The 3 Biggest Problems With The C15 and 3406E.

in this video we're going to be talking about what are in my opinion the three biggest problems with the Caterpillar 3406 II and c15 diesel engines [Music] the cat 3406 II and c15 engines were some of the longest-running simplest and reliable engines ever made they could easily go over a million miles between rebuilds but just because they could doesn't mean they didn't have any problems and in this video we're gonna be discussing what in my opinion are the three biggest problems with them biggest problem number three is spacer plate oil leaks this is a nearly ubiquitous problem on these engines whether it's a 3406 e.c '15 or a Surtsey 15 and when you're looking at here is the spacer plate area under the cylinder head between the engine block if you look closely you can see small oil bubbles pushing out under the spacer plate here's the same picture or a video zoomed in do you see the bubbles that's actually oil that's trying to get back to the oil pan but it's being forced out now the culprit for this is what they call the spacer plate gasket now it's basically it sits under the spacer plate here and it's just a 14,000 thick steel piece of metal it's not really a gasket however it's supposed to seal against the engine block and it does a very poor job of that you can see the spacer plate here and then of course the head gasket is above the spacer plate that's where the head gasket is and the spacer plate is under the spacer plate gasket now there have been various fixes from Caterpillar and the most recent one was a update to put aviation gasket sealant on the spacer plate gasket and while even while doing this you can still possibly get leaks from this area it has helped significantly but it's still an issue with these engines now the biggest problem number two is the overhead and rocker arm designs now this is actually two different problems on the 3406 ease and the early model see fifteens with a single turbo it was mostly a rocker arm design issue and the problem with the rocker arms are they're not strong enough for the valve train and you can see the rocker arms here this is the intake and the other one is the exhaust one that was pointing at two before and what happens is at times the rocker arms were actually break between the camshaft and the valve bridge and you can see this is an underside view of the rocker arms you can see the rocker on the left is actually had a rather rare failure of the button that goes to the valve bridge is actually snapped off but if you look on this exhaust rocker here you can actually see that the casting is rather thin there's not a lot of metal and there's a tremendous amount of force being applied to this area on the rocker arm caused by the valve springs and opening the valves repeated stress on this can crack them now when they went to the two turbo C 15a cert design they made the rocker arms thicker and they did not have the rocker on brake issues as much however they had a much bigger problem though because what they made were instead of bolts they had threaded studs that held the Jake and rocker arm shafts in place instead of bolts from before now these studs while they are strong there's an issue in that the rocker arm shaft sits in a cradle in the cylinder head you can see the wear indicator marks from where that the shaft was sitting on the head here and over time the shaft were wearing to the head and it'll cause a very small gap and what happens is when that gap is formed the bolts can then loosen up and once the bolts loosen up well then you're not holding the rockers and the Jake housings in place and you start to get some rocking action in them and you can get this broken Ivy a /j housings broken rocker shafts the bolts can break off in the head you might have to get a new cylinder head new fasteners now Kat has a couple design fixes the main one they push is a updated bolt design the bolt on the left see updated sign the bolt on the right in that picture is the older design now you can see that this has had a catastrophic failure this will be a few thousand dollars to fix now this engine had the updated bolt design and mainly the difference is just there's an area grooved out on the bolts now you can see on the shaft here that the shaft has been wearing into the head quite heavily and here are the broken bolts now as you can see these are the up they design they have the small area of the relief area machined out these bolts are expensive they're about $60 each the iba housings about $1,200 and the rocker shafts a couple hundred dollars so rather expensive repair just because of the updated bolt design number one biggest problem with the 3406 E&C 15 design is head gasket failures now it's not a actual design problem with the head gasket itself however I don't like how the head gasket has the head gasket the spacer plate shim water Ferrell's and a rings most cat engine just have a head gasket the issue is with the engine block design itself not the head gasket and we'll be discussing that why here you can see that the fire rings blow out and the reason for that is your liners or the cylinders so as you can see on 3406 and the c15 the liners actually sit in the engine block just like a c-13 or 96 Cummins however the liner actually rests on the block opposed to it kind of being pressed in like on a c-13 and this creates an issue we're looking at here is what they call a liner protrusion or a liner projection sheet and what this does is it measures the amount that the liner sticks out of the spacer plate with it installed in the engine block and this is a critical measurement it needs to protrude either between three and a half or six thousandths if you're going to be doing counter bores which we'll be discussing shortly and if it doesn't you get what they call a sunk liner which means the liner has worn in the engine block now these are what the counter bores are you can see that there's a machined area out of the engine block and then these thirty thousands 32 or 34,000 shims are installed to help get the liner height correct what happens is over time the liner even with these shims will wear under the block it will then lose that liner protrusion it'll go from three and a half to two and a half and once it starts getting close to zero you'll start getting this which is a damaged head gasket the combustion gases are passing past the fire ring and entering typically coolant passages this will cause bubbles or compression gases in your cooling system now once this starts happening there's really no fix in a can or anything you can do outside of pulling the engine apart removing the cylinder liners cutting or adjusting your counter boards because that damaged fire ring is typically going to turn into this if you leave it alone and then you're gonna have a huge mess now I hope you enjoyed this video if you did please click the like button and subscribe if you would thank you [Music]

Channel: Adept Ape

Views: 199,901

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Id: oRTjcZDG4Os

Length: 8min 0sec (480 seconds)

Published: Sat May 23 2020