It is HOT & my MPG has dropped

[DA BIG ONE]

It has been hot a hell herein South Florida and my mpg has taken a dump, but, my truck runs great and no trouble codes, so, I wonder if it is the heat, crappy fuel, or combo of both?

I do add 2 cycle oil, and c-booster for all fillups, any thoughts?

[Barry Nave]

Big one.
Yes it's hot ;)
Even up north. I run the Sol-D. When I use the AC I'll get code 36 :confused:
Use to be code 35. Now I want to put the driver out of the Eng.bay. I have a ray gun.
Manfold is always cooler then driver.
Under hood temps are cooler then driver.
Chris, send me a harness :D

[damork]

Not sure why heat causes some trucks to drop in mileage, but mine seems to do the opposite. A couple of years ago I made a cross country trip and was traveling across the Dakotas where actual temps were 103-105F. I got the best economy my truck ever had on that trip - just over 21 mpg. I usually get 18.5-19. I've watched it since then and noticed a trend where higher ambients produces better economy. Dropping to 180F thermostats hit the economy a little as well.

[DA BIG ONE]

Originally posted by damork:
Not sure why heat causes some trucks to drop in mileage, but mine seems to do the opposite. A couple of years ago I made a cross country trip and was traveling across the Dakotas where actual temps were 103-105F. I got the best economy my truck ever had on that trip - just over 21 mpg. I usually get 18.5-19. I've watched it since then and noticed a trend where higher ambients produces better economy. Dropping to 180F thermostats hit the economy a little as well. Perhaps, fuel quality is an issue too here in the hellhole of america. I say this because when I get about 100 miles north fuel quality is much better. How much? Well, it is noticeable no matter if I am on a bike, in my car, or diesel burb.

You got me thinking here because I have noticed the truck running somewhat cooler, maybe one, or, both thermostats are sticking open.

Any of you know the best way to test for bad thermostats on a 99 TD?

[Iain]

I used to boil them in water and use a temperature guage to see when they would open. Just make sure your wife doesn't see you using her good stainless steel pots on her new stove to boil your thermostats. Just trust me on this one......

[moondoggie]

Good Day!

You allow stainless steel pots in your house? I make sure nothing but aluminum makes it into our kitchen - stainless & cast iron make a really bad knot on your head! :eek:

My brother's a mechanic & he always holds new 'stats up to the light to see if he can see ANY light where it should be closed tight - he says an amazing % are leakers from new.

Blessings!

[BuffaloGuy]

Ditto on these trucks liking to run when it's hot. Mine gets better milage and seesm tohave better power on hot days. Just the opposite of what a gasser would do.

I had the 180 tstats in for a while but noticed that it didn't pull as good. Maybe you do have one stuck open?

Confirm on lots of tstats being junkers. Spend the buck on a good one.

Good Luck.
Ken

[DA BIG ONE]

Originally posted by Iain:
I used to boil them in water and use a temperature guage to see when they would open. Just make sure your wife doesn't see you using her good stainless steel pots on her new stove to boil your thermostats. Just trust me on this one...... Hey, How did you know about the new stove?

[markrinker]

Have you been out of town lately, Big One??? :D

[DA BIG ONE]

Originally posted by Mark Rinker:
Have you been out of town lately, Big One??? :D Nope, But a friend went home to catch his wife with the poolguy, worst part, was he did not have a pool