I think there is a reason for that phrase: Ignorance is Bliss -- I'm at the data overload paranoia phase

Oh well, it's getting me to have some stuff done that probably should be done at some point. But I just keep thinking I'm replacing perfectly good parts with hopefully better parts, and the shop will do a good job and not create other issues just doing the work (and I can be worry free when it's all done). That is until I start looking at the data again....

 

I've made notes a couple of times. I keep a logbook on my truck with maintenance, problems and fuel stops. Here's what I got.

31may11 (when i got the scangauge) with 135,923mi on it and 97* outside temp on the a/c panel. I drove a half hour to a spot where the road was kinda flat just for this test.

Common temp @65mph
197/211 spread of 14
Common temp @75mph
202/216 spread of 14
Max spread @ 75mph
198/217 spread of 19
Min spread @ 75mph
206/217 spread of 11
Coolest temps@75
195/211 spread of 16

25Jun11. 136,670mi Installed a coolant filter system but didn't flush.

28Jul11. 138,024mi Replaced coolant filter. It didn't look too bad, a little sand but no goo.

I had gotten used to the temps and they seemed to be creeping up, especially when towing on hills. I saw 148 EOT (didn't note ECT but it was somthing like 220 iirc) and eased off after that truck was often running a 16-18* spread unloaded on the highway.

5may12. 144,016mi Overnight (cold soak) temp check. Truck didn't run for a day and a half but it was hot outside when I checked it after work.
Outside air temp=91, ECT=80 EOT=81.6 TFT=77
Read up on the TSB and did another test.

6may12. 144,021mi. EOT/ECT check full throttle TSB style. Outside temp 87*

198/217 spread of 19
205/225 spread of 20
206/227 spread of 21
209/231 spread of 32 (yikes!)

7may12. 144,041mi. Flushed with restore, CAT coolant, new thermostat.

9may12. 144,155mi. Truck is steaming heavily out of the tailpipe shortly after a cold start. Parked it for repairs.

23Jun12. 144,155 mi. First test drive after oil and EGR cooler replacement. Truck is running much cooler. Seeing common delta of 4 to 6* unloaded. Never over 11* towing.

24Aug12. 145,698mi. Outside air temp 96* EOT check TSB style. I had just replaced the IPR screen and had an excuse for a couple of full throttle pulls .

198/204 spread of 6
205/213 spread of 8
208/213 spread of 5

Of course how long you hold full throttle, and when you read the temp is a variable with the TSB check. But where you are on hills, traffic and what's in the truck makes a variable with the Cruise test also. I realize the test results have a year between them and a lot could change in that time. If you ask me, I have a temp spread of 8*.








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Thanks for posting that data (I would rep you, but I need to spread more love 1st), so thanks is all I can offer. I'm petty sure mine is nowhere near where yours was prior to replacing the coolers. First off, I have a lot less mileage on mine, which is a good thing to be learning all the things to fix proactively.

But I turned the data logging on Torque (damn thing is so cool) and watched several unloaded trips with second by second data, and I did the same as you: looked for hills and tried the WOT "test". I'm hitting some 15-17 deg deltas on a mild day, so do I think it'll get better when I load the truck up and drive in hotter weather. No I don't...

I've bought all my parts, so now it's just following through and taking Dan to the shop 120 miles away (but close to where my folks live).

I am hoping to see deltas afterwards like you see and after a couple hundred miles of making sure nothing is going to come unglued, we'll load up and see what happens...

FTE is great -- I may be paranoid, but I'm at least informed and paranoid

 

Lol. Glad those numbers are of some use. To be honest I think it might be a little general insight but in the big picture different truck will probably act differently depending on what kind of shape the entire cooling system is in including the coolant, truck weight, tune, injector condition etc. Good luck with yours!

 

The variable is why I side step the tsb and take my deltas at full operating temp. with the truck on flat ground at 65 to 70 mph. The diesel tech at my dealer has no problem with this method. My deltas only change a degree or two under the same conditions towing my 31' 5er. I'm usually between 4 and 8 degrees.