78 400 runs cool
 

I finally picked up and installed a fan shroud for my truck yesterday but now the temp doesn't get very warm. I bought the truck 4 days before Christmas 2017 and It didn't have a shroud and wouldn't get warm so I changed the thermostat to a 190* and I got a nice warm heater and the truck would come up to temp but now with the shroud installed it's much cooler. My truck just has the standard radiator and not the big 4 core. I'm wondering if my motor is just wore out enough it doesn't get too hot?

Maybe it didn't leave the factory with a shroud? What fan do you have - how many blades? Is there a fan clutch? Does the truck have AC?
If no fan clutch or AC, I'd believe that it never had a shroud.

A 195* thermostat is what is recommended. The shroud should have nothing to do (or very little) with engine temperature - that's the thermostat's job. The shroud is to make sure air is being pulled through the opening to cool the radiator's coolant once the engine temp gets to ~ 195* and the thermostat opens. It'll close one the coolant gets below ~ 190* allowing the engine to get up to operating temp again. Open/close, etc, etc.......of which, I'm sure you're aware.

Have you the correct thermostat for the 351C/351M/400?

Those idjits at the parts stores hear "351" and give you a Windsor thermostat......not the correct one. Next time in the parts store, ask for a thermostat for a 400 Ford and watch the steppin' and fetchin' on their part. Probably won't be able to help you.

I'll see if I can find a picture of the correct T stat for ya.....this new format ate most of my pictures I had in here. Now I have to search me archives.....Arrrr

https://cimg3.ibsrv.net/gimg/www.for...021dc5d92c.jpg

Correct T stat for the C, M Block. Note the hat.
https://cimg6.ibsrv.net/gimg/www.for...f704ae9aa6.jpg

Correct T stat (left) #RT-139, 195*
Windsor T stat, (right)
Ahhh, pictures!

ALL 1977/79 F100/350 & 1978/79 Bronco 351M/400 came with a fan shroud.

The Super Cooling shroud (D7TZ-8146-D) is different than the standard/xtra cooling & A/C shroud (D7TZ-8146-A).

what temperature is it running at and where are you taking the reading?

It's got a 195* in it and It's for the 400 I hit the wrong #. Now that the shroud is on it's pulling all the air through the radiator and cooling better like it should but I lost heater temp and now my gauge just barely hits the normal line. I better see if I can find a Motorcraft thermostat for it because now I'm thinking it's not the correct one for that motor.

You need numbers not letters.

Also generally the wrong tstat will bypass too much water and it will run hot, not cool.

D0AZ-8575-A .. 351C/351M/400 192 degree Thermostat (Motorcraft RT-139) / Obsolete

1970/74 351C // 1971/82 400 // 1975/82 351M

MCDONALD OBSOLETE PARTS in Rockport IN has 1 = 812-359-4965.

LINCOLN LAND in Clearwater FL has 2 = 727-446-2193.

MILLER OBSOLETE PARTS in Binghamton NY has 2 = 607-722-5371.

Auto parts stores: There's a Robert Shaw version, I found two different part numbers people had posted. One is wrong.

So, it's either 33-192 or 333-192

Is the Robert Shaw the one that Summit sells for the 400? FlowKooler BRA 330-195 by Robert Shaw?

Cool is better than hot! Better problem to have. I have used stats specifically ordered for a 400 from NAPA and AZ and work OK. The 400 stat is not normally a stocked part... a couple days to order. Just make sure your parts guy or gal is getting you a 195 degree stat for a 400 would be my advice. Also a good idea to fit an aftermarket temp gauge at least for check.& diagnostic It does not need to be a high end gauge. A $15 parts store mechanical gauge will work fine. .

Been there too. The original thermostat was a 192. No longer made. You can get a Mr. Gasket ..I believe the number is a 4364. Comes in a 180 or 195. It does have the little hat at the bottom like the original, but it's a hair too short in width and will not seal off the bypass totally. It's as close as you will find in the parts stores to the original. Tim Myer has the correct 180 or a 195 hat style with the proper width hat at the bottom.

I had an original factory 192 in mine I got off ebay until a month ago. Worked fine. My aftermarket gauge read about 195 most of the time and the factory gauge read almost dead center. Just scared me for the upcoming hot summer days. I switched it to the Tim Meyer 180 and now the aftermarket gauge, fed off the thermostat housing..reads about 180 and the factory gauge gets up to the low end of normal, not the center like it did with the 192. . I feel more comfortable this way. I'd rather have my 400 run a little cooler than hotter and keep my oil changed frequently. I've used a temp gun and the 180 is dead on the spot.

My engine builder suggests to run Brad Penn oil with lots of zinc for flat tappet cams and I use 10W40 to keep it cool and a little thicker.

With a fan shroud and no fan clutch, no overheating even at long idles. (I prev used the 180 last summer and switched to the 192 for the winter)

Do you have the correct thermostat ? The 351M/440 DOES NOT use the same tstat as a 302 or 351W. 180 deg # 333-180 OR Tmeyerinc.com Track Boss # 17173; Google TMeyer Inc on FB, excellent photos. The 192 deg # would be 333-192
..
TMeyerinc.com also has a replacement heater hose tube for the 351M/400.