Mcrafty1

I'm not totally in agreement with you on this, here why.....I have owned several class 8 trucks with factory AC...none worked well for very long, most were a 'money pit' to the point of giving up trying to keep working...That's my experience with them. I have never had an aftermarket install but seriously doubt they are any better. I would love to have a system installed that would prove me wrong. I have been around countless units other than my own and find those results similar to my own experiences.

Not likely, The kits came directly from Mack ..... and if so it has six wrong pistons and that wouldn't explain why just number 6 hole is the only one that failed multiple times, I also just learned that the failure that instigated the first rebuild was also a burned piston/broken ring ledge in number 6 hole....that brings the total to three. I'm now beginning to think that the nozzle was indeed the problem. I have a heat gun on the way and will be checking the individual cylinders for heat variances. I'll let you all know the results when I have them.

That's one way to go, my thoughts on that are with the inherent problems any AC unit seems to have I am hoping to get the best NEW set up I can afford and bypassing those problems for a little longer.

I appreciate the effort I understand whats being conveyed here and I'm reasonable sure that isn't the case. That being said I did order a heat sensor today and will be checking the cylinders individually to be sure they're all doing about the same amount of work and number 6 hole isn't getting an excessive amount of fuel/heat. I'll post the results here when I have them.

The only thing that I've done differently during this whole incident is the last time I replaced the piston I replace the nozzle in that hole.....and up to now the engine runs good, however I still worry about it because of its history, at this point I think the heat gun comment is my next move at least that should show me if that cylinder is still running hotter than the rest or not. If the temps are near the same across all 6 I may be home free now. I'll update when I have that info. Thanks to all for all the help.

That should be evident when adjusting valves shouldn't it? If so than yes that has been addressed, the valves have been adjusted multiple times during these rebuild/ piston replacements so I believe them to be working like they're suppose to.

That's a possibility albeit a slim one in this case, the pump builder is a very reputable and long serving shop that is used by most everyone in the area....but everyone makes mistakes, I 'll certainly keep that in mind as a place to look if I find a temp difference in the exhaust.

Great Idea, I hadn't thought of that......that should tell me if there is a temp difference for sure.

That's a ton of money in my book, If you'd have said $2000.00 I'd have thought that a bit high, but doable ......$3800.00 just won't happen for me.

I wasn't lucky enough to have the adult friend finder load So I guess I'll settle for this Diesel Porn It probably can be bit more expensive.......but if you're careful you don't have to worry about catching any STD's from the other members

The Rise........and Fall of the Third Reich. May we NEVER forget.

Thanks, I see now that the compressor, lines and condensor isn't included with this one. I'll have to check and see if they have those to sell or if I'd have to find those things elsewhere

Thanks Paul for getting the picture up for me, it is a nice truck and well suited for the earthwork business I have. A little slow in the highway (65 maxed out) but I don't even push it up to that most times, I'm a lot more relaxed than I was forty years ago and have learned a few things over the years....lol

Thanks all for the warm welcome, I'll be lurking and asking/answering any questions I think I can help with or need help with.

Ok, I'll give it a shot when I have time to sit and play with it for a minute.

Do you recall the name of the manufacturer of the units you installed? I have yet to find one of the between the seat units to compare to the other types. I'm also wondering what peoples experiences are with the roof mount models..ie: do they cool enough to make the entire cab comfortable or just blast your head and shouklders with cool air but not do much else? The price seems comprable to most other styles that I have found, I am still most interested in the between the seat models and would like to find more criteria and some pictures of those.

After looking at the red dot under dash unit the between the seat option sounds a lot less complex and therefore easier to install/maintain but I didn't find those on the red dot website, do you have a link for the between the seat universial models?

Thanks, I haven't taken the time to look yet but I like the idea of the factory look too, I also don't mind the roof mount units but it seems like the air flow coming from above and so near your head my not be such a great Idea...IDK

Will do, Thanks

Administrators...If this is the wrong place for this please move it to where it belongs. I have an RD685S 1986MY I would like some input as to what it intales to install an AC unit into this truck and what is the best option.....Factory package vs. Cab mount and which is the most cost effective in terms of actually doing what it's suppose to do. Thanks in advance for any useful info on this subject.

I'm practicly computer illiterate and haven't yet figured out the picture posting thing but I do know that My business is on Google and if you follow this link...https://allanhanscomconstructionexcavation.workingpoint.com/they have a picture of my truck there. I have no idea how it got there but its my truck for sure. When I figure out how to post pictures I'll put up some myself. (or I'll get my grandaughter to do it for me )

Yes the spray nozzles where ruled out earlier, Thanks for the reply

You done great explaining what you meant to, but that doesn't explain how that could happen, if all injectors are being feed from the same pump...and the pump has been calibrated and known to be accurate, the air is being driven into the engine with the same turbo and the cooling system is working as designed and the water temp never exceeds 200 (very rarely that high) then what could cause the same piston (hole) to burn two pistons to the point of breaking the ring ledges and the other five out live that one by now 2 x's (the original piston after the rebuild....another after that and another season on all five of the others on top of that. That is why I'm scratching my head, I appreceate your input too, thanks

I agree with everything you say, The pump WAS calibrated when it was rebuilt......the only thing I changed the last time around was the piston, rings and sleave AND a new injector, I did the injector change because I suspected the spray pattern was bad, That being said I have run the truck one season since I made this change and so far so good. The only way to know for sure is to pull the head and have a look. I'm not going to do that...oh, and the timing was checked too so too much fuel COULD be a problem but that really don't explain why it's the number 6 hole both times and the EGs staying within spec. It is beginning to be a head scratcher at the moment.

I'm in touch with the rebuilder and hope to findout something soon, if I cant I'll have it done before I start using it this spring. Thanks for the reply.