HOT minneapolis moline

all right guys need some help with a M.M. U, got a U that keeps over heating and when it get to temp it runs right out the top of the radiator. I have changed thermo-stat,replaced bad head gasket,went through the water pump, and flow tested the radiator. what am i missing? heads? cylinders? what was a common problem with the U? and if anyone knows someone that works on these old girls and might know a phone # would be great!

cracked head. Kenny L.

no I did not check heads when I found bad head gaskets I figured that was the problem. i know should have checked heads. and when this thing gets hot it unloads about  3-5 gallons real quick. gary in da up I checked all that. its like this thing hate's me. if it was mine it would be going down the road! 

With radiator filled, engine cold, start engine and look down in the radiator, look for bubbles.  You may get a few when it starts up... if it continues bubbling after about 8-10 seconds, or it bubbles more, and faster, then you have a situation where compression gases are being pushed into the cooling system.  This will both displace coolant from the cooling system AND prevent coolant from getting to pockets at the top of the head, and around the combustion chamber.

Frequently, if you have combustion gasses displacing coolant from the head, the moment you shut the engine down, coolant will flow back INTO the head, and immediately flash to steam, yielding a wonderful green geyser in your face.

Combustion gasses can displace coolant in a myriad of ways.  I'm not familiar with the internal setup of the MM, but I'd look not only at head, block, and sleeves.  Typically, if you have a crack somewhere, it will either leak coolant into the engine (pan, or a cylinder), or out the engine (either the block or head) or into the airflow path (like through the exhaust port into the exhaust path and out) or intake (into cylinder and out).  The airflow path leak will make your shop smell like anti-freeze... and sometimes, particularly with an intake leak, it'll leak enough into a cylinder to hydraulically 'lock' the engine.  If it's leaking into the pan, you'll notice your oil level RISING.

  GIVE ME A CALL   WIL SEND YOU TO RIGFT FELLA WITH PHONE#  HE CAN HELP

Norm I'll give you a call Monday, guess I should have asked you when I was at your place Friday. got the keys to Jim that he wanted 

Had a 160 that done something similar, ended up having a cracked ring. Most definitely has to be a cylinder issue.

A plugged-up radiator is a high possibility... especially if it was rescued with the rad cap or either hose rotted-off (wasps), or had a prior history of overheats (refilling in the field using a bucket from the stream)...

And cleaning it out with a garden hose and nozzle wouldn't be unreasonable, but I don't think I'd feel safe taking a pressure-washer to it, unless it was a really, really weak pressure washer.  The forces generated by the washer tip are well above the strength of the solder joints at the top of the tube and tank.  If one were to pull the radiator, I'd recommend just taking it to a rad shop for a visit to their boiling tank, and while at it, have them flow it, patch up any leaks.  Good thing about this approach, is that if there's a problem, they'll find it pronto... and that may be all that's necessary to solve your problem.

Ditto on the thermostat check before installation.

Gerald J.

Could it be the thermostat got installed backwards? Possibly air trap somewhere, got any bled plugs anywhere? Maybe not!

Minneapolis Molines were notorious for cracked heads with several models. I suspect that but go ahead and check for easy stuff first.

Ignition timing is always affected by point gap and rubbing block wear. Its probably more critical on an 8 cylinder engine than a 4 because the flats on the cam are so short if the cam diameter isn't big on the 8 cylinder engine. That's why its SOP to set the point gap first, then set the timing. And to set the timing each time the point gap is set.

Gerald J.