I review the RAM 2500 Cummins 6.7L Turbo Diesel Top 5 engine issues. The 6.7 Cummins is a strong engine but it does have it's issues and I go over my top 5 as a heavy duty mechanic that works daily with these Cummins ISB 6.7 liter engines



I hope everyone is having a great week! I figured I would talk about the top common issues that we see with our fleet of over 150 buses all with the 6.7 Cummins engine

1. DPF (diesel particulate filter) clogged. These engines are known for having clogged DPFs and trucks that 2013 and below are more prone to this problem then trucks made after 2013. The reason is because FCA wanted to avoid using DEF (diesel exhaust fluid) and having an SCR canister so in order to avoid having high outputs of NOx gases the 6.7 Cummins engine had to run on the richer side of things and therefore caused the engine to create a lot of ash and soot. this ash and soot easily clogged up the DPF filters and caused this issue. Now the newer engine also still seem to clogged up but not as often. The best thing you can do to avoid this is to try and drive your Cummins long distances to get the DPF up to temp to be able to burn off the soot and ash from the filter

2. Turbo issues. we run into a good amount of turbo problems when dealing with the 6.7 Cummins. the turbo rarely actually fully fail but often the we see oil leaks from turbo oil feeds, VGT issues and turbo shaft play. In the video I show you what a siezed VGT actuator looks like and that can cause a lot of issues. the engine won't make boost and throw a lot of check engine lights. the actuators themselves are an electric motor cooled by coolant and those can also fail leading to the same issue. the best thing you can do for your turbo is to idle down the truck before shutting it off.

a turbo can spin up to 100,000 rpms and when you pull into your driveways after driving the turbo is most likely spinning pretty quick. if you shut off the cummins engine right away the turbo is still spinning fast without any oil feed. so let the truck idle for 20 seconds to bring the turbo speed down while still having oil pressure in the engine.

3. Head Gasket Failures. I think this may be over blown but it does still happen to these engines so it is still and issue.

4. Fuel in the oil. This happens when the truck goes into a regen to clean the DPF. fuel is injected during the exhaust stroke and is pushed into the DPF to make it get nice and hot and burn off all the ash. but because of this fuel and seep down the cylinder walls and get into the oil as the fuel is not burned directly in the cylinder. this will cause your oil to lose lubricity and can take out main bearings which is not good.

5. EGR Cooler failure. again pretty common for our fleet to have EGR issues. we often are changing EGR coolers and EGR valves due to these engines naturally being very sooty engines. the soot clogs all kinds of stuff in the EGR pathway and can lead to Cummins engine de-rate

6. CP4 Fuel Pump. This could be a pretty large issue for the newer fifth gen trucks. no longer is ram/Cummins going with the CP3 pump which was very reliable. they are going which a fuel pump that has had a lot of issues in the past. this fuel pump caused the Duramax's a lot of issues and it confusing why ram would want to bring this pump into the mix.

Those are the 5 common issues we see with our RAM 2500 6.7 Cummins engines


00:00 - Intro
01:43 - DPF Filters Clogging up
04:06 - Variable Geometry Turbo Issues
06:50 - Preventing Turbo Damage
08:39 - Head Gasket Issues
10:04 - Fuel/Oil Dilution
11:54 - How to Avoid Regens
12:49 - EGR Failures
15:08 - Cummins Reliability
16:05 - CP4 Fuel Pump Issues
21:28 - Outro