I put back my oem stat a week or two ago and it has been much better. I started thinking maybe my cooling system wasn't up to par, but the Ford 192 usually runs about 190 empty and the mishi 200 was running 206. I would love to have a mishi around 192 to 195, but not any hotter. We are planning a 4000 mile Yellowstone trip at the end of July, so we will see how well the cooling system is working when I am in the summer heat, pulling those kinds of grades, at 22000 pounds gross.

 

I really do like the 200° tstat. I sure hope they do a 192 or 195,
I just swapped it out for an oem one. Got a leak at the housing so will fix that in the morning.

 

How about a 197?

Josh

 

I'd probably be down for that but thinking 195 on the high end would be great based on how hight the 200 is getting right now--aat least for me.

 

Makes me sick to have the oem tstat in. It doesn't regulate very solidly (numbers very up and down quite a bit) Mishimoto--I'll be a test subject if needed for a 192, 195, or 197 tstat if that's in your wheel house

 

Me too, Mishimoto. I would rather have a 192 or maybe a 195. I don't want a 197. A 200 that runs 200 would not be too bad (except for heavy towing) but a 200 that runs 206 just doesn't cut it.

 

I think I'll also throw my hat in for a very good, solid working 195* thermostat from Mishi.

Right now all of my driving is on island at speeds at 55 mph or under and so the temp stays right at about 198*. But, the other day we got a little warm spell where temps reached just above 70* and the ECT was hovering around 201* which is still pretty good. But, if I were cruising through the southwest during the summer, pulling a big trailer I would probably think twice about running this 200* t-stat.

 

yeah-- I agree 195

 

Just out of curiosity what temperature do most gassers run at? My 5.9L Dodge with a stock thermostat likes 202 and with the A/C on it runs at 196.


I think there needs to be a refined number where the engine is running at an ideal temperature, doesn't seem like there is a consensus on this.

 

Yesterday and again today, my truck ran a little hotter than it should

The engine coolant temp went as high as 216 degrees and sometimes stayed there. I had to turn on the heater to cool the engine down even while cruising on the freeway. (I have pictures to prove this)

Today it got hot again, but after a long cruise it started to cool down to around 204 degrees.

I went to the dealer and got a new OEM thermostat that maintains 190-192.

I'm not sure what the issue is, but I hope no one else has the same problem I did.

 

Mishomoto will send a gasket if you request one. I put my Ford one back in yesterday. Temps around 88 outside it was running around 205 -208 unloaded with A\C on.

 

The OEM thermostat comes with a new housing and gasket. I don't mind the 200-204 degrees, but when it's getting hot almost to the point of overheating and I'm not towing anything, that's what worries me.

 

I am getting good at this, replaced the Mishimoto with what I thought was my 192 Ford thermostat on Toreador Diesel's advice, nope, I put my old weak 182 thermostat in so I had to change it a 2nd time to the correct thermostat. Running 192 now. Will probably put the 200 back in for winter.

I don't want to take any chances towing and overheating.

 

With the Ford 192 in I got as hot as 210 today pulling up a pretty good hill empty. The rest of the time it ran around 205-207. I had the AC on high the whole time, but this stat is all over the place. I wish Mishi would make a 192 or 195. They offer a 185 and a 200. 192.5 is right in the middle of those two.


If I just knew the 185 would run several degrees hotter than listed like the 200, I would just run it (at least during camping season).

 

Well, the results are in -for me at least- on whether I can keep the Mishimoto thermostat in my truck for the summer... Nope.

Outdoor temps have been creeping up here in LA (Lower Alabama) and the truck ain't liking it. At 69° ambient I have a nice 204°/202° (EOT/ECT). By 81° I'm seeing 209°/206°. 90° is 211°/208°. All of that is unloaded 65-70mph. An even bigger issue came up on a short 45min tow of the 9k lb fifth wheel. At 88° most of the trip 233°/227°, a little higher after a series of short but fairly steep hills. I'm thinking this is 10-14° higher than I would have seen with the Motorcraft stat. I will be towing larger hills at higher temps later in the summer and can see the writing on the wall. It's not a big job but I don't want to be doing a stat on the side of the road in my "relaxin' britches"

I feel like the cooling system is in good shape, fresh coolant, almost new Mishimoto radiator, low temp spread, cooling fan working correctly etc. It is still running the original water pump as far as I know, but no indication there is a problem with it.

I think I'm going to drop a factory stat back in it for the summer and go back to the Mishi in the fall when temps start dropping. It was sweet back when the temps were cool. I don't have any formal training in thermodynamics but I posted earlier in this thread that I didn't think this would be an issue, I guess I'm missing something.

Mr. Mishimoto,
Any thoughts on this particular truck? I was an early adopter on this, was there any "tweaking" during production, are the early units any different than the ones on the shelf now? If you would like to have this unit back just to check it out, send me a PM. If not, I'll drop it back in come fall. I really don't think there's anything "wrong" with it and I'm not angry about this, as a matter of fact, thanks for trying.