Updated thermostats

[sparks57]

I have to get a new thermostat housing, and I figured I would get the updated thermostat too.



I was told that the updated thermostats have this black insulation and actually fluctuate more.



For those of you THAT HAVE AN UPDATED THERMOSTAT:



Did you have any problems?



Also, did you find it to be worth the money?

 

[PPeters]

Chris:



I replaced mine when my water pump went south, but didn't realize there was an "updated" one. Got mine from Cummins, just gave the parts counter guy my CPL, kept my stock housing. I didn't really notice a physical difference in the parts during R&R.



Pat

 

[dusthomps]

I just replaced the thermostat in my 91 about two months ago. It was the "updated" one. The only thing I really noticed is that the temp gauge starts "swinging" when I'm pulling heavier loads or decided to race some ricers.

 

[sparks57]

Hmm... looks like I might save my money!



Anybody know how much thermostat housings cost?

 

[dpuckett]

Chris,



I can check with a buddy of mine that works at the local Frtlnr dealer, and see what kind of price he can get me for a 1351/ 1579 CPL engine. Or you can do like I'll most likely do to my radiator- use JB Weld on it. But if you plan on topping 500HP, it may not hurt to do it right. It shouldnt be more than $35, but you never can tell. Sounds like a regular t-stat may work for you. Mine fluctuates, but only a little bit. Mom's never moves, and it has been in there 120K.



What is wrong with yours? Or are you just suffering the DTs and getting jumpy again? Another beer, hot sorority chick to chase it with. It'll be our secret.

 

[sparks57]

Will do!



My t-stat dumps really hard... to the point where cold air comes out of my heaters for a minute or so...



So something has got to be wrong.

 

[dpuckett]

Sounds like your T-stat. Is the housing leaking (besides from around the seal)? Or has it been too cold up there to wash it off? Wash it off with some carb cleaner, or at a carwash, and see if it leaks from the housing, or just the outer edges of it, indicating a leaking seal.



T-stat itself should be <$10.



Daniel

 

[TMWeber]

I'm sure it's been hashed out but here's my tale. I got my beloved 93 CTD new. For the first 5 years (100k) no problems with the temp gauge. It would stay on the low/normal mark regardless of grade or outside temperature. (had a 1600 lb camper on) Then one day the guage would go up to about the 3/4 mark, then down to the low mark, then back up, it would repeat this non stop. Changed the t-stat. Still fluctuating. Got another t-stat. Fluct again! Told by DC this is normal Had the rad pulled, pressure flushed, new t-stat. still fluctuating. Still told this is normal dispite how great in ran in the beginning. (it also gets hot going up long grades unloaded, almost to where I would need to pull over to let it cool) It's been another 120k and I have reluctantly learned to live with it. They can put a man on the moon but...



any suggestions or should I just be happy to vent?

 

[sparks57]

Mine stays on that same line... but it will move about an 1/8th of an inch warmer and it will drop almost to the first mark to the left... .



It's not that big of a deal except for that fact that it also corresponded with cold air comming out of my vents.

 

[prototech]

Hey TMweber,

have you checked to see if the fins on your condensor, intercooler and anything else that's in front of the radiator are plugged with bugs and debris? Its all about air flow! I also remember a friend of mine with a 2nd gen had a similar problem and he fixed it with a lower temp thermostat. I haven't changed my t-stat on my truck yet, but on my gas engines I've been having good luck with 180 degree t-stats, but I'm not sure on a diesel so I'll have to do some homework, anyone know for sure? hope this helps?

Proto

 

[EZGZ]

I got this old stewart warner mechanical temp gauge.

Has a 3/4 inch pipe thread adapter with a 1/8 inch inside of that.



I have had it forever and use it for everything from standard transmission oil temp to water or even intake manifold.



True it might not be dead accurate but it is fast and uses no power.



I tape or clamp the bulb sensor where I want and then put some insulation or putty over it. Then with the gauge on the floor of the cab or hanging off the ash tray just watch the action.



Gives you a good base line for back to back testing. If your dash guage is swinging all over the place and the mechanical one is not I wouldn't't worry.



My transmission temp on the Getrag went down 45 degrees just switching from dinasour oil to 15-40 full synthetic. Tested by towing the same load over the same road at aprox mate temps a week apart.

 

[TMWeber]

I would like to clean the fins on the intercooler and condenser. I've heard they can bend quite easily. Before I begin, does anyone have a technique that they find works well?



And yes, I would like to hook up a different guage just to see if there's a difference. Thanks for the suggestions.

 

[sparks57]

Uhuh... good old fashion pressure washing!

 

[3dracer]

TM WEBER

My '92 does what yours does on temp. climbing. I pull a 28 foot camper and mine always creeps up. I found out that the t-stat is fine, but the clutch fan has gone bad. It never does "lock up". I'll need to replace it before summer.....

 

[TMWeber]

How can I test the fan clutch?

 

[bgilbert]

How can I test the fan clutch? TM> with the truck shut off, and cold, grab hold of the fan blade and try to turn it clockwise or the other way. If its locked up/wont turn or is very difficult to turn its bad needs replaced. If it turns freely, its all good. If bad, stay away from aftermarket fan clutch's, buy from Dodge. Bill

 

[TMWeber]

Thanks Bill. I'll give it a try.





Tim

 

[southpaw]

replaced t-stat in my 93 about 2mos ago. The problem, it never got past the first mark and never was warm in the cab. I also thought it might be affecting my lo 13mpg. pulled the stat and replaced it with one from napa. The old one had blown the rubber seal out of the metal diaphram and permanently stuck the thermos open. the change solved the heat problem but has had no effect on fuel milage. and it cycles but not very much.