Vehicle: 1990 w250 4x4 Cummins manual, 200k miles

I bought this truck 3 1/2 months ago and put a truck camper on it, have put maybe 5k miles on it (mostly highway, weekend trips) in that time. Everything has run great until today, although the heater has put out lukewarm at best since I got it.

Yesterday I drove from Seattle to Spokane, 300 miles of 65-70mph highway. Today I drove Spokane to Bozeman, 400 miles of the same.

5 miles out of Bozeman, the engine starts to run rough and sound unhappy, best comparison I have is a rod knock but I've never had my own vehicle do that so I'm just guessing. This goes on for at most 1/4 mile (I'm looking for an exit) then I lose power, and I pull onto the shoulder. When I come to a stop there's lots of steam from the front, coolant not oil.

I look and my temp gauge is at the max, but I had actually been talking to my dad about the weak heater just a few minutes before, and looking at the temp gauge when talking to him, which was normal as always. I estimate that the temp gauge was normal at most 10 minutes or so before this loss of power event, I may have not paid attention for that long . Outside temp was about 20F or even lower. The heater valve had been full open the whole trip until the about 20 minutes before the loss of power, but heater output was very weak. In fact it was so cold I figured my feet would be warmer with the heater off so I shut the heater core valve at that time.

Back to the side of the road - I opened the hood and noticed that the serpentine belt was half shredded and totally off of the pulleys. Upon inspection I notice that the water pump pulley is totally loose like the bearing is gone, flopping around. I assume this took out the belt. Top of the radiator is warm but not hot, lines to the heater core are warm too.

I take out the water pump and the impeller is 90% missing, and clearly beat up. There's a piece of the impeller stuck in the housing which may have jammed it.

I then go get a new water pump, then refit the good half of the old belt (couldn't get a new belt, so trimmed off the bad half to try to make it the last 5 miles to bozeman without a tow). Engine starts, but runs really rough, lots of vibration shaking the truck. Kind of like a gas engine on bad gas. Check the "half belt" and it hasn't shredded itself and is running on the pulleys ok.

I let it idle for about 30-40 seconds then it stops hard, like it stuck not like a running out of fuel slow dying. I did actually forget to add more coolant but can't see that mattering in 40 seconds.

I try to restart but though the starter solenoid kicks it doesn't spin over at all. I hook up another running truck's battery in case mine is weak, same result. I try taking out the water pump to see if it's jammed with shrapnel, looks fine.

I then take off the belt and try to start - I wouldn't run it this way but I just wanted to see if it would spin over - again just the solenoid kicking and no rotation. At this point I didn't have the second truck hooked up but I don't think my battery was actually low.

So, what happened? Clearly the old water pump cratered and took out the belt, not sure why. The truck overheated, but for 10, maybe 15 minutes in 20 degree weather at 70mph on a flat? I figured with a fresh belt and water pump I'd be back in business, but did the engine seize? I guess I could try to turn it with a breaker bar to rule out a bad starter, but since the engine stopped solid I'm really worried. What can I check to find out if I need a new engine or not?

Thanks for reading. I would be extremely grateful for any ideas, and I would be more than happy to provide more details on anything or check something on the truck, it's 15 minutes away and I have a decent set of tools with me.

 

Sounds like your water pump bearing was bad allowing the impeller to grind itself away inside the volute and then finally fail, the low heat output is probably either a missing thermostat or one stuck open not allowing the coolant to warm up.

The engine stopping abruptly could very possibly be the dowel pin or a bolt has fallen into the timing gear train and stalled the engine, this is usually fixable with a new timing cover if the engine dies at low speed rather than at hiway speeds.

Check the sides of the timing case carefully, dowel pin failure will crack and frag the case when the hardened pin lodges between the gear and the case while trying to get out.

Also your year truck has a diaphragm vacuum pump and the bearing on the eccentric fails passing the hardened frags into the timing case with like results.

Best thing for you to do is to pull the timing cover and check the gear train for damage.

Were you able to find the missing parts of the water pump, you really do not want them blocking internal passages of your engine.

The cummins is an extremly durable engine with a lot of rotating mass and for something to stop it dead something has to give.

Sounds like you had multiple failures hoping none were catastrophic.
Was there ever any mention of the KDP or dowel pin being tabbed from the previous owner?
Good luck
Jim

 

Ill try to add to the conversation to keep it going where your 700 miles from home in 20* weather.

The thing that bothers me is running rough after the new waterpump. I don't know as though the kdp or case bolt would make it run rough before falling into the gears. But once it does fall then all stops or blows apart.

On the other hand if the engine was running rough from overheating with extra vibrations that could help bolts or pins loosen and fall out.

Did you happen to notice oil pressure throughout this time? Just before the initial power loss or first restart?

How easy did it start when it restarted after the waterpump? Was it a normal restart ? How much time between power loss and restarting with new pump? Thinking about why it sounded rough, any chance for a fueling issue?


Can you recall more about shutting the heater valve off before , what do you mean by this?

Wouldn't a chewed up waterpump cause poor circulation through the engine and heater core causing low heat as well?

Might need to blead air out of the block when refilling the coolant with an empty block, there is a plug just above the thermostat to loosen. This wouldn't cause any issue in the short time it ran but something to discuss.


