Tomcat588 Posted March 3, 2016 Share Posted March 3, 2016 My brother an I currently own a couple of 2005 CX613's that were formerly Air Product fleet trucks. From what I can tell they have been well maintained through their career at AP. The trucks came to us with 450K and 550K on the odometers. We have been going through the trucks over the last year and a half replacing hoses, EGR's, compressors, turbo's, and other items that needed freshening up. My question is when should we be looking at the internals? I've heard of them needing a "bottom end" at around 750K . Is this necessary? Can a oil sample determine if this needs to be done? Mine now has 650K on it and I run AMSOIL in the truck. It has been running smoothly, and I don't want to spend a bunch of money on a repair that is not needed, even though Mack recommends it. Any thoughts? Quote Link to comment https://www.bigmacktrucks.com/topic/44227-when-to-do-a-bottom-end-on-aset-engine/ Share on other sites More sharing options...
GOOG Posted March 3, 2016 Share Posted March 3, 2016 When I purchased my CH613 in 2003, it had 775K on it. It was a one owner cream puff, and I wanted to do right by it. I went to my Mack dealer and asked if I should roll rods and mains in it. They told me the bearings could easily go a million miles, and that unless the was an oil pressure problem, or obviously a knock, not to do it. I didn't do it and am still running the truck. I have not had one minute of trouble with the truck, and still have great oil pressure. The way I was taught to check for bottom end wear is to get the engine good and hot. Then hop in the truck and watch the oil pressure as you slowly raise the RPM in steps. As engine speed goes up, the oil pressure does as well. Watch that the oil press never goes backwards. If it goes up and drops back down, that is indicative of bearing wear. The oil can't keep the gap between the crank and the bearing filled. I hope this makes sense to you. I've bought a lot of used trucks, and this has served me well. - Tom Quote Link to comment https://www.bigmacktrucks.com/topic/44227-when-to-do-a-bottom-end-on-aset-engine/#findComment-326460 Share on other sites More sharing options...
TRH Posted March 5, 2016 Share Posted March 5, 2016 Monitoring oil pressure and taking samples will definitely tell you, far in advance of a problem being catastrophic. I can't recommend sampling enough, but I've seen engines run well over a million with good pressure and the bearings that came out were still serviceable. Sent from my iPhone using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/44227-when-to-do-a-bottom-end-on-aset-engine/#findComment-326562 Share on other sites More sharing options...
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