cannot find anyone selling rs thermostat for 351M motors. would love to find a 160 and a 180 . does ford still carry thermostats for these dent motors??
If so does anyone have the motorcraft numbers ??

 

Not sure on the rs stat but Autozone carries premium "fail safe" and Duralast brands in 180. The Duralast is working fine in my 400 (std. temp).

 

Autozone doesn't carry the correct thermostat. Napa is the only local place where i've found the correct one.

Ford part number is, IIRC, Rt-139. It is NOT RT-1139.

 

thank you for the ford number I'll hit the ford dealer in the morning and if they have or can order them I'll buy 2 so I'll have a spare

 

If they can find you one, check, double check, and tripple check that they are actually RT-139's. You need the "hat" on the bottom of the thermostat, as seen below when open. You can also get a Napa THM 297 for all of $7.

 

I got my first one with a FlowKooler kit. Seems they are connected? The 333-180 is hard to find now, as is 333-160 ..... but as far as I know the 333-192 is still made, though marketing has changed maybe?

If they get too hard to find, I'll have to use my spare some day ....

.... or remove the "hat" from a dead 333-series and install it on a 330-series .... that too would work. Just a press fit I bet.

 

Crap when I put the motor in my truck I had to go 4 different part stores before I found one that said they had a thermostat for my truck. It was an Auto Zone where I bought it I didn't notice if it had a hat on it or not but it has run hot (hot not over heating)from day one. I guess to be on the safe side I should just order a new one from Napa and put it in.

 

There's your problem. AZ sold you one for a 351W.

 

Found that at Napa they have both the 180 degree and the 195 degree in stock.
What is the argument for running the cooler one rather then the stock one?
THM 197 THM 297

 

Longer warmup times, wasting extra gas, excess sludge buildup...


Stick with the 195*

 

I'ld make sure.

The hat missing will certainly result in hotter temps as the bypass is not restricted so even as the T-stat opens .... much coolant just recirculates through the wide open bypass channel to be pulled through the W-P and shoved back through the engine .... instead of radiator coolant.

On a hotter day at highway speeds, I saw mine steadily rise when I first swapped a new T-stat when I first installed AC and started working on getting the motor to stay cool, I had to pull over and let her cool a bit. That's when I learned .... and lead to me finding out about "the hat" (and FlowKooler stuff and started using RS 333-192 T-stats and modded my WP with a disc).

In the 351W/289/302s, the restriction is the kink in the bypass hose with the flattened insert, that's not there with 351C/351M/400s (that have a wide open bypass when cool to speed heating up and eliminate cavitation, yet which restricts when hot so coolant is redirected through radiator).

 

Just got around to pulling out my t'stat and sure enough it had the wrong one in it. I put the correct one in and it runs way cooler.