Friday, January 02, 2009

Diesel Engine Mechanic Tips


Here are some diesel engine mechanic tips I've learned over the years. I want to keep them basic so anyone can follow them. Keeping things simple and following these tips will pay off in the long run. If you are thinking you don't have time just think about the consequences if you neglect these basic areas on your diesel engine.

  1. Always keep the intake air clean with proper filtration and check the inlet piping and hoses for deterioration.
  2. Make sure fuel filters are replaced consistently according to manufacturer's specs. (probably the most overlooked mechanical solution)
  3. Adjust the engine valves at least once a year or depending on how much mileage accumulated.
  4. Check the coolant for proper protection and replace every 2 years to prevent deterioration. Coolant breaks down and becomes acidic eating away at gaskets and castings.
  5. Check turbocharger and exhaust system for leaks to prevent power loss. Check the turbo shaft for wear or any indication of contact with the housing.
  6. Make sure charge air cooler does not have any leaks to prevent power loss. Turbo boost drops substantially with any core leakage in the cooler.
  7. Check fuel lines for looseness or damage to prevent air entering the fuel system. Air in the fuel causes hard start & no power problems.
  8. Replace coolant thermostats every 2 years. A thermostat that is stuck open or closed causes overheating or cold running conditions.
  9. Load test your batteries every fall to give you an indication of their state of charge. Being prepared before winter starts is a good habit to get into.
  10. Check your block heater as well, which goes without saying how vital it can be when you are on the road and parked far away from any mechanical assistance.
I hope these basic Mechanic Information Tips have helped you. I have seen a lot of preventable break downs because one or more of these checks have not been made. It's preventive maintenance that should be followed to save you headaches down the road.

13 comments:

Anonymous said...

Hi iv been looking at your post about the cat 3116 engine rebuild and funny enough the plant hire firm a work at has a cat 950g with this engine. it had a bad miss fire and excessive smoke. it was sent to cats to be done and the told us it was the injector. 1 day after we got it back it started again so i took the rocker cover off and the adjustment screw on no4 injector was much lower than the other five. so i removed no 3 and 4 rockers and removed the cam followers, turns out the cam follower for no4 injector is broke. To cut a long story short they want £600 for the Dial indicator. Are there any part numbers on the mitutoyo gauge you used or is it specific to cat? many thanks. sam

Dixon06 said...

Hi iv been looking at your post about the cat 3116 engine rebuild and funny enough the plant hire firm a work at has a cat 950g with this engine. it had a bad miss fire and excessive smoke. it was sent to cats to be done and the told us it was the injector. 1 day after we got it back it started again so i took the rocker cover off and the adjustment screw on no4 injector was much lower than the other five. so i removed no 3 and 4 rockers and removed the cam followers, turns out the cam follower for no4 injector is broke. To cut a long story short they want £600 for the Dial indicator. Are there any part numbers on the mitutoyo gauge you used or is it specific to cat? many thanks. sam

John Whelan said...

Sam,
The guage I use is from the complete tune up kit we purchased from Cat.
The guage block, threaded shaft and dial indicator is what you need to adjust the timing. If you're stuck count the threads on the other injectors and do a rough set to get the engine running.
For more info do a search on my blog for "3116" and you will find all the posts related.
I believe I have one post with the individual part numbers for the tool kit.

John Whelan said...

Here is the post with the tool information and how to set up the valves and injectors.
If it does not work you can copy and paste into your browser.

http://schoolbusmechanic.blogspot.com/search?q=cat+3116+adjusting+valves+and+injectors

Anonymous said...

hi john, we have now a litle problem with a caterpillar 3126 when this engine hot, cranck for long time to start, and some time not start, I test the HPOP and is good, try with other ECM because i think that's bad but same, hot not start. what you think is the cause of this fail?. many thanks pedro

Anonymous said...

pedro.

hi john how are you? i hope fine, well we found the problem in the caterpillar 3126, the fault was the injectors the system hidraulic of this, stuck when engine hot.

John said...

Hi Pedro,
A stuck injector will definitely give you problems. Glad you found the problem!

j.bird53 said...

Hi John - hope you can help!
The check engine light came on during idle on my 98 GMC Cat 3116 Bucket truck. I shut it off. It did not die. It turns over fine but it will not start again. Batteries are good, fuel filters were replaced, oil was changed. We even tried pressurizing the fuel tank to force fuel to the engine - but no luck.
We had the CAT mechanic here for 5 hours. It would start and run for 1 minute with ether, but would not continue to run. He said the engine is fine - he showed me there was only one code, high pressure on #2 injector. He removed the injector cover and confirmed there were no leaks in the fuel rail. He concluded the Bucket assy would not allow it to start. Hired the Bucket Mechanic for 3 hours. He confirmed there was nothing wrong with the Bucket assy.
We had the truck towed to a GM/CAT dealer for repair. 4 service hours later they said my ECM showed 7 faults, 6 were injectors. (Why didn't these codes show u for the CAT guy?) They said the ECM is bad and want $1959 for a reman ECM, plus labor. They said they hooked up a "test ECM" and the engine started and ran just fine.
I don't know which mechanic to believe...
John, I heard these ECM's are very durable. Is it common for an ECM to fail as described above?
In this case, is it possible it could be something simple such as a bad ground or would use of a "test ECM" be proof positive that this expensive repair is necessary?
Thanks much - Jay

John said...

If it starts after a test ECM There's not much else you can do. The price is etrocious as usual for electronic modules. I haven't seen any ECMs fail on any of our diesels. We own two 3126 units.

I hope the ECM fixes your problem but I would also check all the grounds! head to toe on your truck..at the starter, frame, firewall etc.

rowell said...

hi ive been looking at your post about the cat 3116 engine. my cat d5m with 3116 engine hard starting and i try to check the injector.can i ask if there is any adjustment in governor to open the injector and let the fuel come.coz im thinking that the fuel doesent go inside the injector.i try to push the linkage of injector and the engine run.if the governor diapramh are broken it can cause for hard starting. thanks hope you can help me

John said...

The rack is moved while cranking by oil pressure to the governor. The diaphragm is moved from turbo boost.
I've had engines that don't start until you depress the throttle. It could be a sticky rack or an internal problem with the governor linkage. Taking apart the governor is a fussy job and you might not be able to do anything with it.
I would check to make sure you're getting oil pressure to the governor first of all.

Anonymous said...

hi john,
my name is emer, from the phils, i have a cummins genset, 625 kva, when we make a full load , the exhaust manifold, starts to get redhot, what could be the reason turbo chargers are ok , ty , hope you can help me with it,

John Whelan said...

I would guess over-fueling or too much exhaust back pressure.