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Hello everyone, long time no talk. Life has been busy and health has been bleh...

 

Long story short i was coming back from utah for a friends wedding and he was moving as well. I towed the uhaul trailer 6'x12' densly packed and very very heavy. Had no problems going through the mountains on HWY 80 EB till about 80 mi from lariamie WY. I was heading up a very long grade and towards the top something bad happened.

 

Here are the stats of when it happened

 

speed 70

gear 6

EGT under 1250 (no more than 60 seconds@1250, i saw it and turned the cruise off and throttled down)

boost around 20psi

rpm appx 1800~ cant remember exactly but was below 2000

oil psi normal ~65

fuel psi 18-20

temp rose from normal 180F to appx 200F when i powered down (within the white brackets)

 

What happened was a knock appeared and progressed to a loud knock quickly. I unloaded the engine and babied it to the crest which was less than half mile. Pulled over and the knock rose to a certain level and stayed there, excess blowby is observed and nothing else abnormal aside from the knock.

 

I havent torn into the engine but i am presuming either a cracked/melted piston or a conrod bearing went to hell or both.  I have my backup vehicle that ill be using for my trip and when i get back ill tear the engine apart.

 

Things i did learn from this, My RPM's were too low, egts were too high and in too high of a gear pushing too hard too long.

 

Fresh oil/filter air filter done before trip 3 weeks ago. zero issues aside from a cam sensor that gets fussy here and there. (was going to replace it when i got back this week as its bolt is stripped...)

 

Anyone have any thoughts or questions?

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Sound like your just flat out towing way too fast. I don't trust a EGT gauge right up to the last degree I always try for a 100-150*F under 1,200-1,250*F which me error to the side of safety. Also I would never tow over a grade in top gear I always back down hook up with 1:1 ratio (5th gear for 6 speed and 4th gear for 5 speeds) and tow at a much lower speed which reduces EGT's, Coolant temps, and increases the boost pressure.

 

Sounds like its time to pull the engine out and rebuild...

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Are you still in the vicinity of Laramie? I have family in Laramie and could touch base with them if your needing any assistance with anything.

I'm trying to picture where about you were on I80 west of Laramie that has that steep of a grade...I know east of town headed over Happy Jack towards Cheyenne is a long 7% stretch of several miles.

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  • Staff

So..... exhaust temps are an indication of cylinder temps and when to down shift. This is the first time I've ever heard any kind of benefit to having an automatic trans. Which I don't like.

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So..... exhaust temps are an indication of cylinder temps and when to down shift. This is the first time I've ever heard any kind of benefit to having an automatic trans. Which I don't like.

 

You could still melt a piston with an automatic...

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I'm not sure what an auto has to do with anything?? I'd be willing to bet your EGT gauge was off at least a bit. I have sustained that hot or hotter for that amount of time and never had a problem. I will admit this was before I came to this site and educated myself!

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I'm not sure what an auto has to do with anything?? I'd be willing to bet your EGT gauge was off at least a bit. I have sustained that hot or hotter for that amount of time and never had a problem. I will admit this was before I came to this site and educated myself!

 

...as a matter of fact, I had my dipricol EGT gauge say more then that when I towed my 5th wheel up a grade. I could hear my turbo maxed out and the engine make different sound. But to this day, it does not consume oil more than common and fires up on the first crank every time...

Edited by hex0rz
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I'm not sure what an auto has to do with anything?? I'd be willing to bet your EGT gauge was off at least a bit. I have sustained that hot or hotter for that amount of time and never had a problem. I will admit this was before I came to this site and educated myself!

Auto trans downshifts seemingly too early when towing or hauling heavy up hills. It will down shift even when you feel plenty of torque still left in the higher gear.

How can you burn a piston if the auto trans downshifts a bit early like that?

Edited by JAG1
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Hello everyone, long time no talk. Life has been busy and health has been bleh...

 

Long story short i was coming back from utah for a friends wedding and he was moving as well. I towed the uhaul trailer 6'x12' densly packed and very very heavy. Had no problems going through the mountains on HWY 80 EB till about 80 mi from lariamie WY. I was heading up a very long grade and towards the top something bad happened.

 

Here are the stats of when it happened

 

speed 70

gear 6

EGT under 1250 (no more than 60 seconds@1250, i saw it and turned the cruise off and throttled down)

boost around 20psi

rpm appx 1800~ cant remember exactly but was below 2000

oil psi normal ~65

fuel psi 18-20

temp rose from normal 180F to appx 200F when i powered down (within the white brackets)

 

What happened was a knock appeared and progressed to a loud knock quickly. I unloaded the engine and babied it to the crest which was less than half mile. Pulled over and the knock rose to a certain level and stayed there, excess blowby is observed and nothing else abnormal aside from the knock.

 

I havent torn into the engine but i am presuming either a cracked/melted piston or a conrod bearing went to hell or both.  I have my backup vehicle that ill be using for my trip and when i get back ill tear the engine apart.

 

Things i did learn from this, My RPM's were too low, egts were too high and in too high of a gear pushing too hard too long.

 

Fresh oil/filter air filter done before trip 3 weeks ago. zero issues aside from a cam sensor that gets fussy here and there. (was going to replace it when i got back this week as its bolt is stripped...)

 

Anyone have any thoughts or questions?

Judging from what information you posted, severe engine damage may or may not have occurred. A compression test will quickly tell you whether you have serious damage. From what I read, yes, you were operating at the outer edge of the performance envelope but not neccessarilly so much so to have definitely caused engine damage.

If the excessive engine knock by you mentioned is severe, I suspect engine damage along with everyone else.

BEFORE you pull the engine you may want to consider this TSB: 09-008-02

10/21/02

http://www.turbodieselregister.com/attachment.php?attachmentid=88693&d=1401901093

Engine knock or rattle sound when climbing a long grade and towing a heavy trailer.

This bulletin applies to 1998-2002 Ram trucks equipped with the 24-valve Cummins diesel engine

(sales code ETC or ETH). Owners may experience an engine knock or rattle sound when

climbing a long grade while towing a heavy trailer. If the condition exists, replace the engine

thermostat as outlined in the service manual. Note: Mopar 05015708AC is to be used exclusively

for this service bulletin. Use thermostat 05015708AB for all other 24-vlave Cummins thermostat

repairs.

Edited by LiveOak
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