Engine/Transmission (1994 - 1998) Temp gage flux

[WDaniels]

Went on an exteded trip a couple of weeks ago and decided to make sure all the fluids were A-OK. The anti-freeze over flow bottle was empty and below the neck of the radiator about 1 to 1. 5 inches. Filled up the rad and made sure that the bottle had fluid up to its required line. Then as I drove on my trip the temp gage started cycling indicating that the thermostat was closing at 150,160 and opening at 190 for the entire 1200 mile trip. My truck has never done that before. So after the trip I reduced the anti-freeze back to where it was before the trip and it quit cycling. Anybody ever hear of something like this.

WD

 

[FATCAT]

My temp gauge has cycled from the 140 to 190 range since day one. I always thought it was normal. I would think it was "abnormal" if it did not cycle up an down. You know your thermostat and pump are working normally.



I don't like to see a constant temp like in my VW Jetta TDI where it stays at 190 all the time.

 

[EKlem]

The cycling of the temp gauge is pretty common. I suspect that by reducing your amount of coolant, the thermostat is open more(less cooling mass) and the antifreeze is not having enough time to cool off before the thermostat cycles again.



A lot of people have noticed that the cycling has gone down if they work their engine harder by pulling a big trailer or by putting on a winter front. I would think that having too little coolant is similar to doing either of these.

 

[Joe G.]

When mine stopped cycling I got suspicious. Sure enough the rubber gasket on the t-stat had slipped and jammed the t-stat. I replaced the t-stat. It's working right again.

 

[WDaniels]

So your saying that it should be cycling. Man does that drive me crazy. My 96 didn't do it either.

WD

 

[WDixon27]

when i got my truck it didn't have a t-stat and when i installed (what is apparently the new style cummins unit) one the temp gauge started doing it's impression of a windshield wiper, i pulled it and drilled two small holes in the inner part so that coolant could flow past the element and it wouldn't get shocked quite as badly and over react, for the last 8-9k miles the temp gauge has pretty much stayed still

 

[WDaniels]

WDIXON27,

how big were the holes you drilled and were in the flange?

WD

 

[WDixon27]

X marks the spot, don't go too deep and damage the spring/element

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i can't remember the exact size as i am always drilling air bleed holes in t-stats for the euro cars i work on daily, usually something small like 1/16", i did two one on each side to get some coolant flow to temper it and slow it's violent reactions

WDIXON27,

how big were the holes you drilled and were in the flange?

WD

 

[Rams-n-Hogs]

My 96 had done it since it was new, and still does it. Freaked me out the first time I saw it happen, and I was towing at the time. Now I would think something was wrong if it didn't do it.