The temperature gauge will go up to the first line, "C" and after a while almost to the next line.
The temp use to run between the "O" & "R" on Normal. So Iam thinking the Thermostat is the problem.

I started this thread on my Oil Cooler dumping oil into the coolant. Though thread is titled blown head gasket.
https://www.ford-trucks.com/forums/1...oh-goodie.html

Engine is all put back together with new Oil Cooler, "O" Rings and Paper Gaskets etc....
I have done 5 water and soap flushes and one flush with Distilled Water. It is filled with the
second Distilled Water flush.

With the flushes the engine temp was where it usually runs. After the first Distilled Water flush we had to run up north
of Reno to look at an old Mercedes parts car of other MB junk. That was a good 60 mile run ea way.
I noticed the temp was a bit lower than normal but still pretty warm. The trip back home the in cabin temp was not as warm
as it was on the way to Reno.
Got home felt the Heater Hoses and they were warm but not hot like they usually are.
I drained the Radiator and block and refilled.

Last night I had to run over to our Church for a men`s Bible study which is a 12 mile run. The temp never got past the "C" line.
I even had a piece of Card Board in front of the Radiator to see if the temp would rise some. Nothing.
probably used some cheap Chinese card Board...LOL...Note to self, Need a better grade of Card Board.

Up to this point I have just been filling the engine and Radiator with water not the Coolant bottle.
I got the Bottle squeekie clean and didn`t want the Radiator puking crap back into it.
So this morning filled the bottle and stuck the hose back in it and topped off the Radiator.
Thought maybe that could be some of the problem, even though I didn`t think it made a difference,
just covering all base`s.
This evening made a 28 mile trip to Carson City to the Veterans hall for a meeting. never got past "C".

So more than likely the Thermostat took a dump.
Last May the water Pump was leaking, so had a shop replace it, and I had a Motor Craft Thermostat I picked up from Ford
4 years ago. Was going to put it in, but ya know how other things take a priority..... the shop installed for me.

We have put 13K miles on the old truck since then. Wouldn`t think a "T" Stat would crap out so soon, but I had one where
the spot weld broke and the Spring pushed up and it would not close.

If things want to crap out, why not in the summer? Not mid winter when it cold enough to
freeze the ***** off a Brass Monkey.


Charlie

 

At least the truck isn't overheating. If you remove the thermostat toss it in a pan of boiling water to see if it actuates. If it works properly you could always reinstall it or just replace it as a MAW.

 

If your running the motorcraft thermostat they're designed to fail in the open state, it may be going out and never closing or failing and staying open.

 

Yes it is a Motorcraft Thermostat that was put in last May.

I was looking at a couple You Tube video`s on how to replace it, or
what parts to remove to get down to it.
Ford part# E5TV8575C
Navastar Part# 1807945C1
Stant part# 14399

I`ll see what Napa and kragan`s has. Ford dealer is 28 miles from here.
Kragan`s is now O`Riley`s...keep forgetting. Some times I call it "OH Really?".

Charlie

 

O'Reilly stocks the motorcraft thermostat where I live

 

I am gonna ask a silly question, but have you considered that the gauge it's self might have worn out? Or the sensor could be stuck? I ask if you would check to see the temperature that your heater can put out. Is it much colder than normal? Or does it heat up your truck just fine? The gauge is more than likely the culprit, they are resistance based if memory serves, and they can get bad readings from a variety of sources. Even the age of the wires they use can cause strange readings. Alternately you can put your hand on the upper radiator hose and see how long it takes for it to get scorching hot and pressurized. To see if the Thermostat is open all the time, or if it opens and starts to do its thing. It will however get a little warm, even with the thermostat closed. These engines have a bypass that always flows coolant. Just FYI.

 

There is just luke warm air coming from the heater. I did have hot air a week ago. I use to drive us out of the cabin.
The 2 hoses from and to the heater Core are just warm to the touch. They use to be almost too hot to hold.
The upper Radiator Hose is also just warm.

I know these gauges are a crap shoot as to being reliable.
Wish I knew where my IFR lazer temp thing is.

Called O`Rilley to see what brand of T stat they have, and is house brand, Murray. Only one they carry
so the guy said. I know they carry Motorcraft in other items. I buy the FL1995 filter there.
Napa had their house brand also, guy didn`t know who made it.

At this point, any T stat is better than what is in there. Just saying.


Charlie

 

actually they ain't Charlie.
the aftermarket T-stats tend to not work in our trucks, and they tend to not work in the always closed position which will cause an overheat.

 

This afternoon I finally got around to digging into the engine and got the Motorcraft T Stat out.
I get the T Stat Housing off and see two pieces of rubber sticking up in the top of the T Stat.
The rubber piece that goes around the side of the lower part, some how came apart. This was
keeping it opened up enough so the engine did not warm up.

Last week just before I had this problem of no heat, I was filling the Radiator for one of my flushes
and let the radiator over flow. Out comes a piece of rubber. How did that get in there?

Looking at the T Stat piece of rubber left, this where it came from. About 2/3rd of the rubber is left
that covers the Stat. The piece that floated out is the missing piece. Mystery solved on that.
Looks just like it was tore off. But what was it that caused it to do that?

