Engine/Transmission (1994 - 1998) Temp Gauge Jumpin

[holmanrd]

Towards the end of last summer my temp gauge started jumping up and down.

After warm up the gauge will slowly climb up to about 190, hold for a couple of seconds then quikly drop down to 150 or so. It will continue doing this the whole trip even pulling. (Unless I'm in the hills)



A couple of months ago I was in a hurry to get packed for a trip so I dropped it off at the dealer to have them change the thermostat. Well that was wasted money, it still does it to this day.



Does this indicate a leak in my coolant system or maybe an air pocket??? It also takes about 10 minutes of driving (5-7 miles) for the gauge to even move past 150/160. I can even let it sit for 10 minutes in the drive way and it still takes a few miles of driving to get it to warm up.



Is this normal? Maybe I am just too used to my old gassers.

Thanks for any input.

 

[ABorchard]

Cummins says,



THE COOLING SYSTEM USED ON THE CUMMINS DIESEL ENGINE EQUIPPED VEHICLES PROVIDES THE CAPACITY AND PROTECTION OF THE HIGHER GVWR AND GCWR RATINGS AVAILABLE ON THESE VEHICLES. OWNERS SHOULD BE ADVISED OF THE NORMAL SLOWER WARM UP AND LOWER ENGINE OPERATING TEMPERATURES ASSOCIATED WITH DIESEL ENGINES.



THE COOLANT TEMPERATURE GAUGE WILL FLUCTUATE ON DIESEL ENGINE EQUIPPED VEHICLES. IT IS INFLUENCED BY VEHICLE LOAD, OUTSIDE AMBIENT TEMPERATURE AND EXTENDED IDLE TIME. THIS FUNCTION IS CONSIDERED NORMAL.

 

[holmanrd]

Thanks Art for the fast reply, that's good enough for me, I'll keep on smoke'n.

 

[tp0d]

Yea, what ABorchard said. There is an updated t-stat avail thru cummins, I`m gonna look into it when I do some springtime work on my truck. Mine has been jumpin from 140-150 to mid-hot on initial warmup, once I get a few cycles on the stat it does the regular jump. .



-j

 

[ABorchard]

Thing I don't like about the updated stat is even though it's a bit steadier is that it runs much cooler on average. I ended up putting my original back in.

 

[DBentley]

I did the updated t stat and the dam thing still cycles up and down. When i got the truck a few years ago I didnt know what was going on so I replaced the t stat 2wice and same thing happened. Save your money and time because it seems normal with these trucks to cycle and take forever to warm up in the cold weather. Once its warm and you shut it down for 15 min in cold weather its like starting over COLD again. The large radiator does its job real well.

 

[RDelissen]

it's indeed one of those quirks with the CTD

Mine cycles the same, unless you've got a load hanging off of it, then it stays pretty stable around that 150-160 mark ...