So, this was the first time I have towed with the mods in my signature, my trailer reads 5,500 dry, though it was wet with two quads, so by that should be 7,000 pounds or so. I feel it is closer to 9,000 pounds (at least gauging how my truck struggles). Last year prior to the mods, I had overheating problems, which I then cleaned out the radiator fins, replaced the thermostat, and had the egr cooler/oil coolers done under warranty. I last towed in November, just before the mods, in the snow, and the fan clutch came on in flat driving about every 15 minutes for about a minute.

So, leaving Friday I get about halfway up the first pass (with 3 to go), the truck overheated, got to the red in the coolant gauge, the fan clutch did not come on once. I had the two tune from Eric loaded. I turned around and the temp gauge dropped right back down to normal. Of course, when I got home, there was coolant everywhere and the level had dropped, needed little less than a gallon to refill. My EGTs never went above 1100 degree, which is what surprised me. I pulled my dipstick and it was not milky in any way.

The one thing I did notice when I was cleaning the engine compartment of white residue, the air filter minder was unplugged, have no idea how long it has been unplugged, might have happened when we did the mods. Could that have caused the fan clutch to not have turned on and cause the overheat? I see there is a sensor attached with wires, so did that mess with the truck?

Or, is it something worse, like the HG? I drove the truck around Saturday without problems and went on a 200 mile drive today, unloaded, with no problems and no further coolant loss or evidence of puking.

I pulled the codes, no codes except for the two EGR codes. The fuel filters are less than 5,000 miles. Another clue, not sure if this is me being weird, but on flat ground, 65 mph, it took almost 20 psi boost to hold speed, a little over 20 to climb small hills, and of course about 29 psi on the pass to hold 55 or 60. In my mind, with these mods, I should have no problems going 65 over the pass (5% grade for 8 miles, was 50 degrees out). When it was stock, I went 60 over the same pass, at 1,200 EGTs and the fan clutch almost constantly running.

Sorry for the long post, but wanted to give as much info as possible for the help. I have put a lot of money into this truck and don't want to put more money into a Duramax (please don't flame me. LOL)

Alright, thanks in advance for your help!

 

1. To hold 65 mph on flat ground you should be around 5 psi boost or less. You're way to high.
2. 29 psi on a grade is to high in my op. for what you are pulling.
3. Your truck should not feel like it is struggling at all with that load. I pull 13 k with no problem at all and about 26 psi on a grade.
4. Good place to check would be to yank the egr and clean it. Check in the manifold while it is out for moisture. Sign of a bad egr cooler.
5. Hope someone can add to this. Good luck.

 

Yeah, when empty at 65 I am at 5psi, which I have heard is normal. Would agree 20 psi is way too high. My truck seems to have power empty, in that I can rip the tires through 45 when I have the street tune in. Just feels wimpy when loaded.

My egr was replaced last year and shortly thereafter I replaced the uppiped and blocked it, you think a dirty egr could be the issue?

I am just thinking out loud here, as I really don't have a clue. My truck only overheats when the psi is over 20 for an extended period. I thought it was the EGR warming the coolant, hence the delete. But I wonder if maybe a seal is bad in the turbo, causing exhaust to dump into the coolant, making it hot (I am not even sure if possible LOL). What are your thoughts?

 

Well here is more info. I took it over the same pass unloaded last night and did not overheat, no higher than 200 degrees for coolant temp, basically got to there and stayed, dropped to 187 on the backside of the pass.

Any more thoughts?

 

This is your first problem. You need the fan when towing.

This could be the second problem. First thing I would do is go back to a stock tune and see if the problem remains. If your fan clutch comes on normally, you have to blame the tune. If the fan still does not run, start diagnosing the fan clutch.

 

That thought crossed my mind. Is it possible they accidentally turn off the fan clutch in the programmer?

 

I have no idea what is or isn't possible. It just seems like a logical way to proceed.

 

The one thing I did notice when I was cleaning the engine compartment of white residue, the air filter minder was unplugged, have no idea how long it has been unplugged, might have happened when we did the mods. Could that have caused the fan clutch to not have turned on and cause the overheat? I see there is a sensor attached with wires, so did that mess with the truck?

As far as the filter minder being unplugged That would not cause the fan clutch not to work causing you to overheat. It would just cause CEL light to come on..It happened to me..When I plugged it back in CEL went off in a couple minutes

 

Your truck will overheat extremely fast without the fan, doesn't matter what tune or if an is running. The 6 liter fan runs a lot. When towing my 8k 5th wheel it is almost continuous. I have two friends with 7.3's and there fans only run about 30% of the time while towing 10k or less. Mine runs about 90% of the time. The engine is putting out more power with less cubic inches and a smaller radiator. The heat is gonna be there. LOL 5lbs of boost is also pretty normal for flat empty driving, that is the benefit of a VGT turbo, you can always have boost at any driving condition. Your turbo should also never run over 26-28 psi. 26 is the factory computer setting and what the engine was designed to handle. I run spartan tunes and my boost never breaks 26 psi. I would say attempt the same pull with the stock tune and see what happens. If the truck pulls fine then you know something is wrong with the tune. If the same thing happens you probably have something wrong with your fan clutch engagement.

 

Thanks for the responses! I will pull it again this weekend.Some people say they pull up hills with 12k and the fan only comes on once. What is your boost at while pulling?

 

I tow an 11k, empty, 5er and the fan probably doesn't run 40% of the time and doesn't overheat. This includes to the Sierras in August. First 200 miles are across the desert usually around 100 degrees.

 

I hate to say it but I think its HGs.

Also make sure your fan is plugged in and the wires aren't cut.

 

Got a picture or description of where the fan plug is? I hope no HG issues. I had burts unloaded to 1,100 degrees with no puking, just runs way hot when there for extended period.

 

Its a plug that goes in the fan shroud just behind the "Powerstroke" emblem. The wires go down to the fan clutch. I have seen 2 trucks in the last week that the fan has cut the wires causing a over heating problem.

 

First all, thanks so much for all the help so far from everyone!

So, I checked this, the wires are fine. There is some resistance when trying to move the fan with my hand.

Today, I took out the program and towed a 1 mile long 5% hill, air temp was 55 with some light rain. On flat ground, at 60 mph, turbo at 19 or so, ECT from 205 to 215. Pulling the hill, came in at 205, about halfway up, at 50mph and 29 psi boost, had to slow down as it got to 230. At the top, now keep in mind only one mile long, was going 25 mph and coolant hit 237. Turned around at the next exit and it cooled down to 230 on flat ground, and was back down to 205 at the bottom of the hill. Trans temp got to about 180. EGT never got over 1,100.

Now, it ran between 205 and 215 the rest of the way home. There is a tiny hill at 35 mph just before my house, it got back up to 230 on that hill, so I pulled in and unloaded. When I got done unhooking my trailer, ECT was back up to 235 and tranny was at 210. So I took it around, between 35 and 50mph unloaded, and it took about 10 minutes for ECT to get back down to 190 (what it normally is unloaded) and tranny took about 15 minutes to get down to 165 (I run at 150 unloaded normally, but in traffic it can get to 195 unloaded).

The good thing, ZERO coolant leakage or puking from the degas bottle, no white residue. From what I understand, that would rule out head gasket?

So, the obvious, I need a new fan clutch. Anyone else have other thoughts for me? The tranny seemed a little hot, it has never gotten to 210 before.

Thanks!