My 1996 John Deere 425 with the 20 HP K-Series engine Model FD620D has a lot of oil blow by coming from the oil fill. It is so bad that will blow the rubber fill cap off the fill tube. There isn't any exhaust smoke so I am wondering what causing this. If I have to pull the engine and overhaul it what is the approximate cost for parts and labor. Thank you.
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John Deere 425 Blow By
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bertsmobile1
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My 1996 John Deere 425 with the 20 HP K-Series engine Model FD620D has a lot of oil blow by coming from the oil fill. It is so bad that will blow the rubber fill cap off the fill tube. There isn't any exhaust smoke so I am wondering what causing this. If I have to pull the engine and overhaul it what is the approximate cost for parts and labor. Thank you.
Excessine crankcase pressure without oil smoke from the exhaust generally means a blocked engine breather.
The cost will be about $ 6.00 for a new breather gasket and about 1 to 1.5 hours of labour so it is a do it yourself job.
You can verify the blocked breather by removing the breather tube from the engine and running it for a short time ( it will be very messy ).
If there blowing from the dipstick tube is a lot stronger than the blowing from the breather tube then the breather is blocked.
the JD web sie has your service manual available on line for free, but you can only view a small section at any one time.
Or you can buy a copy. They are not cheap but excellent value as they are written for owners with almost no machanical knowledge so easy to follow and fool proof.
Thank you for your reply. I have looked on my engine and the John Deere parts site and cannot find where the breather gasket is located. Will I have to pull the engine to replace the gasket? Do you have a John Deere part number for this particular gasket? I am a Senior Citizen, and OLD Man, that needs lots of help. Thanks again.
bertsmobile1
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The breather sits under a cover between the two cylinders.
There is a tube that connects it to the air cleaner.
Under the cover is a gasket, reed valve and on some another gasket.
Over time the reed valve gets gummed up or just plain looses it flex so stops working.
However before you do anything, pull off the breather tube or the air filter cover and fine the tube outlet.
Put your finger over it with the engine running.
It should blow some oily fume.
I it blows only then it might be OK
if it blows then sucks then blows then sucks ie acts just like a hole in the crak then the breather valve needs attention.
If it does not blow at all then the breather valve needs attention.
If that is the water cooled motor with the radiator bolted on top of the engine you will find the breather valve under the radiator.
A bit of a PAI to get at
There is a tube that connects it to the air cleaner.
Under the cover is a gasket, reed valve and on some another gasket.
Over time the reed valve gets gummed up or just plain looses it flex so stops working.
However before you do anything, pull off the breather tube or the air filter cover and fine the tube outlet.
Put your finger over it with the engine running.
It should blow some oily fume.
I it blows only then it might be OK
if it blows then sucks then blows then sucks ie acts just like a hole in the crak then the breather valve needs attention.
If it does not blow at all then the breather valve needs attention.
If that is the water cooled motor with the radiator bolted on top of the engine you will find the breather valve under the radiator.
A bit of a PAI to get at