engine coolant temp questions.

[msggunny]

My SIII is acting weird, well at least weird to me.

After rebuilding my waterpump the following happens.

On days that dont get above 85 the needle stays in the normal range, only about half way up. In traffic, on the highway, it stays the same.

On hot days it will stay 3/4 of the way up to the red while sitting in traffic but will then climb to the bottom of the red while driving. It settles back down once i stop.

A few factors:
New coolant, but i havent had it read to see what the concentration is.
Rebuilt water pump, by me.
Cap is good.
electric fan, mech one removed.
Warn 9000ti winch (could it be blocking that much air?)

It hasnt caused any problems but i was just curious.

Thanks.

[KevinNY]

Sounds fine but you might have a "winter" thermostat in there, one that opens earlier is only a few bucks.

[Paul Rossmann]

I had a very similar problem with my SIII. I tried everything; replaced the water pump, thermostat and even the sensor. Reset the timing, leaned out the fuel mix, went back to the mechanical fan from an electric I had installed and "flushed" the radiator with the Prestone flush about 3 times. She still ran with the needle right under the red. Then one day everything was all right. My conclusion was that there was a partial blockage in the water jacket. Just guessing of course, but it was probably right up close to the temp sensor. It probably broke loose or disolved. There is also the outside chance that I found the right combination of beer and prayer.

In retrospect I think just a good cleaning and making sure that the coolant is flowing is the most important step. Go from there to your timing and carb settings.

[luckyjoe]

I would verify the radiator is clean and free-flowing - no hot-spots or clogs. A good clean rad is essential.

I run an 88C t-stat year-round. My Smiths temp gauge indicates 88C for 99.9 percent of my driving - even fully loaded in Summer, or with a rad muff in Winter.

Regards,

[TCapelle]

Same issue- 72 series 111 "flirts" with Hot mark

I have been experiencing the same issue with my series 111 109

The temp needle raises to the line just before the "hot" red zone.

The truck doesn't seem to boil over or show any extreme over heating symptoms (just is very unsettling)

I plan to take it in to do a quick infrared temp measurement to try and understand if it is actually running at a higher temp.

Already bought the summer thermo- so will install that first then move onto radiator, etc to try and isolate issue (if there is one)?

Any other advice is welcome

Thx,
Tim

[greenmeanie]

Another thing is to pull the temp sender and test it in a cup of boiling water as a control. The sender has a rather cheap connector tab that is only riveted in place. On mine the tab is coming loose which gives false temp readings.

[msggunny]

I think i may have stumbled on the culprit accidentally.

The hose for the vacume advance on my dist was disconnected, it doesnt jump near the top of the guage any more.

Hmmmm.

[thixon]

Alright, now I'm stumped. Your temp problem went away, after you hooked up your vacuum advance? Keep us posted on this one. I'd be interested to know if it comes back.

[greenmeanie]

He essentially had an intake vaccuum leak so was running lean. I can't remember the effect lack of advance would have on temperatures though.

Hmm, that gives me something to research this afternoon.

Cheers
Gregor

[thixon]

Wow, that flew right over my head! Yeah, I guess all that air being sucked into the advance tube would cause it to run a bit lean. Geez, I had more beer than I thought last night.

[LaneRover]

When the vacuum advance on my 73 Ford was out of whack I boiled over at the top of a long hill. Once fixed I never had the problem again.