2018 eco boost diesel transit overheat issue

[tonytransit1580]

2018 diesel high roof extended transit cargo converted to camper 75k miles, bought and converted recently. Had the catalyst replaced so it would pass smog test at time of purchase. Haven’t done any other mechanical work to vehicle expect service.

I live on the coast in cooler weather. Did one 2.5hr up hill road trip in 85f weather towing a small boat.. no issues.

Have it on a cross country road trip now and a heat wave hit as we are in central US. Going up long hills in 90+ Deg F heat it will over heat, dash shows “vehicle over heat please pull over” warning. Also does same if I turn on the AC in 90f plus weather on flat highway. Temp gauge goes up. I turn off AC if it’s on, crank cabin heater up full bore and it drops right back down to normal temp. No check engine light. Also noticed loss of power today on a long grade when it started to over heat.. only wanted to do 50mph.. getting passed by semis.

Any ideas? I read fuse block showing fuse and relay for low and high speed cooling fans.. so assuming so electric fans ontop of mechanical.Anne one of these faulty.. although this wouldn’t explain loss of power. Those fuses weren’t blown. I don’t know how to check relays. Considering buying new ones tomorrow to swap in.

Dealer where I’m currently at on trip can’t see it for a month..

[2tall]

Don’t know if Ford has used the same digital thermostat in Ecoboost engines but the symptoms sure sound the same.

The thermostat in early Ecoblue 2.0 engines is known to fail and Ford knows about this since they have an updated part.

There’s some more info in this thread: viewtopic.php?f=65&t=200444&start=15