Hey all,

First let me say that I have a brand new radiator, new T-stat(180), new cooling sensor and brand new coolant mix. Both fans work as they should.

My '91 L98 has been hovering between 220 and 240. Now that the summer is pretty much over, it has been cooling down somewhat but still hangs around 220 even when on the freeway.

It's really driving me crazy.. The car is pretty much stock so mods aren't the issue. There's no loss of pressure or power so my heads seem to be ok.

any suggestions?

 

Do you still have the air damn under front end? How about radiator shroud? Both are necessary for effective cooling. Other problems could be air in the system, thermostat stuck open (coolant moves too fast through the radiator) or even bad radiator cap not allowing system to pressurize correctly.

 

That's normal. It will continue to run that hot unless you make changes, like an all-aluminum radiator, lower thermostat, run the fans independently from the computer,.etc. I think you said you put a 180 stat in there. It may be too low for the factory set-up. They were designed to run w\195 stat. When my car was stock, if I put a 180 stat in, the car would run very hot, because the water wasn't staying in the radiator long enough to cool. Hope this helps.

 

The radiator shroud and front air dam are still there and in great condition.. I correct myself with the T-stat.. it is a 195. I'm looking at the packaging right now.

 

Might try a 180* Also (often over looked) Get under car and sqeeze the bottom hose end to end and see if it will pinch flat. Being that your getting hot running down the road, Your pump is probably sucking (for lack of a better word) your hose flat, therefore reducing the flow of coolant when your thermostat opens. Your bottom hose should have a spring coil in it or be of the ribbed type.

 

The lower hose is about 2 months old as well as the water pump.. I had to replace that one on the side of the road. Let me tell you what fun that is in Az Summer heat at around 1pm. SCORCHING..

 

I would still check it! It might be wrong. If you can sqeeze it, it aint good. U did put the thermoustat in with the copper side down right?

 

yup

 

I used to live in Az. Stationed in Ft. Huachuca in 71-72 you sure don't want to leave those tools in the sun! Man I don't understand why your car is so hot! Mine never got that hot. Running down the highway it always ran ex. temp as the thermostst I had in it. A 180* stat. should work ex. in that area!
Still, after you have got the car good and warm, sqeeze that hose! if you can get it flat, I garantee that's your problem! With the new pump, them. and radiator you wouln't believe how fast it will suck the coolant through the bottom hose when the therm. opens. A good sign that it's happening is it will run hotter at highway speeds because of the engine RPM. Only other thing I could suggest is your temp. gauge is off. Especialy if it's the factory dash gauge. A new sending unit or after-market gauge might be in order.

 

Thanks .. I'll try what you've suggested. Thanks for your help.

 

Its kind of funny we went over this today in class, and the professor said the thing most overlooked in a heating situation like this is if the gauge is reading correctly or not.

We have a drag car at our school and the temp gauge kept going to 240-250 and none of the professors could figure it out, so they threw new parts at it. (new this, new that, changing parts at random hoping something would fix the problem).

Our heating and A/C instuctor told them "forget the gauge, is the motor really overheating? can you smell it, when you take an infared reading is it too hot, is the coolant boiling?" The answers to all normal indications that the engine was overheating, besides the gauge was "NO"

It ended up being a bad ground on the gauge causing resistance in the electrical and causing the gauge to read too high...

check the gauge too

 

I believe I already suggested that!
BTW, sweetS10v8, Are you following me? And, is that your 89 form? Looks nice! I've got an 88, Did yours come with the WS-6?
Only diff., I've got the wimpy 305 but it kicks on the auto-cross track! I think Formula's and T/A's were intended for road racing more than drag racing though, at least from the factory's point of view.

 

Yup, thats my car. Found it in NJ, no door dings, rust, or dents. Perfect. It just had the typical bad paint, and blue smoke. So I flew out and got it, drove it home had it painted. Then threw on some Zaino, and this is what I got. I love the car, and still running like a champ with 147,000 miles on her. I wouldnt believe anyone if they had this car and said it had 147k on on it. It also came with a folder about an inch thick of records of every oil change, lube, coolant flush....etc (even the oil filter part # used, lol)

 

I have a 160* in mine and the second fan wired to a switch at my control. The best I can get the temp to stay at is 200. I have tried everything, that is the best I can do unless it is 40* outside. If a run a 180* it runs at about 220*. I was told I was doing good.

 

EVERYTHING? I don't think so, or you wouldn't be running hot!
If you haven't replaced the radiator yet, It's probably half pluged up with crap! If you have, then you must need more cooling capacity (larger radiator). I found my radiator was half pluged when I blew the end tank seal in an autocross last year and when I replaced it and a 192* thermostat it runs down the highway and in town at 170-180* BUT, that's with a 305.
Your radiator needs to be larger so it will have the coolant capacity for your modifications. Also, it doesn't make much sense
to put a 160 or 180* stat in if your fan switch is set to come on at 212* Even with a manual switch, if the capacity isn't there you won't have enough cooled coolant to replace the coolant that the engine wants evertime the stat opens.

 

No, it is a 3 core high flow alum raditator. Better than the ones they put in vets.

 

I see! Are you running an aux. trans. cooler? Everything in your sig. makes heat, High stall, steep gears, supercharger, especialy if you have raised the boost level, and bored the block. I would be happy to keep it at 180-200*. If your not running a trans cooler, you might try installing one before the radiator to help cool the fluid before it goes into the radiator. I am by no means a wizard, but if I knew your exact set-up I might be able to help with something you've overlooked.
Kewl?

 

It is supercharged running 8 psi. I also have 3.73 gears. No aux trans cooler. It probably wouldn't hurt though.

 

5 to 10* sound good? Hot tranny fluid going through your radiator is like puting a heater on the end of the tank. The larger the cooler, the beter it cools, so go for the big one!

 

Thirdgen cooling systems are terrible. Start by removing the factory fans, (even the dual fan setup) and placing them neatly in the nearest trash recepticle. Then proceed to install a real fan setup with a real shroud, etc.

 

using electric guages on a drag car!!!!! what are they teaching you there