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ok guys, my 1991 camaro with 305 tbi, bone stock, no mods
i swapped to a 4 row aluminum race radiator and dual fans, and a seperate trans cooler, along with new 180 thermostat
then driving it runs great, around 170-180, but when i turn on the air conditioner it gradually works its way up to 220 degrees
what causes that, thats why i swapped to the bigger radiator in the first place, only when ac is on it gets up that high
only thing left to swap is a new water pump, but runs normal with ac turned off
anyone ever experience this issue? only 32,000 miles on her now, so i dont understand why it hits 220 with ac on, then turn off ac, and it eventually drops to around 170
im too old not to have ac in the car, so i definately need it, i just want it to stay around 180 all the time
any help or suggestions? pics of her included, my 1991 camaro aka #dirtyeyez #dirtyeyezcamaro
Running the AC is additional load on the engine. Depending on the condition of your R4 compressor it can get pretty extreme. So you know when the AC is running the Condenser will generate heat as part of the process. That heat is being pulled through the radiator by the fan. The fans that you are running , do they have a shroud? Good brand moving good air??
Running the AC is additional load on the engine. Depending on the condition of your R4 compressor it can get pretty extreme. So you know when the AC is running the Condenser will generate heat as part of the process. That heat is being pulled through the radiator by the fan. The fans that you are running , do they have a shroud? Good brand moving good air??
yes it has a shroud, they are twin 12 inch fans, so what can i do to get it running cooler with ac on? i havnt ran it long enough to see if it passes 220, i cut ac off when it gets there
Unless you car was boiling over overheating before you wasted your time and money replacing the cooling system components. You car was designed by GM to run at about 220F. Should be somewhere in the 210F to 230F range as indicated on the dash gauge.
Unless you car was boiling over overheating before you wasted your time and money replacing the cooling system components. You car was designed by GM to run at about 220F. Should be somewhere in the 210F to 230F range as indicated on the dash gauge.
no boiling over, never, and wasnt a money waste, i always wanted the 4 core aluminum rad, future plans for 500hp 396cid, so itll be great for that.....
as i said, 220 is too hot for me, i want it 170-180...., my 97 z71 silverado stays 180ish constant, summer/winter/heat/ac, dont matter, 180
Oh, you're one of THOSE people. Those who don't understand how cars are designed and think they "know more" than the factory engineers even though they have NOT A CLUE what the engineers intended or how they achieved it.
Sorry to hear that. Truly, my condolences.
Best to get used to it working RIGHT. Which it seems to be doing.
Well, considering that the single electric fan in my 83 Camaro DIDN'T EVEN COME ON (fan switch - BY DESIGN) until 235° more or less, I'd put 235° more or less at the ABSOLUTE LOWER LIMIT of "too hot".
Can't say about a Silverado. Butt you're into a little different situation there; they DESIGNED that vehicle (VEHICLE mind you, has NOTHING to do with "305") for things like construction sites, farm use, etc. Most trucks seem to run around 205 - 210° most of the time, a bit hotter sitting still with the AC on.
What makes you think 220° is "too hot"? (besides some kind of 2-yr-old "I want")
Well, considering that the single electric fan in my 83 Camaro DIDN'T EVEN COME ON (fan switch - BY DESIGN) until 235° more or less, I'd put 235° more or less at the ABSOLUTE LOWER LIMIT of "too hot".
Can't say about a Silverado. Butt you're into a little different situation there; they DESIGNED that vehicle (VEHICLE mind you, has NOTHING to do with "305") for things like construction sites, farm use, etc. Most trucks seem to run around 205 - 210° most of the time, a bit hotter sitting still with the AC on.
What makes you think 220° is "too hot"? (besides some kind of 2-yr-old "I want")
going off every other v8 chevy ive had , manage to keep them all under 200, even a drag carmontecarlo with a 480horse 355, and it ran 190-200 on powertour
those two 12" aftermarket fans are probably not powerful enough-could swap for higher power dual fans or a big single 15-16" fan that has decent sized motor and blades.
First, what I've learned in about a year and a half of owning a 91 TA Vert 305 TPI car and a 94 TA Vert 350 LT1 TPI car, the respondents to your question are correct.
I'm an old guy too, (69,) and I like AC. The 91 still runs R12, and the 94 is 134A.....and I live 65 miles south of Fort Worth.. It's hot. I'm getting about 43 degrees out of the vents on MAX....
Now some answers and background....I have a 71 Cheyenne shortbed 350, still running R12 with a 180 thermostat, and the most I ever see is about 190.
I have a 15 Silverado Crew 5.3, with a custom tune from Lew Eaton, (www.diablew.net) that runs normally about 205, and will creep up to 215 ish.
when he tunes, he does nothing with engine temp, because that's how they're built to run.
The 94 at highway speed and general cruising on moderate days will run 160 ish, and then when I slow down at a light will creep up to 185 ish.
On these really hot days, I've seen 200/210, but once I start moving and the fans kick on, it cools right back down, if everything is working correct electrically.
Like you, I'm not necessarily comfortable with these higher temps, being an old gearhead. I've only had the 91 about 18 months, and the 94 a year.
I'm considering a manual override for the 94.
My 91 is different. It never sees above 180 ish, because the previous owner installed a performance chip and 160 thermostat. It came from www.tpichips.com. Am I more comfortable with that? Yes. Is it the right way to go? I think either way is ok.
I think that the chip guy where my chip came from can get you what you want. He also makes chips for TBI cars.
You should call or email for info.
when I run my a/c, my engine actually runs cooler. that is because both fans are running all the time. sounds like you have a fan/radiator combo problem.
