93formulabird

iTrader: (2)

k guys my car overheated once in traffic because the fans never kicked on. I found a fuse which was blown in the engine bay box for the "A/P - Fan" and replaced it. That made it so the fans kicked on when I would turn the A/C on but that was it. I recently replaced my waterpump and replaced the Coolant temp sensor which is inside it. My fans still do not turn on at all(except when the A/C is on). I waited until the engine got to 230-240 ish and still nothing. Checked all relays for fans #1,#2, and #3 all work fine. They do not turn on when I jump the #5 and #6 cables on my OBDII port also.

What else can I do?

Car is a 1996 Formula lt1 w/ only 30k on it.

Something tells me the answer is behind what caused that "A/p - Fan" fuse to blow, but I dont know.

BlackBirdWs6Zzz

iTrader: (6)

Boy let me tell you i am having the same problem. I have the same year 96 LT1 Ws6 and the same thing happened to me. I happened to be sitting in the parking lot with the engine running for 15 minutes i suddenly looking at my temp gauge and bam it was way in the red zone, i shut it off IMMEDIATLY and the cap cracked and shot coolant all over the engine back, and it created a small crack in the radiator. I replaced the cap and radiator and later found out it was because my fans aren't turning on when they are supposed to. Read my two threads here

https://ls1tech.com/forums/lt1-lt4-modifications/486216-relays-gone-bad-already.html

https://ls1tech.com/forums/showthread.php?t=486216

These should help you. I just happened to buy a manual switch setup for myself today. Someone suggested it may be the computer "forgetting"/malfunctioning" and just NOT turning on the fans when it's supposed to. They said this could be fixed with a tune. I plan on getting a tune after so for right now I am going ahead and installing a manual switch to turn on my fans when i want. I also just replaced my A/p fan fuse (25) and it just did the AC fan. I replaced my relays with new ones from auto zone for coolant fan #1 and #2. Here is a link to where i bought my manual switch. https://ls1tech.com/forums/showthread.php?t=486216

It's cheaper then the "SLP" crap which was like 80 bucks (yeah right)

It may take 2 weeks as it says because they are customly made so....but i do mostly highway driving so my car cools itself on the highway. Good luck and if you figure it out please PM me and let me know! Hope this helps! We seem to have the same exact problem!

SIDE NOTE: I though LT1's had OBD1's?????????? You have a OBD2? Maybe I'm wrong?

infinitebird

iTrader: (11)

If the computer is not turning them on at all then a tune is not going to fix that. There has to be some kind of issue causing that.

96+ is obd2

93formulabird

iTrader: (2)

wow that is interesting how we have the same problems. Its very frustrating. I suppose I will look into getting that fan switch but It would be nice to have the pcm be able to turn them on. I can see myself forgetting to flip the switch and the car overheating again..lol

93formulabird

iTrader: (2)

Well if the fans turn on w/ the a/c on then the computer must know how to turn them on its just not doing it at the correct temp or something. If a tune wont fix it what will?

infinitebird

iTrader: (11)

I don't know but there's nothing in the pcm that says to only turn on the fans with the ac.

BlackBirdWs6Zzz

iTrader: (6)

The thing is when you turn on the AC its basically "a switch to turn it on"
I believe only ONE fan comes on for the AC.

Not so much a tune will fix it but a "reprogramming" of the computer may fix it. I don't know how much this will cost etc. But we are having the same problem. So for now i reccomend the switch. But i think its DEFINITLY the computer. cuz i JUST BOUGHT BRAND NEW relays and it still didn't work. But here is the thing. My buddy had a test liight and found the ground and power hole in cooling fan 1 and stuck just a simple speaker wire in each and bAM the fans came on.......so its weird!

Also if you get it tuned, you can tell them to tune it so the fans come on earlier, as early as you want i guess. I'm putting my 170 stat back in this weekend.

