I towed a 3,000 pound trailer that was empty for 200 miles and had a 58 to 62 degree spread while running 72 MPH. I then towed it back with approximately 3,000 pounds of stuff (helping a friend move to Orlando) for a total weight of 6,000 pounds. I maintained the 58 to 62 degree spread while running 65 MPH. Bumping the speed to 72 caused and increase of about 2 degrees on average. I do understand that the temp spread recommended by Ford does not apply while towing but I post it for the use of anyone who's battling a problem of this sort or just for comparison's sake.

The truck will have a new front cover, low pressure oil pump and water pump installed tomorrow (07-10-13).

I have talked with the techs a my favorite shop...after disassembly but prior to reassembly we will measure and photograph the old parts and new parts to compare tolerances. We'll then run it and see what happens.

I'll report in when I have more info.

 

Actually Ford's procedure specifies a "careful WOT to achieve maximum boost" for measuring the temp differential. Many people find ford's procedure "difficult to apply" so people adopted the 65 mph on open ground measurement.

Why have you risked an oil cooler rupture by driving it that way? It is a lot more expensive when that happens! Also (again), oil temps that high can cause an issue with protection of the engine components!

 

Not only the oil cooler rupture, but if the oil filter standpipe melts down the engine block is TOAST, FUBAR, SCRAP, totally beyond repair and recovery. It then becomes a $$$$$ repair instead of a $$$ repair.

 

The risk has been carefully considered...based on our research, I have not hit the 253 degree threshold that seems to be a hard limit. I've been close, very, very close, but never hit it. The highest EOT I've seen is 251 degrees with the ECT at 190 to 200 degrees. Additionally, I'm changing the engine oil every 2,500 miles and having a sample tested.

The truck is being disassembled as I write this (8:40 am EST, Wednesday, July 10, 2013). We'll have some fresh data either late today or tomorrow. I'll report back when I have it.

Thanks again to all who've been so helpful.

 

BEST of luck!

 

I was at the repair shop a few hours ago and found some interesting things:

1. We discovered some serious marks in the LPOP gears and LPOP case from what appears to be a failed lifter at some point before I purchased the truck. We've had the oil tested twice with no metal showing in the oil and we know for sure that the short block has 20mm dowels and should be 18mm which means it was changed at some point prior to when I bought the truck. The assumption is that the short block was replaced and they used the old front cover/LPOP assembly.

2. We found considerable erosion inside the front cover around the water pump. The pump impeller is in good condition (a new pump is being installed just to be sure) but the areas adjacent to the pump impeller have been eroded away to 1/16" deep and about the same amount wide.

3. The cooling system is clean as a whistle...no grime, sludge, foreign matter or anything of concern coming out of the filter when we change it. So I'd say we got it clean inside with one rinse and two Ford spec flushes.

That's all for now...the next report will hopefully have me complaining I can't get my oil temp above coolant temp...

 

LOL - Fat chance of THAT happening!!!

 

Glad you found the problems finally.

 

A picture of the erosion is needed.
"Considerable" and "1/16" cross-sections" do not go along with each other. I would also be interested if the impeller is solidly locked to the shaft in rotation. I've never been a fan of the plastic impellers.

 

Yep, I've heard of the plastic impellers slipping on the shaft and not moving enough water.

 

What years have plastic impellers?

 

ALL MODEL YEARS have plastic impellers.

 

A man has to have dreams! But I'll settle for the 4 to 8 degree spread I had. If all goes well I'll have a 2 degree spread like another poster mentioned.

 

I will bring the old parts home and do my best to get some clear pictures showing the erosion of the surfaces.

 

Thanks. Will be interesting.