If you're running a C15 or 3406E diesel engine, you may have experienced your engine missing. So, why does that happen?
We're taking you through how that coolant can get into your engine and what you can do about it.
Need parts for your 3406E or C15? Call our ASE Certified Technicians to make sure you get the right parts the first time!
Caterpillar 3406E, C15, & C15 ACERT engines all use the same style cylinder head, injectors, and injector cups (see images 1 & 2 below). The injector on these engines seats directly against the cylinder head casting, not on the injector cup.
The seat is located below the injector cup and should completely seal the cup from combustion pressure and heat. (see images 3 & 4 below). The injector doesn't actually even touch the injector cup.
One issue with this design is that it is possible for the injector to not seat completely against the cylinder head. This may be due to imperfections in either the head casting, the injector, or both.
If the injector to head seat is not sealing, it will let engine cylinder pressure go past the seat and pass in-between the cup and injector. When this happens, the cylinder pressure and heat can now reach both the injector o-ring and the upper injector cup o-ring. These o-rings will then fail as they were not designed to withstand the high cylinder temperatures and pressure.
These engines might be similar, but there are a few key differences. Learn more about how the C15, C15 ACERT, and the 3406E differ in our blog post!
Burnt injector o-rings
Carbon buildup or tracking on the inside of the injector cup or on the injector body above the sealing line (see images 6 & 7 below).
Traces of coolant or leaking coolant around the injector cup.
Fuel in the coolant
Engine miss from combustion pressure aerating the fuel
Overheat of the injector tip causing a miss
The injector body is worn, warped, or damaged.
The cylinder head casting is worn, pitted, or otherwise damaged.
The injector hold down bolts were improperly tightened or stretched.
Image 1. Complete injector for 3406E / C15
Image 2. 3406E / C15 Injector Cup
Image 3. Seating surface of injector tip to cylinder head
Image 4. Seating surface of injector to head is below the injector cup
Image 5. C15 Injector shown installed in the injector cup
Image 6. Start of carbon buildup due to leak at injector seat
Image 7. Carbon buildup due to leak at injector seat
If you notice this failure in your CAT C15 or 3406E, it's important that you get it taken care of right away, before it can cause even more problems in your diesel engine. Highway & Heavy Parts can help you get the diesel engine replacement parts you need to keep your engine running for miles to come.
Think you might be having a problem with your cylinder head components? Read our post to learn the symptoms that you need to replace your C15 cylinder head components.
Not sure what diesel engine parts you need for your repair? Our ASE Certified Technicians can help! Call us at 844-304-7688, or request a quote online!
We get it- when you need Diesel Engine Parts, time is of the essence. That's why we've developed the HHP Online Quoting System.
Just fill out the form with your name, engine information, and the parts you need, and our ASE-Certified Technicians will get back to you with an estimate. It's as close to magic as a diesel engine gets!
Originally Posted November 13, 2014; Edited April 5, 2020