Hercules LDT-465 - significant amount of diesel in oil even after FDC bypass

[Kalmek]

Hello there, i'am new here. I found this forum while looking for reason, why there was diesel in oil. I found the FDC bypass manual so i did that and changed the oil. Truck would start normally, but after letting it heat up for 10 mins, there was again a significant increase of fuel in oil. I wonder what that might be? It's not small amount, oil lever rised significantly after that 10 mins. Any suggestions what to check or what might be wrong?
Thanks a lot

 

[ToddJK]

Just to be clear,
you bypassed the FDC ✓
You changed the oil ✓
You drained both oil sides of the oil pan?
Check oil level one minute after engine stopped with the dip stick bottomed out but not screwed in?
You smell diesel in the oil or is this just based on oil level?
Any pictures of the engine including the IP with the FDC and the bypass?

Understand I'm just looking for clarification as to not throw assumptions out first. If there is diesel being added to the oil, from the sounds of it, it's a considerable amount in a short period of time.

 

[ToddJK]

fuel in engine oil multi fuel motor

fuel in engine oil multi fuel motor. Anyone know why?? I am getting a fair amount of fuel in my oil on my multifuel motor. Anyone have any ideas why? I am running diesel.

www.steelsoldiers.com

Here's a thread that might help.
There's also other issues that can cause fuel to leak into the oil.
I just used the search function, advanced search, typed in "Fuel in oil injection pump FDC bypass" and a ton of threads over this very issue was shown. Hope this helps.

 

[kenn]

Hello there, i'am new here. I found this forum while looking for reason, why there was diesel in oil. I found the FDC bypass manual so i did that and changed the oil. Truck would start normally, but after letting it heat up for 10 mins, there was again a significant increase of fuel in oil. I wonder what that might be? It's not small amount, oil lever rised significantly after that 10 mins. Any suggestions what to check or what might be wrong?
Thanks a lot

Ok, fellow noob here. Are you sure it is diesel in the oil and not oil draining back? The reason I ask is that I got to experience the "oil rise after shutdown" yesterday after changing my oil for the first time. There's a good bit of oil in the filters and it takes a while for it to all drain back after shutdown. I filled my engine cold to within 1/2" of the full mark. I fired it up and let it idle and checked for a leak. I then took two around the block trips checking again. Then I took a 10 mile trip. When I got home I let it sit for mabye 45 minutes and the oil moved up to the second mark on the line which is the "after sitting" line and it was just below the top of that line. I think it's probably about 1.5" of difference. Good luck with this. I'm terrified something catastrophic is going to go wrong every time I check/inspect/repair something lol.

 

[M35A2-AZ]

You need to check the oil 1 min. after you shut down the truck, It is stamped on the the dip stick.

 

[ldmack3]

Hello there, i'am new here. I found this forum while looking for reason, why there was diesel in oil. I found the FDC bypass manual so i did that and changed the oil. Truck would start normally, but after letting it heat up for 10 mins, there was again a significant increase of fuel in oil. I wonder what that might be? It's not small amount, oil lever rised significantly after that 10 mins. Any suggestions what to check or what might be wrong?
Thanks a lot

Welcome. You are in the right place for help.

 

[Kalmek]

Just to be clear,
you bypassed the FDC ✓
You changed the oil ✓
You drained both oil sides of the oil pan?
Check oil level one minute after engine stopped with the dip stick bottomed out but not screwed in?
You smell diesel in the oil or is this just based on oil level?
Any pictures of the engine including the IP with the FDC and the bypass?

Understand I'm just looking for clarification as to not throw assumptions out first. If there is diesel being added to the oil, from the sounds of it, it's a considerable amount in a short period of time.

I drained both sides of the oil pan.
Checked after about 1-2 minutes after engine stopped.
There is surely diesel in oil. It smells diesel and the oil is noticeably thinner.
I have no photo and i suppose there is nothing much to be seen. Everything was stock when the oil level started rising before. Which was also sudden - truck was fine for about 4 years and then after one weekend of driving, there was really significant oil level increase. Then i did the FDC bypass and oil change. I checked many times that i did FDC bypass right according to manual on this forum.

In fact there was so much oil increase now, that in that 10 minutes of engine running, oil began to seep throug simerink (or gufero, idk how they are called in english - just the sealing ring of crankshaft).

