Onan

[wshelton]

A few questions? I have a 7.5KW Onan diesel Mod MDJE. I have had a slight oil leak for years now when running this unit for 10 to 15 hrs. Just enough leakage to dampen an oil absorbent cloth. I found what I thought was the problem and replaced the gasket to the fuel pump which you could see a slight trace of oil leaking down into the pan the Gen set sits on. Well it appears this gasket has failed too and this slight leak is still present however there was a great deal more leakage this last time out. Ran unit about 15 hrs. Cloth was covered with oil and only lost about a 1/2 qt of oil to top off. I think there is another leak behind the unit I cannot see due to installation(starter side against bulkhead). Two questions: What is on the other side that could be leaking? What about using a gasket seal in lieu of a new gasket on the fuel pump this time? Never used this stuff. Now just how dangerous is my running this unit with this oil leakage from fuel pump dripping down bottom part of engine block. The leak on the back side is a puzzle, however I think it is way down on the block. Let just assume emergency shut downs are not working.

I shot this engine with my IR heat gun and the hottest area near the leakage was 179 degrees.

Thanks

 

[rsmith]

A few questions? I have a 7.5KW Onan diesel Mod MDJE. I have had a slight oil leak for years now when running this unit for 10 to 15 hrs. Just enough leakage to dampen an oil absorbent cloth. I found what I thought was the problem and replaced the gasket to the fuel pump which you could see a slight trace of oil leaking down into the pan the Gen set sits on. Well it appears this gasket has failed too and this slight leak is still present however there was a great deal more leakage this last time out. Ran unit about 15 hrs. Cloth was covered with oil and only lost about a 1/2 qt of oil to top off. I think there is another leak behind the unit I cannot see due to installation(starter side against bulkhead). Two questions: What is on the other side that could be leaking? What about using a gasket seal in lieu of a new gasket on the fuel pump this time? Never used this stuff. Now just how dangerous is my running this unit with this oil leakage from fuel pump dripping down bottom part of engine block. The leak on the back side is a puzzle, however I think it is way down on the block. Let just assume emergency shut downs are not working.

I shot this engine with my IR heat gun and the hottest area near the leakage was 179 degrees.

Thanks

I've got the same gen doubtfull a new gasket would fail but the way ON-NO's shake chances are the bolts are loose or the oil is chasing down the bolt threads. If you have to, use permatex aviation form a gasket not the silicone stuff. But gaskets are made to work without goobering them up. Most of the oil leaks I've had have been pan gaskets. That and valve covers are the only 2 leak spots on the back side. Unless you have a main seal slinging oil.

 

[eze2bme]

Will ... I had a similar oil leak several years ago on my MDJE ... and upon close observation found that the flexible rubber oil hose had a slight crack at one end fitting ... replaced hose (part # 501-003) and no leak since. Maybe look at the oil hose?? This hose comes off the side of the oil filter assembly and connects to the oil gauge/low pressure switch assembly.
Tom

 

[Canuck Dennis]

Lube oil or fuel oil, you reference the fuel filter so I assume fuel oil,I replace the filter on mine and cured the issue, that's before I replaced the complete generator.

 

[sgharford]

Here's a parts manual you can download: http://jubault.michel.free.fr/docs/ONAN-MDJE-6.0-7.5-parts_manual.pdf

I had the fuel pump off and disassembled on my MDJE over winter. I believe oil is suppose to be present on that side to lubricate the cam that drives the fuel pump lever up and down. Hope someone else may be of more help - good luck with her.

 

[bigbill]

you have to put sealer on the fuel pump bolts, they go through the block, so oil can run down the threads. on my 15 kw, the oil fill/ dipstick tube cracked, and leaked only when running, i pulled it off, braized the crack and all was good.

 

[wshelton]

Thanks to all of you. I did not put a sealer on the bolts to the fuel pump so that could be the issue and it is lube oil that is leaking which appears to be where the filter attaches to the block although the threads makes sense.

Tom, the part you mention I will look at as well #501-0003. Do you have a good place to order parts? Just tried to order 501-0222, 501-0223, and 501-0007. Not in stock at MTS power.

I will look at dip stick tube, would never guess that and the bolts on the back side of the unit is hopeless to reach and/or examine.

WHAT IF???? I continue to run this will it catch on fire??? My IR check was 179 degrees at the hottest point. Assume emergency switches fail.

???????

 

[rsmith]

It takes a lot to set lube oil on fire. If it didnt there would be a lot of toasted up Detroits. I did set my solid lifter '68 Corvette on fire once when I was adjusting the valves. But the oil was running down the header sidepipes which were probably close to 1000*.

 

[sgharford]

Tom, the part you mention I will look at as well #501-0003. Do you have a good place to order parts? Just tried to order 501-0222, 501-0223, and 501-0007. Not in stock at MTS power.


???????

Try M&D Mower, that's where I got mine over winter and they had in stock. http://www.m-and-d.com/ONA-501-0003.html

 

[eze2bme]

Will ... I order from the local Onan/Cummins dealer here in Columbia, SC.

 

[Trojan]

Find what you need on the net . Cummings is a rip off. They charged me 65 bucks for the 5 blade water pump impeller. I later got 5 off the net for $2.50 each.

BILL

 

[jim rosenthal]

I agree. To say that Cummins/Onan is "growth oriented" understates it considerably. Growth is one thing; gouging is quite another. Interestingly, I don't find Cummins ENGINE parts to be out of line with respect to other companies.