Really hate asking this question
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
Well, "may" contribute to sludge formation. Generally the idea is always to get any engine to the normal operating temperature as quickly as possible. This is optimum with respect to fuel economy, pollution, and engine wear.
Enginering studies found engine wear cut by half by using a 195 versus a 160 or somesuch. Do any OEM cars or trucks ship today with a 160? It was my understanding they were used in the pre-glycol coolant days, they used methanol. Dunno.
Enginering studies found engine wear cut by half by using a 195 versus a 160 or somesuch. Do any OEM cars or trucks ship today with a 160? It was my understanding they were used in the pre-glycol coolant days, they used methanol. Dunno.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
351C/351M/400 use a different thermostat than I-6 and other V8 engines.
DOAZ-8575-A .. 192 degree Thermostat (Motorcraft RT-139).
1970/74 351C (cars only) / 1971/78 400 / 1975/78 351M
D7PZ-8575-A .. 180 degree Thermostat (Motorcraft RT-310).
1977/79 F100/350 351M/400 / 1978/82 Bronco 351M/400 / 1980/82 F150/350 351M/400 / 1980/82 Econoline 400.
D9TZ-8575-A .. 192 degree Thermostat (Motorcraft RT-1026).
1979 F100/350 & Bronco / 1980/82 F150/350, Bronco & Econoline (400).
DOAZ-8575-A .. 192 degree Thermostat (Motorcraft RT-139).
1970/74 351C (cars only) / 1971/78 400 / 1975/78 351M
D7PZ-8575-A .. 180 degree Thermostat (Motorcraft RT-310).
1977/79 F100/350 351M/400 / 1978/82 Bronco 351M/400 / 1980/82 F150/350 351M/400 / 1980/82 Econoline 400.
D9TZ-8575-A .. 192 degree Thermostat (Motorcraft RT-1026).
1979 F100/350 & Bronco / 1980/82 F150/350, Bronco & Econoline (400).
Senior User
Joined: Feb 2016
Posts: 247
Likes: 2
NumberDummy, I am so glad you are here. I used the Mr. Gasket 4365 per guidance from the local speed shop. Summit Racing confirms that it is used in the Ford 400. However, I notice that they state that it is for the year 1980. That is strange, the 400 did not change thermostat housings that I know of, or did they? I am speaking of the copper skirt, should the thermostat have one do to the chamber below it?
I have one in my 400 and it looks and fits like the Robert shaw.
I will be changing to a NAPA thermostat With the correct 11/16 flange.
I have one in my 400 and it looks and fits like the Robert shaw.
I will be changing to a NAPA thermostat With the correct 11/16 flange.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
NumberDummy, I am so glad you are here. I used the Mr. Gasket 4365 per guidance from the local speed shop. Summit Racing confirms that it is used in the Ford 400.
However, I notice that they state that it is for the year 1980. That is strange, the 400 did not change thermostat housings that I know of, or did they?
They did 1980/82.
However, I notice that they state that it is for the year 1980. That is strange, the 400 did not change thermostat housings that I know of, or did they?
They did 1980/82.
1977/79 F100/350 / 1978/79 Bronco // 1977/79 FoMoCo Passenger Cars.
No 351M/400 engines in cars after 1979. Cars prior to 1977 used a different t/stat housing.
EOTZ-8592-C .. 351M/400 Thermostat Housing / Obsolete
1980/82 F150/350, Bronco & Econoline (400 only).
Tuned
Joined: Sep 2003
Posts: 348
Likes: 2
From: Northern Michigan
So I should be good with this one?
Stant SuperStat Thermostats 45359 - Free Shipping on Orders Over $99 at Summit Racing
Stant SuperStat Thermostats 45359 - Free Shipping on Orders Over $99 at Summit Racing
13468 will get you a 180 degree thermostat.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
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Tuned
Joined: Sep 2003
Posts: 348
Likes: 2
From: Northern Michigan
$6 made in USA. Stant never was Creme de la Creme. Just parts that work.
Tuned
Joined: Sep 2003
Posts: 348
Likes: 2
From: Northern Michigan
Part #: 48-46820-1
Alt Part #: D9TZ-8575-A
http://www.oehq.com/partpix/motjpg/rt139.jpg
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
Now I'm hearing they are to be avoided. Just Sayin'.
Cargo Master
Joined: Dec 2008
Posts: 3,221
Likes: 323
From: SW PA
None of the t-stat's listed in this thread are the correct ones. (except for the original motorcraft P/N's by numberdummy)
Will they work good enough? Most likely.
Do they function as per original design? No they do not.
I have seen a person selling the correct custom made ones on ebay for Pantera's and 351C's for about $80.
Will they work good enough? Most likely.
Do they function as per original design? No they do not.
I have seen a person selling the correct custom made ones on ebay for Pantera's and 351C's for about $80.
Thread Starter
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New User
Joined: Jan 2016
Posts: 22
Likes: 0
From: Lindenhurst NY
Thank you for all your help and steering me in the right direction. I ended up getting a motorcraft rt-139 probably paid to much but at least i know it's correct. Now on to the rest of the cooling system. Next up radiator re-core, heater core, water pump and hoses. Trying to go through this truck system by system. Hopefully ending up with a bullet proof slide in camper mobile.