Archived Low engine temp

[sadams]

I noticed yesterday my engine temp was only running 140 even after driving it a considerable distance and on a grade, plus the air coming from heater was just luke warm, even on highest setting. I'm thinking the thermostat is stuck open but am curious, since I just got it back from dealer two days before for the recall 970 throttle linkage fix (thank you TDR magazine this month for info as it was ready to break, and of course, dealer never checked or told me of recall). Is it possible doing this fix job they could have disconnected any wiring that would affect this? This AM I started and ran it and it came up to normal temp. I'm new at this site (and owning a diesel) so need any help avail.

P. S. I have a boyfriend who is a mechanic and I'm sure he'll like me telling him how to fix it. Ha

Sharon



96 3500 stock, automatic, 354

 

[Ben Rumson]

Thermostat?

It sounds like your thermostat might not be closing all the way. You could put it in a pan of water on the stove and watch for it to open with another thermometer to tell the temp - or you could just replace it.



When you do, use a genuine CUMMINS t-stat. This will give you as little temp fluctuation and consistency as possible. It would elimintate this as a possible cause before looking any further.

 

[illflem]

Sharon, on your vintage engine it's very common for the gasket that goes around the tstat to come off and hold it open. Some folks remove the gasket and toss it, others put it back on. You should also check that your temp gauge is reading correctly with a themometer.

 

[sadams]

thermostat

Thanks for the quick response. I took it out today and ran it a ways and the temp came right up to operating temp, even hauled a load of hay and the temp stayed right at its normal temp range, plus the heater was putting out good heat. I guess it just stuck yesterday on that one trip, but I find that strange that it could get "unstuck". I think I will order the Cummins thermostat as I bet its a matter of time bef. that happens again. Where do I get "Cummins parts" so I don't have to go to the "stealer" for it. I paid $400 for a starter from them ($250 to up it in), $50 for a fuel filter (& $70 to put it in), $35. for an air cleaner, and I've had my fill of them at the dealers!!! I've got to start learning how to do this stuff at home.

 

[illflem]

Buy it from Cummins. Find your closest dealer here http://www.cummins.com/service_locator/index2.cfm If it's too far away you can order over the phone with a credit card and they will ship UPS.

 

[rrl989]

sadams,



My tstat has been replaced twice in 80K miles. Try www.genosgarage.com for your maintenance items / filters.



Ron

 

[dan.poitras]

Sadams

The 96 vintage cummins original thermostat was totally made of metal. The problem was when the blocks were cast some sand residue was left in some blocks and partially blocked open the thermostat when it got hot enough to open fully.

The cure is the updated thermostat now has a rubber seal around the opening to cope with any foreign material that may be caught in the valve. This was a common problem when these engines were new and we had to flush several of them.

By just replacing the thermostat should cure your problem.

Any kenworth, navistar, freightliner or dodge dealer have the updated stats, just give them your engine s. n.