I cant get a Cummins t-stat kit until next Wed (go figure) and I need to replace mine. I got one from NAPA, its 180 deg.

I have never been big on aftermarket t-stats, but is a NAPA one i could trust?

Also what years are affected by the small hole condition? mine was built 12/00-cause there isnt a template in this one.

Thanks

 

I've been running one in my truck for 2 years with no problems in this Az heat.

 

From what I have heard and seen in many threads on this board NAPA is one of the few trusted aftermarket places for quality parts... and from my experience are the only place that has people that actually know something about engines.....

 

i have a mechanical temp guage, so ill just keep my eye on it. Iff all else fails, ive spend 6.49 to buy some time...LOL

 

NAPA and Checkers carry alot of the same brand of parts, but NAPA charges more for them. off the top of my head I can think of u-joints

 

I was just looking, is there 2 seals on my 91? I got a thick rubber with kinda a lip on one end, is there also an outer seal that i need?

 

I just bought the Cummins kit for my '92 and installed it and it had one rubber seal to hold the 'stat in place and flat plastic gasket that went between the lift hook and the engine.

The Cummins unit looked to be a 180* 'stat and my truck has never run this hot. It now actually gets up about 1/3 of the way on the gauge. Never got over 1/4 before. I guess the old stat has been stuck open since I got the truck or else the difference in style made the old one not seal. The new Cummins 'stat has a rubber plug on the engine end to seal the passage causing it to bypass. The one that came out just had a flat plate to fit against the bypass passage and it apparently wasn't doing the job.

 

I`m using a Gates t-stat, 180 deg, I figure all the stats (cept the oe cummins) are prob made by one or two companies (Gates,Stant,Robertshaw...ooops thats three). The stat i got has a jiggle valve built into it to release trapped air, but if the one you have doesnt have one just drill a small (and I mean small) hole and clock it in the 12 o clock position.

 

I've been told that the difference in the NAPA and Cummins t-stats are that the Cummins one starts to open earlier(160*?) and is fully open at 180*. The NAPA one starts to open at 180* and is fully open at 185*-190*.

I run a NAPA one in my truck in the winter and noticed that it does run warmer(more heat from heater) and higher on the gauge, just above the 1/3 mark.

The Cummins one goes back in for towing season and typically runs just below the 1/3 mark.

 

If you guys can get your hands on an IR temp sensor, shoot the stat housing when its warmed up and read the temp - no more guessing or estimates. They're pretty common now and not that expensive either.

I also drill a small hole in mine too.

 

The opening temp should be stamped on the t-stat. I'm sure the Cummins stat I have is a 160*. Can't remember checking it, but I'd love to put in a 180* for the winter because of the WARMER heat. I know the old stat was a Cummins stat and read 181*.

 

You'd think so but apparently on the Cummins one its the fully open temp.