What To Look For In A Used Diesel Engine? Used Diesel Engine Inspection.

in this video we're going to be discussing what to look for in a used diesel engine might want to think twice about getting this one hey guys josh with the dip tape channel and in this video we're going to be discussing a subject that I get questions comments and emails on all the time and that is hey what do I need to look for in this piece of equipment truck RV bus that I'll be purchasing that has a diesel engine what do I need to look for in that engine to ensure its not gonna cost me a lot of money down the road now before we start this video disclaimer any piece of equipment any truck bus with a diesel engine there's nothing to say that you're gonna get a 10 miles down the road it's not gonna eat a valve or throw a rod or have some sort of catastrophic electrical failure nothing you can do about that but what we're trying to avoid is you buying something that's been abused or has a current problem that maybe the owners trying to hide or doesn't know about and can cost you a lot of money down the road now why am I not talking about the entire truck the transmission the wheels the hubs all that why am i focusing on the engine well for two reasons one is the engines the most complicated and most costly piece on this piece of equipment and by judging how the engines been maintained usually you can tell how the rest of the vehicle has been maintained okay so that's why we're gonna be focusing on the engine here not only that if you wanted to talk about everything on a truck or a piece of equipment the video series would be really really long and I'm just trying to focus on the engine here okay so let's get into the video so if you're trying to make a checklist on your diesel engine that you prove be potentially purchasing and you kind of want to go through each individual component the way I'm gonna lay it out is kind of by symptoms that would cause you to want to dig a little further into it so we'll need to talk about fluids we need to talk about smoke check engine lights things like that so first thing I want to focus on is smoke and the reason for that is it's obviously the easiest to see and there's not a lot of inspecting you need to do to see that hey why is there white smoke coming out of the exhaust pipe or the blow by to if it has one so let's get into smoke what you need to look for what's normal what's not normal what you really need to be concerned about okay no irregardless of what make or model engine diesel engine you have it's gonna have an exhaust system and that exhaust system should be blowing only clear exhaust fumes you don't want to see any colored smoke coming out of there we don't mean bluish white black green anything weird coming out of there is a potential problem that cost you a lot of money now the one exception to that is 2006 and older engines under acceleration or if revved up are almost always gonna have a small amount of black smoke coming out of them now maybe the previous owner has modified the injectors or the pump timing and it's creating more black smoke than normal that's not necessarily a good thing but that might be a modification that doesn't indicate a problem with the engine now what's excessive well if it doesn't clear up right away it's probably in its indicated of a problem with the engine I'm talking black smoke here now why the Year designation of 2006 to 2007 well pretty much all on highway diesel engines that'd be in your RV in a truck or a bus 2007 or newer are gonna have something called a DPF a diesel particulate filter and the DPF job is to catch black smoke which is particulate a carbon residue from combustion and it's supposed to not allow it to pass out of the exhaust stack now if you're say looking at a 2010 RV that has a DPF and under acceleration you're seeing a lot of black smoke or even just a small amount something's wrong with that system now older DPF sometimes will pass a little bit of soot but if you're seeing a lot there's something wrong either the DPF failed or someone's modify the DPF hollowed it out it could be cracked you could have a problem with an injector or some other fuel related item even a boost related item that's causing excessive black smoke that's a problem DP FS are extreme expensive so if you're looking at a newer vehicle with a DPF and you see black smoke you really want to have that checked out because it could cost you thousands of dollars okay let's talk about the other colored smokes here so white bluish or green all those are bad and depending on which one usually White's the other most heavily found one is you probably have either coolant fuel or oil getting into your exhaust system and those are never a good sign so if you have coolant getting into your exhaust system that means you probably have a cylinder head that's cracked and needs your cooler that's cracked or leaking a cracked cylinder head there's a lot of potential problems there if you see white smoke I would say definitely want to have it checked out further before buying a vehicle that's emitting any sort of non black smoke out of the exhaust system now what about other types of smoke they might be wondering what other types of smoke would there be well most older diesel engines were talking 2006 and older which still