I just inherited a 96 Dodge 2500 5 spd with 523000 miles on it. I managed to get a hold of the shop that looked at it a few months ago. It has a leaky front crank seal (pretty obvious) and "supposedly" a head gasket. They tell me that it is sucking water through the exhaust. Problem is the truck does not appear to be losing water and it isn't blowing out the tailpipe.

What I do have is a slow start 2-3 seconds before it fires off, no black smoke and low on power. It doesn't miss and gets around town fine. I pulled a an empty 2000 lbs trailer behind it and for lack of a better word it was gutless. Struggling to maintain 55-60 through the hills. It didn't overheat though. It ran the same as always once the trailer was off. As far as I can tell the filters are fine, and the lift pump was replaced about a year ago. I am hoping for something simple like OFV and dreading the possibility of the IP.

Any ideas on where to look next?

 

If nothing has been turned up, then this is perfectly normal performance. Stock these things suck *** with a trailer. If the IP hasn't been messed with, then that's your power problem. It would be especially noticeable with a standard as there's no slipping to get the R's up and build any boost to help out.

The slow starting issue could be bad grounds or simply bad batteries. It also be a slipped/poorly timed IP, or simply one that's advanced too far for the dropping temps. You didn't fill in your info, so I have no idea if this affects you. Obviously if you live in Mexico this isn't your problem.

The front crank seal is so common as to be considered normal, especially with half a million miles on it. It's probably been leaking well over half it's life, and putting a new seal in won't necessarily stop it. Over time they actually wear a groove into the crank, which makes it impossible to seal. Sometimes you can install a new seal backwards, which offsets it to a less worn spot on the crank, which can help. You can also add a breather to the oil fill tube or one of the valve covers to vent some of the crank case pressure, which can also help; but if it's making any boost at all and you use it then you should probably just get used to seeing a drip under it because there's no keeping that crankcase pressure in even with vents and other tricks.

 

As far as I know this truck is still bone stock. No timing adjustments.

My Uncle used to tow his 28' bumper trailer around and barely notice it was there. Last month he had to struggle just to get it over the hill to get it home. So something has changed.

As far as the crank seal, couldn't it be fitted with a repair sleeve?

 

If it's bone stock, it isn't going to be blowing black smoke. The factory tune is diametrically apposed to it. That said, it does sound like something isn't right. Generally RV trailers are surprisingly light, even at 28', but it's most definitely a lot more than 2K. My best guess would be that the problem is in the IP, but I'd start with a new fuel filter. Wouldn't hurt to put a mechanical gauge on it to see what the fuel pressure is. Moving down the line from there, if the pump has never been messed with than it has almost absolutely lost timing, and the timing from the factory was conservative at best. I've seen 12V's with a third of your mileage with timing that had slipped so far they barely ran. This could affect how quickly it fires off, and be costing you power. Either read up on bumping the timing, or find a reputable 12V guy to bump it for you. Shouldn't cost more than a couple hundred and that's on the very, very high end. I used to pay my guy $125, but he's done it so many times for me now he doesn't even charge me anymore. For someone who has done it a lot, it's a very fast, very easy process. As for the head gasket: that isn't it. Of course I can't be positive without looking at it myself, but unless it's visually losing measurable amounts of coolant this isn't your problem. Many of us have crammed so much boost into our heads that we lifted them right off, and had permanent streams of coolant going everywhere it didn't belong until we pulled them off and fixed them, but they were leaving puddles everywhere and blowing apple martinis out the exhaust and still pulled like raped apes. My money is on your problem being fueling.

 

The trailer I pulled this weekend was just an empty 14' single axle trailer and it really didn't want to pull it up a grade at all.

A fueling/timing issue would make more sense. Since I can't ask Uncle if it was a gradual or sudden change it leave me a bit in the dark. I will probably have to take it to the local Cummins certified shop. For a logging community we have a dearth of trusted diesel mechanics.

I will keep watching the coolant to see if it is going away but with the last 200+ mile run to get the trailer it didn't appear to lose any.

I am comfortable taking care of the crank seal (and checking for the KDP). I will have to read up on timing the IP.

I want to get the mechanicals squared away first and add some gauges to monitor. I currently don't have a pressure gauge to check the fuel pressure. Just one more thing to add to the list.

 

Just know that with the mechanical LP a fuel pressure gauge is a tricky proposition, as the violent lopeyness of the LP makes for a tough time getting a good reading. If all you want to do is check it, tapping in a mechanical gauge under the hood will work best. If you want something installed for long term monitoring, it gets a little more complicated.
The sooner you get some gauges in there though, the clearer your picture will be of what's going on. Boost and EGT can help troubleshoot a whole heckuvalot. FP is nice, but as I said, can be more of a PITA than most people think it's worth. I am not one of those people, but I also rely on my truck to the tune of four digit miles a week so it's had more opportunity to pay for itself in one month than most people have in a year. Hopefully someone with more IP experience will chime in here soon. Good luck.

 

Installing a fuel pressure snubber or needle valve will prevent a gauge from being destroyed buy the pulses of the LP and allow you to get an accurate reading.

First thing to do is hook up a fuel pressure gauge. It doesn't have to be a permanent installation but you do want to have it in the cab so you can see the pressure at WOT. It's a really simple thing to do and it is an invaluable diagnostic tool on these trucks. This thread shows you exactly what to do. How to check fuel pressure on a 12 valve - Dodge Cummins Diesel Forum

Once we know what your fuel pressure is doing we can help guide you to a solution. It's more than likely an issue with a lack of supply pressure going to the IP and not the IP itself.

Yes, a repair sleeve can work if the crankshaft seal surface isn't too damaged.

 

Gauges are definitely near the top of the list of things that will be added. A mechanical fuel pressure with a snubber is going to be one of them.