89IROC5.7

I know a lot has been said about this, but there is some conflicting info on what temp is normal for stock. I have an 89 IROC 5.7TPI with dual cooling fans that runs perfectly cool with just a little forward motion to get some air in. in traffic, however, the primary driver's side fan will not turn on until around 235 or 240 degrees.I have a manual switch, but that seems kind of a crappy fix. I want to keep the car in mostly stock configuration, with the standard 190 degree thermostat--I just want the fans to come on not so far after that. If I buy the popular Hypertech switch that turns them on at 200 and of at 185, won't they just stay on all the time with my current thermo? I replaced the Coolant temp sensor in the manifold. Should my ECM be turning the primary fan on sooner or is their something broken? What can I do to have the fans work with a stoch thermostat at keep it under 220 or so? Thanks guys...

Dan91Z

220 is right around where it should be in traffic for a stock one..

89IROC5.7

should the fan not start until 240 though or is this a problem

Guest

The fan is set to come on at 226 degrees according to the stock 89 chip I have, and turn off at 220.

If it doesnt turn on until 240, that sounds like a problem to me.

West Coast GTA Man

The Hyper tech switch you are talking about is designed to go with a 180 degree thermostat. I just installed the Hypertech switch (The one you are talking about), but instead of a 180 thermostat, I installed a 170. The car runs great, and seems to stay around 170-185 degrees on my gauge.(But who knows how accurate my gauge is) It is the best thing I have done. I think 220 degrees is ok, however, mine was not just staying there, it was creeping up to 235-240. I feel that is too damn hot. I believe from the articles I have read that the fan should come on at 234 with the stock switch. If I put the air on in my car, both fans come on. If I have no air on When I start the car, the driver side fan automatically comes on, and when it gets around 175-180, on my gauge, the passenger fan comes on. I don't think this is correct either though since the fan is not supposed to come on until 200 degrees with the hypertech switch I just installed.(But my gauge might be reading low) I don't think that the driver side fan is supposed to come on immediately when I start the car either, but the car is running cooler, so I am happy. I have noticed, that with the air off, when I start the car, the driver fan comes on, and if I pull over a few minutes later, it is off, and if I watch it for a minute or two, it comes on. But I can't drive with my head under the hood! LOL So it is hard to see what is going on all the time. These fans can be tricky, and confusing. At least to me! HyperTech also sells a switch that comes on at 185, and is supposed to go off at 165, but you and I know, that that sucker will never shut off.
take care man & good luck
Mike


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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber).

89IROC5.7

sound like some good advice. thanks guys

MikeInAZ

When GM calibrates for "normal" op temp they are calling for 90°C which converts to 194°F. Which would explain why GM installs a 195° thermostat as their choice for stock.

On my 86 single fan T/A setup fan turn on temp is 234° by design so a fan coming on at 240° would not be unrealistic, however I agree with Madmax, it might indicate a problem.

By design or not GM's "temps of choice" are too hot. If it were my car I would drop in a 170° thermostat and get an adjustable fan relay and set it to come on 20° higher at 190°.

West Coast GTA Man

Hey Mike in AZ, how are you man! Good advice! I am going to do that next! Did you get that Radiator info I sent you??
C-ya
Mike

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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber).

Vader

Hey, Mike!

The upgraded PROM has a turn-on at 107°C (224°F), not 234°F. Another benefit!

Got a TPI on that '53 yet?

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Later,
Vader
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"Let the bodies hit the floor!"
Adobe Acrobat Reader

87CamaroChris

If you don't mind me asking, where does someone get a 170° thermostat?? Just asking because I ordered what was supposed to be a 170° t-stat (AC Delco part number I used was 10220957) but when it got here it had a "180" stamp on it.

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1987 Camaro Sport Coupe
305ci 4bbl (LG4)
3.23 Gears
THM 700-R4 Automatic Transmission
All Stock

MikeInAZ

87Camaro I got that part number from Willie's article. They probably substituted for you. GM Parts Counters really freak when you order this part. They are so "application oriented" they want to know what year, what car, etc. As far as I know it is the correct number. Many people have received this part.

WestCoast: I'm doing well in New Mexico now. I'm pretty sure I got your info and thanks.

Vader: Thanks for the update on the temps on the upgraded PROM. Glad GM finally took at least a step towards reality......LOL.

I really do want to put a TPI in an older truck actually and I have some ? for you.

But NOT my 53 Trans Am. There was only ONE of these made and I want to keep it near stock. I'm pretty sure it's worth several million dollars.

Vader

Mike,

Aren't you concerned about the dust, hail, and infamous New Mexico rock storms? I'm reserving a slot in the garage to safely store your '53 TA, out of the elements and heated in the winter. I'm sure it would be a LOT safer here. Just leave the keys so I can just "start" it once in a while to keep the seals wet. The weather is great for a short 2,000 mile trip right now....

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Later,
Vader
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"Let the bodies hit the floor!"
Adobe Acrobat Reader

89IROC5.7

hey vader, do they have an upgraded PROM for the 89 IROC 5.7TPI? how would i get that from GM?