JD 950 Cooling system overheating

[airportrep]

I have been a member for a while but would be considered a lurker. I have enjoyed reading the many messages and have learned a few things along the way. Now it's my turn to present the problem and ask for help.

My 950 has been over heating and although I have changed out the t-stat, checked air filter, water pump, and am in the middle of changing out the head gasket, I have not found a visible culprit yet! Any suggestions on what else to look for?

Regards,

Joe

 

[Turbys_1700]

Blow out the back of the radiator. If the radiator is clean, water pump and thermostat is good, and head gasket is OK and you are not losing coolant I don't have another suggestion. What are you doing that causes it to overheat? You may just be overworking it.

 

[DK35vince]

I had a JD 850 that was over heating.
I blew the radiator out all the time and it would still run hot.
I took the radiator to a radiator repair shop and had it cleaned inside and out.
Overheating problem went away.

 

[tman1020]

I have heard of John Deere 750&850 being difficult to get all the air out of the cooling system especially after a cooling system flush. Read a couple different posts on here were guys were pulling their hair out trying to figure out why they were overheating. Kept trying to flush the system out and having the same problem. Finally with persistence they seemed to get the problem solved.

 

[airportrep]

I didn't mention blowing out the back of the radiator but I had done so. It started heating up if rpms were taken to 2200 or so and kept there, such as grading, digging, snow plowing, etc. There has almost always been a lot of blowoff at the blowoff tube. This got worse toward the end. When I finally shut it down for good, I could barely pull a trailer, loaded with a cord of wood, up a hill. It has been worked hard over it's 28 year life but the last 5-8 years it gets maybe 75 hours each year.

 

[airportrep]

There was some evidence of rust at the middle cylinder on a three cylinder engine, on and around the piston top, near where the fuel injectors spray out onto the piston and in the exhaust side of the middle cylinder. Yet the head gasket show very little if anything.

 

[DK35vince]

There was some evidence of rust at the middle cylinder on a three cylinder engine, on and around the piston top, near where the fuel injectors spray out onto the piston and in the exhaust side of the middle cylinder. Yet the head gasket show very little if anything.

Have the head checked for cracks

 

[Jerry/MT]

I have been a member for a while but would be considered a lurker. I have enjoyed reading the many messages and have learned a few things along the way. Now it's my turn to present the problem and ask for help.

My 950 has been over heating and although I have changed out the t-stat, checked air filter, water pump, and am in the middle of changing out the head gasket, I have not found a visible culprit yet! Any suggestions on what else to look for?

Regards,

Joe

Possible culprits: Air side of radiator clogged, radiator core clogged, pressure cap not holding correct pressure, slipping drive belt on water pump, damaged water pump impeller, collapsed lower rad hose when engine is rev'ed to higher speeds, clogged air filter, leaking injectors. these are the first things that come to mind for diesel engines.

I would not expect the head gasket to be the issue unless you saw continuous bubbles in the coolant when the engines was running.

 

[whis]

have the radiator cleaned at radiator shop

 

[airportrep]

Thank you all for your suggestions. I will take each one to heart and let you know as I go. I wish I had done a compression check prior to removing the head but such is life.

 

[hsc749]

Possible culprits: Air side of radiator clogged, radiator core clogged, pressure cap not holding correct pressure, slipping drive belt on water pump, damaged water pump impeller, collapsed lower rad hose when engine is rev'ed to higher speeds, clogged air filter, leaking injectors. these are the first things that come to mind for diesel engines.

I would not expect the head gasket to be the issue unless you saw continuous bubbles in the coolant when the engines was running.

Hello Jerry,
I got a 950 a while back and have noticed the thing has "continuous bubbles" in the coolant overflow with the radiator cap on but there isn't any coolant in the oil or exhaust. Wouldn't there be if the head gasket was blown on the coolant side? Could a cracked head be the culprit here?? haven't run a compression check on it yet and it does overheat. your feedback would be appreciated. Thanks!

 

[Jerry/MT]

Hello Jerry,
I got a 950 a while back and have noticed the thing has "continuous bubbles" in the coolant overflow with the radiator cap on but there isn't any coolant in the oil or exhaust. Wouldn't there be if the head gasket was blown on the coolant side? Could a cracked head be the culprit here?? haven't run a compression check on it yet and it does overheat. your feedback would be appreciated. Thanks!

Your hijacking this post and that's bad manners. However.....

Yes to both but a leaking head gasket is more probable unless you have some additional knowledge that leads you believe it was a head crack( running with water for a coolant and encountering freezing weather, etc). Look for the simple things first. Sometime cracked heads require magnaflux examination to detect. In any case, you'll have to pull the head to find out.
Before you do that, re-torque the head and recheck for bubbles in the coolant.

 

[hsc749]

Sorry, didn't know-- but Thanks!