"Cam's Ol' Blue"- 1986 F-150 Base Ex-State of Oregon

Today I got done most of what I was hoping, with a few surprises mixed in.

My kid and I started the day early...





 

The first order of business was draining the radiator. Luckily it has a plastic drain cock that was easy to open.

While the coolant was draining, I replaced the oil pressure sender. And aftermarket part was installed. I removed it and installed the new stock one.

At this point, the coolant was drained. So I set the bucket aside for now. The coolant looked to be in pretty good shape, but I decided to replace it anyway.

Next, I set about replacing the thermostat. I found the old thermostat in there was a 180 degree unit. I went back to stock at 195 degrees.

I took the opportunity to pull the temperature sensor plug and put a little dielectric grease in the connection.

The block was a mess under the thermostat housing. It took a while to scrape off the old dried oil, grease and old gasket.

Old thermostat versus the new one. Old one was 180 degrees, and the new one is 195 degrees (stock temp).

I then reassembled the thermostat and housing. Before adding coolant and starting the engine, I replaced the temperature sender in the back of the engine. I thought I was planning ahead by draining all the coolant out of the radiator, but since the truck was parked facing uphill, I still spilled a bunch of coolant when I pulled the old sender.

One last thing before adding coolant. I installed the new pre-heater hose under the air cleaner. As mentioned before, the old one was gone.

I filled the radiator with coolant and started the engine, letting it warm up to make sure I had a working oil pressure gauge, and I waited for the thermostat to open and the temperature gauge to register. Of course, I thought this whole process had gone very well. Boy was I wrong. As the engine was running, I noticed coolant dripping down out of the thermostat housing. So, I tightened the two bolts slightly, and "crack!", I broke the housing and out came coolant.

I put this part of the work on hold until I could go to NAPA again. In the meantime, I hunted for the warning buzzer and found it where it was supposed to be. Luckily the previous owner simply unplugged it, instead of snipping the wires.

After we got back home, I set to work fixing the broken housing. I took the old one off and of course tons of coolant spilled out. I then realized the hard way that the outlet and bung for the temperature sensor was a separate part. Because I don't have a vice, I ended up smashing the old housing into small pieces, then grabbing part with Vice Grips and part with Channel Locks. Luckily, I was able to get them apart. I wrapped the two housing bolts with pipe thread tape, put new Lock-tite on the smaller pipe when I reinstalled it in the new housing, and bolted up the housing. I topped off the coolant, started the engine, and no leaks!
After letting the engine warm up, I have a working temp gauge again. Whew! Time for a beer.

Productive day Cameron, Thanks to your ever so cute assistant!

Yes, good day.  Even in spite of the broken t-stat housing.  The ones of those that I've seen broken were because the stat had slipped out of the notch and was holding the housing away from the block.  But some of the housings for the 300 have a system that prevents that.  Did you figure out why it broke?

All the side mount Ford thermostats I see come with an adhesive gasket to hold them in place while you get the water neck on.


ETA: Cam, your daughter's cute as a button!  

Definitely a well-deserved beer! And I get a serious case of 'deja vu' looking at your truck pics!

Quick question for you or anyone who knows, which temp sender works with the gauge? I was of the belief that it was the sender on the block and that the sensor at the thermostat was for the computer or something else... The EVTM actually calls it 'Ported Vacuum Switch'?!

I think 10884 is the one:

Yes, you are right. The sender on the back of the block is for the gauge. It has just one wire going to it. The sensor coming off the thermostat housing is for the computer.

And Gary, the thermostat housing gasket I originally bought with the thermostat was peel and stick. But not matter how much I cleaned the surfaces, it still would not stick. The thermostat itself did not have any adhesive of any sort with it, so I sort of had to juggle the t-stat and housing when I started the bolts. Somewhere in there was a leak, so I tightened, but I went a little too far and the brittle old housing cracked just to the left of the right-hand side bolt.

I don't see anything that looks like a 'relieved' emoji, so imagine one and insert it here...
I've already deleted the computer sensor and it would have been a pain to replace it as I've changed the orientation of the heater core feed/return pipe.

Excellent work and reporting!