How hot is too hot?

[egsimpson]

Pulled a 30' gooseneck with an all terrain forklift today from ky to wv. About a 250 mile run. In the hills of ky everything seemed fine, plenty of power, ect around 190-200. Once I got into some of the longer, steeper grades in wv, ect was imo way too high. Around 230-240F. Both my LBZ's run hot like this and I can't stand it. As soon as you let out or come off grade, ect drops quickly. I've never thought either of the clutch fans work properly. I think they should kick in sooner than they do. It was only 54 degrees today. Truck just had head gaskets, new water pump, new thermostats, hoses, everything. I've read where others say that high of temp was the norm, but I really think I'm going to end up destroying a motor. Thoughts, comments or suggestions welcomed.

 

[Harbin_22]

When my ECT gauge is at 210 it is really on 185* so 230-240 would only be 210ish

 

[whitetrash21]

X2 ... my idiot guage wouldn't move until actual ect climbed past 225 - 230....then the dash guage began moving

 

[x MadMAX DIESEL]

How were yall measuring coolant temp to verify?

 

[Harbin_22]

Efi

 

[egsimpson]

Unfortunately, mine is by the factory gauge for now. I used the Diablosport in my other truck a while back and had a definite 235* on a hill.

 

[baggedLB7]

I was hitting upwards of 240 ect towing our boat over some long steep grades in the summer time but I was also running at 75 mph and that reading was off my edge insight.
I installed an oil cooler like the one out of the oil cooling thread and it dropped my ect up to 30 deg with the same boat and grades.
This is the oil cooling thread.
http://www.duramaxdiesels.com/forum/showthread.php?t=38321

 

[THEFERMANATOR]

When my ECT gauge is at 210 it is really on 185* so 230-240 would only be 210ish

The factory guage goes to 190 at 160, and will stay around the 200-210 mark from 180 to 225. At 235 it will move up again to about 230-235 and stay there until it gets up close to 250. I was told 225-235 is the norm as teh fan clutch doesn't even kick in until 225 actual engine temp on mine(I have a different guage that is much more accurate), and this is with a severe duty HAYDEN fan clutch. The 2 stats don't even go full open and close off the bypass for full cooling flow until 215-220. If you want it to run cooler, you can run a 00 6.5 diesel fan clutch if it has a 21" fan blade(LB7 and LLY), but the 06+ 22" fan blade would be a bit much load for one. The 6.5 is designed to ru nat 205-210 VS the 225-235 the DURAMAX is designed to run at, so it would kick the fan in a bit sooner.

 

[whitetrash21]

How were yall measuring coolant temp to verify?

CTS evolution

 

[egsimpson]

I read all 36 pages and the several hundred posts on the oil cooling. Definitely an eye opener.
I pull a lot of equipment, a lot of the time, so going to pursue the oil cooler route.
Additionally, I found one water leak on my dually. The oring on the heater core pipe coming out of the thermostat housing was weeping. Changed it and later noticed that when I crack the reservoir after running I didn't get pressure. Checked oil first! Good to go. I then switched the cap with one of my other trucks and it built pressure. Surely it's not going to be this easy?
I pulled a 30' gooseneck 300 miles this morning weighing 31,248#. Up and down a lot of terrain from wv to western ky. Air temp was 36 this morning and 63 upon arrival. Engine never got over 210 today, but you can tell when oil temp goes up, pressure drops.
I'll let y'all know if anything changes. Thanks.