver side fan comes on when the a/c is on but neither of the fans come on at all even at 235 degres fortunately the car doesnt overheat but i feel that the fans are the issue and or the radiator to some degree.Ive heard of fuses and relays im not sure where their located so i can check them again any info on this issue is apprecited and thanks again

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Thanks to all for the info and i have checked alot thats been suggested except the hot wiring  of a particular fan could you tell me exactly how thats done?I have noticed that the driver side fan comes on when the a/c is on but neither of the fans come on at all even at 235 degres fortunately the car doesnt overheat but i feel that the fans are the issue and or the radiator to some degree.Ive heard of fuses and relays im not sure where their located so i can check them again any info on this issue is apprecited and thanks again

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If it is actually getting to 250 deg, it IS overheating! I would suggest that you maybe get/borrow an infrared temp gun and actually check the temps...the gauge may be wrong, and that would explain why the fans are not coming on when you think they should be on. If the fan is coming on with the A/C, then that fan, and relay are good, as are the fuses for that fan.
The ECT(engine coolant temp) sensor, which sends coolant temp info the the ECM, is different from the temp sensor, which ONLY supplies info for the gauge. Your ECT may be fine, but the temp sensor for the gauge may be flaky....


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Joel Adams  
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Previous owner installed a fan ovverride switch that allows me to force one or both fans on at any time.  That was useful when my Vette was overheating.

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Rarely indicted, never convicted

     Thanks to all for the info and im still having temp issues and from what iv read im going to remove the radiator and clean it maybe replace it and while im in there check out the cooling fans now the primary fan on the drivers side comes on only when the a/c is turned on but i dont think either fan works like they are supposed to  on their own, how do i check them? i have read that you can wire them so that both fans come on when the primary comes on but it doesnt come on as you can see this is my first vette actually a surprise birthday present from my awesome wife a 1990 convertible and it has issues but im gonna try like hell to her road worthy now that i know vettes run higher on temps im not so worried but i do need to get the cooling fans fixed plus is there a video on intake removal cause mine has a intake leak on the passenger side that must be fixed...again any and all info is greatly appreciated and im so glad i found this site cause you all help others so much and to me thats pretty cool

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Bill, I sent you some troubleshooting info, and the cooling fan wiring diagrams....hope those help. 

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Joel Adams  
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

  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.

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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. 

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Like helpos (Paul) and Vette2100 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.

Good tip, HW -- I'll give it a try too.

C.

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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Joel Adams  
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

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.

Got it this morning and thank you AA ...... Lots of good info here -- cheers for taking the time.

Colin.

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. 

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  Chipmonks?!?! ?



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Joel Adams  
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Nice Solution Taylor -- I like it.
Colin.

the screen is a good idea,i use regular window screen,very easy to clean.mid America and ecklers sell fan sw and relay to bring the fans on earlier and lower your temp.the dirt under the radiator has to be real bad to effect the temp.they normally run hot.get the kit and you will be happy.

I've heard a little about this extra "fan switch" that can be installed to control the fan(s).

I"d like to install this but know nothing of what to buy and where it installs.

Can someone explain please. I have a reasonable understanding of mechanics and electricals (have many tools) so I'm not completely in the dark.

Thanks,
 Colin.

 The Coolant fan relays are on the drivers side of the radiator (2).  1 wire from each is the ground which turns the fan on.  On 90's the primary fan ground is light blue with black and the secondary fan is dark blue with white.  Strip some insulation from each wire and wrap some # 16 wire on each separately and run to two toggle switches you have installed somewhere convenient inside car (knee bolster?)  Run one or two wires to ground.  I use the horn ground.  You can turn on either or both fans and the ECM will still turn them on also.


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stacking fans can be tricky, and my car had a plugged bleeder tube, the one that comes off of the top of the radiator (one the dealer I bought the car from couldn't figure out) I used speedo cable and a drill to clean min out and it fixed the cars over heat issues. NEXT  I installed a mechanical thermostat for the fan, have been doing this for years on most all of my cars, the fan is hooked up to run at set temp and runs when car is shut off, lowering engine compartment temps. the trick is to install the thermistor at the bottom of the radiator, this allows the fan to run for about a minute after the car is shut off. installing it around the top of the radiator is not a good idea. 

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found the bucket grommets for my 2002 headlights on ebay

What is the best way to get at any debris that might get between the condenser and the radiator? Do you have to pull the units all the way out or can you get at it and clean it out while on the car? I live in Texas and the summers get HOT and humid. My '92 Vette does as some others have said here. On summer days at 103-105 degree temps the car runs about 200-207 on the road and at a stop light it gets up to close to 230+!  Oh yes I do hear the fans coming on and always when the air is on.

Any help here would be appreciated.

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never gets that hot here in florida, I use commercial condenser cleaner. that can be found at Grainger, and Ice32 a additive that seems to lower head pressure,

variable orifice tube

now I installed one of these on my 90 gm 4x4 1500 truck and it has preformed very well with 134, but have not used one on my vette yet, it's got 120,ooo miles on her now and this summer I will be installing a new compressor, and will install one, at that time. you must make sure your ac is working at peek performance, as this is a significant heat source that can cause RUN HOT issues (driveability) 

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found the bucket grommets for my 2002 headlights on ebay

what I use is a electric fan thermostat control, the relays are on the drivers side of the radiator, and I have been doing this for years with all of my vehicles here in florida, it allows me control of the fans, and I hook it up so when the car shuts off the fan can run and cool the engine compartment off,(runs for about 2 minutes) just remember to install the thermister (probe,bulb) LOW on the radiator. If you install it on the top of the radiator, I will guarantee a dead battery is in your future.

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found the bucket grommets for my 2002 headlights on ebay

I HAD THE SAME PROBLEM.  I INSTALLED A NEW CHAMPION RADIATOR FROM PERFORMANCE RADIATOR. ALL ALUMINUM 3 1 INCH CORE AND VERY REASONABLE.  PROBLEM IS SOLVED.

LIKE YOUR IDEA AND PROBLEM SOLVING SOLUTION.  I WILL USE THAT ALSO. THANK YOU

Don't care if these motors are designed to run hot.. I haven't got the b*lls to run at these temps as you don't get a lot of warning of impending doom!

|UPDATED|7/13/2017 1:03:27 AM (AZT)|/UPDATED|


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Been through the overheat thing. I replaced the rad with a stock rad and it now runs cool all time.

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Forgot to add that I replaced the radiator too and dumped all the AC kit and just replaced the pump with an idler. Didn't mind that as it was part of my weight reduction obsession on my '87 anyway.

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Install a relay switch to activate the second fan.  I have never had a problem with overheating since

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