ACMOC
Login
ACMOC
Discussion
FUEL LEAKING INTO OIL: Can I fix it? HELP!

FUEL LEAKING INTO OIL: Can I fix it? HELP!

Showing 1 to 4 of 4 results
Ol George
Topic Author
Offline
Send a private message to Ol George
Posts: 19
Thank you received: 0
I have a CAT Grader S/N is 71D438 (1959 or 1960 model) It's old but still strong.
Trouble is: there is some fuel leaking into the oil. Not a lot but enough to be concerned about. I can run it but would rather not because it thins the oil too much.
A mechanic said it might be a seal at the fuel injection pump to the block.
Any ideas on what the problem might be or how to fix this?
Please click on the photos below to enlarge the view of the fuel pump housing attached to the block.
Is the 'seal' or 'O-ring' that needs replacing visible in the diagram? (part #)
This forum has helped me before and I'm confident with the info I get here.
Thanks, Ol George

[attachment=1956]Copy (2) of Fuel Oil leak 005.jpg[/attachment] [attachment=1957]scan0001.gif[/attachment]
Attachment
Attachment
Please log in or create an account to join the conversation.
Sat, Jul 19, 2008 11:48 PM
Old Magnet
Offline
Send a private message to Old Magnet
Posts: 16,694
Thank you received: 16
Yes, that is a common problem with these old Cat's....The "O" ring that seals the fuel chamber at the joint going from the filter housing to the fuel injection pump housing drys out/shrinks, allowing fuel to leak down into the sump. You will have to pull the fuel injection pump/governor assembly to access. Should only be one seal on the late D318 where the earlier ones have the same seal at both ends of the pump housing that should be replaced together.
Please log in or create an account to join the conversation.
Sun, Jul 20, 2008 12:24 AM
Ol George
Topic Author
Offline
Send a private message to Ol George
Posts: 19
Thank you received: 0
Reply to Old Magnet:
Yes, that is a common problem with these old Cat's....The "O" ring that seals the fuel chamber at the joint going from the filter housing to the fuel injection pump housing drys out/shrinks, allowing fuel to leak down into the sump. You will have to pull the fuel injection pump/governor assembly to access. Should only be one seal on the late D318 where the earlier ones have the same seal at both ends of the pump housing that should be replaced together.
I have added a photo and diagram; can you see which part needs replacing?
Looks like it might be part # 1H5959 which is listed as a 'seal'.

Obviously, I'll need to bleed the system when done, but I was thinking I could do this repair myself... What do you think? I have already fixed one seal to one of the injector pumps. If I can manage this repair, I might as well replace the remaining five. Maybe....
Please log in or create an account to join the conversation.
Sun, Jul 20, 2008 1:44 AM
Old Magnet
Offline
Send a private message to Old Magnet
Posts: 16,694
Thank you received: 16
Reply to Ol George:
I have added a photo and diagram; can you see which part needs replacing?
Looks like it might be part # 1H5959 which is listed as a 'seal'.

Obviously, I'll need to bleed the system when done, but I was thinking I could do this repair myself... What do you think? I have already fixed one seal to one of the injector pumps. If I can manage this repair, I might as well replace the remaining five. Maybe....
The seal I'm referring to is a 8B4967....you have to look at the fuel injection pump housing diagram for the part. Would be a good idea to replace the 1H5959 also while your in there.
No reason you can't do the repairs, it's pretty straight forward, just a little awkward to get the nuts on the back side.
Please log in or create an account to join the conversation.
Sun, Jul 20, 2008 3:29 AM
SJ
Offline
Send a private message to SJ
Posts: 1,890
Thank you received: 0
Reply to Ol George:
I have added a photo and diagram; can you see which part needs replacing?
Looks like it might be part # 1H5959 which is listed as a 'seal'.

Obviously, I'll need to bleed the system when done, but I was thinking I could do this repair myself... What do you think? I have already fixed one seal to one of the injector pumps. If I can manage this repair, I might as well replace the remaining five. Maybe....
I think the seal you need is an "O" ring seal and is toward the top of the front housing where the tube (ferrule) sticks out and is a 8B4967 and you,ll need a new gasket too when you take the housing off. It would be a good idea too to change that lip seal at the bottom that slips over the drive for the camshaft to drive in the lower housing. That is the 1H5959 and the gasket for the front of the housing is 4F5148 where the inj. housing bolts to the front filter housing. Also the transfer pump seals can cause fuel to get in the diesel oil so you might want to replace them too.
Please log in or create an account to join the conversation.
Sun, Jul 20, 2008 3:33 AM
Showing 1 to 4 of 4 results
YouTube Video Placeholder

Follow Us on Social Media

Our channel highlights machines from the earliest Holt and Best track-type tractors, equipment from the start of Caterpillar in 1925, up to units built in the mid-1960s.

Upcoming Events

Veerkamp Open House 2025

Chapter Fifteen

| Placerville, CA

Stradsett Park Vintage Rally

Chapter Two

| Stradsett, Nr Downham Market. Norfolk PE33 9HA UK

Chapter 2 The Link Club's AGM

Chapter Two

| Faulkner Farm, West Drove, Wisbech, Cambridgeshire, PE14 7DP, UK
View Calendar
ACMOC

Antique Caterpillar
Machinery Owners Club
1115 Madison St NE # 1117
Salem, OR 97301

[email protected]

Terms & Privacy
Website developed by AdCo

Testimonials

"I also joined a year ago. had been on here a couple of times as a non-member and found the info very helpful so I got a one year subscription (not very expensive at all) to try it out. I really like all the resources on here so I just got a three year. I think its a very small price for what you can get out of this site."
-Jason N

Join Today!