Mediocre heat
Cargo Master
Joined: Jul 2000
Posts: 2,281
Likes: 18
From: Northern California
Had a simular problem with my 88 460, found out that ford runs the A/C while your on EVERYTHING but vent!
When you run defrost, the AC is ON!
I checked the temp and it was about 120, hot enough once it gets thru the whole cab, but when I pulled the AC wires, it got hot enough to hurt!
Point: look at the blend door, remove the glove box door then the heater cover and while your at it, clean the thing out. New heater core cost me $19 @ autozone. Check for vacuum at the lines, a simple break can ruin everything.
One of those kitchen cooking temp guages can work pretty good.
When you run defrost, the AC is ON!
I checked the temp and it was about 120, hot enough once it gets thru the whole cab, but when I pulled the AC wires, it got hot enough to hurt!
Point: look at the blend door, remove the glove box door then the heater cover and while your at it, clean the thing out. New heater core cost me $19 @ autozone. Check for vacuum at the lines, a simple break can ruin everything.
One of those kitchen cooking temp guages can work pretty good.
Senior User
Joined: Sep 2004
Posts: 484
Likes: 0
From: SC lowcountry
One thing I haven't seen addressed in this post is the Tstat installation - If 460 is like 302 (horizontal), it is very easy to let the new T'stat slip down when putting housing inplace, either leaks or breaks housing; put the tstat in housing and stick gasket on housing with gasket sealer to hold in machined recess, then put on block/intake, be sure tstat stays in place.
Don't recommend gaskets with glue, the last one I used leaked thru the gasket material and was hard to isolate location of leak.
Don't recommend gaskets with glue, the last one I used leaked thru the gasket material and was hard to isolate location of leak.
New User
Joined: Nov 2005
Posts: 4
Likes: 0
Thermostat stuck open
I just had this same problem on my 1993 F150 300-6. The thermostat was stuck open. When I removed it, the valve wouldn't budge. Sure glad it didn't get stuck closed! That would have been a real treat.
