Cracked head on a MD

Brad in WI · May 10, 2011

Is there some way I can check to see if I have a cracked head on a running MD WITHOUT removing the head. I was thinking of removing the spark plugs and putting an air hose blowing in with 30 or so PSI and having someone else watch in the radiator for bubbles. I tried looking for bubbles in radiator when it was running but I was unable to see bubbles with the water flowing and the vibration of the tractor.

Anonymous-0 · May 10, 2011

might try taking the fan belt off so water doesn't circulate. don't run it more than a minute or 2 so it doesn't overheat

D Slater · May 10, 2011

Won't tell you much, with the starting valves open pressure will go past the rings. With starting valves closed to check the starting chamber the pressure will leak past the valve.
Pressure check of the cooling system may tell if there's a leak somewhere in the system. With a old radiator limiting pressure and a cold engine it would be a long shot finding anything.
If you work the tractor hard and it starts pushing coolant from the radiator thats a good sign, also after the tractor sits 24 hours after working it crack the oil pan drain plug enough to just drip. Look for any antifreeze in the first drips. Or you can just say its cracked and be right more often than not.

Hill-Billy Rock-Star · May 10, 2011

Snap-on sells a tester that checks for combustion gases in the cooling system.

pete 23 · May 10, 2011

I pressure test engines for coolant leaks all the time and it does work. You have to have piston on exact top dead center compression stroke or disconnect valve linkage so valves are both closed at bottom dead center. You will see the air come up in top of radiator if leaking but you of course won't know if it is a gasket or crack.If you use a leakage tester made for this it will show percentage of leakage past all parts like valves and rings. You can also do as other posters have said, take belt off, fill radiator to very brim and run it for maybe a minute. You may not see bubbles but coolant will rise immediately if you have much of a leak. Now days, the modern way is to use the tester in coolant to check for combustion gases. I believe these old engines always leak just a little so don't know if the tester shows any amounts for reading it.

M Diesel · May 10, 2011

Pete, my experience is very limited with these, but my IH diesels foamed the radiator a lot when things went bad. It was way more than obvious. Nothing noticeable at cold idle, but when warmed up it was a veritable bubble bath. Is that the norm or do small leaks prevail?

sflem849 · May 10, 2011

Why do you think the head is cracked? If this is just for curiosity I would leave it alone before you do wreck something. If there is coolant in oil or oil in coolant I think you already know the answer and I would just take it apart. (that job stinks...trust me. Not to mention the $165 head gasket set.)

Brad in WI · May 11, 2011

I had it out on last sunday and washed everything up really good. I had it idling off to the side while I put other tractors away and when I finally got back on the MD I noticed antifreeze seeping out of the top of the radiator cap. It has done this before under a very long hard pull with the disc but never noticed it before after just an idle. I haven't noticed any oil in the radiator and haven't checked to see if there is antifreeze in the oil pan.

sflem849 · May 11, 2011

(quoted from post at 02:54:51 05/11/11) I had it out on last sunday and washed everything up really good. I had it idling off to the side while I put other tractors away and when I finally got back on the MD I noticed antifreeze seeping out of the top of the radiator cap. It has done this before under a very long hard pull with the disc but never noticed it before after just an idle. I haven't noticed any oil in the radiator and haven't checked to see if there is antifreeze in the oil pan.

Ouch, sounds pretty similar to mdiesel's experience. If it is cracked Pakes Engine down here in Janesville is pretty good at fixing them and is pretty reasonable as well.

Brad in WI · May 11, 2011

I actually have two more complete heads at home and I know where there is a bare one that is crack free

M Diesel · May 11, 2011

(quoted from post at 02:54:51 05/11/11) I had it out on last sunday and washed everything up really good. I had it idling off to the side while I put other tractors away and when I finally got back on the MD I noticed antifreeze seeping out of the top of the radiator cap. It has done this before under a very long hard pull with the disc but never noticed it before after just an idle. I haven't noticed any oil in the radiator and haven't checked to see if there is antifreeze in the oil pan.

They are fussy about the level being too high, and that level isn't all that obvious just by looking. A bit too much and they will spit it out the cap.

sflem849 · May 11, 2011

I fill mine so that I can just touch it with my pointer finger...seems to work for me. I have short, fat fingers so if you have long fingers you may want to adjust that measurement.

Cracked head on a MD

Brad in WI

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Anonymous-0

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D Slater

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Hill-Billy Rock-Star

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pete 23

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M Diesel

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sflem849

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Brad in WI

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Brad in WI

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