Onan oil filter threads damaged

[Carm]

Onan 7000. Performing the season-end oil change yesterday, the oil filter was really hard to get off, had to use a breaker-bar on the oil-filter socket to break the filter loose. That's a really bad omen. Instead of spinning right off, I had to really work to unscrew the filter.

Once the filter was removed, I had a look at the threaded mount on the generator: all the threads are damaged and the tip, with the last couple of threads, was missing. Looked into the oil filter and there's the broken section stuck in the oil filter threads.

I am assuming that I've run into the age-old problem of dis-similar metals fusing together - the steel threads on the oil filter bonding to the aluminum threads on the generator.

In any case: now what? The generator has to come out so I can get at the damaged filter mount. But then what? If there is enough material left I might be able to clean up the remaining threads with a die. Maybe.

Has anyone had this issue? How did you fix it? can it be repaired?

[rgatijnet1]

When installing any spin on oil filter, always coat the gasket surface with wheel bearing grease, NOT oil. Oil will tend to harden from the heat and make the filter difficult to remove. Wheel bearing grease can handle the heat and will allow for easy removal when the time comes.

[wolfe10]

Ivylog wrote:
I would try cleaning up the first thread of what's left and try putting a new filter on and off several times to clean up the softer threads. If this does not work then you can replace the entire adapter.

If the threaded part is steel, I agree.

But if it is aluminum and threads are pulled off as the OP described, I would not take a chance on it. Too easy for the oil filter to "feel" tight (buggered threads) and potentially blow off the oil filter or its gasket.

[Carm]

Hi all, I am the original poster. I thought it would be appreciated if I provided an update on my oil filter issue.

People on this site never disappoint. I think that I now have all the info I need thanks to all of you that provided the great feedback.

To answer questions:
Model and Serial: Onan Marquis 7000 7NHMFA26106D, serial H933071141.

Who installed the last filter? I did. The filter that was so hard to remove was a Fram XG3614 installed hand-tight about this time last year, the generator was used 41 hours over the last year. I ran the generator for an hour under load (both air-conditioners and a 1500 watt heater) before shutting down and removing the filter and draining the oil.

I stuck a small camera under the generator shroud and took some macro pictures: Enblethen has it 100% correct - my unit has the Onan filter adapter, and thanks to RLS7201 (Richard?) for posting the image of the adapter.

To jwmll and your comment about metric vs US threads: That's a good question. I wonder if the Fram XG3614 filter has a slightly different thread? That could certainly cause the thread damage. This was the first time I've ever used the XG3614 filter.

I have the Bounder all winterized and wrapped up. Next Spring I'll remove the generator and perform a full service (it's about time anyway) and clean up the threads if I can or replace the filter adapter if I can't. Either way I've now got enough info to not stress about it all winter

Thanks everyone!!

[Ivylog]

I would try cleaning up the first thread of what's left and try putting a new filter on and off several times to clean up the softer threads. If this does not work then you can replace the entire adapter.

[jwmII]

S.O.P. for filter installation is hand tight and usually 3/4 turn further after contact and still by hand. The same for removal,although in practice removal frequently requires a boost from a filter wrench and then removal by hand. Coming off hard all the way with tools required is really out of the ordinary. I have to wonder if you got ahold of a filter with a different thread pitch. Maybe a metric thread being applied to a u.s.s. thread or vice versa. Many techs might not recognize any difference and just force the issue. Apparently worked ok until removal time came. You are getting good advice here and I would follow their lead and order the proper parts from Cummins. Check this also. Many cummins/onan filters will cross over to Kohler numbers and again vice/ versa. As well their may be some of each that look alike and have different threads. This is one reason it is so important when purchasing parts and accessories that serial and model numbers be provided.

[WILDEBILL308]

The best way to get the right part is call your local Cummins/Onan dealer with your year, model number and your serial number.
Bill

[RLS7201]

Enblethen has it right




Richard

[wolfe10]

Yup, with model and spec, you/we can easily look up a parts breakdown to see if the threads are part of an adapter, the block or threaded into the block.

[enblethen]

Here is another style of Onan filter flange. You will need to try to find a repair manual for your exact model. This one looks to be pot metal or aluminum.
Onan filter adapter

[45Ricochet]

ArchHoagland wrote:
Who installed the last filter? And where did you buy the last filter?

X2

I've read they come stock with lug nut type torque from the factory :E But that shouldn't be the problem with a 1994 genny.

[ArchHoagland]

Who installed the last filter? And where did you buy the last filter?

[Sully2]

Take it to an Onan repair location and let them work it out.

[Fleet_Man]

Remember to warm up the engine, generator or vehicle, before attempting to remove an oil filter. They are always easier to remove when they have been warmed up.

[Billinwoodland]

Sounds to me like it was cross threaded when it was put on. I'm a great Monday morning QB BTW. Please let us know what you find and the solution. Good luck.

[gbopp]

Maybe you could try some great or anti-seize on the threads when you get it repaired.
And maybe it was just a bad piece of metal that finally failed.

It is an unusual situation. I've never had a problem with my Onan 5500.