I have a 2018 3.5 ecoboost with towing package and 106k miles. I started slowly losing coolant, saw the drip on the bottom of the water pump and took it to a dealer. The water pump, 3 seals and one gasket were replaced and the system pressure tested. It cost an arm, leg and lung. I picked up the truck and within 10 miles the temp readout above the temp gauge came on and started rising, at 278 I slowed to pull over and the temp started dropping. The fan was on high. The dealer looked at it again and said there was likely an air pocket.

I've driven probably 250 miles over the last two days and although the temp gauge never does rise, the fan is frequently on high. This is new behavior. I drove two miles up a small grade, from cold, at 34f degrees out and the high fan will come on for a while. This hasn't happened before with my first 106k. Any guesses?

Thanks,
Jim

 

Duplicate

 

Was the thermostat replaced? If so it could be bad or not the correct one.

Forum is full of this exact same problem, think all were solved with the installation of a correct thermostat.

 

Find an independent shop next time. You'll get better work and spend less.

 

probably air in the system, have you checked the coolant level?

 

That's what the dealer said about the overheating issue. That has been "fixed" but now I have a fan that runs on high an inordinate amount of time.

 

Thermostat was not replaced, but a Thermostat gasket was replaced.

 

next thing is a thermostat (motorcraft only). i do remember reading about a faulty head temp sensor causing the fan to run all the time. But I would isolate the thermostat first and make sure that isn't the issue.

 

I don’t know the 3.5, but seems like the next thing would be to monitor the actual temps, that shouid tell you if the problem is the tstat is part of problem or not.

 

278 is really hot, hopefully the engine isn’t hurt. At least you have the dealers poor workmanship documented so if it pushes a head gasket out that should be on them not you.

All late model engines should have the coolant system vacuum filled whenever it is opened up.

It’s impossible not to have air pockets in various places when you do it the old fashioned way.

Frustrating to hear stories like this - dealers should all have this equipment.