Hey guys. I picked up a new toyhauler (about 14k lbs.) in Michigain on Monday. I've stopped in Rapid City SD OMW back to Colorado.

My engine temps are really starting to worry me. I first noticed it while pulling small hills in Wisconsin at about 60-65mph.

The temp will go from 205* to 218*, when the fan kicks on, I let up in the throttle, but the temps will keep rising until over 230* (I hit 240* while coasting a few times) after about 15 seconds the temp quickly goes back down to 194 in a matter of seconds. I noticed that once the temps start to drop I can get back on the go peddle and the temps will continue to drop rapidly.

Also tonight going thru eastern SD I hit a big thunderstrom and the outside temps went from 90* to 60*. Now I can get the ECT to swing from 176-230* This is leading me to belive I have a slow/sticking thermostat....I hope.

Truck is stock with the expecption of a Diesel Site coolant filter and a gryphon tunner in lvl 0. All fluids, filters, and levels are where and what they should be. EGR and Oil cooler where replaced about 5,000mi ago.
EGTs are about 950-1050*

Coolant IS puking from the degass bottle, but might that just be from the coolant getting too hot?

Please guys, I have go over Vail pass in two days and I dont think the truck will make it without becoming FUBAR.

oh and I've been driving all day and half the night for the last three days so my grammer and spelling might....suck. So bare with me... haha

Thanks guys

 

It could be a possibility the thermostat is stuck open.

 

im going to the local dealer to see if they have any input...and if they have a thermostat in stock. Luckly I brought some tools with me and a thermostat is something I can change.

 

what are the corresponding oil temps?

 

Another thing to do is when you come to a hill is let her slow to about 50 mph and engage the tow hall. If the temp continues to climb drop another 5 mph and pull the tranny down to 3rd gear. With that type of load you need to let the gearing do the work, not your engine in hi gear. That's one of the reasons you have a 5 speed tranny.

 

Hey guys. Bad news, the truck quit on me this morning. No start while hot. I started a new thread on it since its (most likely) a different issue.

Anyways EOTs were within 15* of ECTs exept when the ECT's dropped below 190* then it didnt catch up right away, but when the ECTs got above 220 the EOTs followed to within a degree or two.

Ive got the 4:30 gears and the TowBoss package. I've been towing In TH mode since I hooked the trailer up, and I tried to shift into 3rd while on some of the bigger "hills" but it didnt do anything for the temp issues. It did seem to be better for the engine tho.

Ill say one thing about the 6.0. It likes to work! even when it got hot it didnt want to slow down! haha a gaser would have begged for mercy. lol

I figure the cooling system should be up to par when facing small hills like these, but IDK is 14K alot of weight for these engines? I have no problem slowing down for big hills and passes, but gentle slopes?

 

well It looks like 2 issue to me. sorry about the luck. this concern is more related to boost the a t-stat. it sounds like as boost goes up temp goes up, boost drops temps drop.
If im correct what you are in fact seeing is the heads lift and bolts strech. so Im thinking time for head gaskets. the upside is they should be able to fix the nostart at the same time.

 

I had the same symptoms and the coolant would puke out. Rapid temp swings that would drop down if I let off. I tow a 40" toys hauler around 14k as well over a couple of steep but short grades on my way to Oceano Dunes from central California to the coast. Drove and towed the truck like that for over a year alway with an eye on my EGT's. Finally got tired of adding coolant and took it to the dealer. First dealer told me plugged oil cooler and flushed it. Went to tow again up a grade and this time I had no where to stop and it overheated bad. But made it to destination. Drove back home about 40 miles in the morning over same grade and it did fine. Took it in and Dealer said blown head gaskets, plugged oil cooler and failed EGR. Replace all under warranty and no longer overheats, pukes or experience temp swings. Now I am experiencing other issues like going into limp mode and got a code for low turbo psi. Before blowing the head gaskets I have towed this trailer for 2 years without problems so I think if you address the weak spots of the 6.0 it should be fine towing 14k.