Made in CHINA 6.5td dual thermostats

[DA BIG ONE]

Ran into a problem with 6 month old thermostats sticking open.

Pull em out and find the (big) back gaskets (on stat body) on both of them somehow managed to get pushed into and stuck between the thermostat valve and its body.

Most obvious is "MADE IN CHINA" stamped on em.

[john8662]

The Delco units have done the same thing. I have no idea why the rubber thing is on there in the first place. The Robertshaw stats don't have this feature, probably for good reason.

J

[Robyn]

With the dual stats the rubber ring is the seal and this seals the T stats to the housing.

[DA BIG ONE]

The Delco units have done the same thing. I have no idea why the rubber thing is on there in the first place. The Robertshaw stats don't have this feature, probably for good reason.

J

Do they have a larger diameter body to make up the space the gaskets used to occupy, or?

Can that gasket just be removed from any other thermostats, or?

[DA BIG ONE]

With the dual stats the rubber ring is the seal and this seals the T stats to the housing.

I understand the thermostat lip gasket seals the stat and housing, but that big rubber one encasing the back of the stat body seems to have no reason for being there.

[daustin]

That's the seal like Robyn said. There's a catch on that though, there's 2 thermostat housing casting types with different depth "depressions" for those. The deeper one is the type with the rubber seal, the shallow one utilizes the old-school gasket. A lot of parts systems/books lists them as interchanable, but in reality they are not. The Made in China thermostats are junk IMO.
Don

[CapnAmerica]

FWIW...I have been using the Mr. Gasket 4367 (proudly built in China) thermostat, originally for big-block Mopar engines from the 70s, in both my '96 and '85 Suburbans. Being an inveterate (NOT invertebrate) cheapskate, I haven't installed a dual-stat setup. However, the last two of these--from two different sources--have stuck...the first stuck closed going over a mountain in TN, and the second stuck open (would NOT heat up), then later stuck closed (heated rather well, thank you!). Gaskets are the garden variety--cheap-o paper-looking one over the lip. Or, in the case of the last emergency fix, black RTV, which hasn't had a drip yet.

Question of ??? - What other stats have a high-enough flow to help avoid overheating? To help avoid manufacturing defects like sticking? What's the difference between the OEM size and the ones inthe dual-stat system?

Thanks!

[daustin]

I had several stuck thermostats in the last few years on both trucks and my
9C1 caprice too. I got better results with the SS Diesel thermostat or Robert Shaw thermo's. No more sticking, a little more expensive but worth the few extra $$. Don't recall where i got the Robert Shaw's, it was a vendor from here or the diesel place. I'm still running the single setup on the 3500, haven't had to move to the dual setup yet.
Don

[Robyn]

Going to the HO water pump and the dual stats is a very good move on these engines especially if you are working them a lot and even a better idea if you live in a hot climate.

The best stats I have heard of are the Robert Shaw stats. 180F opening

The factory Delco stats are fine but the 190F is just too hot.
By the time the stat/s are open and the coolant is flowing to the radiator the temp is about 215 or so and then it takes time for the radiator to transfer the heat and then there is the lag time for the viscous fan to respond to the temp and turn on. Its very common in warm weather for the engine temp to reach 230F before the fan is fully hooked up and the temp starts to drop.

Too bloody hot me thinks.

JK sells a lower engaging fan clutch that will help some.
Personally I have been working on a Horton electric clutch that is switched with actual water temp and also has a manual switch to overirde the system and allows the fan to be run constantly and at full speed.

When pulling a hard grade its easy to just turn on the fan and leave it run to keep the temp in check.
For those times when mom and the kids are using the rig the auto controls will take care of things handily so there is no need to worry.

The only issue with this setup is that it is not commercially available and the HO water pump must be fitted with a flange from a Powerstroke of mid 90's vintage.

This is not a biggy but not exactly a bolt on in 15 minutes either.

Good luck with the stat issue

Robyn

[MTTwister]

I got my Robert Shaw's at Checker Auto - in a prestone box. Still about $12..

[JohnC]

Robert Shaw is a British actor. He was in Jaws.

Robertshaw is a thermostat manufacturer.

[MTTwister]

musta gave him an enema before they stuffed him in the box.

[Kennedy]

Same top quality stats still on the shelf here. Used to be in Robertshaw boxes, now in Prestone boxes.

I don't think you'll find many DP supporters selling the cut rate junk...