changed thermastat and coolent now temp is going up and down can anybody help or will it work it self out maybe air in the system?

 

5 to ten degree temp fluctuation is normal. When you tow it should hold a little more steady.

 

That's totally normal!

If you feel the difference in temp between upper and lower hoses you will notice that the lower hose is like very cold. When the termostat opens (gauge showing higher) it will dump a load of cold water to the bock and it will close the thermostat back up (guage showing lower).

 

it all depends on how far it is going up.

are you going past 190*?

 

no its not going above 190 but it used to stay below 180 unless it is under a load it is just running hotter than normal

 

did you install the same temp range thermostat? and was it a cummins t-stat

 

Mine will go about a whole needle width over 190 when the T stat opens and then fal below then 190 mar kabout 2 needle width. Current temps outside are about 40*F. My T stat is a napa 190*F.

Now if it was hanging over the 190 mark and not coming down then the T stat is most likely going bad. This is assuming you go no load on your truck and your no racing. The Napa t stat has a wider mouth and tends to allow more coolant flow over stock Cummins.

 

Mine gets same results as Mopar1973man with my factory T-stat... gradually back and forth between 200* and 160* when warming up. If you stay on the hwy for half an hour it should quiet down to just below 190*.

RJ

 

I changed mine out last summer. Mine was fluctuating too much when I was pulling the cattle trailer. It would go up to 200*, and I did not like that.

I put a new 190* in from Cummins, and it stays at 190* all the time. It will fluctuate a little bit, but not much. Thats the way I like it.

 

Mine never reaches 190! The needle stays almost 1/2 way between the mark just above 140 ( I think this mark indicates the normal range) and 190 ... fluctuating up and down very slightly.

 

piperca


when was the last time you changed your thermstat mine the seal was gone and it was going by the seal

 

I've only had the truck shy of one month. Lord knows when the thermostat was last changed! Does my earlier post indicate there is a problem with the thermostat? Should the engine be running warmer than that? It takes me a good 10 miles to get up to operating temperature ... is that normal?

 

In my 2001, it takes me about 5 miles to get up to 190. Thats unloaded, and normal driving.

Last night when I drove my new '98 home, I noticed that the temp never got higher than the mark between 140 & 190. The same mark that Piperca is talking about.

 

I agree...

My truck takes about 5 miles of 55-65 MPH to get the temp up to 190*F. This is the first time it opens at. Then it falls about to about 160*F and starts going back up! about 30 miles and it is staying at 190*F mark.

If the temp is staying lower then the T Stat is sticking open. I know this would have a effect on how the VP44 is going to inject fuel and MPG.

Like on the gasser dodge trucks they are talking of pulling 195*F and putting 180*F t stat's in to fake the computer into thinking it colder and inject more fuel! They do sometimes throw MIL codes because the engine never reaches operating temp in time.

 

I'm 10 hwy miles from work. This time of year, after 60 sec warm up in driveway, I don't get to 190* either....unless I had it plugged it.
Take it out on the hwy after startup and watch it closely...should climb to just above thermostat opening temp (180* or 190*) and than drop suddenly, as cooler coolant pours into block. Than slowly climb back to operating temp. If not, thermostat is stuck open!

When you say "never gets to 190*"...do you mean before you get to work?



RJ