Now why did this Motorcraft rubber gasket or what ever it is come apart? It`s probably a seal to keep
coolant from bypassing it. If I drop it back in there and button it back up, it might work just fine.

Since I could not find one in my area, I picked up one at NAPA. Made in china of course.
Comparing the 2 of them, the NAPA one has a thing that rattles in it, read the Motorcraft one has a BB
or something to let the air pass through. I don`t notice it or hear it rattle. Seems I read it is suppose to be
loose and rattle or what ever?

The truck is going to be running in the morning which way I go, not that difficult to dig back into it to replace
the T Stat. Now that I have done it once. It was 9deg this morning, could use some over heating.

I`ll start looking for a Motorcraft Stat, Summit Racing has them and the are just up in Reno, can have it the
next day. Maybe I should have a couple on hand. LOL

Charlie

 

Can you take the gasket/oring off the cheap one and put it on your motorcraft one?

Also the bb bypass is in the coolant neck iirc. I always drill a small hole in the outer ring of the thermostat so it can pass the air out.

 

The rubber part is molded on to the body pretty good. Doesn`t look like it can come off.
As I mentioned in my first post, had a shop install it when they did my Water Pump.
Wonder if when the guy installed it, the rubber got pushed up a bit to start the problem?
Haven1t installed one in these engines, don`t know how tight of fit it is into the hole.

Charlie

 

Right, I've got a spare I bought from an IH truck dealership a few years ago. Just looked and didn't pick at it but the rubber is on there tight. If you need it, the International part number is 1807974C94. And as stated, it has to be a Motorcraft or IH.
Me neither, but I bet it's a snug fit which would account for needing the rubber sleeve, never seen one on any other thermostat.

 

I installed a Motorcraft tstat in my 6.9l IDI. With the rubber around the body of the tstat it fits snugly in the block. When I disassembled my spare 7.3l IDIT I found a parts store style tstat in it and it didn't fit at all. It was the same type of tstat that's in my Oldsmobile. You could actually see an imprint on the tstat housing gadket where it was sitting (wish I took a pic). There was a good 1/8" gap on one side of the tstat since it didn't fit right.

 

SHE LIVES....YEAH!!!!

thought long and hard on whether to put in the NAPA after market T Stat or reinstall the Motorcraft one w/o the
rubber piece that goes around the body. It must be there for a reason...right? But it is what caused the no heat
in the first place. Got stuck in where it opens up and let water to bypass and not let the engine get to operating
temp. Not sure what ripped the rubber in the first place.

So I decide to reinstall the Motorcraft one. The paper gasket I got at NAPA has a paper you peel off to expose
the sticky. Like a Band Aid. Stuck it to Thermostat Housing, but left the other side dry, and bolted it up.

Pay attention as to how the various pieces go back together. don`t get ahead of your self. I put the Alternator
bracket on first, then realized the large bracket for the fuel filter has to go on, then the Alternator bracket.

After I got it off, place the filter bracket then the Alt. bracket in front of it. Thread in the long alternator bolt into
the alt. bracket, and thread it into the captive nut. Then thread the long bolt into the alt. bracket and through the
hole of the filter bracket, then makes it easier to locate the threaded hole in the engine. After that, the other 2
short bolts will more or less line up to bolt it together....... makes since?

Bolt the Vacuum pump back on, leave the bolts loose. There is a clip that bolts to the filter bracket for the fuel
supply hard line. Put this of first before the Alternator, or you will have a difficult time getting the bolt and nut on.
Another one of my Boo Boo`s.

Install the Alternator, big bolt, then the curved adjuster bracket. Put Alt. Belt first and adjust it, then the Vacuum
Pump belt and tighten it.
Connect the 2 Neg Batt. cables, Fill Radiator with water....what`s leaking????? OH upper Radiator hose, tighten it
and still pouring out under the truck. That damn Thermostat Housing because I didn`t add any gasket sealer.
Ya know that stupid feeling you get.....

Well diving into it the second time was a piece of cake, Iam an expert now...LOL 10 min and I had the Thermostat
Housing off, HF Heat gun drying things up, Air hose to blow out the threaded holes. Gooped the gasket with Permatex
brown goopy gasket maker in a tube. Got all the Brackets, back on, bolted down, belts tightened, Radiator topped off,
Batt reconnected, HF Heat gun shoved down the intake for a few min, and she came to life.....NO leaks...Yeah.

Took her for a run to town, 7 miles ea way, temp now, the needle sits on the "R" of Normal. Got heat...YES!!!.

So I guess you don`t really need that rubber piece around the bottom of the T Stat. we`ll see how it goes.

I was looking on Rock Auto and the T Stat`s are $17, on Summit racing $22, So think I will order a couple and have
them on hand. These auto supplies down here only have their own brand name products for the most part, and are
chicom made.
Here you can see the list Rock Auto has. The Motorad and Motorcraft you can rotate the picture to see them at
different angles. Looks like the Motorcraft is the only one that comes with the paper gasket.
https://www.rockauto.com/en/catalog/...hermostat,2200


Charlie

 

I don't know, there's been countless guys on IDI forums over too many years that say they had cooling problems unless a IH or Motorcraft thermostat was used. That RT1049 looks correct and shows the correct IH part number but if it's foreign made I'd pay the extra bucks and buy from a dealership as important as a thermostat is.