Lethal Z

This is a computer problem. As stated in another thread. I checked everything, fans, relays fuses, fuseable links everything. ECT sensor replaced, even the temp sending unit. Nothing, the only thing that would cause the fans to come on is when I turned on the AC. In the end it was the computer. I wish I had an answer why but it was definately in the computer. As soon as I swapped computers the fans kicked on normally when the car got to temp. Short of the fans not comming on, the old computer worked fine but it would not turn on the fans. This obviously is a common problem because there are way to many places I've found on the net that sell kits to manually turn on the fans.

BlackBirdWs6Zzz

iTrader: (6)

That is very true! thank you for your feedback! Now is there another way to fix this instead of swapping computers? Where can this be fixed to reproggram the computer and HOW MUCH will it cost. I already have my switch on the way but it would be nice if i forgot if they came on like they were suppose too. Thats not asking much is it!

Lethal Z

Yeah I hear ya. Im still trying to research and find out if there is a way to correct this without swapping the computer. I just recieved my set of service manuals from the dealer. I'll post anything I find out.

geedub6893

I dont think my fans work either... my car runs at 210 all the time it does get close to 220 when i am sitting in traffic though... i jumped my fan to the battery and they come on but i still cant get them to come on... not even my ac will turn them on

BlackBirdWs6Zzz

iTrader: (6)

Looks like this is a universal problem!

67SS&99SS

iTrader: (7)

Did you replace the sensor on the driver's side cylinder head? I think that one is the one that goes to the gauge in the car. I replaced all three relays, that sensor, thermostat, water pump and the sensor on the water pump on my uncle's 94 Z28 before it would start cooling right. I think his main problem was the waterpump though. 1/2 the bearings were gone in it. lol. You may want to flush the coolant too. Dexcool tends to gum up the radiator and the block if it isn't changed often enough.

7901 WS6

iTrader: (6)

I am glad this thread came up, cause I having a Cooling issue as well. Can some one tell me what fan is the primary and which is the secondary? My t/a runs at 200 ish temp, and in traffic or stop lights it will start climbing up to 210, and the pass and go to 220ish. I never hear the fan come on, but at idle I left it run when i was in park and popped the hood to check the fan moving if it was operating. The driver side one was not, however it looked passanger one was not sure though, but my temp started to decrease, back to 210. I swear though out on the road it was staying up a 220ish for awhile, and I was starting to smell somthing in the car, and got concerned. What is the stock temp for the fan(s) to operate at?

infinitebird

iTrader: (11)

Your fans do work if it does not get over 220.

To everyone that thinks their car is overheating:

If it doesn't get over 235, then that is normal behavior.

The stock settings are:

FAN 1 ON: 226
FAN 2 ON: 235
FAN 1 OFF: 221
FAN 2 OFF: 230

It sounds like a lot of people who posted in this thread are experiencing the normal high temps the lt1 runs at stock. I think the thread starter has a different problem though, as he stated that no fans came on even at 230-240.

Also, normally you cannot hear the fans while driving (I can't really), that doesn't mean they are not working.

I highly recommend getting a tune so the fans come on sooner. My car never got above 195 after I changed the temps for the fans.

93formulabird

iTrader: (2)

Any know if a tune will fix my problem w/ the fans not coming on at all? I know they are not because its gotten clsoe to 240-250ish.

BlackBirdWs6Zzz

iTrader: (6)

I would say YES. Do yourself a favor and put in a 160 or 170 degree thermostat (don't worry, they are only like ten bucks and you can do it yourself very easily ) and when you get your tune, tell them to program it so your fans come on 180 or something. So no matter what it will always be cool. To tell you the truth I don't like it hitting 210 degrees at all. Makes me worry. It makes me feel more comfortable when it's just above 160.

INfact i will be putting my 160 deg thermo back in this weekend so i won't have to worry. Cuz if my temp is already at 200 and it starts to overheat, its going to overheat that much quicker because i'ts already half way there.

Hope it works! Let us know what happens!