time for new thermostat?

[tobaccogrower]

I've noticed the old rattle trap is taking longer then normal to heat up lately. also, my temp gage will stay at the 2nd bar forever. then creep up to the 4th bar(3/4 on the gage). then suddenly swing back to the second bar. is this normal with our cooling systems? I never really paid attention till the other day it caught my eye. I'm thinking normal operation it should hover around the middle of the gage?

 

[RWherley]

That's what mine dose, always has but only in cold weather.

 

[Bob Beauchaine]

The wide swings are not a new problem with the OEM thermostat. The newer Cummins 'stat helps to solve that problem - sorry I do not have the newest P/N from Cummins. The very first line with the C above it is just the cold start line. The lines connected to the arc would be the operational temps. The first line in the arc is about the point which the KSB stops advanceing timing, the second line is the normal engine operating temp - the wide swings you see are due to the 'stat and are under normal conditions OK. I see the same swings with my OEM guage. I did install an aftermarket coolant temp guage and that only moves 2 to 4 degrees.



A good freind was having wide swings on the temp guage on his '93 so we installed my old fan and that helps to keep temps under control. I am running a Horton fan and even towing with it on in 100 degree days my temps will stay at 180 degrees.



I would replace the 'stat and see how it affects the wide swings as a first step.



Good Luck

Bob

 

[tobaccogrower]

finally got around to doing my stat. went to napa and purchased superstat part# thm532090. its a 195* stat that is too big to fit in out first gen housings. I belive it may fit the second gen housing. its 63mm compaired to our 53mm. little trimming on the bench grinder(couldn't get it in the lathe) and it fits like a glove.

seemed to heat up a little quicker then the one I took out. the needle sits between 5-6 oclock on the guage. no crazy swinging! only time will tell how it performes when the cold weather gets here. i'll keep you all updated.

 

[HHhuntitall]

And don't forget, these trucks are getting broken in. Piston friction isn't what it was new, so it can take longer for them to warm up with less friction in the cylinder walls..... My '97, in freezing weather, won't ever come up above the 140* mark until you drive it or idle it up...

 

[michaelsflowersjr]

I wish i could help, i just bought a used 96 model with 268,000 miles, when driving it home in 38 degree weather it never got but just above 140 degrees. I bought a gates brand thermostat from Genos Garage, installed it. Radiator was leaking, replaced it, replaced hoses and installed new water pump when i fixed my KDP. And NOW, it gets to about 180 degrees idling, then when i drive it drops sharply to 140 or less (in 40 degree outside temps). And this is the real temperatures too (the heater is warm at idle and just barely warm going down the road) call me a moron, but thats what i thought the thermostat was suppost do?? So im back to not knowing what the hell is going on

 

[Bob Beauchaine]

Keep in mind that the 2nd gen cooling system has a larger capacity - 23 quarts. I believe - as compared to the 1st gens 16 quart system. The design of the 5.9s cooling system lends itself to these wide swings more so with a larger cooling system. Cummins worked on this problem and their newest thermostat was an improvement. I would always go with the Cummins product in this area. As stated above I see wide swings on my OEM gauge but not on my after market Auto Meter gauge.

In upper 20s to mid 30s where I live I see my heater blowing warn to hot within less than 5 miles of driving. I was born in upstate NY have seen temps. a low as -23 when I was younger.

Bob

 

[HHhuntitall]

Also, a coolant system needs to be flushed regularly. Failure to do so will leave rust and other contaminants in the system, that, when run after installing new components, can be run through them. A new thermostat may have something in it, not allowing it to close all the way....

 

[DVolk]

I don't want to burst any ones bubble , but if a system is dirty a flush will do nothing !!! If the system is dirty the only thing that will clean it is to pull the radaitor and take it to a good radaitor shop and have the tanks pulled and have it rodded out and the header ran . Then once all of that is done you fill the system with a good 50/50 then add some water soluible oil to the system a cup will do you or you can buy the pre mixed stuff , its the same stuff just not as concentrated as the water soluible cutting oil you can buy at Napa . I use it in all my equipment and never have any problems period . Antifreeze don't were out it just looses its rust inhibitors after time the addive insurures it dont . If you want to be fancy you could add a coolant filter .

My Dad was a 30 year Radaitor Man and i know what im talking about .

Bob, What part of Gaston you at , my old stomping grounds !!!

 

[Bob Beauchaine]

Donovan

I am east of Gaston proper on SW Lasalle Rd.

I have also purchased a Griffin aluminum radiator and I'm toying with the use of Evans coolant. It costs quite a bit more but it does have a very long life - 500,000 miles - minus 40 freeze point and a boil point over 300 degrees.

Bob

 

[DVolk]

I know that road ive been on it a time or 2 . Ive seen that evans product also some of that " water weter " I don't know any one
of whom used it before I know its exspensive . My recomendation is if your in Beaverton stop into Macs Radaitor and talk to Dana and see what she says tell her I sent you in there .