Afternoon guys.....I posted a message a couple weeks back and checked out the leads you guys provide. Which I think helped, but we are still having a issue.

Ok here is the deal….I have a 1985 F150, the motor blow and we swapped it and put in a 1987 block then used a mixture of parts.

Problem: The truck is over heating when the heat is on and after a day of driving the coolant gets way low, but there is no sign of any leaks. I think coolant is ending up in the oil pan.

What we have done...
1) Replaced the thermostat
2) Replaced the water pump (new 1987 model)
3) Took the water pump off and ran water via a hose into the block to make sure it came out the other side. Also did this with air. Both of which worked.
4) Checked the temp gauge.......
5) Pressure tested the engine for leaks. Which worked out fine.
6) Bought the book about the truck and did all the reading on the cooling system
7) Checked the heater core seems fine no leakage in cabin.
8) The radiator seems to look very new and it worked perfectly with the old engine.

Questions
1) Is the manifold that was on the 87 block different from the one from the 85 block?
2) Do you think it could be possible that a gasket isn’t line up?

What I think……I am fresh out of ideas, but I think that head gaskets or manifold is my issue., but who the hell knows at this point. I did see in a couple posted you guys mentioned that if coolant was low engine will run hot. The thing here is it's always running hot and VERY hot when heat is on.


Thanks again for your thought and assistance......

 

check your oil dipstick first thing. if your coolant is leaking from the intake or head gaskets, then your oil should read very high. try this first then get back with us. also the oil will look very milky if it has water in it. you want to be sure that if it has water, to find the problem immeddiately.

also, do you have a radiator overflow tank??

 

Why did you repost the EXACT SAME THING?

https://www.f150online.com/forums/sh...d.php?t=269254

You never even replied to your first thread, and I told you what the problem was there.

 

I was thinking the same thing, water pump spinning the wrong way.

 

like Steve states in the other thread. sounds like the water pump spinning the wrong direction.

heres a pic of the two different covers, if you are using the V belt set up then you need the cover on the left with the 85 pump, with the serpentine belt you need the cover on the right with the 87 pump.