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Discussion Starter · #1 ·
I have a 98 Dodge 2wd with 127k 5spd with gear venders overdrive. At 30k the turbine housing was replaced with a non wastegated version with a upgraded exhaust manifold and the pump retimed by a very good shop. I think it is in the "marine" configuration, but I don't really know. It has been used primarily for towing a car hauler and I purchased it from my friend at 100k. No issues, great truck.

However, yesterday something happened and I think I'm screwed. I had just entered the expressway with my car hauler and set the cruise at 75mph 1800rpm 5th over. Engine temp was 150 (still warming up). I started going up a slight grade, looked at my EGT as I normally do and it was reading 800 with boost about 24psi. Normally it would be about 1200 based on my experience. I know this was wrong because I do this trip all the time so I checked the throttle and the cruise had it pinned, so I kicked off the cruise. Then I thought the engine was getting louder but wasn't sure so I pushed in the clutch and the engine died. I tried to restart it and it won't turn over (with or without the clutch pushed in and trans in neutral), it is mechanically locked.

Now, I design and build race engines, but know nothing about diesels, however, I would have thought that if I melted the engine from too high EGT it would simply lose power and have blowby. I have no idea and don't know what could have happened.

I changed the oil about 100mi ago with Mobil 1 delvac diesel oil and filled up with diesel right before the trip. Changed the fuel filter with the oil change and put a new radiator in and have a later model aluminum intercooler. It had the dowl pin fix previously. Truck has been great and I'd really hate to think that I ruined the engine (being a race engine builder).

Know a Cummings specialist in my area? Was looking at remanufactured units yesterday and it looks like 5-5.5k for a long block and 7.5k for a complete engine. However, I would kill me not to know that the crank was std/std. I don't want old junk. Should I consider having mine rebuilt if it is bad?

Any advice would be appreciative.
 

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You could try turning it over by the crankshaft balancer bolt by hand . But if it is seized up your probably right.Toasted.
 

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Wow, that sucks man. Some weak spot could have just gave way, I don't guess you would know without tearing it apart. I race, so you should know as well as I do, when you build up an engine to make more power its can go at any moment.
 

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Discussion Starter · #4 ·
I forgot to mention that as soon as I pulled over, I checked the dipstick and the oil was warm, but not hot and it didn't smell like it was burned. I had good oil pressure the entire time. I did pop the radiator cap and it was under pressure, but when it came out, it was only warm, not hot. I also smelled clutch, so perhaps it isn't the engine but something else???
 

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Even though the clutch is pressed in the input shaft is still turning. Could be the tranny seized.
 

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it could have been athe lift pump
 

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AlGores worst nightmare
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Is it an early '98 12 valve, or a later '98 24 valve motor? Easiest way to tell is read the fender badge. If it says Cummins Turbo Diesel it's a pre '98.5 12 valve, or it will say Cummins 24 valve Turbo Diesel. If it's a 24 valve you're in the wrong forum, go to the 24 valve forum. I suspect injection pump in that case.
Diesel motors are very similar to gas motors, no real mystery. They still have pistons, valves etc. The difference is in the fueling. There's no air limiter, they're wide open all the time, power/rpm's are controlled by how much fuel is injected.
Other questions, any fluid leakage?
What kind of noises, where were they coming from?
Does the starter try to turn the motor?
Does the clutch feel different?
The motors are very durable, some of the other systems are questionable.
Don't buy a motor just yet.
 

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Even though the clutch is pressed in the input shaft is still turning. Could be the tranny seized.

How do you figure that?....

Thats the entire purpose of the clutch, to make or break the connection between the flywheel and input shaft!

Even if it was a toasted clutch it would still just move the entire truck. Never heard of a seized tranny stopping an engine, ive seen alot of them try to seize and the tranny loose the battle though!


Anyways, i would first off try to figure out if its seized or hydrolocked. Its an easy enough job, i would just pull the injectors. If the tips dont tell you the story looking at the crowns sure as heck will
 

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Discussion Starter · #9 · (Edited)
It is a 12v CPL 2175. Everything happened in the span of 30 seconds or so and thinking back, I may have made some incorrect assumptions based on my worst fear. As this was happening I thought that the engine was getting louder and as I was pondering it, the gear lever began to shake. I pushed in the clutch to see if the noise was real or my imagination (first tow of the season) and when I did the engine died. I let the clutch out to pop start it, and nothing, the RPM did not go up which it would have given the crank position sensor whether or not it was running and the truck and trailer did not slow down at all. Thinking back, the clutch seemed very soft when I pushed it in and that seems odd, and perhaps all I did was smoke the clutch in my gear vender overdrive (which is awesome BTW). Maybe this is a trans issue (hopefully). When I changed the fluid over the winter after 27k miles the oil was much dirtier that I would have expected and there were metal filings in it.

The starter just goes click and all of the lights dim like it is attempting to turn the engine over.
The clutch feels fine now, but did feel weird when it happened.
No fluid leaking
No appearant water in oil or oil in water
I am VERY careful about EGT and towing and know this truck very, very well, what it does, etc. It isn't hopped up much from my understanding and is in a form that it could have come from Cummings in a marine application.
 

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A little long on the oil changes, Cummins (no "G") reccomends 6k normal duty, 3k severe duty oil changes.
I think I'd start checking drive train issues. The 5spds had an issue with the nut that holds 5th gear on, coming off. Usually that only causes 5th gear loss, but with the O/D who knows.
 

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Man thats a bad one. Well I've had this happen to a friend of mine. He was toating 15k the input shaft broke off in the nv4500, now that said, he did not have all of the same symptoms you descirbe. You loosing egt's and power may point to somthing differant but can you still sift to Netural and maybe get a wrench or socket and breaker bar on the balancer and turn it over? Good luck buddy
 

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Will the truck move if it is in nuetral.. Im thinking MAYBE the clutch got hot enough and "melted itself to the pressure plate. If the trans or the gearvendor seized up and the clutch is siezed also it wont turn over. But I suppose the truck rolls since you probably got it home. So that was alot of typing for nothing.:thud: Oh well!!
 

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Since EGTs were low i would say it wasnt something seizing up (other than the motor)

If the tranny or GVOD was locking up the increased load should have caused higher EGTs!
 

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Discussion Starter · #14 · (Edited)
No, no, no, I change the oil every 5k on the truck and the gear oil has been changed every about 30k, 27k in the last case.

I never felt a loss of power and the GVOD worked properly and was rebuilt recently (leaked after 80k miles and was sent back to GVOD who rebuilt it). I was cruising at 75 until I pushed in the clutch and the engine died. I think the EGT probe was not reading correctly as it should have read in the 1200 range and at the end of last year I think it was reading incorrect at times because it wouldn't read at all. I was going to replace it this spring.

This transmission already had the 5th gear nut come loose and has been opened up and the fix applied.

The truck was flatbedded to my shop where it sits. Was too disgusted to look at it over the weekend.
 

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Well, that eliminates some things. Let us know what you find out.
 

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If all the internals look good other than the pistons, rebuild it yourself. If you can build a race engine, you can handle the 12V, they are pretty simple, IMO. The hardest part is finding someone that has the equipment to do the machine work. -Nicholas
 
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