Engine/Transmission (1994 - 1998) Overheating Problems Need Help Please

[McLaughlin]

My truck overheated a couple of days ago while pulling my horse trailer (about 12-13K loaded) over Vail Pass and by the Eisenhower Tunnel. Here's the details about my truck since my Dad's truck is listed in the signature.



96' CTD 2500 4WD Auto, 244K miles

DTT transmission with 3rd gear drum, smart controller, dipricol transmission temp, egt and boost, #6 plate, big injectors and green filter, pac brake



I have NEVER had a problem with overheating before and the truck usually runs really cool. Temps without the trailer usually average 150-160 and egt's of 400-600. With the trailer, coolant usually is at about 160 - 180 and egt's around 600 - 800.



All my trouble started when I started climbing the hills toward Denver. I took it out of overdrive and decided to slow down and turn my a/c off also. This helped a little but the coolant temp went to 220 and egt's were at 1200. I slowed down to about 20 and crept up the hill. This was enough to keep it from completely red-lining. Any time I tried to accelerate, the truck would bog down and within a few seconds there would be a huge cloud of black smoke.



When I got to the big hill before the Eisenhower tunnel, I drove up at 5 miles an hour and ended up stopping part way up to let things cool down when the coolant temp neared 240. The egt's stayed at 1250. Also had the heater on to try to cool things down. It billowed black smoke and had the same low power symptoms.



The truck now runs hotter and is staying in the 600 - 1000 egt range when driving locally without a trailer and the coolant level is fluctuating beween 140 and 200.



In both cases, when I made it to the top the temps came down significantly, but not as low as usual. The coolant has been changed within 6 mos and looks normal. Oil and transmission fluid are full. The t-stat was changed on Saturday hoping for an easy fix but it hasn't solved the problem. Radiator was drained an refilled and doesn't seem to have any problems. The air system was also pressurized and no air leaks could be found. The fan does not have any oil on it and is fairly clean. The only lack of power I noticed was on the uphills (with trailer) and there is no noticeable lack of power while driving in town or up hills with no trailer.



I read a lot of the posts but don't know enough to draw any solid conclusions - help is greatly appreciated



Thanks ~ Erin

 

[PRattenbury]

If you're losing power and blowing a lot of black smoke with high EGT's you either have a boost issue or too much fuel going in. Do you have a boost gauge? What's it doing? Lower than normal?

 

[JFaughn]

Uncontrolled fuel , bad injector , look at turbo , wiggle side to side & in & out , does it spin freely ?
Exhaust plugged , maybe a baffle came lose in muffler .

 

[McLaughlin]

Additional info.

Before when going up the hill, the boost was only at 10 psi. As mentioned before we tested the intake system to 30 psi without hearing any leaks. Removed the cat and muffler (kind of a pain). Afterwards the boost will go to 20psi. EGTs climb fast but also drop fast now where before they would climb and just stay high. No significant smoke noted. Just slight haze at idle.

Wastegate is not connected (never has been).

Also checked fuel pressure at input to injector pump. Idle pressure is 20psi, pressure at 2500rpm is 24-25 psi.

Checked turbo. Noticed a tiny bit of front-to-back movement (can't see it just feel it). No side-to-side movement.

Checked exhaust brake. Appears full open. Appears to open and close normally.

Checked air filter. Removing the filter doesn't not seem to make a difference in turbo spool up or boost pressure.

 

[wcjp]

Did you hear the fan clutch engage? Is tire and tire height the same as the past?

 

[McLaughlin]

Did you hear the fan clutch engage? Is tire and tire height the same as the past?

Good question. Don't remember hearing the fan engage. Tire is different (a BFG mud terrain) but same size as before (P265R75-16).