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im in the process of buying a 2016 kw t680 with 376,xxx miles. Cummins ISX15 2350 450HP. I did an inspection as well as I could in the way that the rawze book said and major items checked out fine so I took the truck to inland Kenworth for the full dyno. I was told that it would take a day or two to finish the dyno since they were busy so I just left the truck and picked it up when it was ready.

the result were

"perform full dyno. no check engine lights or warning lights became active. the engine oil pressure at idle was at 30psi and at 1300rpm 32mph the oil pressure was at 42psi. the blow by at idle was at 0" and at 1300rpms 32mph reached to 3". the fan engaged at different times while the unit was running but it never went over 220 degrees. the unit did not overheat. the boost pressure climbed to 35psi."

Im not too sure but it seems a bit off that the blowby at idle being 0 seems almost too good to be true. The tech who performed the test also didnt have the rpm set up so I cant see the torque figures. I paid 569 to have it done, is that a big enough concern that I should go back and ask them to re do it?

https://imgur.com/a/HjWrETs

this is an image of the dyno results
I did notice on the way to the kw dealer which is around 15 miles away from the dealer im purchasing from the fan engaged and disengaged erraticly. It never overheated or even went above 170 on the gauge. Im hoping its something like the coolant temp sensor. Besides that the truck ran and felt great im just trying to make sure the results seem normal.
Erratic fan could be something simple and more than likely from the AC running. If it's getting low on charge or if it's slightly overcharged they will kick in and out erratically.

But I wouldn't just shrug that problem off. There's a list of other problems that can cause that also.
A dyno report simply says that the engine is running without immediate problems. A test drive while riding the brakes hard a few times would have done pretty much the same thing.

- Did you inspect the overhead cam?. That would be revealing on how well the engine was maintained, as well you can see how badly the engine is sooted up.

Post some pics of the overhead cam and other things that u find it if you can.

--Next is to do/inspect the fuel pump as well, as its getting close to the mileage that they explode and take out the whole engine without any warning.

3" of blo-by sounds a bit on the high side to me too. Maybe make a video of what the blo-by looks like with the oil fill cap off and the engine idling and when stomping the pedal a bit.


Aslo pull the exhaust away from the back of the doser pipe, inspect the doser injector and crank the truck up with a piece of white paper in front of the exhaust stream, see if it gets spattered with coolant or oil,.. see of the engine is smoking because of worn out valve guide seals, etc. (very common on 225 and 2350 engines).

Your also going to want to take the DOC and DPF off it and take pictures of their faces, see how much buildup is on them, and check faces of them for signs of any seepage of coolant or oil from the engine.

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i am thinking that i would be a used truck dealers worst nightmare...lol
Ill be doing that tmr and update this post with pictures. Thanks for the replies.
Rawze is right on the money. No valve cover off inspection or fuel pump rebuilt verification is a huge bargaining chip and must be addressed.

How many hours on unit, an often overlooked item.

Is the dealer claiming this engine is ready for a Cummins warranty contract? Not endorsing Cummins warranty, just wondering how much faith dealer has in unit

I’m sure your paying a fair price for this unit, nicely and professionally demand answers before signing contract, you are not buying it from an auction.
(06-26-2019 )Rawze Wrote: [ -> ]----
i am thinking that i would be a used truck dealers worst nightmare...lol

Get your daughter rigged up with a hidden camera, and PLEASE make a video...
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