Cat D5C Bogging down and loosing power

[coloradoinsane]

OK so here's the back story. We just bought this 1998 D5C hydro dozer. Had been using it intermittently but not for very long until we noticed It has been starting to overheat. Found the oil cooler plugging due to an oil leak. Now that we were able to use it longer we are noticing a couple other issues. It is starting to bog and lose power especially going up a hill. I changed fuel filters again which seemed to make a difference for a little while. Noticed when I went to prime the fuel system that the seal around the priming plunger was leaking fuel out. When the head and replaced the priming pump. Once again seemed to run good for about 2 hours until started having the same type of load issue. Ran a new rubber fuel line from the tank in case of obstruction and ran air to the tank in case of debris. When disconnecting the fuel Line upstream from the water separator and fuel filter I do get gravity feed from the Fuel tank so i'm not thinking that we are dealing with a plugged line there. No black smoke coming from the engine so I know it's not overfuling.Definitely seems to be getting starved of fuel. Ideas?

 

[Nige]

Ideas?

There wil lbe a drain tap somewhere on the tank (LH side rear IIRC) for removing accumulated water and sediment. When was the last time it was opened.?

Somehow get a good look inside the tank. Do the insides look shiny or covered in green/black deposits.?

if you stil lhave the old fuel filter you removed try cutting it open and see what there is down in the bottom of the pleats in the filter media.

 

[coloradoinsane]

Thanks for the reply. I know the exact drain you are talking about. Doesnt look that it has ever been opened. Still has the paint seal.
Looking inside the tank the fuel looks good and clean. Tank about half way down has light surface rust where you can tell it probably sat one winter half full.

I dont have any of the old filters (have changed them 3 times). I noticed it starting up again yesterday when going up inclines or under load its bogging.

 

[Nige]

Just the same as the fuel does you should always start from the tank (IMHO at least) when chasing fuel issues, especially if the machine is a somewhat unknown quantity.

If the fuel supply line to the engine has a shutoff tap on it just below the tank it might just pay you to pull that apart. There may be a screen or restriction in it that could be clogged with something.

Once you have the tank/lines sorted, pull the head off the water separator/fuel filter assembly, remove all the plugs, elbows, etc, etc, and blow air or push a wire through them to ensure they are not plugged.

I'm not sure but you may have a small screen in a fitting as the fuel enters the FIP. You didn't post a S/N and there are 20 or so different D5C models so it's hard to be certain.

 

[Dave Neubert]

does your dozer have a fuel pressure gauge should be around 30 psi