just an FYI if your fuel mileage is down

[drunk on diesel]

I've had a Mini Maxx on my truck since the day after I bought it.

I've always monitored ECT and EOT. Here a few months ago, I noticed my ECT was down from it's normal 195-197 to 192. And as I coasted down coming off the highway, it was down to 188.

Thermostats were hanging open.

I had a big drive out to west TX and back and asked my mechanic if I'd be alright. He said yes, but you're going to be down a couple MPG.

Well, I've been nursing the truck for almost 3 months. Just been way busy. I don't idle the truck, and I don't putt around town. If I'm driving, it's at highway speed, and the truck will maintain 188-192 most of the time.

So I'm about to take a 3-4wk vacation in Colorado, and I know I'll be doing a lot of short trips, slow speed/no load, and colder ambient temps, so it's time to get the thermostats done.

Coming home from my buddy's shop last night doing 67mph, ECT was 195-197, and the lie-o-meter showed 19.4mpg

I KNEW what I had going on because I had a good scan gauge type display in my mini-maxx, but without it, the water temp dummy gauge on the dash showed to be just fine.

I DID get a CEL indicating "coolant thermostat performance" twice, but only here in the last month.

If you seem to be down 2-3mpg without any good explanation, I'd monitor the ECT PID and see what your TRUE temp is. You might be due for some thermostats!

[docweld]

thanks for the tip, I have only 78,000 on my 2000 7.3 and was wondering if I should change the coolant and stat. Looks like I should.

[drunk on diesel]

I don't see it being a huge problem on a 7.3, but can't hurt to PM the thing anyhow

the emissions are so strict on the 6.4, they have a tight optimal temperature range, and if you're not in it, it works hard to get there

[4playin]

How was it changing them out? Is there a write up on it?

[srjd]

Whenever coasting down a big hill mine drops to 188 other then that the average temps are 194. I have a random puming problem and dealer thinks its thermostats. I think my thermostats are fine maybe I am wrong

[drunk on diesel]

Originally Posted by 4playin

How was it changing them out? Is there a write up on it?

it's a PITA if your EGR coolers are still in place (as mine are)

hence paying my mechanic a few hundred to do it for me!

[4playin]

Yeah I should of known but just thought I would ask.

[APEX 06]

I seem to be getting low water temps. Highway 192-194 rolling to a stop sign it drops to 186-188. Outside Temps have been around 40°.

[drunk on diesel]

I'm betting thermostats hanging open. You'll likely get a coolant thermostat performance code before long

[APEX 06]

Originally Posted by drunk on diesel

I'm betting thermostats hanging open. You'll likely get a coolant thermostat performance code before long

Where are the thermostats located, easy job or hard and are they cheap.

Sent from the can!