Looking to know the necessary tools and techniques to repair a Caterpillar C13 engine? In this article Adept Age shows you a day in the life of a diesel mechanic while working on the engine’s turbocharger. The CAT C13 is mainly used in Class 8 vehicles such as semi-trailer trucks. 

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What is a Turbocharger

A turbocharger is a turbine-driven forced-induction device that increases an internal combustion engine’s efficiency and power output by forcing extra compressed air into the combustion chamber. Turbochargers are commonly used on truck, car, train, aircraft, and construction equipment engines. They are most often used with Otto cycle and Diesel cycle internal combustion engines.

C13 Turbocharger

Caterpillar C13 Turbocharger

So this job here, we’re going to be mounting the low pressure turbocharger and some other items on the side of the engine.  This is a job I’m actually finishing up for another mechanic that unfortunately, sometimes you have to follow up on jobs if someone gets sick or goes on vacation. Things like that you may have to follow up, which is unfortunate but sometimes you got to do it.

I am mounting the low pressure turbocharger here and somehow they find neutron stars to make these turbochargers out of because they are pretty heavy. Basically it sits on this cradle here and then it has these mount bolts that run through the bracket and go up into the turbocharger to hold it in place. That is what holds the low pressure turbocharger in place.

C13 Mount Bolts

 copper anti-seize on C13 mount bolts

Now these are the mount bolts with their really long spacers and you can see I’ve got some copper anti-seize on there. I use that on pretty much all exhaust fasteners. It’s just a good habit to get into. I can see the lower turbo there was actually the high pressure turbo and they are actually different turbochargers, one has a wastegate, one does not. 

Lining Up the Turbocharger

You’ve got to get these lined up because the tubes run between both of them and they supply each other with air and exhaust. So after you get it mounted, I’m going to have to install the oil lines, all the baffle, exhaust intake lines and the precooler. So just trying to get it lined up here, so I’ve got lined up.

Checking Turbocharger Turbine

Whenever you’re doing turbocharger work, it’s a good idea to check your turbine and make sure that it spins freely. Most turbos have this clamp that if you loosen it you can spend the inlet or exhaust turbine or housing and then you can check your turbine. You always want to check it if you rotated or moved your housing.

Mounting Back the Turbocharger

So did some work here obviously, we’ve got our low pressure turbo mounted, we’ve got the bolts in, there’s four, got your oil lines, oil and supply line, got the brace for them. You’ve got your exhaust tubing between the turbos, the baffles, the inlet tubing and installed the precooler and new precooler lines and clamps. I have our alternator, I have insulated the wiring going to it and the exhaust tube from the low pressure turbo (had to clean the valve cover base and install new internal harnesses).

C13 Injector Harnesses

So after this I had to get the valve cover base cleaned up, find some bolts for it. Find the injector harnesses. One of them had not been ordered so I had to order that. Now some people may not know this but on the injector harnesses there’s actually numbers on each one, because on some of the engines you can actually mix them up. But if you look at them closely you can’t because they are numbered.

C13 Cut to Length Seal

On the C13 you have your intake valve actuator oil pressure sensor that is in the valve cover base. So we’ve flipped over your valve cover base here and we’re going to be installing some new seal for it.  This is on most CAT valve cover bases a cut to length seal that CAT likes to use and a lot of your time as a mechanic is resealing things. Whether they be, you know, valve cover, valve cover bases, water pumps, structures, rare structures, front structures, you know, cylinder had a pretty much everything on an engine has a gasket and can leak something.

Cleaning the Valve Cover Base

I am not the fastest mechanic in our shop but I am one of the more thorough ones. I’m very particular when it comes to installing seals, gaskets, things like that. I always try to take a little bit of extra time, make sure they’re cleaned properly and that the new seals are installed properly. Because the last thing we want to do here is having to pull this back off. So what we’re doing here is you’re just cleaning out the old silicone and gasket material from the valve cover base. Making sure there’s no residue or anything in there because you want it to be clean.

Applying Silicon to Seal

Now we have our new valve cover seals here and there’s two different styles on the C13. There’s the cut to length style and there’s a one piece one. The cut to length one is more typical to find. So on the cut the length one, you’re going to start at one end and there’s an overlapping section and were our overlapping section is, as you could see there, I’ve applied a little bit of gray oil resistance silicon.

Inserting the Cut to Length Seal Within Cover Base

You’re then going to feed the new seal in place like above, make sure you don’t twist it or it doesn’t get bunched up. Then you’re going to take it to where it overlaps and you’re going to cut it to the right length, right there, so that it overlaps about little over an inch. Then what you’re going to do is you’re going to take silicone and apply it to the overlapping other end and then you’re going to insert it into the overlapping portion.

Now the very first engine I did, I didn’t use the overlapping portion and the cut the length, I saw that and said hey add a one piece seal and I put the one piece seal in there and then it leaked and I had to pull it off. So do not try to use the one piece seal if it has the cut to length. Now after you have installed you’re cut to length seal where the two meet, you want to apply a little bit of silicone.

Chemical Used in the Mechanic Field

Now speaking of sealants, this is sealants that we’ve been using on the cut to length seal. There are a lot of different chemicals you use.

  • There’s the anti-seize I was using earlier,
  • Now on pretty much every job, there’s Molly Denim Lube that’s for cylinder head bolts,
  • We also are going to have thread lock, there’s blue thread lock, there’s red,
  • We have a sealant for pipe fittings,
  • We also have Teflon tape.

There’s a ton of different chemicals you’re going to use in the mechanic field.

Valve Cover Base and Jake Housing Installed

So after that I installed the base, I ordered the right sensor, the IVA or pressure sensor, installed the injector and the Jake housings. So you can see I’ve installed the valve cover base and the Jake housings. Now I’m going to be torquing the Jake housings.

Torquing the Engine Correctly

A large percentage of the time as a mechanic is obviously installing things and torquing them properly. Now when it comes to torquing, I tend to torque things more than once. I’ll usually go through, especially on overheads, anything in the overhead, I like to go back and forth and make sure everything’s torqued properly. Now for using a high quality torque wrench, this should not cause the fastener to become over torqued and I would much rather have a fitting or fastener torqued to let’s say 76 foot pounds opposed to 75 at the spec then to miss one or have them unevenly torque. So always go through, go back and forth, torque everything properly, make sure everything’s seated, you haven’t missed any bolts or anything. Then I always go through and torque strips everything and these bolts torque the 75 foot pounds by the way. So this is kind of a snippet of what a standard day is in the shop working on engines. There are always little things, you know, installing hose clamps, looking up parts and other information throughout the day but this is the majority of the day.

So that was a pretty standard day there in the shop. I’m doing a lot of engine work, we mostly do a lot of engine work.