Good evening. I got rid of my last diesel a few years back but just picked up an '03 Excursion with the 6.0. Has 200k miles but is in great shape and seems to be running pretty well. I had a Scangauge sitting around so I hooked that up and have been monitoring EOT, ECT, TFT, and FICM voltage. I've had 6.0s in the past so I am well aware of the recommended delta of less than 15 degrees for EOT and ECT.

Here's my issue. I've only had the vehicle for about a month and most of the driving has been about 15 miles each way to and from work (mostly highway at 60-65 mph). I've never been able to get the EOT over 180. I figured since it was a short drive maybe it didn't have enough time to really warm up.

Went shopping about 2 weeks ago. Trip was about 50 miles each way cruising at 65-70mph the entire way. The highest EOT that I observed was 185. I haven't been able to get ECT above 170.

Today I drove it for about 20 miles of 60mph cruising and when I got home EOT was 180 and ECT was 163. TFT was 147.

I'm stumped. I can't imagine that a 50 mile drive at 2000 rpms wouldn't get EOT and ECT up near the 200 degree range. Outside temps have been in the 40s-60s. If I remember correctly, Ford's TSB advised that you get the truck up to operating temperature (ECT at least 190) before checking the deltas. I can't get ECT anywhere near 190 even after an hour drive at 60+mph.

Thoughts? Maybe ECT sensor is bad? Maybe Scangauge is bad? Both? Something else?

 

Bad thermostat opening too soon?

 

This^^^^^^

 

Thanks guys. Out of town for a week or so but as soon as I'm back I'll try replacing the tstat and see if that resolves the issue.

 

X3....make sure you read up on seating the thermostat in the 6.0 forum....I came across it after the fact and I’m not sure mine is seated properly in the housing as I’m only seeing ~180-186 depending on ambient temperature.

 

Yep, old thermostat. These 3 way stats usually fail open or at least fail to close fully.

 

Moved over to the 6.0L PSD forum.

Stewart

 

Be sure NOT to get it from Ford. Get the 200* stat from Amazon ( ) or drop by an International dealer and get one of there's.

 

Ideal ect’s shold be middle 190’s to 205. I personally like the low 200’s for efficient running.

 

This is what you want.
The Motorcraft T-stat really does not last very long.
The One that they installed at the factory is a different story.
But when the time comes this is the one you want if not running
the higher temp one from Mishimoto.



Just visit the nearst IH dealer and your going to be happy with this one.
It's not the cheap Chinese junk.

 

Assembled in USA using Canadian parts....

 

https://www.finditparts.com/products...tar-1839304c92 international,never used them before myself,finditparts

 

Better than one made in China with Chinese parts.

 

I put a Stant in about a month ago after the 5th Motorcraft went nuts in as many years. After about a year the temps start fluctuating 10-20*, the last one only lasted 6 months. So far it is working better than any of the Motorcraft, it will hold 190-192 towing or empty with ac off. Stant is a US company but China is stamped right in the top. If this one takes a dump I'm going IH. I don't see the point in a 200* stat for the price.

 

Agreed!