Thread: Operating Temperature

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sbc was running crappy after 97,000 mlles. Would not get up to OT. stayed around 120*.
Pulled the ThermoStat and boiled it. Opened right up.
Dropped the new 190* in the boiling H2o and it opened a little but remained about 1/2 closed.
Installed the new one and now she runs (perfect) @ 210* on the factory gauge.
Never compared before so I figured if it opened it was OK.
The spring must have weakened after so many cycles ( metal fatigue ? )
Anyway, just my experience that might help somebody.

Mine runs 120, 130 with new stat. Never gets warmer. is that wrong?

Yeah, i'm pulling the stat right now. I guess a 190 oughta do.

I just hate having to wait all day in line at the corner Advance place. Hafta pack a lunch.

Get the model that goes to full open when it fails.

I don't know if you saw my earlier thread on this subject, but my gauge was reading 120 until I moved the sender to the front (it was in the back) of the intake. Now it gets up to the correct temp, in fact the other night I forgot to turn on the fan when Don was having his transmission problems, and it went to 220 on the gauge.

I'm going to switch out thermostats on mine when I get back home from Billetproof, mine never gets over 150 going down the road, and the electric fan will cool it down from 180 to 150 at a light. Right now I don't want to tear in to it, but I know 150 is too cool.

Living in Florida, this is sort of a blessing, having a too efficient cooling system, but I know it needs to get around 180 for the sake of the motor and complete combustion.

Don

Well, I'm stumped with mine for sure.

I took out the stat, bought a new 180. The old one was a 195 so I must have tried to adress this problem before. Boiled em both with 2 thermometers One a meat thermomerter, one my radiator cap with the built in thermometer.

Both thermometers agreed. The new stat opened at 180, the old one opened at 195. Just like theyre supposed to. Cooled em down and both shut completely.

Put the old stat back on. The 195. Fired up the car an let it warm up.

Well,,, As warm as it gets.

Cap said 130. Gauge in car said 130. Now just so everyone knows my gauge in the car is taking the reading offa the front of the block right where my idiot light sender is located. I just teed off with plumbing to keep the idiot light sender.

Checked upper hose. No circulation.

Plain as it is that engine just isn't getting warm.

Now what? Grille tape?

Most engines should be running at 180 - 200 normally. If running to cool, your gas is not detonating as it should and you could be washing down your cylinder walls with the excess gas which can lead to early ring problems and sludge. Plus wasting gas. The gas sold today pretty poor compared to what it was 40 years ago. To get the most out of your motor, it should be running at max efficiency which usually is at 180 -195 degrees. FI engines usually 195+.

If you are getting varying results and your temp guage(s) are all correct, might want to try a differernt thermostat by a different mfgr, sometimes it could be a product error.

Of course I could be totally off base, and usually am. Which would explain the straight jacket my wife makes me wear from time to time.

I know what you guys are saying............logic would tell you that if you sit idling an engine will eventually climb to a point where the thermostat opens and the water flows to the radiator. If his hose is cool it says the thermostat didn't open, but my thermostat is a 160 and my engine stays at 150 going down the road, and the hose is semi hot to the touch. I can keep my hand on it, but it is warm to the touch.

Dan is having a radiator built right now by PRC and is worried it won't cool his 455 Olds. I told him if mine is any indicator, he might have just the opposite problem.

Don

Just thinking
Another item to check - was the sending unit in the manifold installed with a sealant -i.e., Permatex, Teflon tape or other type. The sender needs a GOOD ground so what you may be reading is from an improperly grounded sender. You don't want ANY sealant on an electrical water temp or oil pressure sending unit. If there is factory sealant, that's OK as it is a dielectric sealant. If it is a Bourdon liquid filled tube, which most Chebbies had, sealant should be OK

Denny, yep, as usual, your explanation is very clear. Makes sense.


Dave, I knew that about electrical sending units, but I had to goop the h*** out of the sender because that particular threaded port has been weeping since day one. I tried thread sealant, silicone, and finally got it to stop with a big coating of good old fashioned permatex non hardening # 2. I had to torque it tight too, I think that hole is tapped goofy or something, the other 3 are fine.

But I know the temp is actually accurate, because I can literally hold my hand on the top hose for as long as I want and it isn't uncomfortable. If I tried that in my daily driver it would be way too hot to even touch.

I'm going to see what it does on this long trip this weekend, then probably bump up to a 180 when I get back.

Don

Originally Posted by Itoldyouso

Denny, yep, as usual, your explanation is very clear. Makes sense.


Dave, I knew that about electrical sending units, but I had to goop the h*** out of the sender because that particular threaded port has been weeping since day one. I tried thread sealant, silicone, and finally got it to stop with a big coating of good old fashioned permatex non hardening # 2. I had to torque it tight too, I think that hole is tapped goofy or something, the other 3 are fine.

But I know the temp is actually accurate, because I can literally hold my hand on the top hose for as long as I want and it isn't uncomfortable. If I tried that in my daily driver it would be way too hot to even touch.

I'm going to see what it does on this long trip this weekend, then probably bump up to a 180 when I get back.

Don

Oh well - worth mentioning, Don - there's lots that tape 'em up and wonder wotinhel happened. What you really need if you have a 15# cap is a 192/195* thermostat - boiling temp with that pressure is ~250+/-

Besides that - you have just upset me - it's finally "warmed" to 33* here today with 18/20* "promised" for overnight for the next 2 nights and I can't even get my chassis out of the basement garage to the regular garage to install the body because I'd bury it in the back yard which is mush from all the rain

Originally Posted by Good Wrench

Now just so everyone knows my gauge in the car is taking the reading offa the front of the block right where my idiot light sender is located. I just teed off with plumbing to keep the idiot light sender.

If the bulb is not in the coolant flow you're probably reading air temperature.