# Experience changing a head gasket on a YM240?



## Guywithayanmar (Sep 8, 2021)

Hi All,
New to writing in this forum but I've been lurking around ever since I bought an older YM240 (circa 1977-1981.) I'm about to dive into my engine to replace the head gasket and, because I live in Canada and need to order my parts from Hoye's (and wait for them to cross the border), I want to order everything that I need before I get started. I've already replaced the water pump.
I expect that I'll order the head and valve cover gaskets along with an exhaust gasket just in case I need to remove the exhaust. 
What else should I expect to have to change???
Should I order studs and nuts?
What about main front and rear seals (just in case)
Valves or seals... or pushrods or rocker arms??? 

Nothing that I was seeing had me worried about how some of these things were doing before I determined that I needed to do the head gasket but I'm wondering if once I start digging in am I going to see things that are obviously worn out... or perhaps notoriously worn out?

Any advice or discussion of experience would be greatly appreciated.


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## harry16 (Dec 8, 2011)

Good Morning Guy, welcome to the forum.

Here is a head gasket replacement procedure from Hoye Tractor:






Yanmar Head Gasket Replacement Guide







www.hoyetractor.com


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## BigT (Sep 15, 2014)




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## bmaverick (Feb 20, 2014)

Guywithayanmar said:


> Hi All,
> New to writing in this forum but I've been lurking around ever since I bought an older YM240 (circa 1977-1981.) I'm about to dive into my engine to replace the head gasket and, because I live in Canada and need to order my parts from Hoye's (and wait for them to cross the border), I want to order everything that I need before I get started. I've already replaced the water pump.
> I expect that I'll order the head and valve cover gaskets along with an exhaust gasket just in case I need to remove the exhaust.
> What else should I expect to have to change???
> ...


With a 1977-1981 era machine, it's vintage. Not only change the head gasket, it would be wise to do the overhaul kit as well. The issue is, it's a huge undertaking, but well worth it. The kits can be ordered from several vendors. Some vendors have a more robust and complete kit over others. So, shop around for kits that includes EVERYTHING and then some.
On the Yanmar Tractor Owners Group site, we have the vintage vendor suppliers listed and all their contact info. Some are fully equipped and others are more like distributors.
The link is in my signature below.

A YM240 = YM2000. However, there are era differences. For example, the first generation of your machine are known as Tree Frog Green. Then a second generation in Yanmar red. Then an upgraded 3rd generation. A 4th generation YMG240/YMG2000 variant does exist, but those machines are different, so don't go there looking at parts for the 'G' machines.

So, what color is your machine then?


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## Guywithayanmar (Sep 8, 2021)

bmaverick said:


> With a 1977-1981 era machine, it's vintage. Not only change the head gasket, it would be wise to do the overhaul kit as well. The issue is, it's a huge undertaking, but well worth it. The kits can be ordered from several vendors. Some vendors have a more robust and complete kit over others. So, shop around for kits that includes EVERYTHING and then some.
> On the Yanmar Tractor Owners Group site, we have the vintage vendor suppliers listed and all their contact info. Some are fully equipped and others are more like distributors.
> The link is in my signature below.
> 
> ...


This is great to know. My tractor is green. I went looking for a picture of it but all I could find was one with my hands underneath the cowling. You can see the colour in this picture. It was taken before I changed the water pump a while ago. I bought the tractor a couple of years ago who bought it from a guy... who probably bought it from a guy... you get the picture. When I got it I didn't use it very much before the water pump seized while I was drag harrowing my acreage. I replaced the water pump and alternator belt but I've also had to replace the battery, starter solenoid, and finally the ignition switch. Now it is overheating and there is oil outside the block and my coolant isn't clear when I drain it. Considering I had put fresh coolant in fairly recently when I did the water pump I had expected it to look better. The rad is not plugged, the new water pump is the correct one and it works, and the block is not plugged either, so I'm down to the head gasket. It is clearly leaking externally and I am pretty certain that it is leaking internally as well. The last time I ran it the coolant boiled over and previous to that when I shut it down after a short run I could hear the coolant boiling. Hoses are tight and not leaking so the coolant loops should be tight.

I'll take a look at your link and see what I can find.

I appreciate the help and moral support.


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## bmaverick (Feb 20, 2014)

Guywithayanmar said:


> This is great to know. My tractor is green. I went looking for a picture of it but all I could find was one with my hands underneath the cowling. You can see the colour in this picture. It was taken before I changed the water pump a while ago. I bought the tractor a couple of years ago who bought it from a guy... who probably bought it from a guy... you get the picture. When I got it I didn't use it very much before the water pump seized while I was drag harrowing my acreage. I replaced the water pump and alternator belt but I've also had to replace the battery, starter solenoid, and finally the ignition switch. Now it is overheating and there is oil outside the block and my coolant isn't clear when I drain it. Considering I had put fresh coolant in fairly recently when I did the water pump I had expected it to look better. The rad is not plugged, the new water pump is the correct one and it works, and the block is not plugged either, so I'm down to the head gasket. It is clearly leaking externally and I am pretty certain that it is leaking internally as well. The last time I ran it the coolant boiled over and previous to that when I shut it down after a short run I could hear the coolant boiling. Hoses are tight and not leaking so the coolant loops should be tight.
> 
> I'll take a look at your link and see what I can find.
> 
> ...


Your deduction is spot on. Head gasket.  

Just be glad it's not a Mitsubishi MT series. The way it's setup is like a vehicle. When the head gasket goes, the cylinders going on the down stoke will empty the radiator in a matter of a few mins. Then the engine blows or seizes thereafter. 

There are manuals here on the site in the Resource Manager. If you need more info, I bet I get dig more up.  

I have a slew of info just on the YM240. Here's just a taste.


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