Do not try this at home!

I've been having problems with my belt tensioner. Turns out the shaft the pulley sat on was out of round, causing the pulley to track off true from time to time and thow the belt.

Its fixed now, but the other day, I was on the road to my house when the belt came off. The road is approx 3 miles long and pretty flat, with only 2 hills. The road is also under construction, so there is no shoulders or any pull off area.

Anyway, the truck throws the belt as soon as I make the turn, and I am left with a quandry. I cant stop because there is no place to stop. And I dont want to continue on and overheat the truck. I figure I will split the difference and go as far as possible and maybe make it to one of the subdivisions where at least I can get off the main road before engine temps get out of hand

Heres where it gets interesting. On a flat, level road, at 25 miles an hour, the 6.5 will convection cool good enough to keep the engine temps around 200! Going up one hill I saw the coolant temps peak at about 225-230, but they went back to around 200 after the hill.

Of course, steering a cc dually with no power steering is a damned hard affair, but I made it to the house. The engine never got hot, and it didnt puke out any coolant. I found the problem with the tensioner, replaced it and the belt and the truck is none the worse for wear.

I guess diesels dont make much heat until you fork the hay to 'em.

Tim

Probably why the damn things don't heat up, at an idle, during the winter.:mad:

Tim,

Did you try the max defrost trick, high speed fan, temp control on hot, windows down to pull some heat off via the heater core, I had to do that once when my IC hose blew and I was getting no turbo assist, hooked up to 18K# trailer load with 80 miles to go when it let go.

That's what resulted in the several coolant system schemes between the 6.2 and the 6.5LTD - the 6.2 had problems even getting up to temp in wintertime, would just barely warm the cabin.

I would suspect the tensioner action pivot is worn - it is un-lubricated aluminum contact - even the spring wears into the aluminum components.

If the spring were to break, the actual slop would be very evident.

Turn on the a-c, watch the tensioner in action to get a real sense of the problem.

I

That's what resulted in the several coolant system schemes between the 6.2 and the 6.5LTD - the 6.2 had problems even getting up to temp in wintertime, would just barely warm the cabin.

I would suspect the tensioner action pivot is worn - it is un-lubricated aluminum contact - even the spring wears into the aluminum components.

If the spring were to break, the actual slop would be very evident.

Turn on the a-c, watch the tensioner in action to get a real sense of the problem.

I

The actual stub shaft that the pulley bolts to was out of round. I just happened to see it pop the belt off after I got it home and reinstalled the belt. I noticed that the pulley looked out of line a bit. The pulley bearing looked/felt fine, so I miked the stub shaft and found the prob.

Tim,

Did you try the max defrost trick, high speed fan, temp control on hot, windows down to pull some heat off via the heater core, I had to do that once when my IC hose blew and I was getting no turbo assist, hooked up to 18K# trailer load with 80 miles to go when it let go.

Duh. Never even thought of it. I have used that trick in the past, but I guess my brain was overheating. (It was somewhere between "damned hot" and "front gate to hell-hot" that day)

Tim

Don't know if the heater trick woulda worked anyways with no waterpump coolant circulation...

If you had to mike it to see the difference, then that more than likely was not the problem.

Watch the tensioner when the engine is running with the a-c on, and conceptualize that the tensioner arm has been pivoting like that since the moment the engine was first cranked and running - then check the numbers on your odometer.

There are no bearings or lubricant at the pivot point on the arm or the bracket.

What usually happens after this first warning shot is, you're out in the middle of nowhere in the middle of no-man's time, no dealer, and the thing craters completely.

Simple matter to replace it, after all those accumulated miles, 'specially after it is courteous enough to give you a mild warning event, first, eh?.

It might work a little; it seems to me that there should be some convective circulation going on w/o the pump working.

Simple matter to replace it, after all those accumulated miles, 'specially after it is courteous enough to give you a mild warning event, first, eh?.

Well, I did replace it. tension arm, pully and belt.

So far, so good.

Tim

Good - usual failure is, it binds up in the position of least tension - belt flaps off with associated damage.

Emergency fix - since it is bound up - use a 1/2" breaker bar to force it back into a position of max tension, hope you can make it back without incurring many more incidents along the way.