Mr. Gasket/Robertshaw Issue?

[BobQ]

While doing some routine maintenance, I put a new Mr. Gasket #4367 (Robertshaw) 180 degree thermostat in last week in my '83 K2500. Now the temperature gauge needle barely gets off of the 100 degree mark. Previously, with the old thermostat (which was the original I believe and was a 180 degree also) the needle would sit roughly halfway between the 100 and 200 degree mark. I even exchanged the new thermostat for another #4367 180 degree and it's about the same (just barely off the 100). I stuck a thermometer in the radiator after driving the truck for about a halfhour and the temp was only 130.

Anyone else experience this with these thermostats? The only other things that I've changed on the truck were the belts and hoses. I've only had this truck on the road for a couple of months and have not had any previous temp issues. Any ideas?

Thanks!

[Robyn]

Never used those.

I have a 180F from GM in my 6.5 and it runs very close to 180F

Best
RC

[BobQ]

From what I've read here on The Diesel Page, these are the one's to use. It's in a Mr. Gasket package now, but they are actually the old Robertshaws as I understand. It looks identical to the thermostat that I pulled out of the truck which I assume was the original since the truck only has about 64,000 original miles on it. I don't know.

[Warren96]

I tried using a 180 Robertshaw in mine with the same results. Too COLD. So now I use a 195( Stant 45479 ) from a big block Chevrolet, with the single spring in the winter and spring and the dual spring 180 degree Robertshaw in the hottest part of the summer. Good luck with your cooling system and keep us posted with what you find.

[BobQ]

Hi Warren,

I've decided to leave the 180* Mr. Gasket in for now. The weather has gotten hot here lately; 100 degrees today and around 105 yesterday. So, for the summer, I'll leave the 180 in. In this hot weather, the temp needle has climbed to where it used to be with the old thermostat (around halfway between the 100 and 200 degree marks). I'd still like to put a thermometer in the radiator after it's warmed up in this weather to get another reading of the actual temps.

[Warren96]

Have you ever seen those "point and shoot' temperature sensing guns? Those make a great way to take any doubt out of what the temp is. I have seen them for as little as $29.95. Great testing tool. And by the way , when your done testing your stat, you can use it to be sure your beer is at the absolutley perfect temp every time.

[BobQ]

Yeah, I've seen those temp guns. We used to use them at my old job. That's a good idea, maybe I'll try to pick one up. And using them for monitoring the beer temps would be a great side benefit. :D

[Kennedy]

In order to "gauge" a thermostat's opening temp you will need a probe in the engine near the wax pellet. By the time coolant hits the rad cap (cold tank in this case) it has been cooled. My finding with the RS stst is that when it's cool and you are loafing they run cool. When you get them under load they do a very nice job of keeping your engine cool. Come winter my 1996 ran a 195° stant super stat and one OE stat as I like my heater to kick butt.

[BobQ]

Thanks for the info John. The other 180 RS that I had swapped with the store for this one was open by 180 or 185 (I placed it in a pot of water with a thermometer). It's been getting pretty warm here lately (mid to upper 90's) so I'm going to keep the 180 in and run it.