Do you have a place to work or are you out in the snow?

Good luck. Hope its something you can get worked out.

 

sounds like your engine has locked up, see if it will turn over with a tow

 

Starting with the low heat output, could be a leaking head gasket. And the water pump going out finished it off filling one or more of the cylinders with coolant. Hydro locking the motor, also goes hand in hand with the running rough before shutting down. If it were me I would fill up with coolant pull the injectors and crank it over and see if you get any coolant out of the cylinders..

 

There isnt any good reason for it to lock up solid while running, so trying to power through whatever is holding it up sounds like a bad idea that could end with some very costly broken parts. I'd think turning it backwards by hand to see if its free would be better, if it turns back try forward by hand to see if it hits the spot again?


Sounds like the guy is in a bad spot so lets list some items that could lock up a running engine and see how to eliminate it from the possibilities. No matter how stupid the idea may be lets list it and eliminate it:


What could lock up/ instantly kill a running engine:

1. KDP/case bolt in timing gears
2. siezed main bearings
3. hydro locked (water, fuel, blown headgasket, warped head, cracked head?)
4. injection pump not turning (sheared shaft/key/drive gear fell off??)
5. no fuel (fss lost power, gelled up, air lock)( wouldn't cause engine to lock so probably not)

 

I am guessing that after the water pump cratered and dumped out all the coolant, it overheated badly enough to seize up a piston in its bore. It's possible that the head warped badly, but at that point I don't think there would have been enough coolant left that high up in the engine to hydrolock it.

If you can't turn the engine over with a bar, make sure you remove the starter and try turning it again. I've seen a couple instances where the starter drive stayed engaged with the flywheel, effectively locking the engine.

 

I suspect that you had a low coolant level prior to the water pump destruction.
You will get little/no heat if this is the case. Just guessing here .... you may have damage in the head.
As others have expressed ...... good luck to you.

 

6. Dropped valve ....

 

Cascade .... how are you doing? Hope things will work out for you. Please keep us up-dated.
Greg

 

Thanks for all of your responses!

Jim Lane I don't know that the KDP has been tabbed. One of those things I had on my short list to check/do, but unfortunately hadn't done yet.

I wasn't able to find all the pieces of the water pump, my plan was to drive it the last 5 miles with my fingers crossed then have the cooling system flushed.

Taterfarm I have the same question, it seemed to be running rough in the last few hundred yards of highway before I lost power completely, then also at idle before it dead stopped. Question is why would a dowel pin or debris cause it to run rough before stopping?

I'm pretty sure I would have noticed an oil pressure light very quickly. When I restarted with the new water pump, oil pressure light went off immediately after start as normal. I also should mention that I checked the oil after all this and it was a little below the safe line, but not super low. Oil looked good, didn't see metal in it or cloudy/antifreeze.

Starting after the new water pump was a slow start, but not long cranking. Normally it bangs right off in the first rotation or two. It probably took me a couple of hours to get and reinstall the new water pump, maybe 3. Engine was cool on the gauge by then but still felt warm to the touch.

Running rough: truck had plenty of fuel, and had been running great on that tank, had burned about half of it. What do you mean by a fueling issue?

Oh, I didn't really mean heater valve. I had had the heat going the whole trip, but moved the slider from "heat" to "off" about 20 minutes before the incident. Temp slider was still on hot. I was thinking that this could have somehow contributed to the water pump cratering, but now I doubt it.

I don't think my water pump was chewed up since I bought it because I drove it loaded in the mountains over the summer and the temp stayed under control.

Truck is out in the snow now, I don't have a place to work on it but I can't move it from where it was towed to either without a running engine!

Greed 93 can you tell me more about what you mean here? "Hydro locking the motor, also goes hand in hand with the running rough before shutting down." I do like the idea of pulling the injectors to see if it spins over and was hydrolocked.

Torquefan do you think it could really have overheated badly enough to seize a piston in 10 or 15 minutes at 70 on the flat? I didn't think about the fact that the cratered water pump would have lost all the coolant, but you're right, it would have.

Conclusion I'll go look for damage to the outside of the timing cover, try to pull it, and try to turn the motor with a socket both ways, and report back.

What I don't understand is why would any of these issues cause the engine to run rough for a short time before it stopped hard?

 

I think hydrolocking is out as a cause because when I restarted the engine and it idled rough there shouldn't have really been any coolant above the water pump, so no additional coolant should have been leaking into a cylinder.

 

Here's my thoughts.

try barring the engine over, if you can't try it backwards

Personally I think it overheated bad enough to cause major damage

10-15 minutes with no coolant is a long time. Regardless of the ambient temperature.

Piston stuck in bore is my guess. You could pull injectors and look at the nozzles. Also could use a inspection camera

 

I agree. Unfortunately.



Fuel issue was on running rough but sounds like its not it. with such a quick repair its unlikely anything changed there. It was wishful thinking for an easier repair.

I would hold off on bothering the timing case, no reason for making it run rough before so there is a different issue occurring. Front seal isn't something to mess with out in the cold.



Did any coolant come out when you removed the water pump?

 

Yep, unfortunately I do. I would think that if an engine loses all its coolant, critical damage can be done in a couple of minutes at highway speeds. I sure hope that isn't the case, but I'm not real optimistic.