papa tiger

Or jack the front of your truck up. Have you experimented with the configuration of the drive belt? Is it on correctly? Some try their own path to putting one on only to create their own migranes. If good cover radiator start up and steam holes will force air out and open the thermostat up eventually. Watch the temp gauge to not go over 210 and your ok. Once the thermostat open up and gets the truck up to operating temp uncover some of the radiator core to allow air and manage the temps until all the air is out. If everything is ok than good. Thermo must control the lowest temp the engine operates at. That is its designed tolerence. You may need to bleed out some of the PSI and do this repetedly for a 1/2 hour or so. Remember the motor isn't really warmed up for quite some time say 15 minutes. Don't know your temps there but at 20 degrees or so its perty slow. You should have -35 F. antifreeze or so with tester. Don't be afraid to run the engine up hot and shut it off and allow it to cool back down, it will pull in coolant from the bottle to replace, fill pockets as it cools off / syphon into itself. If this doesn't work for you you need to go to your local radiator shop for proper repair of you coolant system.

1997F150XLT

That is a cool looking tool that snap on has there. To me it just seems that air in the system would cause an over heating issue. And I get that it may not be at the temp sending units but I have taken readings on at least a hundred points on the engine and the cooling system. None have been over 160°F. I am thinking it has to be something with the thermostat. I had heat last year in the winter. I didn't open the cooling system between then and the time I had no heat. The first thermostat I pulled out was stuck open. I must be doing something wrong in terms of thermostat replacement. I almost wish I could reverse the flow someway.

papa tiger

The o-ring holds the thermostat in place and the cover wedges it into seat. It would have to be the original gooseneck fit. Sometimes a cooling system can be difficult at first and if you heat it up by blocking off the radiator it should clear itself out when it cools back down a couple of times. Otherwise the manifold gooseneck area are suspect of damage/wrong parts. Believe the v6 has a notch to locate the thermostat. Just a note. LOL

papa tiger

Did you get your problem fixed ? Re reading your first post I believe you still have clogged heater core or clog in water feed to it or from it.

1997F150XLT

nope no fix yet. Is there a certain way that the thermostat needs to align?

cool50

It looks like a year has gone by on this post. I'm new here and every time I have had a problem I have been able to find it here and fix it. I have the same problem I have changed the t-stat no change. I do not think it is trapped air in the system because the system was never open to introduce air into. Also, I believe that if it was a clog in the system that would cause a overheat condition, so I do not believe that is the case. I do get heat at low fan settings. This is not good, I'm used to getting nice and hot during the winter. Well, if ANYONE can help thank you.

RLXXI

Thermostat stuck OPEN is usually the cause of these symptoms. The water won't stay in the engine long enough to heat up before it gets pumped back into the radiator to cool down.

RA042124

I am new to the forums and have been experiencing the exact same problems. What was the outcome of the problem? It is NOT the thermostat. I have changed mine 3 times with the current one being a ford stat. I too read lower temps with the laser gun all over the motor and hoses. I have check the water pump replaced the temp sender back flushed entire system. I have been driving around without my fan on and gain very little heat from that but still is not up to full operating temp. Also replaced the radiator cap. I have a 1997 f150 with the 4.6. Any help would be great aside from replacing the tstat for the 4th time. I had read in another forum I found that one theory was a bad head gasket leaking exhaust Into the coolant putting hot gas at the stat causeing it to open premature

I noticed once or twice when opening the radiator cap the smell of rich exhaust. Where can I get the fluid tested to see if exhaust has been entering the coolant

kdemler

Fx4redneck,
Believe it or not, I just got the problem solved and it ended up being a clogged heater core; yes the problem I initially started with. Actually it was a leaking core. Once I finally replaced the radiator and still had a cold lower hose (return), I knew the only option left was the heater core because I'd replaced everything else. This has to be the most frustrated I have ever been with a vehicle issue. I'm not sure about the exhaust smell you are getting but I would have the coolant checked; I have heard the blown head gasket issue as well. Hopefully that is not your problem.

Things I replaced:
Heater core
Blend Door (it was cracked at the actuator base)
Blend Door Actuator Motor
Thermostat
Water pump
Radiator

Good luck

RA042124

Thank you so much. That is next on my list to accomplish I have a new core and blend door to put in. Hopefully that is my only problem.