Was test driving a truck to buy today and was getting on freeway going 75 about a mile down the road reduced engine power and wrench light came on not a good way to start a test drive any ideas truck ran well until that point. 37000 miles still under eng warranty just a little Leary they cannot check out until mon morning

 

Moved to the 6.4L Powerstroke Diesel forum.

 

Could be something as simple as a sensor. Bottom line is a fault was detected and it entered a safe mode to prevent further damage.

 

Hi Thermo, welcome to FTE!

Unfortunately things sometimes go wrong with engines as complex as these are, but for the most part they do pretty well. With as much engine warranty as there is left I wouldn't hesitate to buy it once the problem is corrected. Scott is probably correct in that it's likely a sensor problem.

Take a look around and also make sure to visit the TECH FOLDER found at the top of the 6.4L forum. Lots of great info to be found there that would be beneficial for you to know before you make the purchase.

Let us know if you get the truck, and be sure to post pics!

 

Probabaly something simple. Really like the truck well just don't want it to be a cronic problem if I buy truck! Talked to sales person today and won't have a diesel tech until Monday morning to diagnose problem. I will send updates when I find out more. 2008 f250 Xlt 4x2 crew long bed.

 

Talked to service dept today and they said 1 of the engine thermostats failed not sure which one I know there are two. And from what I have read they take 3 hrs book time. Could not pick up truck today.will tomorrow arranged to drive truck for a couple days before buying so I could check over and make sure no other problems.

 

Glad to hear they found the problem! Did you notice what your temperature gauge read when it went to limp-home mode?

 

Well I looked at it a couple times and showed normal. With the 2 t stats I wonder if 1 is for main coolant and one for egr system?

 

Nope, there is only one cooling system on these engines. You're thinking of the 6.7L! .

There are two thermostats that control flow of coolant to the radiator, if one is stuck open I believe you'd be overcooling.

 

I suppose hyper extended was the issues. My temp guage will move just to the right of center at 220F.

 

Actually there are two fully independent cooling systems on the 6.4. There is a separate system with a separate pump and radiator for the fuel cooler and variable turbo actuator.

 

Correct, but I do not believe there is a thermostat for that system.

 

I bought the truck today. They let me drive it for a couple days. Great dealer ship seem very knowledgeable on diesels. Buckeye ford London Ohio. Rural dealer stocks a lot of diesels. Found no other problems hope it stays that way.hope to be a long time ford enthusiast!

 

Congrats. I love mine and it pulls like nothing else.

 

I am pulling my 30 ft Airstream wed and will put it through its paces.I pulled it before w/ my dad's 6.0 liter and that truck pulled it great.excited to see power.have driven it no load andhave never seen anything about dpf cleaning approx. 400 miles is this normal.I know it has latest software update.