Radiator cap on (most?) Yanmars is 13 psi. 7psi also works well.

[California]

OEM spec for the radiator cap on (most?) Yanmars is 13 psi. 7 psi also works well.

I hope this is convincing:

YM240 Parts manual: Cap # 124450-44590.

Numerous sellers online: 124450-44590 = Deere CH18207 which is 13 psi.

These Deere and Yanmar numbers are listed to fit a broad variety of Yanmars and Yanmar-built Deeres.

I did a very unscientific test on our current batch of caps (made by Kent) and the best I could tell they are 13lb. I used a digital scale and compared to several original Yanmar caps that we had left over. I do know that we used 7lb caps for many years also and had zero problems. Both work just fine.

I guess it all comes down to how much over the boiling point you really want to run your tractor?

With a 50/50 mix of antifreeze and a 7psi cap- your coolant will not boil until about 240 degrees. With a 14lb cap & 50/50 mix you increase the boiling point to about 260. The temperature warning lights should all come on at under 220 so both are well over that number.

 

[normde2001]

I apparently bought my "new" cap from Hoye about 10 years ago, so I still don't know what psi it is.

 

[winston1]

I apparently bought my "new" cap from Hoye about 10 years ago, so I still don't know what psi it is.

You need to buy a test kit.

 

[normde2001]

Not that important, works fine. I may borrow 1 when I go back to the farm in Oct. to satisfy my curiosity.

 

[clemsonfor]

Thanks California for putting this in a place where it is more searchable and easy to find. Winston, you should put your posts from the "loader thread" in here stateing the manuals where you found it etc. That way all the sources are contained in one spot so that if this comes up again in another 10 years and were all older and forget more we see can see where we last beat this horse.

 

[winston1]

Page 54 in the 135/155 repair manual states radiator is pressurized at 12.8 psi.

Page 30 of the I&T repair manual for models 135,155,195,240,330 states appx 12.8 psi and is maintained by the radiator cap.

Repair manual for 220/226 states on page 220-05-3 "when cooling system pressure exceeds 13
psi a valve in the radiator cap opens to allow steam to discharge into the expansion tank, where it is condensed."

 

[normde2001]

FWIW, Hoyes RC-28 radiator cap , pn 121120-44592 is definitely 7 psi. or at least was at the time purchased. I forgot I had it and ordered another one of unknown psi.