Another overheating question

[cousindave]

So when idliing gauge reads normall. Only reads in the red when giving it gas. Already flushed the radiator, block and heater core. Took out thermostat, and running without stat. Oil is nice and clean. No smoke coming out of the tail pipe. She runs excellent starts in less than one crank. I was thinking a timing issue but she runs so well. I checked timing a few months ago before this issue started and it was ok. Any ideas?

[albersj51]

Bad gauge? Have you verified it is in fact running hot using a thermometer or something in the radiator?

[cousindave]

I stuck a thermometer in the radiator after gauge read in the red. I got 145° . Let me add that I'm running without the thermostat. Also, when I oened the raxiator I noticed the antifreeze was foamy. Is that normal? I also noticed the smallest pinhole leak out of the radiator. Could that cause the foaming? Or even the overheat conditions? What temp is overheating in a series III? thanks

[cousindave]

Another thing i noticed is that temp gauge goes back to normal when i coast down hill. It only hits the red when I'm giving it gas, especially uphill. Also notice lack of power or could that be my imagination?

[LaneRover]

Another thing i noticed is that temp gauge goes back to normal when i coast down hill. It only hits the red when I'm giving it gas, especially uphill. Also notice lack of power or could that be my imagination?

At first I was going to post a response saying that I had a Series III where all of a sudden the temp gauge just started reading hot.

But the fact that it goes up and down with giving it gas or when coasting tells me it isn't the gauge.

[cousindave]

Thats what i thought too, but i don't know where to begin. I flushed rad. Both hoses are warm and i can't feel the difference in temp between upper and lower rad.
Would an intake or carb leak have these symptoms?

[SafeAirOne]

How's your fuel gauge? I had a bad voltage stabilizer that would do just the opposite and barely move--Overheating was at the top of the "N", as in 'normal' on the gauge.

Have you checked the cold and hot resistance of the temp sender? Here's a ROUGH (+- about 8 deg F) idea of where you should be reading at different temps (yes, I had nothing better to do one day):

[siii8873]

I am suspect the voltage regulator or a ground problem. When you rev the enging the voltage will increase in the system. I don't know what high voltage will do to the temp reading so I could be wrong.
I am having a high reading on my SIII currently. AFter I shut the truck down and got in it the next day the gauge is reading 1/3 way up stone cold, used to be at bottom of scale. I have not done anything with it yet as I'm not sure what would make it offset. Thinking ground or volt reg also.

[JHK07]

So is this just an idiot gauge? cold/ normal/ hot????

I would suggest one that actually reads Temp. Atleast that way it can be tested in hot water along with a thermometer of some sort.



I ran my series with a T-stat stuck open this spring. I never saw over 110 degrees.


Kinda also thinking w/ these guys also, as in bad ground, or voltage increase. My experience w/ a loose ground though is it makes everything "weaker", "dimmer".


Bad connections or some bare wire hitting some metal will do some crazy stuff......


Do any other gauges act goofy ?????

[cousindave]

The fuel gauge reads normal so I am assuming its not reg. Also with tstat stuck open yoí got a reading of 110 I am getting 145

[LaneRover]

Any chance the water pump impellor isn't pumping much anymore?

Or that your timing advance isn't working too well?

[Nium]

I stuck a thermometer in the radiator after gauge read in the red. I got 145° . Let me add that I'm running without the thermostat. Also, when I oened the raxiator I noticed the antifreeze was foamy. Is that normal? I also noticed the smallest pinhole leak out of the radiator. Could that cause the foaming? Or even the overheat conditions? What temp is overheating in a series III? thanks

Normal operating temp for a 4 cylinder should be between 180F and 200F. Overheating would be 220F+. The thermostat wouldn't even open until the temp reached 72C or 162F (Series III manual thermostat rating).

Foamy antifreeze doesn't seem normal.

IMHO a pinhole leak would keep the cooling system from maintaining the correct pressure of around 9 lbf in^2 (which is the rating of the radiator cap according to the Series III manual)

[JHK07]

What about an air pocket/ bubble in the cooling loop? When i changed my T-stat a couple of weeks ago I think i had 1. It overheated on 1st start, bout 220, i shut it down immediately.


Anyway, jacked up the front end and added coolant as engine was running.

Goosed gas pedal w/ hand... add more coolant. Repeat as necessary.

It got to 180 plus and the new stat opened.

[cousindave]

Hi everyone, thanks for the responses! Had time today to install a new mechanical pump to the old bird. Guess what? The temps never go above 140° without the thermostat. But, there is alot of foaming in the radiator. Went to napa and got some radiator cleaner. Wish me luck!

[cousindave]

Ok, so i used napa radiator cleaner. Stuff is awesome! Gray crap came out of the petcocks. Nasty. No more foam in the radiator!! Totally psyched!!