When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I just put in a new temp sender unit and a new t stat. Old sender never worked so I decided to put the new one in while doing a radiator flush and new t stat. Truck runs fine. Doesn't overheat and steam over bit the needle shows al the way over on the p and pretty much stays there whether I'm driving or just idling. Is this normal for these trucks to run a little warm. It's a 1977 400.
Also, I know the t stat is opening and can see movement in the radiator but not sure how fast it should be flowing?? Help! Totally new to old fords!
Make sure you installed the correct thermostat. Most part stores do not carry the correct one and will sell you the wrong one. The correct one will hat a "hat" on it that when the tstat opens the hat closes off the bypass that is open when the tstat is closed.
That looks like the t stat I put in although it says motorad on the side. Has the hat. But that isn't what it looks like on my engine. Just looks like a 3/4 inch steel pipe just below surface of where t stat goes. Is that the bypass??
What temp should I be running at?? Can I simply take temp reading once it's warmed up by putting a temp probe in the radiator water??
That looks like the t stat I put in although it says motorad on the side. Has the hat. But that isn't what it looks like on my engine. Just looks like a 3/4 inch steel pipe just below surface of where t stat goes. Is that the bypass??
What temp should I be running at?? Can I simply take temp reading once it's warmed up by putting a temp probe in the radiator water??
I'm not sure on the pipe. OEM temp. is 195 degrees
Get yourself one of those little infared laser thermometer guns. That will give you a good reading, and once you have one you'll find all kinds of things to shoot it at! Lol
Lol. I was just pricing them. I'm gonna get one! I don't want a aftermarket temp gauge cause I love the stock interior but want to know if I'm actually runnin hot or if it's just the gauge??
ok. Im gonna take some temp readings tonight but still have a couple questions. What should my radiator "flow" look like when my t stat opens? If OEM temp is 195 then what would be acceptable running temp range?? 195-205 etc.?? And lastly, if my temp is in an acceptable range, should I just not worry about it? I guess I am trying to avoid putting in a new water pump if I don't need to. THanks
Pretty sure it's my t stat. It has the "hat" but I got it at oreilys. My outlet looks like this
, not like the one in pic in above post. The robertshaw and motor craft t stat look completely different. Robertshaw looks like brass skirt seats on the brass seat in pic above. I can't find a rs 333-192 anywhere. I did find a rt-139 but then started reading forums about the rs 333 being better? Looks like it would be better if my outlet looked like the one in butwheats post.
I know I'm beaten a dead horse with this thread but Im just curious…Any thoughts on why the two thermostats are so different. The Motorcraft ft-139 looks like its identical to the aftermarket stats that also have the "hat". As far as the bypass outlet, why are the two pics so different. Is one for a 351 and the other (like mine) for the 400?? Thoughts…..?
If it regulates and stays steady that is a good sign. From that it sounds like the system is working. Also no steam. That's good also.
Agree the "p" in temp sounds a bit high on the stock gauge but not overheating. With a factory replacement stat rated 192 or 195F, not far off. As posted above, the stock gauge is an "indicator" but may not be accurate in an absolute sense. For diagnostic, I prefer a parts store mechanical gauge vs infrared. The parts store gauge reads water temp directly and is cheap (+/- $10-15). If you want to be sure, suggest you install the parts store gauge to check.
With a parts store gauge, you should see around 200F or a touch less with normal running. Running down the highway at light load, maybe 195-200F. Run hard, a bit more. 210F is starting to get warm, 220F warm and 230F of concern... although it won't boil until 250F+ with pressure cap and anti-freeze.
Thanks for the advice! I did check it with an infrared gun last night and it seems to be running nice and cool. Temp gauge in truck is obviously reading wrong. I could find a spit on the motor, radiator hoses, t stat housing etc. , that was over 175 degrees. Top hose was cold until engine warmed up and then got warm so the t stat seems to be working although it is from Oreily's. I did find the RT-139 so I will probably put it in anyway just because I found one and for piece of mind. Also gonna hook a different gauge. Thanks again.
I took it for a drive before I took temp. It is getting cold up here already so outside temp was only about 40. Between outside temp and infrared gun, probably wasn't that accurate of a reading. Not sure why I would be running too cold- t stat is a 192.
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
