kdemler

I haven't had the chance to dive into the truck to test my theory yet. The truck isn't my daily driver so other things have taken priority.

stilbo

Metering plates will be an interesting concept. Be sure to closely monitor your head temps as these things are prone to head gasket leaks on good days. Never mind the nightmare a warped head would be.
Let me know how it went when you find anything out.
If your temps don't go up with a 0.125" orfice you have to have some sort of bypassing (if that's even possible) going on.
I'm in the same situation as I have a take-home company vehicle so the F is used on weekends, hauling or end of the world snow storms.

stilbo

If you DO NOT see an appreciable increase in operating temps.....

Could low temps be attributable to low combustion temps?

Ignition timing, fuel delivery or?

How many miles do you have on yor F?

I'm at 206K....

stilbo

Sounds like you may be pulling your t stat hsg before me so...

I was reading something in a Crown Vic Lincoln forum regarding 4.6 engines running cold... The writer sounds very knowledgable and referenced a few factory suggested proceedures in cooling system repairs.

One thing that really caught my eye was the method that he uses when doing an r&r on the t stat is..... he pours coolant into the manifold through the t stat opening, filling the block and waits until all air has escaped... he even removes a heater hose at the engine to aid in air removal. He obviously isn't talking about an F because I've looked at the heater hoses locations and never mind that...

But what really got me thinking was.... I checked the cooling system capacity in the owner's manual and attempted to add that amount but it seemed like I was not able to get 3-4 Qts into the cooling system after a complete drain and that was also after a flush with the radiator hoses removed...

This might be simple but it could be possible that even though we think we have bled all of the air out (burping the hoses), there could still be a signifigant amount of air in the sytem or "airbound". Fill the block through the t stat hole, install the t stat and housing then remove the upper radiator hose at the radiator and fill the radiator and upper hose then reconnect them... That connection point is pretty much the highest point in the system. You then could add (or remove?) coolant to the resevoir.

I won't be able to try this until this coming weekend at the earliest but if you are thinking about working on your F before then, you might try this before you install an orfice plate.

I owned a BMW 530 and remember having one hell of a time getting trapped air out of the system. I also remember that I finally bought a manual and filled the system in several steps that included r&r of the hoses in the purge process....

Hey... It's probably worth a try....

stilbo

http://www.crownvic.net/ubbthreads/u...Number=1973039

stilbo

I thought that the guys talking about parking their trucks, front end up hill were nuts but it's starting to make sense....

I might run the F's front passenger side tire up on a ramp and leave it there, and once it's cold remove the upper radiator hose and hope for nothing but air. If that's the case, I'll fill the upper hose and radiator with coolant....

Nver thought to ask but....

You ARE using 50/50 coolant mix right?

stilbo

Maybe the simplest means of purging air?

Loosen 16 Lb coolant resevoir cap. Run vehicle with heater full on for 30-60 minutes.

With the cap on tight, trapped air may not be able to easily escape.

?

stilbo

Then again..... The resevior's only tie-in to the system is the the lower radiator hose which is the LOWEST point in the system.....

Ford designed this system to trap air.

Honda cooling systems have a second cap on the cooling system at the highest point.... guess what that cap is for....

A tee with a removable cap on the tee on a heater hose (high point) would probably be the best option for purging air.......

stilbo

Just thought of something else....

The "COLD LEVEL" on the resevoir would infer that the engine and anything else in the cooling system that is higher than that "COLD LEVEL" line would have air in it?

?!?

1997F150XLT

It could be the case. I read the forum in the link and that guy had a worn thermostat housing. I don't think that is my problem I replaced my housing when I did the tstat. Now maybe its not seated the correct way. I am going to look at it tonight. When I did the tstat I had coolant all the way up to the top of the intake. I will look at filling it up more but I don't think that is the problem. It 99% has to be coolant getting past the thermostat all the time. I think that I will pick up all the thermostats and housings that I can and see if I have any measurement differences between all of them.