[Erik_H]

So after messing around with cooling issues a while back, I got it all sorted out (I thought). I just have one nagging question. With a 180 tstat, the car warms up and stays steady at 195 all the time: at idle, cruising the interstate, warm weather, hot weather, etc. About the only thing I've read about that I haven't done yet is cut down the top hose a little at the tstat housing to lower it some. My first guess would just be that the 180 tstat is not opening at 180, but I went through 3 of them, all from different sources and it still does the same thing. I'll say that I am totally fine with it at 195, I just wonder why it's there and not at 180 or so. Anyone want to chime in?

[Old Goat 67]

More info needed. What does the temp rise to at first warm up? 180 or higher?

Temp gauge calibration checked for accuracy?

What does thermostat housing & radiator read with infared gun?

In short, do you really have an overheating condition?

Or, is it false?

[Erik_H]

I can hit the housing and rad with the infrared later today. The temp rises up to 195 within 5-10 minutes after starting up cold. Like I said, I wouldn't call it overheating since it stays at a constant 195. It very well could be that the Autometer gauge is not reading correctly, I'll try to ohm out the sender later too. I printed off the instructions from Autometer.

[Old Goat 67]

Sounds like you either have a un-calibrated temp gauge, or you really have a 195° thermostat in there.

Infrared gun will help narrow it down, or a couple of resistors from Radio Shack to check the temp gauge. You may not be really overheating.

Charles

[Erik_H]

I know the tstat is a 180, I just checked my Summit order (of course it could have been put in the wrong box I suppose). I'll post back the surface temp readings, but even that will only be a hint since it doesn't tell you the actual coolant temp.

[Old Goat 67]

Originally Posted by Erik_H

I know the tstat is a 180, I just checked my Summit order (of course it could have been put in the wrong box I suppose). I'll post back the surface temp readings, but even that will only be a hint since it doesn't tell you the actual coolant temp.

So, shoot the water below the cap or the sides of the radiator tanks, or the heads, or all of the above. Or worst option, borrow mama's cooking thermometer when she's not looking. I'm not gonna be held responsible for that last suggestion!

[lfdsteve]

Just because the thermostat is rated at 180 only means it opens at that temp, not that it holds the car at that temp.
My tahoe runs 195-200 all day long, 220000 miles and still going.
I think 195 is just fine FWIW
Steve

[Erik_H]

Thanks Steve, and I agree. I'm fine with it at 195, was just curious why it was 15 degrees above the tstat rating. It just seemed a bit more than it should be. I think too much about this stuff, overactive brain!

[Erik_H]

I shot the infrared at the radiator hoses, the tanks, and the manifold next to the tstat and nothing was above 180 or so. I did notice that the sender and the adapter holding it in have either teflon paste or tape on them. I was reading that this is a no no since the sensor needs to ground itself through the threads. I'll redo that this weekend and see if it makes a difference.

[Old Goat 67]

Originally Posted by Erik_H

I shot the infrared at the radiator hoses, the tanks, and the manifold next to the tstat and nothing was above 180 or so. I did notice that the sender and the adapter holding it in have either teflon paste or tape on them. I was reading that this is a no no since the sensor needs to ground itself through the threads. I'll redo that this weekend and see if it makes a difference.

Ahah. Now you can concentrate on the real problem and forget about the tough expensive things. Maybe no worse than adding a small resistor in series to get the gauge to read about correct.

Charles

[Pontirag]

the tstat temp rating has little to nothing to do with the temp the car runs at,

the tstat opens at 180. the radiator, the fan and the waterpump have more to do with the running temp than the tstat.

you could put a 160 tstat in your car and it would still run at 195, which is pretty good by the way.

if you want to lower the temp further, its time to start dealing with details like

impeller clearance
wire support in radiator hoses
fuel mixture
ignition
separate plug wire 5 and 7
vacuum leaks
oil consumption
clean radiator inside and out

[Old Goat 67]

Originally Posted by Pontirag

the tstat temp rating has little to nothing to do with the temp the car runs at,

the tstat opens at 180. the radiator, the fan and the waterpump have more to do with the running temp than the tstat.

you could put a 160 tstat in your car and it would still run at 195, which is pretty good by the way.

if you want to lower the temp further, its time to start dealing with details like

impeller clearance
wire support in radiator hoses
fuel mixture
ignition
separate plug wire 5 and 7
vacuum leaks
oil consumption
clean radiator inside and out

Huh?

[Pontirag]

HUH, What?

[rexs73gto]

The T-stat opens at 180 deg,s but to make it stay there you have to add other items in the cooiling system to keep it there. Possibly a new rad. or bigger rad. Maybe something added to to the coolant inside the rad. But the T-stat does only one thing. It opens at a prescribed temp., only. The rest is up to you to add or take away items or licquides or bigger or better rad. But from what is written here the T-stat is doing just what it should when it should.

[68 Firebird]

Hey for what it's worth 195 is ok!!

I just got back from a 25 minute drive and it's 96 degrees out. car will now
stay at 185 running down the road and climb to 190 at a light. Then drop to 185
once moving again. I tried 3 different t-stats and they all acted different even
though they said 180. the 180 superstat seemed the most consistent.

But hey last summer before I made the upgrades it was 210 on the highway and 200
around town. I would have been happy with 195!!!!!

Get out there and enjoy that car.

It's officially beer thirty and my pool is calling. ITS HOT OUT!!!!!!!!

Gerry

[Region Warrior]

Back in the day(factory) they ran 210-215 w/a 195 stat.

[Erik_H]

Agree with all, thanks for the comments. It is hot as balls here too, and getting hotter. It crept up to almost 210 idling in traffic this morning which made me a tad nervous, but I think even that is probably just fine. I'm spending 2-3 hours at the dyno tomorrow getting timing and carb tweaked so Im anticipating a more efficient engine with less heat too.

BTW, I cleaned the thread sealant paste off the sensor and it did nothing. Must have had decent contact anyway.

[Pontirag]

is it blowing water out? if not, then your probably ok

dont go too lean for the sake of gas milage. these are muscle cars from an era when gas was like 23 cents a gallon.

a good electrical connection is important but its also important that the ohm range of the sender be compatible with the guage. I think your ok there too because 195 is ok. 205-210 is pushing the envelope though.

also put a sender on the side of the head next to the center two exuast runners if there is a threaded hole there. usually that is where your engine gets hottest and thats where it will get hot first. it would be ok to put a temp guage next to the center exaust runners on BOTH heads to see if one gets hotter first,

and an oil temp guage will also confirm the existance of and extent of any cooling problems. Hi heat, hi humidity and hi altitude also can cause temp issues.

[Erik_H]

I have a remote filter, oil bypass tstat, and setrab cooler in boxes in the garage waiting to go in also. Probably overkill, but I like to err on the conservative side. I also think I[m going to put on a recirculation tank in place of the rubber hose dumping out to the ground. At least that way I know there's no coolant being puked out.

[Pepi]

Originally Posted by Erik_H

BTW, I cleaned the thread sealant paste off the sensor and it did nothing. Must have had decent contact anyway.

Actually teflon tape will help show a lower reading. As the car warms up, the resistance in the sender drops. High resistance= low temp, low resistance= high temp.

So the tape would add resisteance to ground.