So I recently just bought my first truck. A 2012 fx4 supercrew 3.5 eco boost. And I notice the temp was getting pretty high. Never to the H but has anyone ever figured this issue out? I have done millions of research and there's no solid fix for it. One guy I read that he just put a 180 degree thermostat in and it fixed his and others have done external trans/oil coolers . Upgraded intercooler and radiators and still not a solid fix. Any experts?

My boat is just a aluminum 14ft boat with a few add ons Maybe not even 1500lbs.

 

Hello and welcome! I tow a 3500# camping trailer and have a 2014 3.5L Ecoboost and have NEVER had an overheating problem.. My tow driving has included some steep climbs in the Rocky's and Sierras too. When towing, I've never seen it drop below 4th gear during those climbs. There's nothing special about my truck, it DOES have the tow package, but that's really all.

I don't think changing to a colder thermostat is a reasonable fix either.. Yes, it DOES delay the engine warming up from a cold start, but that is not good - you want the engine to reach normal operating temperatures quickly, to prevent wear and save on gas. Once it DOES reach normal operating temperature though, the 180 degree thermostat would be locked open and the coolant temperature would simply depend on the health of the cooling system. The engine should run at slightly above 212 degrees, as I recall. and the only thing that keeps it from boiling and overheating is the pressure in the cooling system, the antifreeze percentage (which should be 50%) and the condition of the radiator, water pump and cooling fans. If all those things are good, there is one thing that can cause overheating though, a "kinked" lower radiator hose. If the "spring-like" thing inside that hose has decomposed, the hose will collapse under the suction of the water pump and that will lead to overheating. You should squeeze the entire length of the lower hose to see if there's any "give" in it. If there is, replace it.

- Jack

 

First of all, what is "pretty high"?

What temperatures are you concerned about? Coolant? Transmission fluid? What is the temperature range that you are seeing, and how are you reading it?

 

I was thinking with the lower thermostat the fans will just kick on earlier then 200

 

this one. After i took this picture it did get a little higher then that but never to H cause once I eased off the gas it went back down . Coolant levels are good. No coolant leaks.

 

The temperature gauge in these trucks is really mostly just a "switch" that moves into the normal range when the engine reaches normal operating temp. It's not really useful to predict impending overheating. For that, you need a Cylinder Head Temperature (CHT) readout which you can get on some addon devices that plug into the OBD port. I say CHT rather than "Coolant Temp" because it's a more reliable measure of the cooling system's efficiency.

Your gauge value looks fairly normal to me, though, and I wouldn't be too concerned. Yes, it's slightly higher than what I see on mine, but it's still in the "normal" range. What was the outside air temperature? When was the cooling system last serviced?

The fans are not controlled by the thermostat. The thermostat just opens to let coolant through at a lower temp with a colder one, so it slows engine heating.

- Jack

 

Yeah I've done research and heard about the CHT sesnor. I just bought the truck 2 weeks ago and tried taking the boat out on a Saturday. It was a bit rainy and temps were in the 60s that early morning. The temp gauge did go higher then that and i recently just bought a Bluetooth scanner so I can read all my sensors but haven't took it out yet. Anything I can do to the cht sensor?

 

No, there's nothing you CAN do or should do to the CHT sensor, except change it if it's defective (unlikely). It's been a while since I paid any attention to "normal" CHT values, but my rapidly fading memory seems to put them in the 220-225 degree range.

- Jack