Hey folks. A buddy of mine runs a used "everything for sale" lot and has a '99 C6500 (3126 / 6spd manual / 25950 GVW) there that I'm interested in. In its former life it was a roll-back wrecker and now has a new custom 15+4' backhoe beavertail bed on it. It has 328K on it, but runs like a top...no smoke and just a little dampness at the seals but no leaks. My buddy's going to get the service records from the towing company and I'll get an oil analysis done before I buy it. I can get it for less than 6K and it would work great for my business. My question is concerning the 3126. I've read everything from crap on the diesel pickup sites to 500-800,000 miles on a couple of expeditor trucking forums. What are your experiences with the 3126?
I don't have any experience with the 3126, but my 3116 was a fine motor. I know a lot of people hated them, and they were terrible in some applications. With that age and price, the condition it's in now is more important than what it might do five years from now. The 3116 is not a "user serviceable" system, like some of the cummins or internationals. With the 3126 being electronic, I don't know how different it is from other electronic engines?
Decent engine. Hard starting like all the engines with huei injectors. Not my top pick of an engine but not the worst either. Ours is in a crane so it works hard getting to the job then sits and basically idles all day.
I have one in my service truck. 130k miles, drinks a gallon of coolant and uses between a half gal and a gal of oil a day. blowby is so bad that people I sit next to at stoplights think its on fire! its days are numbered. I don't know what it went through before I got it but I've never seen one this bad. I think theyre a pretty good engine overall, mine just had a hard life.
Before we rebuilt ours it smoked more out of the blowby tube then it did out the exhaust. It was amazing how it could fill the cab up with smoke when the fan kicked on.
Bad engine. They have a number of design flaws that are very expensive and have never been ironed out. They can't stand being over-revved even a little bit. There are numerous problems with head gaskets, injector cups, etc. that lead to coolant/oil/fuel mixing issues. The HEUI (hydraulic) pump likes to give out and shrapnel the engine hydraulic passages which can't really be cleaned out very thoroughly so it just gets a "good enough" treatment along with 6 new injectors and hope the shards don't take out the new stuff. The new pumps are as bad or worse than the original ones when they give out, and very expensive. Now that the years are going by, Cat and aftermarket support is getting worse if it was ever very good in the first place. This is a stupid guess but I estimate the premature major failure rate at about 50% on these so there are a lot of people who will have had good service, but plenty who haven't. I wonder if the easy long high speed service of expeditors has made theirs last longer? Usually they are found in small trucks driven by low wage help so a lot of the problems could be aggravated by abuse. They throw bottom ends if over-revved even a little bit, but yet they have to be revved near the governor to make any power and the lack of torque back-up and narrow power band is very frustrating to drive, coupled with the usually less than adequate (cheap) transmissions they usually have on them. Finally, I learned one additional fun fact at least on the higher HP ones: they will only provide the higher power for a period of time until the computer calculates that the EGT is getting too hot (no sensor, they just use things like air temperature and fuel input to calculate) and then they will cut back power to keep from melting the small engine down. This is another frustration when driving as this happens sometimes in 30 seconds when you are trying to climb a long hill. Some of this may only apply to the C7 and not the 3126 but most of the major flaws are common across them all. I think I missed some stuff, too. But you said the truck was cheap, so in the end who cares about all this stuff, right? I would buy it with the understanding that if anything major goes wrong, it will be junked, the engine, if not the whole truck.
Thats interesting that the engine detunes itself. It's underpowered but plenty drivable most of the time. Sometimes out of nowhere it will Hardly get out of it's own way. I never thought the engine was that bad. There are lots worse engines out there.
Name me one from a contemporary time period.
I have experience with my own 3116 and like it so far. Had to replace my water pump which was cake. A little underpowered but it gets the job done with no problem. A friend of mine had a 3126 and it had way more power but the 7 speed stunk bad. So I think the 6 would be a eaton or fuller which would be a plus. Fuel mileage was not bad at all on both trucks. Both were 7 ton legal dumps. If its below 50 at night you gotta let the intake heater run for like 3-4 minutes to have it start easy but other than that no complaints so far.
I have one with a spicer 10 spd behind it. Runs good, but i dont put more than 500 miles on it in a year