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Topic: Radiator Cooling Fans

in Forum: C4 Cooling and Heating Systems

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Radiator Cooling Fans (1/14)
6/30/10 9:46pm

tyharrison
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Vette(s):
1992 Corvette C4

Joined: 6/30/2010
Posts: 3

I have a 1992 C4 Corvette. One fan comes on at 227 degrees and goes off at 217 degrees. Same fan comes on when the A/C is turned on. Other fan does not come on and it is a new fan. I have checked the relay and it is good. When is this fan supposed to come on: at what temperature and when? Is there an inline fuse for the fan, because I cannot find one. Where would it be?

I also unhooked the fan that works and let the motor get to 230 degrees and the new fan never came on. At that point I just turned it off! Even with this problem resolved I would like to know how to get the temperature to run 200 degrees or cooler.

Any ideas of what is going on?

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Radiator Cooling Fans (2/14)
7/1/10 1:41pm

96LT1
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Powhatan, VA - USA

Vette(s):
1996 Polo Green LT1 Coupe

Joined: 3/20/2009
Posts: 305

Your primary fan temp is correct ( I think the spec is 225* on temp)......the secondary fan on temp is 232-233* and off at 225*

I gave a quick answer before (my bad)---i'll try to answer your questions now--the primary and secondary fan relays don't have a fuse--they both use fusible links-- try this -remove the secondary fan relay---find the terminal with the red wire--check with a test light or VOM it should be hot all the time-if it's not fusible link may be bad. If you have voltage then jumper the red wire terminal to the pink and black wire terminal (this is the power for the secondary fan ) the fan should run assuming the fan ground wire is good. If the fan runs at this point--then it's likely not getting hot enough for the ECM to turn on the secondary fan. If you want cooler operating temps the solution will be to have the ECM reprogrammed to run the fans "earlier" at lower temps. Also you may or may not know--as i and other members have said before be sure the radiator is clean inside and outside---airflow and clean radiator fins are very important. Hope this helps Smile

Vaughn

96LT12010-07-01 17:57:41

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Radiator Cooling Fans (3/14)
7/1/10 10:48pm

Adams' Apple
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Duncanville, TX - USA

Vette(s):
1985 Coupe-L98/Auto,Bright Red/Carmine. 1974 Coupe-L48/4speed, Medium Red Metallic/Black Deluxe.

Joined: 3/18/2009
Posts: 2230

Yep...the pusher/secondary fan will only come on at 230+ temps, but it should also come on at a lower temp with the A/C on, depending on the pressure switch operation for the A/C, and if the PCM commands it. The pusher on my '85 will come on at idle, with the A/C on, if the high side of the A/C gets up there due to engine temps in the 225 range.
230deg on these engines is not "too hot", even tho that goes against everything we learned in the old days. These engines were designed/engineered to run with elevated engine temps...which is the main reason they started specifying Mobil 1 oil. Running one too cool will actually cause more wear on it.

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Radiator Cooling Fans (4/14)
7/5/10 7:45am

C4Shane
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Charlotte, NC - USA

Vette(s):
-1993 LT-1, Coupe, 6speed, white/black -1986 L98, Coupe, 4+3, Black - SCCA TT Racer -1979 L48 Coupe, Auto, Red/doeskin

Joined: 5/15/2010
Posts: 26

These fans do come on at a high temp - and that is what GM wanted for a variety of reasons. But, Mid-America Motorworks does sell a kit that lets you switch on the fans manually. I have it on mine for when I am in hot summer traffic, and it brings the temperatures down nicely.

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C4s: 1993 LT-1 coupe, 6-Speed, White w/black 1986 L-98 Coupe, 4+3 Trans, Satin Black w/red-black interior - SCCA Time Trial racecar.

C3: 1979 L-48 couple, auto, Red w/doeskin interior.

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Radiator Cooling Fans (5/14)
7/10/10 9:42am

tyharrison
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Vette(s):
1992 Corvette C4

Joined: 6/30/2010
Posts: 3

To Vaughn,

I just joined and am having trouble replying to those who have answered me. I wanted to thank you for your information. I installed toggle switch under my spoiler and will turn it on mannually each day. I also thank you for telling me about dirt between the radiator and condenser coil. There is dirt, it looks difficult to clean out. Any suggestions on how to get to this area??? Another great piece of advise is programming the EMC....where is this located?? Do I need to take it out?? This seems to be a good idea. I do not like it running so hot. This is a great site and I am thankful for all the advise. Parts house says I have a 180 degree thermostat but I believe it's got a 195 in it. I would like to change it when I have the EMC programmed, would like it to run 180 or so. One of the reasons I am wanting to cool the car down is I have a front main that leaks and it doesn't seem to leak at cooler temperatures.

So glad I found this site. You guys have been very helpful and it is much appreciated........Ty

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Radiator Cooling Fans (6/14)
7/10/10 9:45am

tyharrison
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Vette(s):
1992 Corvette C4

Joined: 6/30/2010
Posts: 3

Thanks Joel for the advise. I appreciate all your help. Hope to keep in touch. Just joined this forum and I am glad I found it. ......Ty

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Radiator Cooling Fans (7/14)
7/10/10 10:49am

96LT1
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Powhatan, VA - USA

Vette(s):
1996 Polo Green LT1 Coupe

Joined: 3/20/2009
Posts: 305

Your best bet on cleaning the radiator would be to remove it and use a garden hose to clean out the crud in the cooling fins---maybe using a cleaner such as "Mean Green" to help loosen the dirt. Don't Scrub or clean the fins by hand or use a pressure washer (some are strong enough to do damage)---this will also give you a chance to clean the AC condenser fins in the same way while it remains in the car.

