1981 ford f150 300 inline 6. Thermostat was stuck open.. the job was going well until i got the new thermostat in there. I used gasket sealer on the opening at the cylinder head then stuck the gasket on there, tightened the elbow housing bolts on to 18 foot lbs and filled the radiator with coolant. The stuff starts pouring out of the elbow housing so i tighten the bolts a bit more. Wrong. The aluminum housing cracked so now i have to replace it. I have two questions for you guys.
1. How do i get the thermostat in there straight before tightening? it doesn't lock into the housing so its just wiggling around in there how the hell did they get it in straight to begin with? i tried using a flat head screw driver to hold it straight as i tightened the bolts but obviously it still wasnt straight because it all leaked out without even turning the engine. My manual says to place it in the elbow housing and turn it clockwise to lock it in but there are no locks to be found.

2. What is the name of the piece that attaches to the elbow housing that the heater hose fits onto? it's got those vacuum lines coming out for god knows what.

I'm uneducated and any input is greatly appreciated! Thank you all.

 

If your thermostat doesn't lock in as some do, then get one of the self-adhesived gaskets, and stick it on the housing to hold the thermostat in.

Don't know the answer to the second question as I don't understand it. Perhaps a picture?

 

Or, you can use a rubber band and a pencil to hold the thermostat in place till the bolts are tight.

 

1. Only a genuine Motorcraft thermostat will have the lock the Ford manual is referring to. You push it into the thermostat housing and turn the thermostat and it will lock into place. Then put the gasket on the housing and bolt the assembly on the intake manifold.

The stock thermostat temperature rating is 192.

2. The heater hose elbow or connector that screws into the intake manifold will have two ported vacuum switches. I know that one of these will operate the EGR valve, and I think the other operates the evaporative emissions or if you have an engine computer, electric temperature switch.

Click the link below for pictures of 81-F-150-Explorers gallery:
1981 Ford F150 4x2 - 1981 F-150 Explorer Custom

 

Any sort of glue or even a little rtv around the edge of the thermostat will hold it in place long enough to push the elbow against the engine to hold it in. Don't let go till you get the bolts tight enough to hold it against the engine.

 

Be careful buying a replacement thermostat housing.
I bought one at Auto Zone, the two holes were not in the right position.