 

[kenn]

I found this thread as part of my "research" and it may be helpful to you. If you search "making oil" you'll find all sorts of gems.

Mechanical Booster Pump "making oil"

After going through all of the possible areas on my multifuel M35A2 trying to figure out where the truck was leaking fuel into the crankcase, I finally figured it out. I had done the FDC bypass, replaced the 3 seals in the hydraulic head and shut down lever, didn't have the flame heater on the...

www.steelsoldiers.com

And if it is a seal, I've used this vendor several times:

INJECTION PUMP GASKET SET FOR M35A2 AND M54A2 5702663

HARD TO FIND COMPLETE INJECTION PUMP GASKET SET FOR M35A2 AND M54A2 SERIES MULTI FUEL POWERED MILITARY TRUCKS. THIS IS A 28 PIECE SET, AND EACH PIECE IS INDIVIDUALLY MARKED AND A PARTS LIST IS INCLUDED WITH EACH KIT. INCLUDED IN THIS KIT IS EVERYTHING YOU NEED TO PUT NEW GASKETS IN YOUR...

www.bigmikesmotorpool.com

 

[davidb56]

is the flame heater removed?

 

[ToddJK]

From what I've read on the other threads like some that were shared here, you have an issue with the IP and it has a bad seal. A bad flame heater can also contribute as well, but if all else is done, the IP is suspect.

 

[Kalmek]

Everything stock so I suppose flame heater is still installed. Have to look. Thanks again for all the replies and suggestions.

 

[rustystud]

I'd check the fuel booster pump on the Injection pump. There is a seal on that shaft that can go bad and allow fuel to go straight into the engine.

 

[ldmack3]

I'd check the fuel booster pump on the Injection pump. There is a seal on that shaft that can go bad and allow fuel to go straight into the engine.

Can this be checked without removal?

 

[kenn]

If you go back and read the thread I posted above, there is a youtube video of him testing the booster pump in a vice. As he is explaining it, he states that he had 10 gallons of fuel show up in his crankcase! Obviously it must have happened over multiple oil changes give that's about twice the total...

 

[gimpyrobb]

Can this be checked without removal?

Not really. The fuel booster has a shaft thats about 2.5-3 inches. It will hit the steering box when trying to remove. Your best bet is to pull the IP and then remove the booster. It sucks, I know. I will see if I can dig up some pics I took a while back.

 

[ldmack3]

My steering box is outside the frame.

 

[williamh]

I would suspect the injection pump is leaking into the crankcase

 

[Kalmek]

We decided to change injection pump bacause there is refurbished one for good price. But there are no markings on the shaft to "synchronize" the IP with the engine and I am bit overhelmed by the manuals to this engine. Anyone knows where to find proper install procedure fo IP?

 

[ToddJK]

We decided to change injection pump bacause there is refurbished one for good price. But there are no markings on the shaft to "synchronize" the IP with the engine and I am bit overhelmed by the manuals to this engine. Anyone knows where to find proper install procedure fo IP?

There should be a marking on a tooth that needs to be in line. You can search for "IP replacement; Injection Pump replacement; swapping out injection pump in M35A2, ect, either in the search bar above, or on Google and then type steel soldiers after it and you will have a list of threads you can read through. Some guys will post very detailed threads on how they swapped, timed, ect, their ip to their deuce's engine. I'd also search for Tactical Repair on YouTube and watch his injection Pump video's. While he may not show a direct install, he will give valuable advice on parts for alignment and to make things easier. It can be a challenging job and many may be hesitant to mess with it, but once you do and you learn it, it's quite simple to understand, just time consuming and tedious.

 

[Floridianson]

So you looked over both manuals? There is the TM9 and the LDS trouble shooting manual here on the board. It might seem difficult but it realy is not that bad of a job. Also if you decide to replace the IP remember to replace the rubber oil feed from block to IP. Was going to tell you to call me but I see you are not anywhere close. The important part is finding #1TDC. It can be done one of three ways. One is before you remove the IP the other two can be done after IP removal but as said we must be on #1 TDC for install of IP. Number one before removal might be the easy way to get to TDC. LDS465-1 Multifuel Engine Troubleshooting Manual | SteelSoldiers