The Cat 3126 Engine. Know Your Engine. Caterpillar 3126B and 3126E.

in this video we're going to be discussing the good old caterpillar 3126 hey guys dress for the adaptive Channel and in this video we're going to be discussing my favorite small cap diesel engine the 31:26 we're also going to have a destruction of the week segment at the end of this video and before we get into the video I'd like to thank Greg Martin Miguel bill Chris max and Jason for helping to support this video if you would like to support the making of these videos Adept api comm on paypal alright let's get into the video so caterpillar never made a light duty diesel engine they made medium duty and heavy duty and medium duty are basically they're 31 16s 3208 c7s 31:26 is c9s the heavy duties are to see Thirteen's the c 15s and 3406 is things like that so why is it 3126 my personal favorite well I find it to be more reliable and easier to work on and the earlier and the later model engines and we'll be getting into the specifics on that throughout this video so let's get into the specifics of this engine first thing is a walk-around of the engine so now I walk around here and then take side of the 31:26 cat engine and on the back of the head you're gonna have your fuel pressure regulator on the right there next to the lifting bracket and then starting in the back of the engine you can see your ECM there it's the black box with the lettering on it your p2 connector we have your oil pressure sensor on your oil manifold also you can see your side covers there we'll be discussing those in a little bit and you can see the oil pouring out of them pretty common problem there moving up to our intake manifold we have your booster pressure sensor we have your Inlet air temperature sensor we have your Inlet air heater solenoid your fuel filter housing you can see your injection actuation all your Huey pressure sensor the aluminum colored item here that's your Huey pump that's a round top one and you can see your timing sensors here and some more oil leaks of course those are your timing sensors there's two there into your front structure above the power steering pump so some of these engines are gonna have air compressors you can see your serpentine belt and there's also a small V belt there and let me show you where your coolant temp sensor sensor is it's a little hard to see but it's right there behind the Huey pump under your fuel filter now onto the exhaust side of the engine so we have your thermostat housing uses two thermostats and this one were to have a line running across it about an air-compressor but it does not you can see your exhaust manifold there behind your intake tubes you have your turbocharger oil return line oil cooler oil filter and another oil leak looks like rear structures leak in here between the block and the rear structure and that's your walk-around okay so it has a quick walk around of the engine let's discuss some of the specifications of the engine so the 31:26 was a engine that was designed after the 31 16 and before the c7 it uses basically the same block as both of those engines and it is an in-line diesel engine six cylinder it uses a Huey system for the fuel system Huey is hydraulic electronic unit injector it is a three valve per cylinder engine it has two intake valves one exhaust valve it has a single turbocharger the intake is on the left side of the engine the exhaust is on the right side of the engine it uses a gear driven oil pump it uses a belt driven water pump it has two thermostats it has piston cooling Jets it does not however have wet liners which is a negative because that makes rebuilding this engine more difficult than the heavy duty engines which have wet liners it could be had from seventy-five horsepower all the way up to 330 horsepower it had a 16 to one compression ratio and these engines were made from the end of 1997 up till the end of about 2003 they actually were making these they were still making them when they started making the c7 which was the engine that took the place of the 3126 so why do I like this engine more than let's say the 31 16 or the c7 well it's kind of it has the best of both worlds between the 31 16 and c7 and I'm going to discuss kind of what I mean by that so the 31 16 most of the items on the engine were similar as far as the block it didn't have wet liners things like that but it changed it's very complicated internal wrack mechanical fuel system to the Huy system now the Huy system is not the greatest fuel system ever designed but a lot of the smaller diesel engines at the time we're starting to use this system as a way of getting away from the rack or the high pressure pump that the older engines used to use so this being a Huy system the fuel system is much easier it's much more simple there's no camshaft that actuates the injector it's strictly high pressure oil so let's discuss the Huy system a little bit so if you're unfamiliar with a Huy system basically the engine supplies normal oil pressure you know you're 30 to 70 psi of oil pressure to something called a Huy pump the Huy pump is in place of the 3116 governor that used to be there and the Huy pump takes that will say 60 psi of oil pressure and then it bumps it up considerably anywhere from about 800 psi all the way up to about 3500 psi then supplies that high-pressure oil to your injectors and that pressure is used to push the injector plunger