plenty on the road are gonna have a blow by tube and on older cars this would have been called a road draft tube and some manufacturers still call them that but what this is is this is crankcase fumes that are basically combustion byproducts that push past the rings during combustion and it's a normal process all engines have this on the newer engines though it's usually in a closed-loop system where the blow by fumes are getting reintroduced into either the exhaust or the intake and they're trying to burn them or filter them out but on an older one you can usually see the volume and if the volume is very high or it looks high to you that can be a bad sign that can mean that you have excessive wear in the engine now this could be caused by many things air compressor cylinder wear valve seals the turbocharger but usually the number one cause is cylinder where so if you have large amounts of blow by at least visually you probably want to dig deeper into that most dealerships can do what they call blow by test which will measure the vol blow-by and if it's excessive you're probably dealing with a worn engine although there is a possibility you might just be an air compressor or a turbocharger but all those items are expensive of course the rebuild in a worn engine being the most expensive so look out for blow-by on older engines it's harder to tell on the newer engines with the closed crankcase systems but if they have excessive blow by they're probably going to be getting a code which will be excessive crankcase pressure or high crankcase pressure because the system will be not able to deal with the large amounts of blow by in the crankcase and they'll be throwing some sort of check engine light so check out for those check engine lights but I'll be talking about more of those in the future in this video okay so moving on from our fumes we want to be talking about fluids and there's really two fluids you need to concern yourself with in an engine that is your coolant and your oil now the coolant not quite as critical and there's not as much you can test for it there's actually coolant samples you can take and mostly they're gonna tell you the additive concentration and the concentration of water to coolant but outside of that they're not going to tell you a lot of internal engine problems unless of course there's a ton of metal or dirt or something in the corn but really we're gonna be focusing more on the oil now there are oil sample kits and they're relatively inexpensive most dealerships will have them regardless of manufacturers some places will do a quick analysis where they can tell you right away or you can purchase a small vial and pull an oil sample yourself and send it in and within a few days you can have an analysis done that will tell you is there fuel dilution in the oil is there coolant in the oil what is the metal content of the oil of course the metal there's gonna be some metal in all oil but this will tell you if there seems to be excessive and anything outside of the normal range is usually an indicator of either of either poor maintenance or an engine problem let's say it shows high fuel dilution well that could mean you have a injector that is leaking fuel into the engine which may be an injector is not expensive but if the fuel dilution is high enough that means the if you the oil viscosity has been decreased because fuel is very light oil and that can actually damage your bearing so you might see higher metal concentrations if it has high fuel dilution : EW oil is very bad as well that could indicate a crack Ted a bad head gasket bad EGR cooler there's a lot of things to look for there but if you're not gonna take a sample there's other things you can look for yourself you can look at the oil itself now most Diesel's the oil is gonna be pretty black that's just normal if you've never looked at a diesel engine you pull the dipstick and it has 2,000 miles since last oil change the oil is probably gonna be fairly dark stomach some exceptions to that but most diesel engines are gonna black oil after a few thousand miles now other than the oil just being black you need to look at the condition of the oil now what do I mean by that if you're wearing gloves you can rub the oil between your fingertips you can do this without gloves of course but it should be slightly tacky as you separate the oil between your finger and your thumb it should stick a little bit if it doesn't that can indicate pure dilution without getting a sample that's a good way to tell you can smell the oil you would be looking for any sort of weird like coolant sense normally coolant the oil in high enough concentrations will turn the oil kind of it's kind of a grayish mayonnaise color also rust on the dipstick tube is an indicator that you've had moisture usually coolant in the crankcase or currently oven in the crankcase and that's bad that can be really big expensive repairs so check for rust on the dipstick tube outside of that there's not a lot you can look for in the oil itself just by looking at it so I recommend an oil analysis if the current owner will let you pull one if you want maybe he's trying to hide something or maybe doesn't want to wait a week for you to get your oil sample back ok so moving on from your fluids you want to do a visual inspection of