Engine Operating Temperature

[bcomo]

I keep reading stuff that says "Run untill engine reaches Normal Operating Temperature". Yet, I've never found anything in writing that says exactly what that temperature is.

With a candy themometer, I see my thermostat open at 180. Then if I let it idle for about 15 min, with the cap off, temp climbs to 185-190.

On the road, daytime, it cruises at about 185.

At a stoplight, it may climb to 190-195.

After shutdown, and re-start in 2-3 min, it may read 200.

So -- again, what do they mean by "Normal Operating Temperature"????

[FeFranco]

Bart,
I have been told by mechanics that the beginning of your operating range is when your thermostat gauge opens. And the range can go up to 20 degrees above that. Your boiling point will be effected by the psi of your cap, ie. 14# cap will increase boiling point by about 14 degrees. Now the biggie is, do you have a catch can off of your expansion tank? The fluid will expand, especially after shutdown and needs someplace to go. If you have a catch can it will overflow into it, then the fluid will be drawn back when the pressure equilizes. This will allow you to top-off your radiator and not worry about spillage problems. I hope this helps.

[bcomo]

Franco:

Thanks for the information. It does help.

I have a 180 thermostat, and stock brand new 13# cap. I do not have a catch can as I have never had any overflow out the tube at all.

So, that would mean that my low reading of 180, and highest reading of 180 +20 = 200 degrees, would be normal for what I have.

Since I'm not getting any boil over, even after shut down, I would think that my cooling sytem is running OK.

I guess that I could make things a little better if I went to a 15# cap next time.

Thanks again.

[6TB1RD]

I have a Thermocouple Digital thermometer that I use at work, I am going to take it home this weekend and snake the sensor into the expansion tank by way of the over flow it will record the low and high temp wile it is turned on and see what my 352 runs at under pressure.

Just curious

[bcomo]

Hey, I'd be interested in knowing that.

I'm just surprised that the shop manual doesn't state what the normal operating temperature should be for a 352, 390, 430 etc. and how to test it.

Surely there must have been a way for them to tell if an engine was running in the zone --appart from a boil over to say "now that's really hot". Our temp gauge isn't a big help in that area.

We do alot to try to reduce cooling temp, but what is the goal? Is it to keep the temp at around a certain number, or just keep it from boiling over -- I dunno

[6TB1RD]

Ford Might not know either

What I find really strange and may be not I do not ever remember any of the Fords I have owned to ever have numbers on there temp gages.

I looked up in my shop manual for my ranger and it says normal operating temperature is anywhere between the N & L (NormaL) on the temp gage

Be for I replaced the radiator in my truck it showed between the O & R but every time I turned the truck off it would boil over (even thou the manual said it was with in normal limits ) Now it was only 19 years old. with the new radiator water pump and hoses it sits on the A the whole time it is ruining But now it does not boil over any more

[6TB1RD]

I just tested the temp with the Thermocouple Digital thermometer.

These were just sitting in the driveway idling for about 30 Min.

The temp raised to 174 the thermostat opened at 165. ambient air temp was 75 were having a brake from the 100's.

exhaust temps at the tail pipe were 235 on drivers side and 240 on pass.

next Friday after the power steering rebuild I am going to take her out for a drive and check the temps then.

I will post more then.

[bcomo]

Now that's interesting. Are you running a fan shroud?

I remember John Byers post saying that he figures engine temperature is right around ambient temp +100.

Will be interesting to see what the temp is when driving.

[6TB1RD]

No fan shroud here (soon though).

After the P/S is done I will get the readings, I was going to take her to my Grandson's B/day today put can't put my self in the mood to drive with out the PS.

I was going to set up 3 senors 1 in front of the radiator 1 behind and 1 in the tank and read all three to see what the actual temps are.

[FeFranco]

George, what temp thermostat do you have?

[6TB1RD]

165 ?

I believe it would be a 165 not to sure I never checked it before I put it back in the car after the rebuild.

But I thank it opened about there I was not watching when the temp jumped from about 145 to 174 (was 145 turned away to check the exhaust temp came back and it was 174.

When I check it out on a drive next week (I'm trying to barrow a Graph Thermocouple from work need special permission due to the cost of the equipment. ) hooked up to the 3 sensors will give me what I'm looking for.

[byersmtrco]

Boy. we've (I've) beatin this one to death, but ambient + 100 is pretty close. I don't have a real gauge yet, but I have a pretty good idea what it's running by the stock gauge. While moving (any temp outside) the needle is on the E (180 deg) When sitting still (at a light), it will creep down to the middle (straight down) That's 190-192. On a warmer day (80 +) it will creep into the M. I guesstimate that to be in the 200-205 range. However, it will only do that idling in gear. If I put it in Park and step the idle up (slightly) it goes right back to the middle or towards the E (185-190) or creeping along 10 mph in heavy traffic for 40 min. I was sweatin it that day, but the car wasnt.
If I shut the car off and re-start it (eg; getting gas) it will go over to the P, but goes right back down.

Overall, I'd say average running temp is 185. The shroud and big fan only help when sitting still or going real slow. After 35 mph you prob don't need a fan or shroud.