The OEM thermostat for all LT1s was 180*--they are also made/shaped different then other small block chevy thermostats --they were designed for the LT1 reverse flow cooling system and ONLY the LT1.

The ECM--- assuming all LT1s are the same (i'm not positive) should be under the hood/left side close to the firewall and above the battery. It would need to be removed and sent to one of the many online companies and reprogramed to run the fans at a lower temperature. One company popular w/Vette owners is "pcmforless"--but there are many more online. On the later C4s ( i think 95 & 96s) buying a handheld programmer would be a option, but as far as I know-- no one offers one for your '92. hope this helps.

Vaughn

PS--- didn't mention it (likely goes without saying)---but reprogramming the ECM would elimanate the need for the fan "toggle switch" Smile

96LT12010-07-10 07:55:03

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Radiator Cooling Fans (8/14)
7/10/10 11:34am

[QUOTE=tyharrison]I just joined and am having trouble replying to those who have answered me. [/QUOTE]

What sort of problems are you having, as far as replying/posting? Please P/M me if you are still having trouble.

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Joel Adams
My Link

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

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Radiator Cooling Fans (9/14)
7/10/10 9:30pm

eddie20890
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lanoka harbor, NJ - USA

Vette(s):
1990 L-98 white/ red/black leather interior targa top auto 1975 L48 blue/black leather interior t tops auto

Joined: 3/22/2009
Posts: 1363

as far as reprogramming the ecm on my 90 it has a prom in it and you can have a chip made that goes in between the prom and the ecm with all the changes on it. this way you can use the car until the chip arrives and then just install it and if you ever want to go backto the original settings you just have to remove it.don't know if it's the same on newer models.

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Radiator Cooling Fans (10/14)
8/12/10 11:19pm

VIN_#_00521
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Omaha, NE - USA

Vette(s):
Early production C4 Corvette Coupe ( 02-20-1983 is the production start date )

Joined: 8/12/2010
Posts: 5

I have a 84 C4 with CFI the fan will not come on @ any temp and it will heat up unlet i turn on the fan manually i now have it connected to a swith under the dash and i cant rely on the engine turning it on, so i will turn it on at start-up sometimes i dont need to since im moving at highway speed ( 70mph ) and it is steady temp of 207 degrees I have a new relay and a new temp switch it still wont turn itself on-------- is there a way to mount a fan in the front somewhere one out of a savage lot car ? one that I can switch on as a pucher fan for in town driving and not have to worry about the main fan turning on ? what else can I check for this ? it wont come on at temperature ( which is ??? 234* ? ? ? ??

Need some help on this anyone in the omaha area ? ?? ? come by and help me fix it ?

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Re: Radiator Cooling Fans (11/14)
6/14/16 4:21pm

1994 Vette
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Magna, UT - USA

Vette(s):
1994 Sting Ray, Dk. Red, Auto, 5,7 L.

Joined: 6/14/2016
Posts: 5

My 94 C4 coup 350 began heating up but not boiling after my wife and I arrived on a 350 mile trip to Idaho. Both of the cooling fans and AC was working fine. I took my Vette to a Chevy dealership in Nampa and had a radiator flush and a new thermostat installed. This seemed to solve the problem. I also had an oil and filters change and when I got home I found that the mechanic had forced the shorter air filter bolt in the wrong air filter hole and separated the plastic knob from the bolt. I had to order a new one from Zip Corvette parts, you would think a mechanic would know his job.

|UPDATED|6/14/2016 1:21:29 PM (AZT)|/UPDATED|

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Re: Radiator Cooling Fans (12/14)
6/15/16 12:11pm

TLAVAC
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beaufort, SC - USA

Vette(s):
1990 Turquoise Corvette (his) & 1990 Turquoise Corvette (hers)indy festiville car for sale

Joined: 9/1/2009
Posts: 37

ok when the engine runs hot,you loose power and waist fuel.I have owned my 90 c4 since 92 and my wifes 90 c4 since 2000,they both have a power stat and low temp fan sw 185deg on 170deg off.I also have a power stat of 160 deg .both cars run stronger and cooler with better fuel mileage and hpThe part#244481 sw and wirung,244427 160 power stat from Corvette Central.These parts are good for 86-95c4s.good luck.TLAVAC

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Re: Radiator Cooling Fans (13/14)
7/10/16 6:11pm

VegasVet
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las vegas, NV - USA

Vette(s):
Custom stalker kit, modified engine, new paint

Joined: 3/18/2014
Posts: 12

What is power stat?

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Re: Radiator Cooling Fans (14/14)
7/13/16 1:18pm

wolfuser
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Vette(s):
1987 C4 convertible 350ci auto white / red / white top appx 18k mls

Joined: 11/15/2012
Posts: 13

if you dont change the thermostat to (say) 180deg, there is no point in reprogramming the ECU, as the fans would fight the thermostat which tries to get something like 195degs.

180degs should be ok and giving peace of mind. dont go below that or the engine will think it s too cool and enrich the fuel mixture. I ve rigged a switch into the interior to manually turn on one fan or the other, as I dont think it s doing a large engine like the 350 V8 any good to see temp fluctuations between 230 and 180 degs as soon as one enters a town or something.

cheers

Wolfram

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