changing the T-stat

[shendren]

i got the new t-stat from cummins. however, after reading the last post somewhere on the board that i have to take the serpentine off, i don't think i am ready. does the belt really have to come off? how tight does the belt need to be when putting it back on? is the service manual any help? i will go out and get it in a few minutes and see what it has to say. any comments would be appreciated. thanks. scott.

 

[barryg41]

It's not that bad. I pulled my brothers radiator and changed his t-stat.



Yes, the belt has to come off. You have to lossen the aternator brackets before you can get to the t-stat.



The idler pulley will take care of the tension.



The service manual is the bible!



It wasnt that bad... . if you need more help after reading the manual... . PM me...



Barry

 

[sewman]

I never took the belt off when I changed my T-Stat all you need to do as I remember is take off the bracket on the alternator,

& then the 3 Tstat housing bolts & take it off.

Bob

 

[shendren]

thanks. scott.

 

[barryg41]

I tried the same thing leaving the belt on but I had to end up pulling the belt to get the bolts back in the bracket. I guess I wasn't holding my mouth right. And that was taking shortcuts reading the manual.



I'm glad you were so lucky, Sewman!

 

[sewman]

Barry,

Scott's truck is a 96 & yours a 99 could the 24(improperly valved)

tstats be different than the correctly (12)valved

Bob

 

[barryg41]

I am sorry... . my brothers truck is a 96... didnt say that

 

[illflem]

Removing the belt is no big deal, 30 second job, two minutes if you take your time. On the tensioner pulley arm there is a square hole a few inches down from the pulley. Just insert a 3/8" breaker bar in the hole and release the tension by twisting the arm. Take care to note if your belt routing matches the diagram by the radiator, the diagram is wrong on some years.

 

[barryg41]

Hey Bill,



Not to get off the subject, do they make a t-stat that will make the 96's (or other 12 valver's) stop swinging so much with the engine coolant temps? Or is it just the nature of the beast?



Oh, yeah..... the 24v, (improperly valved) you dont have to remove anything but the bolts and the hose.

 

[C Schomer]

I don't think I moved the alt. at all or touched the belt. Just unbolt the housing from the block and alt and leave the alt hang by the lower bolts - it was a piece of cake! The new stat helps swing but as soon as the weather cools off, I put cardboard in front of the radiator. I leave a hole ahead of the fan clutch for a little air. The clutch won't know when to engage and it will overheat without that! Then I start blocking the coolers when temp drops more - leaving the center area open. Cardboard is plentiful and works good! Craig

 

[Don M]

barryg41,



the new thermostat will deal with the swing. It did in mine at least.



part# 3828499 its about 23 bucks



housing gasket # is 3927305 'bout 3 bucks



Don~

 

[barryg41]

Man... . is that stealer price or what? We've always wondered why it swang so much. But $23!?!?!?



It never has hurt anything!.



Thanks Don for the Info... .

 

[illflem]

When I installed the new thermostat it mellowed the swing but ran too cold. Ended up doing what I should of in the first place and used a 190° Stant t-stat from Napa, $8. 99. Still swings a little until warm up then holds steady. What works best for me for winter is grill inserts and fanless, helps keep the intake temp up also. This isn't for everybody, Montana tends to get a bit cold...

 

[Don M]

illflem,



I am running way too cold now as well. I gotta say it never gets over about 150. It was around 65 degrees here today.

The most I have seen with the new t-stat is about 160.

Way to cold to burn all the fuel I have. It wont run the right way for at least 10 minutes of driving. Is the NAPA part the same dimensions?



Don~

 

[drawson]

I have had 4 stat go south on me in 118K. all of them the rubber insulator had came off and was holding the stat open. This last time I went with a Stant 190 deg stat and it does cycle like the OE one did but the temp is higher and the heater has worked better this year than ever. I got it at a Car Quest for $7. 95.

 

[barryg41]

So I am guessing that... any t-stat is going to make 96' engine temps swing? I put a 190 in his truck but it stills swings. I never drive it but he says it does a little better. When yall are pulling a load does swing the same?



We dont use a winter front... . I tried a cardboard front with a 10 inch hole in the middle. But the ambient temps go up and down so much here that I just gave up... dont really need it.



I bought the PS High Idler to help faster warm ups. Havent really had a chance to try it yet.

 

[illflem]

Barry, the cycling problem isn't the t-stat, it's the overbuilt cooling system on our trucks. Seems like it was designed to pull a freight train in 100° weather. I've often thought that during cold weather that you could even remove the radiator and just the heater core would be enough to keep things cool.



Don, the t-stat dimensions are the same as they are for many gassers for the last 20 years. Just ask for one that fits your engine.

 

[sewman]

I had the Tstat for the gasser 1995 dodge w/a 360 engine in my truck for a couple of years.

Works for me.

Bob

 

[shendren]

wow. thanks for all of the responses. i ordered the t-stat from genos but the part number was not 3828499. i'd have to check it to see. i think i'll do the illflem thing and buy the one from napa. so it doesn't look like i'll have to remove the belt after all? thanks again for all of the input. scott.

 

[HoleshotHolset]

What would one consider to be 'cold enough' to run fanless? It gets cold around here (MA), but not Montana cold... ...



Darn truck takes forever and a day to warm up fully and even then the heat isn't that great... . or maybe the heat is good and all of the heat is falling by the wayside due to the fact that I have no insulation on my cab floor (no carpet. . just painted steel!).



It seems that most service manuals tell you to take off the belt anytime you are dealing with anything related to the accessory drive system, whether you need to or not... . just like they tell you to make sure its in park, wheels chocked, E-brake engaged, case of beer cold and ready for consumption, batteries disconnected, peanut oil at 325*F for frying up some munchies, and other stuff like that.....



Matt