the engine itself now you're most likely not going to see any mechanical damage to the engine but you do want to look for signs of it you don't want to see any pache drops of the block or the head as far as like someone's maybe put jb weld on any components or some has mismatched pain over certain parts that can indicate maybe not the best repair to something and I've seen a lot of blocks and heads and aluminum components that have had some sort of jb weld done to them oil pans as well that can indicate a previous failure and not a good repair job done to it but those are relatively rare usually what you're looking for is leaks and what I mean by leaks is Quandt exhaust and oil leaks now coolant leaks of course mostly hoses but you might see let's say you had you can see a coolant stream or evidence of a clone strip out of an exhaust port that's a bad sign that could mean of course you have a quart leak in a cracked head or an EGR cooler or a head gasket or an oil leak we're here structure on the block or the block and the rear structure that could be bad that's a really expensive fix on any engine because you're gonna have to pull the transmission and pull the rear structure now most older diesel diesel engines are gonna have some sort of evidence of oil weeping past a seal or a sealant and just because there's a little bit of black soot or black oil residue on a seam if it's not wet or dripping not really a huge reason to be concerned about it especially on large seams such as the structures or the head to the block but just to let you know of course there shouldn't be any there it's just older Diesel's typically have some sort of oil residue somewhere on them if it's not dripping though it wouldn't really constitute a leak now of course hoses things like that those are relatively cheap easy to fix as far as coolant leaks now the other one you need to look for is exhaust leaks and these can be hard to find sometimes because the exhaust leak won't typically show itself on the exhaust manifold or the turbocharger because the carbon that leaks out of the exhaust is going to burn off of those components because they're so hot so what you're gonna be looking for is on the head or the block by the exhaust any sort of black suit not oily black suit but just it almost looks burned that one indicate an exhaust leak and even though an exhaust leaks usually just the gaskets blown out the gasket usually blows out because you have a fastener fail now you might have a broken stud or exhaust bolt in the head or the turbocharger and if you can't get it out you might have to buy a new cylinder head or a new turbocharger or an exhaust manifold you're talking thousands of dollars especially if it's the head if those components cannot be properly repaired with a new fastener pen and on what's broken of course now the next step of course is to run the engine and you might want to say oh we need to listen to the engine yes you do need to listen to the engine the problem with Diesel's of courses they're very loud and depending on what model you're looking at there's of course hundreds of different types they can sound like they either have a valve failure or a loud fuel knock that it might be normal unless you're used to certain engines cat 31:26 when cold under acceleration seem to have a loud fuel knot that's almost inherent to the engine that doesn't mean is a problem with it so and lots of people don't even hear if there is a problem because they're not used to what that engine sounds like when it's normally running about many drivers come in with low power complaints and if they have one or more multiple dead cylinders and they didn't know it and they're in these trucks all the time unless you're attuned to listening to a certain model diesel engine it's really hard to tell just by listening of course what it's supposed to sound like now of course any sort of loud knocking that's constant and seems to increase with our p.m. that's usually a bad sign ticking and tapping unless it's really loud and seems to be concentrated to one part of the engine also not usually a good sign but usually we need to test by performance of the engine not just by what you think might be a problem so of course you want to run the engine you want to look at it and you want to inspect it when it's cold and when it's hot because maybe there's a problem that when it gets hot it has a worse leak or a coolant leak or maybe when it's cold it as a coolant leak not when it's hot there's a lot of things to check for you want to put the engine under a load as well know what I mean by that heavy acceleration or you know if it's a machine move some dirt you want to see what the boost is boost is the number one best indicator of the performance of the engine what do i mean by that well if you have weak injectors or a turbocharger leak or the timings off some for some reason any of those are gonna cause lower than normal boost now you might say well what's normal boost well that really depends on the engine you need to find someone that knows that engine and can then ask them hey you know this 5/9 Cummins what's normal boost under full load they would know or you can look up in some sort of specification book what normal boost is if it's really low you have a problem and that could be maybe a quick fix