internally to the injector to fire your cylinder so it's still firing fuel obviously it's just using your high pressure oil your Huey pressure to fire the injectors now the later model the c7 which took the place of 31:26 also had a Huey system but there's some differences between both of them and I think the 31:26 was a better system okay so really what's the difference between the c7 and 31:26 Huey systems at least the ones with the Round Top huey pump well the nice thing about the Round Top Huey pumps is they have an external driver for the Huey pump now why is that a good thing well on the later model ones the square top ones the drivers internal and non-replaceable the part is not available from cat so you'd have to change out if you have a Huey pump problem or a driver problem get change a little pump out and you're looking you know about a thousand bucks from cat for that but if you have just a driver problem on the round top ones you can change this a driver out and it's a little less than two hundred dollars from your cat dealer which is obviously a lot less than the whole Huey pump not only that it's much easier to change out and if you're wondering what's under that round top on your Huey pump there's nothing in there a lot of people think it's a filter it's actually just an accumulator if you ever were to take it off there's nothing in there it it just is used to store oil in the pump to obviously help with starting because it takes a little while to fill that pump so what other issues in the Huey system make it a little bit better than the later model ones well there were a lot of Huey pump failures on both the Round Top and the square top ones but it seemed like they were more common and could be more catastrophic on the square top ones but the other thing that is nice about 31:26 and their Huey system is the injectors now what do I mean by this they both have injectors both expensive well to 31:26 the injectors are much much easier to remove they change the o-ring and the more like little backing rings and they change the design on the c7 the c7 injectors are much harder to get out than the 31:26 ones the problem is the 31:26 ones they have kind of a more funky bolt design and the ball are more expensive and you're supposed to replace them when you change the injectors but they also do not have a calibration file unlike the c7 so if you own one of these 31:26 and you need to change an injector out yourself you can there's no programming of the ECM there's no a trim file to change out if you're doing an injector only on the c7 s you have to worry about that so that makes them a little bit nicer so this engine could be had with two different style oil pans there was a seven inch five gallon sump oil pan there's also a nine and a half inch seven gallon oil pan design and your maintenance intervals are gonna be about ten thousand miles or 250 hours of runtime per engine service and then about every two thousand hours or every hundred thousand miles you're gonna want to get your valve lash adjusted and the valve lash on this is the easiest valve less you could possibly do it's fifteen and twenty-five thousandths 15 on the intake twenty-five thousands on the exhaust and that's it there's no IVAs there's no injector adjustment you can do a valve lash in under an hour if you are familiar with these they're quite easy to do yourself outside of that there's not a lot of periodic maintenance you have to do this other than just expecting for leaks and things like that now these do have a separate V Bell Drive for your water pump than the main serpentine belts so I'd like to see sevens where the serpentine belt runs your water pump this is gonna have its own small V belt that's gonna be on your pulley off of the crankshaft that's gonna run your water pump and you're gonna want to get that changed if you ever are doing your serpentine belt and that belt can be kind of a pain not necessarily the belt but the adjuster for it is not a automatic tensioner for such as like your serpentine belt it's a manual tensioner so you have to get in there and tighten it and loosen it and it's it can be a pain to get to also the bolts they can strip out or break because they go into your front structure those can be kind of a pain outside of that there's not really much maintenance problems with this engine so speaking of problems what are the main problems this engine tends to have well I already mentioned that it doesn't have a wet liners so if it's starting to eat a lot of oil or you're starting to get a lot of blow-by and you're thinking of a rebuild well that's gonna cost you some money because no liners to remove so you're gonna have to either get a new short block or a long block or remove the head remove your pistons and have new press in sleeves installed in the engine which is not very cheap other issues with this engine similar to the c7s the oil pump idler gear can fail and while not super common this can cause a low or no oil pressure condition so if you ever have the oil pan off to inspect or just for a leak you're gonna want to look at the idler gear on the oil pump to see if it's starting to wobble it shouldn't have much play in it now this uses a push rod design with the camshaft in the engine block and it has followers or lifters that are bolted to side covers on the intake side of the engine and the side covers are a big source of oil leaks if