Question for ncwayne or others

You seem to know your way around cats well as I'm sure others but I've been looking at a d5g the oil pressure only runs around 20 psi the salesman says his mechanic says it's fine because is not about pressure it about volume which I'm sure is partly true but how would you know about the volume it is moving? Would you be afraid of it or is there anything I should look for to do with the oil pressure? I've only seen pictures from a buddy that was in the area cause the machine is several hours away. It has around 9000 hours with a rebuilt blade and under carriage. Said it was used to made pads for oil wells in North Dakota it whole life. Thanks for the input

If I'm looking at the right machine, it should have a 3046 engine in it. That's one of the Mitsubishi/CAT engines. Based on what I can find, the low idle pressure on that engine is .5 BAR or just over 7 psi. At 1500 RPM that pressure should increase to a minimum of 21-22 psi, with a max pressure anywhere between 42 to 71 psi.

The other guy is right in that volume makes a lot of difference, but pressure and volume go hand in hand. The pump might put out the volume but not be able to develop the pressure. If there are excessive clearances in the bearings, or the pump is worn, it won't put out enough volume to overcome the wear, and the pressure will drop as a result. On the other hand, the pump can be worn internally and not capable of putting out the necessary pressure regardless of whether bearing wear, etc is excessive or not.

Ultimately, have your guy check the pressure on the machine both hot and cold. If it holds the pressures above, when hot, then it ought to be OK. If it can't hold the minimums at both idle and at 1500 RPM, you have either pump issues, or wear issues in other areas of the engine, and it's not worth it unless you get a really good price.

Typically a rebuild will run you around $2000 per cylinder. That includes pulling the engine and putting it back in, as well as machine shop charges, parts, rebuilt turbo and injection pump, etc, etc. Usually anything but a major part being messed up will be covered by this pricing.

That ought to give you some negotiating room if it checks bad. Too, if the pressure is in the lower range, and you don't plan to use it a lot, you might get enough life from it to get you through quite a few years before anything HAS to be done. Like everything else though, there is no guarantee......

Good luck, and if you have any more questions feel free to post again.

Wayne

Thank you for the advice I will have him check it out

I would be concerned if at 9000 hrs it has not had engine work. Have a d3g with the same engine and after an hour or heated up it seems to run a little more than that. At this point mine only has 2000+ hrs.