like a CAC boot work to be very expensive you also need to look at coolant temp is this thing getting hot or maybe it doesn't never gets hot because there's no thermostat in or the thermostats stuck open what's the oil pressure oil pressures can vary widely as well on certain engines c12 cat can idle at 15 psi that's actually fairly normal that is above the specification for a minimum oil pressure for that but on a c 15 that would be below it so you need to know what your particular engine is and you know if oil pressure seems low to you check on it that would be another good reason to get an oil sample done outside of that check engine lights let's talk about them I'm gonna have a blanket statement that you should not buy a diesel engine that has an active check engine light without at least having it checked out by someone that really knows what they're talking about and the reason for that is let's say you have some sort of sensor fault like a coolant fault that could be just the sensor or it could be the external harness or it could be the ECM or it could be an indication of the water pumps bad and it's not flowing coolant or maybe this something's wrong with the radiator itself or the fent there's a lot of things to check for if there's an active code so if there is an active code you definitely want to get it checked out I would say by the dealer but maybe there isn't a dealer where you're at if you know a reputable diesel mechanic that knows that particular engine they can look at it and check engine lights like I said can indicate bigger failures especially in newer engines any sort of a mission code that can cost you thousands of thousands of dollars it could be the scr system that's the DEF system it could be the DPF you might have an art head if it's a cat or a variable geometry turbo that's extremely expensive any check engine light it's a bad sign and it needs to be looked at right away that doesn't of course mean that you should not buy that engine you should just have it checked out because last thing you want to do is buy it and then have it at the shop for two weeks and get a bill for $5,000 right now what about logged or stored codes that aren't active well most newer engines are gonna have some sort of logged code they have so many sensors and they can pick up codes right away and maybe you have a one logged event from one sensor a hundred engine hours ago you know it's probably not a problem but if you can see that hey this faults been on and it's had a hundred occurrences over the last two hundred hours it's probably gonna be a recurring problem you don't have it looked at of course log faults typically aren't gonna be displayed on the dash so you need some sort of code reader or better to have a dealer or someone you trust look at the engine and go from there and tell let them tell you what they think the problem could be so we've talked about pretty much all the problems that can go wrong with the engine as far as leaks the fluids check engine lights performance you also need to check that everything works a lot of things are controlled by the engine that you may not think about like the cruise control or if there's an exhaust brake or a compression break like a Jakub system if you want to road-test this as I already mentioned before if those systems aren't working that of course can cost you a lot of money make sure every system works does a/c work does the heater come on maybe it's the middle of summer you still wanna make sure the heater works you want to see if the cruise control works if it doesn't that could be a big wiring problems but you could something like an RV where you've got 80 feet of electrical wire and multiple different body modules and stuff that can come in conflict with each other and a lot of the times those systems won't throw a check engine light or any sort of code displayed they might just not work and you want to make sure they do work the Jakub system or an exhaust brake you want to make sure those kick on and they work because those is welcome to very expensive especially on the heavier duty ones the Jakub systems the housings themselves can be maybe thousand dollars each you might have three of them he can indicate a problem with the ECM or the wiring harness you know all these systems need to work does the throttle work does it go fully on fully off of course the brakes everything else that's unrelated to the engine for the most part but the air compressor is driven by the engine so if it's not building air if this is an air brake setup that's also related to the engine you want to make sure that that system is working the power steering pump usually driven by the engine is it working is the parser steering system working normally these are all things you need to look at okay now of course I can't cover everything on every engine but if I was looking at a diesel engine these would be the main things that I would recommend to anyone I know to look for and if they all check out you've done your due diligence okay hope you enjoyed the video [Music]

Channel: Adept Ape

Views: 332,469

Keywords: Used Engine, Diesel Engine, Cat Diesel Engine, Cummins Diesel Engine, Detroit Diesel Engine, Engine Inspection, Diesel Mechanic

Id: Ygp9On9tPrM

Length: 21min 59sec (1319 seconds)

Published: Mon Aug 13 2018