you have oil coming out of the intake side of the engine somewhere it's most likely coming out of these side covers now the bushings that hold the rollers on for the lifters can fail sometimes if you get a dead cylinder or weeks owner sometimes it's not an injector you might have had one your followers fail and that'll damage the camshaft and the follower so you'd be looking at getting new lifters and a new camshaft the biggest problem on these is it's a huy system and the huy systems can fail and the injectors can fail quite often they're not cheap either the pump or the injectors aren't cheap the lighter watt model ones with the square pump on the c7s they tend to have a lot more problems with the pump failing and wiping out all the injectors and they made something called a Huey kit that would replace all of that is a set and it's very expensive your look at almost four thousand dollars just in parts costs to have that replaced outside of that there's not a ton of problems but you know you've got your follower issues and your injector issues and they can give you a real headache monetarily speaking also being a huy system these are not the best for cold starting or hard starting conditions common rails are much easier starting in general so are the older high pressure pumps the heat pumps are not or the huy systems aren't very good in cold starting conditions mostly because they're relying on the oil pressure to fire the injectors and of course cold oil doesn't flow very well and they have a bad tendency of being hard starting most of them have Inlet air heaters and that can kind of help you might want to turn your key on let the inlet air heater heat up for about 30 seconds before starting them but there's still not very good cold starting engines now if you do own one of these engines there's one thing you need to check that hopefully has been updated already for you and what that is is a Huey oil supply line update so between the Huey pump and the cylinder head is your Huey oil supply line and I already mentioned that the Huey oil is very high pressure you know up to about 3500 psi well the original oil supply line was a steel braided rubber hose that ran from the Huey pump to the cylinder head and over time that hose is going to get extremely brittle and can crack and can leak on you now if I were to boot and it can get extremely brittle and over time it can crack or leak on you now if I were to blow on you just blow up it would very rapidly spray extremely high pressure oil all over the place you know potentially squirting on the turbo causing a fire if this was in an RV it might you know spray up through your cab spray over your alternator all over the place it's a real issue well there's a fix for this and it's your Huey oil supply line update kit so it takes it from a steel braided hose it goes to a steel solid line and you can you the repair yourself all you're really doing is removing the line off the Huey pump and then the fitting going to the head and they're quick connects and you're gonna be installing a bow ring boss - oh ring face connector on the Huey Pompey on the cylinder head and then installing that line if that has not been done you if you own the engine you know this engines almost twenty years old now you will want to do that right away and any dealer could do that for you as well but it's a job you could do yourself with some basic wrenches and some mechanical know-how okay that's not of those problems they're there they're generally good running engines they're simple to work on very little specialty tooling needed to do anything on them they do have an ECM that you would need CAD ET to communicate with if you wanted to do any sort of advanced troubleshooting but in general you can do most items yourself even running the overhead things like that are fairly easy and these are metric engines meaning that all the bolts are metric you know 13 millimeters 16 militar millimeter things like that and that's about the gist of these engines I hope you enjoyed this video we are gonna do our destruction of the week segment now [Music] this is our second installment of destruction of the week and this engine came in for a lot of exhaust smoke and this is a c7 s that's a lot of oil there's a ton of oil in this intake and it was smoking a lot out of the exhaust so pull the intake tube off found a lot of oil this is the outlet of your charge air cooler it's got about an inch of oil in it you can see it was getting pretty hot as well the inlet side of the charger cooler also about an inch of oil in it so next thing I check was the turbocharger and full of oil the turbocharger had failed and dumped oil into the intake and out of the exhaust now that it's a real problem because this has a DPF and the DPF was totally saturated basically garbage so you're looking at 3000 for the turbo about 3000 for the DPF plus CA C cleaning + labor so you are looking at about $8,000 total parts and labor to repair this failed turbocharger quite the big repair there hope you enjoyed the destruction of the weekend hope you enjoyed the video thanks for watching [Music]

Channel: Adept Ape

Views: 165,182

Keywords: 3126, Caterpillar Diesel Engine, Diesel Mechanic, Destruction Of The Week, Diesel Engine, 3116, Cat Diesel Engine, Diesel Technician, C7, Acert, Caterpillar, HEUI engines

Id: cj2wfZwMJP4

Length: 18min 23sec (1103 seconds)

Published: Thu Mar 29 2018