My car is an 82 TA, 305 LG4 Q-jet, no overdrive with 3:73s.

With a 195 t-stat, the car gets up to 220 on the freeway(55-70 mph) around 3 grand on the tach. With the heater on, sometimes it comes down. The ambient temp ranges from 0-20 degrees right now.

One mechanic said it's fine, it's in the middle of the temp gauge. Right now the car gets around 11-14 mpg, he says if I were to put in a 180 t-stat, it would be around 10. Another mechanic said 220 is hot.

I asked if a colder spark plug would make a difference, and was told only a few degrees.

 

Our cars are designed by GM to run hot to aid in emmisions. 220* is normal. I'd be worried if it were 240-250* Around 260* they will start to overheat.

 

A 'colder' spark plug wouldnt make any difference here, from what I've been taught about what 'hot' and 'cold' mean. Basically, its not 'hot' and 'cold' in relation to actual water temp, but more or engine setup.

Anyway, 220 is not too hot. Ideal running temp is usually around 210*, so I wouldnt worry about it. Its warm, but its not hot.

 

my car all summer ran at 170 and that was on my aftermarket gauge.

 

Good point... my factory guage is buggered and reads high too... forgot about that... the factory guages suck.

I suggest buying a mechanical one (mine was like $10), hook it up in place of the factory sending unit, and see what the temp REALLY is.

 

Does it only get hot on the freeway? What about at an idle? Check and see if your air dam is in place underneath the nose. Without that, youre sure to run hot.

 

I purposly removed my air dam and all that plastic shrouding. My car runs at ~195-205* :shrug:

 

Why would you remove it???

 

Well, first I didn't like the look or it hanging out from under the car. Then I didn't like the way it looked when you look at the rad. It seemed to me like it would be more effecient if the air had more surface area to be distributed over, instead of having to pass through those 2 "tunnels" to get to the rad. So I chucked it. And for me it worked, lowered temps ~5-10* Idle, hwy, wot, whatever.

 

Before you decide what to do, replace the temp sender that runs the gague. It's between the #1 & #3 spark plugs on the driver's side of the engine. The senders can get whacky over time. Not that this will definitely make the gague read accurately (it's only 1/2 of the equation- the cheap factory gague itself is the other half) but it's worth a shot for $10 and a little wrench time.

Gague in my wife's 92 regularly reads somewhere between 5 and 15* hotter than the CTS sensor, which the ECM uses to measure actual engine temp. ECM says the engine is 205, gague says 220. Both new senders. It happens.

 

220 is not that hot, most of the thirdgens run that hot. Plus I believe that the second electic fans doesn't even turn on til like 225, if i remember corrrectly.

 

Don't trust the gauge. My '88 IROC says 220° but it's actually 40° off, the actual temp is 180° as read from the ECU.

 

Its a Q-jet, so the coolant sensor is right above the t-stat. It was replaced when the check engine light came on, some time around 9 months ago??

 

OK, I could be wrong about the temp sender location on the older carb'ed engine. Just make sure you're actually replacing the sender that runs the gague (it's only got 1 wire going to it), not the Coolant Temp Sensor (CTS) that talks to the ECM (it's a 2-wire sender with a weatherpack connector). Even on the old carbureted engines there are 2 different senders.

 

TransAm12sec, the temp sensor for the gauge is on the drivers side head. There is one single green wire that connects to it. Look down by the exhaust manifold. The temp sensor you replaced is for the computer.

230 degrees is definately hot for the old engine driven cooling fan cars. My '84 LG4(and 71 and 73 T/A) runs all day long right around 200-210 degrees.

 

im gonna be the first to call on this one. how does watertemp have anything to do with fuel mileage? granted i have an od tranny, but with a holley on top and 4.10's out back and a 160* stat, i see about 20-22 highway mileage. i use an electric fan from a v6 in my car and never see above 180* temps.

 

hmm. I couldn't drive my car 10 min without it overheating, with a missing airdam. Install airdam, and instantly, car runs normal. I wonder why such a difference?

Also, for a stock sbc in our cars, I read that 220 w/iron heads is optimal normal operating temp. for these cars. Am I incorrect on this? I installed a toggle switch wired to the electric fan in antisipation for 100 + degree days in summer, but other than that, why do so many people want their cars running so cool, (excluding aluminum headed engines, i know they need to be under 220 granted warping temp).

 

I thought your car had a mechcanical fan and if that is the case it could be the thermal fan clutch.