When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I was pulling a 25" gooseneck flatbed with a 3K load.
Well besides it was Hot temps the Deltas look like they are within the 15* Spec or Realy Realy close considering you was towing when those numbers was taken
I am leaning towards a Bad Thermostat or Bad Front Cover and or a Water Pump Problem or maybe even junk in the radiator that needs cleaned out to let the Air flow pass threw the Radiator fins to cool properly
and with Diesel Fuel in the Coolant you have a Bad Injector Cup in the Head and the Best way to fix it is New Heads Sorrey
I have read the Injector Cups are able to be changed but its Very Hard to get them to Seal Back up so thats why folks go with New Heads
I flushed my system using Cat cooling system flush. as to what it might or might not have cleaned out I can't say. the flush chemical was in the system for about 5-6 hours of driving to/from and around the city shopping. basically fully hot the whole time. 2 R/O water flushes afterwards it still looked like medium iced tea. the only drive since that really matches the ford test, I had straight water in but my delta went down about 4-6 degrees. perhaps the cat chemical dissolves stuff rather than knocking it loose as particles. 115,000 without a coolant filter, just switched to red ELC , still gots me a great delta (:
Took it over to the shop and told him to replace the head, new OEM head gaskets on both sides, ARP studs and new degas bottle. This better be the last thing to go wrong for a while because I'm running out of money.