# alot of blow-by



## rjg340 (Jan 5, 2009)

hi guys,

I have a John Deere 650 with a 2 cyl. diesel, and it has started to produce a lot of blow-by and internal crankcase pressure. I know some blow-by is normal, but how can I check what might be going south on this motor?

Any help is most appreciated.

Thanks.


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## MFreund (May 2, 2008)

Sounds like the piston rings are worn and letting combustion pressure into crankcase. You should be able to tell with a compression test.


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## Live Oak (Dec 22, 2003)

Sometimes with excessive blow by you can run the tractor for a prolonged period (a few hours) under a very heavy heavy (max. load) and this will sometimes help seat the piston rings back in on a tractor that has sat a long time or gets very occasional short use. 

This is not a cure for a worn out engine that is about ready for overhaul. How many hours are on this engine?


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## rjg340 (Jan 5, 2009)

> _Originally posted by TF Admin _
> *Sometimes with excessive blow by you can run the tractor for a prolonged period (a few hours) under a very heavy heavy (max. load) and this will sometimes help seat the piston rings back in on a tractor that has sat a long time or gets very occasional short use.
> 
> This is not a cure for a worn out engine that is about ready for overhaul. How many hours are on this engine? *


There is a little over 1700 hours on the tractor.

I am new to the diesels, how do you check the compression?

Thanks.


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## MFreund (May 2, 2008)

Sorry for the slow reply. 

You have to remove the injectors and screw in a guage. It is much like a car. I don't have a tech manual for the 650 but for the 655 it lists 335 psi for the mininum. Hopefully someone will have the exact procedure and specs!!


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## Live Oak (Dec 22, 2003)

1700 hours should not be anywhere near worn rings or a rebuild. Do you own a bush hog or finish mower?


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## rjg340 (Jan 5, 2009)

Finish mower, 4" box blade, and it has the JD 67 FEL.

I think it my be a head gasket, as I found the radiator empty the other day when i went to move it.


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## Live Oak (Dec 22, 2003)

If the radiator was empty and their is serious blow by, I am thinking perhaps the anti-freeze coolant may not have been up to par? I sure hope not. If that IS the case, it won't be cheap to fix. A head gasket would definitely behave this way, but if so, what cause the head gasket to blow???


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## MFreund (May 2, 2008)

If your radiator was empty you likely have a head cracked or head gasket out. Fill it with water and see if you get bubbles at the top of radiator(with engine running). If so it is one or both of the above problems.

I'm not saying this is the cause but as coolant ages it becomes slightly acidic. If you have a weak acid, what in the cooling system would it eat first? gaskets and seals. 

There are indicator strips for sale at the auto parts stores that tell when a coolant flush is neaded. Usually antifreeze is only good for about 2 years.(by their scale) Flushing coolant system is easy compared to a head gasket repair.

On another related topic. If you have General Motors vehicle with Dex Cool antifreeze and it is over 3 yrs old. Do a coolant flush NOW. The antifreeze solidifies and plugs radiators and heater cores.


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## rjg340 (Jan 5, 2009)

well, I live in central Florida, so we have not had a real bad freeze here since i got the tractor. I have looked around at the head gasket prices, and it looks like I can get one for around $20.00. 

I cannot seem to find a tech manual for this tractor except old JD manuals that the Ebayers want 170 bucks for.

To top all this off, I had a freak tornado touch down on my property last Tuesday. wiped out my horse tack shed, threw my new chicken coop into the side of the horse trailer, pushed over several hundred feet of 3 board fence and completely destroyed all the decorative aluminum metal fence and electric gate I had across the front of my land. The bright side is the house & horse barn is still standing, and no one was hurt.

Thanks for your help guys.


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