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I just found out my 98' JD 425 has a severe Blow By issue and the dealer is saying my best option is to just replace the engine as would cost just as much to replace the engine that it would to tear it down and rebuild it (dealer labor rate is $120/hr). I have two Options. First is replacing with a Kawasaki Water cooled engine ($2500) versus a Vanguard Air Cooled Engine. ($1700). The tractor has 455 hours on it.

The original Engine is the Kawasaki Water Cooled engine. Which engine would you recommend I go with. I understand the pro's and cons with each I am just trying to see what others think?
 

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I’d vote for another water cooler Kawasaki mainly for less future problems


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Liquid cool. 455 hours is hardly broke in. These were built to use and not sit around. Like thats only a little over 20 hours of use a year.
 

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Discussion Starter #6
All, Thanks so much for your input and replies. I am taking it to a local small engine repair shop on Saturday and getting a second opinion as @joneill4 suggested. If I do have to replace the engine I will go with the Kawasaki liquid cooled engine.

Thanks all for your replies and advice and I will keep you posted on what I find out and end up doing.
 

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Bad head gaskets are very common on those engines. Get it checked out by someone that is familiar with them. Fantastic engines. I've seen some with over 3000 hours still running strong.
 

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If you replace the engine, might just as well upgrade while you are at it. These guys have a 25 horse for similar money, and its a direct replacement. Other companies are out there as well.
 

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If your usage pattern is going to be the same (~20 hours per year) and don't live in the desert or push the engine to its limits, I'd probably go with the Vanguard engine.

With that said, 450 hours is nothing for that engine. Assuming you haven't abused the engine, I wonder if you don't just have gummed up piston rings from lack of use. I'm usually against any type of oil additive but perhaps an oil change and the maximum recommended amount of Marvel Mystery oil followed by a couple of hours of hard running might clean it up. It can't hurt if you are already planning on replacing it.

As David Wells points out, it could be a bad head gasket but it seems you would be losing some coolant or have contamination as well.

.
 
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Find a reputable shop and have them repair the engine. Do it right, do it once.
 

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I'll jump on the fix what you've got dog pile. With 450hrs that is barely broke in. The dealer doesn't want to truly troubleshoot the issue. He just wants the easy way out.
 
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It could just be that the rings are stuck with those low hours on that old of a machine, as it was not worked hard enough over the years. I would try pulling the spark plugs and putting a few ounces of ATF & acetone mixed 50/50 in each cylinder and letting it sit for a day, then spin the engine with the starter for 10 or 15 seconds with the spark plugs still out (some or most of the liquid willl be expelled) then put a few ounces of the mixture back in each cylinder, wait a day, repeat every day for a week, then after spinning the engine the last time with the starter, put the plugs back in and start it up and run it hard for several hours, doing whatever you can to put a load on the engine (pull a plow through the dirt if you have one, mow some deep thick brush, lift multiple heavy loads with the loader if it has one, etc.) And the rings may just free up and the blow-by will stop. You could also try the old "pour some Seafoam right into the throat of the carb while its running" trick (The 425 has a carb, right? I think it is the 445 that is fuel injected, but I might be wrong there, If it has fuel injection then you would need to mix the Seafoam with the gas in the tank at a higher than normal ratio). There are several videos on youtube of people doing this. If it works then you are a couple of thousand dollars to the better If not, oh well, it won't cost you more than a few bucks for the ATF & acetone or Seafoam, and you'll still be back where you started.
 
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Don't forget the plastic cam gear and water and oil pump gears if you rebuild it. It will only be about $300 more and then you will have a 20-year engine. I am not sure but if it lost only one tooth off the cam gear it may produce a smoking issue that is the result of off timing of the valves. At the low hours you have, it may well be the cam gear that is causing your problem.
 
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