Overheat&Repeat

Hey Guys,
I’ve looked through all the discussions but have not found anything related to my issue.

2012 F150 XLT 5.0 228k miles

I found a coolant lake beneath the truck from the y-pipe and figured probably a good time to replace the pump and thermostat too.

Filled up the coolant let her warm up drive her around the block and the fans started howling. Still had coolant in degas. Hot upper and lower hoses and heat blowing.

Replaced the o’Reilly’s thermostat with an autozone. Filled her up tried every burping method I could find. Nose up high RPMs let it cool down and repeat. Tried doing an exit to exit loop on the freeway and as soon as I stop needle touches the red run it a couple seconds in the 3k rpm zone and drops right back down. Heater air is hot.

so I have hot heat, fans are blowing, hot upper and lower radiator hoses, coolant and cold fill line. Gets hot when I slow down.

Please help me out.

BareBonesXL

Looks like you have the electric fans. So, revving the engine to 3000 RPM only moves more coolant. Kind of implies a bad water pump.

People do not like non-Motorcraft thermostats but hard to see how revving to 3000 overcomes that unless it's just pushing more coolant through a small opening.

2011_aka_Ticky

This seems to happen every time someone uses a non motorcraft t-stat.

Overheat&Repeat

Ya I found the one thread on that one. I ran it again today for an hour or so with degas cap off then drove it around pretty hard and it drank an additional gallon of coolant. But I realized the hose after the thermostat was still pretty cold.

BareBonesXL

There is this entertaining thread. Start at Post 100. You might need some cardboard.

https://www.f150forum.com/f2/frustra...5/#post7062314

Overheat&Repeat

Thank you, but man does that seam like a bleak outcome haha.

So just ordered a $72 motorcraft thermostat from eBay due to everyone being out of stock. Which I will verify works on the stove.

Current plan is to drain everything, swap thermostat, pull water pump to make sure that hasn’t shattered or do something weird. Raise the front end like the manual says and try and get the fluid in based on the steps. And then Pray really really hard before going on a drive.

I will post an update if anything changes between now and then, if anyone has any suggestions I’m at a point where I will try anything.

EQCM24

Hey ya'll, first time posting on this site. I think that I was able to read all posts to this thread. I had a mechanic do some work on my 2011 F-150 SLT coolant system. Next day my truck sounded as though it was taking off on a runway because both my fans were kicking in. He had replaced my thermostat with a non-OE from O'Reilly's AND added standard green coolant to replace what he had lost. I went to the dealership (something I usually try to avoid), purchased an OEM Motorcraft Thermostat and some of the recommended MC orange coolant concentrate. After flushing my system, replacing the TS and filling up with the Orange, I have had no problems with overheating again.

BareBonesXL

I wonder what the difference is? Do they not fit correctly and stick? There's no sensor in the coolant stream, temperature is calculated from the CHT sensor, so it has to be a flow problem. Weird.

[F2C]MaDMaXX

It's ever so slightly different on this engine in that it runs a cold-side thermo, but it doesn't really explain why we consistently see threads with this very problem, and the issue is always an after-market thermostat causing the problem.

Overheat&Repeat

So I had had the truck worked on by a shop previously for coolant issues and the week after I was having a terrible time with over heating. Actually to the point where they had to come get me because of limp mode. They had it for two more days and it ran fine but it was also $1200+ for that time.

I did notice that the motorcraft t-stat has holes along the main shaft that the springs are around. Almost like it has a sleeve around it. The Ford fit versions from oreillys and autozone do not. Also both brands are made by Motorad a mass parts producer. It was basically taking out a lemon to put a lemon back in.

Still had over temp issues on a 5 mile drive today but the motorcraft one is on the way. Hoping Monday or Tuesday to get it put in