I'm betting somehow, this "drag car" didn't have it AC on at the time.
Your car sounds like it's working EXACTLY RIGHT. "I just want" is NOT the same thing as "it's not right". Modern (let's say, since the mid-late 70s, when they quit using cork and paper and shellac sealer and other crappy gasket materials that disintegrated due to heat) engines are DESIGNED to run hotter. It DOESN'T HURT ANYTHING. Sure, you can "get them to run cooler"; but there's NO BENEFIT. There's no there there.
In case you can't tell, MY point is, you're barking up the wrong tree. There's NOTHING wrong with it as-is, and NOTHING to be gained by changing it the way you "just want" it changed. Enjoy your nice comfy AC (I won't live without mine, either!) and accept that it's working just like it's supposed to.
And your point is ...??
Modern (let's say, since the mid-late 70s, when they quit using cork and paper and shellac sealer and other crappy gasket materials that disintegrated due to heat) engines are DESIGNED to run hotter. It DOESN'T HURT ANYTHING. Sure, you can "get them to run cooler"; but there's NO BENEFIT. There's no there there.
Interesting you mention this, a lot of guys in my other car world run cooler thermostats, these are post 2004 cars. I haven't bought into it yet, because the computer detects it and has issues, there are work arounds, but non-the-less..... They claim it prolongs hoses, wiring, other things around the engine and near the cooling system. but my thoughts are the engine itself still gets hot. hoses, and other cooling system parts, maybe? but everything else,, I've had my doubts. They also say the only reason it is run hotter is for emissions
Iunno... I have a 2004 with over A QUARTER MILLION MILES on it... all-original hoses exc top rad hose... :shrug: Runs at the factory temp which seems to be about 205ish
and if you're using the gage in the dash to determine the engine temp, best to check with some alternate method. that system is does not always provide an accurate picture of the state of nature at the sensor
wiring the fans to be on when the ignition is on means they are running during start up. not always a good idea to combine the fan load with the starter motor load. a good sluggish start from a weak battery could blow some fan fuses (providing they are fused)
To add to what Sofa has said, 220 seems perfectly normal for a stock LO3. It is an all iron motor with an iron intake manifold and cast exhaust manifolds. It is a giant heat sink compared to other mills with aluminum and composite parts (which have more thermal resistance). GM also ran these motors hotter to achieve certain mileage and emissions standards. Your car appears to be running 100% normal. The stock AC condensers on these cars are also terribly inefficient. All this adds up to heat, albeit within normal limits to which your car seems to be within. I also second the comment on gage temp. A good secondary source is needed to truly see your actual temps. The stock gages are really just dummy indicators for the most part that warn you if you hover too far from nominal. Accuracy is not their strong suit.
Anything between 190 and 230 would be ideal for a sbc. I use a 180 degree thermostat and a 185 degree fan switch with a stock radiator and stock single fan in a drag car which I cruise on the street with frequently. It will cruise at 190 and in traffic on a 100 degree day will get to 200-210 with no ac. I would say 220-230 in your case with ac on is perfectly normal. If it still worries you, go sit in traffic with the ac on and if it doesnt get any hotter than 230-235 your perfect. If it gets to 240 then start looking onto it. These cars don’t have as good of airflow through the front end as a truck, so you can’t necessarily compare two small block chevys to each other when they are in different chassis. A 91 will be fuel injected to so its best for it to run at around 190-230.
Last edited by skippermatt; 08-14-2023 at 12:30 PM.
Anything between 190 and 230 would be ideal for a sbc. I use a 180 degree thermostat and a 185 degree fan switch with a stock radiator and stock single fan in a drag car which I cruise on the street with frequently. It will cruise at 190 and in traffic on a 100 degree day will get to 200-210 with no ac. I would say 220-230 in your case with ac on is perfectly normal. If it still worries you, go sit in traffic with the ac on and if it doesnt get any hotter than 230-235 your perfect. If it gets to 240 then start looking onto it. These cars don’t have as good of airflow through the front end as a truck, so you can’t necessarily compare two small block chevys to each other when they are in different chassis. A 91 will be fuel injected to so its best for it to run at around 190-230.
Nobody has mentioned that he could be missing the air dam under the car....It HAS TO BE THERE FOR AIRFLOW!!!
Nobody has mentioned that he could be missing the air dam under the car....It HAS TO BE THERE FOR AIRFLOW!!!
yes, air dam is there, and in great shape.....
like i said, it only gets that high with ac on, when air is off, it stays around 170-180, never gets higher than that no matter how hard you run her, wide open or heavy traffic in the heat..... only when ac is on it gets over 180, around 220, i havnt run it to see if it goes any higher, just switch it off when its gets to 220 to let her cool back down, fans are wired to run full time, guess ill just run it and see if it goes past 220, if not maybe swap to a new water pump, its only got 32000 miles, but she sits alot, sit for 13 years before i got her, and maybe gets 250 miles a year since i got her in 2019.....
when I run my a/c, my engine actually runs cooler. that is because both fans are running all the time. sounds like you have a fan/radiator combo problem.
I cannot test what you said in my 91 TA because it has a chip and a 160 thermostat...........but I tested what you said in my 94 TA, and you are correct. With the AC on, the car DOES RUN COOLER. Never realized that until I deliberately tested that.....
I think pics / brand of your fans can help... they MAY be junk / cheap aftermarket crap.
But for me, I use Ls1 fans and they keep the ac and motor plenty cool I just go by the gauge but the fans come on a bit after 220 and they come down to maybe 190 ish or so...
08-12-2023, 02:24 PM
