MuncherRS

i have a 1991 camaro with the stock 305 motor and the temp gage says 240 when i drive around for longer than 25 minutes but will not get any hotter, the electric fan will come on around 235. im thinking that the gage is inaccurate. does any one have an idea of what i should do

J91

Get another gauge... @ 240 both fans should be on, are they?

MuncherRS

i have one electric fan and it does come on

J91

Your gauge is probably off. You can do two things.
1. Buy a infared thermometer, and measure your engine temp at the thermostat and hoses, to find out where the temp really is.
2. go to jegs or summit and buy a aftermarket temp gauge.

I know my temp gauge reads about 15 degrees too hot and my tach reads up to 1700rpm too high. I have replaced both w/ aftermarket AutoMeter gauges...

henryd3

iTrader: (128)

It may not be that far off either. The fan switches are notorious for being unreliable and may be starting to fail. You might consider one with a lower temp turn on like these https://www.thirdgen.org/forums/cool...ernatives.html

MuncherRS

my camaro will run hot after about 25 minutes of driving with the ac on and when i turn the AC on the fan comes on so even if the fan comes on it will run extremly hot but my gage mite be off ,, iam thinking that i need to get a new gage, flush my radator, put in a new thermostat and maybe get a new water pump and see if that helps

henryd3

iTrader: (128)

Yeah, its important for the radiator to flow well and the thermostat to function properly. Check true temps before replacing everything in sight, that could be the only problem. Any other signs of overheating besides the gauge? If you want to stay original, I've got a spare gauge cluster middle piece that has the four gauges. Came out of a 92 305 TBI

MuncherRS

what signs of overheating should i look for?

camaronewbie

If it's overheating you'll have bubbling in the resevoir.

Is the stock air dam under the radiator?

MuncherRS

i have not had any bubbling in the resevoir and i do have the stock air dam under the radiator

henryd3

iTrader: (128)

Have you watched the temp gauge from startup and seen the temp rise until the thermostat opens, and then the temp goes way down before it begins to rise again to make sure its opening? Also detected by feeling the upper radiator hose getting hot when it opens. Is this a sudden new symptom or has it been sneaking up and getting progressively hotter?

Maeryk

check out you thermostat first.. water pump next (make sure A is opening and B is circulating well), double check the temp gauge (you can use an IR or just jam a barbecue thermometer gently betwixt the fins on the rad, see what it's reading). double check your engine airflow.. also, do a visual down the front of the rad, make sure it's not packed full of dead bugs and dust, and check your fluid.. make sure you have the right mix of anti freeze/boil in there. It helps with heat dissipation.

I once found a ridiculous amount of crud stuck between the trans cooler and rad that was causing overheating issues, though not on a firebird. That was on the 69 AMC Rebel.

deadbird

The fan switch temperature for a TBI 305 is 238°F. The electric fan on a TBI engine is controlled only by the fan switch.

SW505 (autozone) is a 215° turn on fan switch. Works well with a stock temp thermostat.

Start with making sure it's clean between the the a/c condenser and the radiator. It's just as important that air flows through the radiator.

mike f

i am haveing the same proplem car will go up to 260 when driving

MuncherRS

iam going to put in a new thermostat (a 195degree i think thats what the stock one is)and a new radator because it was leaking before i presure tested it, after i presure tested the radiator it stoped leaking which is making me assume that the coolant is dirty

MuncherRS

[quote=deadbird;4664304]The fan switch temperature for a TBI 305 is 238°F. The electric fan on a TBI engine is controlled only by the fan switch.

the fan comes on automaticaly at 238 and when i turn on the air the fan comes on, if that is what you ment by Only the fan switch

sonjaab

My 84 HO runs 220-240 all the time on a hot summer day with the a/c off
or on! I have my fan on a switch and run it all the time if the engine is
running.

NO boiling over into the overflow bottle either.

deadbird

I should have been more specific,I suppose. The fan turn on temp. is only controlled by the fan switch.

MuncherRS

I put a new thermostat in, flushed the radiator and it still ran hot but then 3 weeks later the heater control valve broke i replaced it the next day and my car runs so much cooler now it is weird.

1988CamaroSC

iTrader: (2)

mine runs in the 160s tanks to the 160 tstat. only reaches the line between 100 and 220 on the gauge.

Guest

I replaced everything.... Still runs 230-235 tops. I don't care because i know it's fine...

leo27030

Hi on my 91 camaro the temp gauge gos to the line just before the hot marks before the fan comes on ,does anyone know what could cause this ??? also I've never heard or seen it bubble at that temp.