955 cooling system problems

[Anonymous Poster]

Hi I am new her so her is my first post.
I was mowing along a hill side with my 955/60in mid mount mower and noticed that alot of coolant had came out of the over flow tube off the raditor, I then looked at the dash and saw the idiot light for the coolant temp being to hot was on as well. So I then drove down to the base of the hill so I could investagate this problem further, I shut the tractor off so it could cool off. I opened the hood up and opened the raditor cap to the first position to see how much was in there the coolant over flowed over everything- later after thinking about what had just happened I realized that what I had just done was stupid and should have none better than to do that because there was going to be pressure built up in the cooling system from operation and being hot. What I dont under stand is why It over heated in the first place it has never done this before. Most of the time when I mow it is 90+ degrees out and I dont have any problems so why would this happen when it is 40 degrees out. Any help on what needs to be fixed would be much appreciated
Thanks
Jonathan Pye

 

[motelman]

You are very lucky, my cousin had very severe burns on her arms and face from an over-heated tractor that took a long time to heal up from.
Try the obvious first, check and clean the radiator.
If that is OK, the thermostat may be sticking shut and not allowing the coolant to flow from the engine through the radiator. If the thermostat is OK, you may have a faulty water pump.

 

[Anonymous Poster]

Whoa! You didn't (my first though) but reading on. He did.
Glad you ok buddy!! Thats the main thing! whew.

Onto business: check your radiator screen.
On my 4300 i have the outside screen the grill,
then i have another behind the battery, it slides up and down in a slot, I clean this out several times if mowing in heavy dusty dead grass etc... I've carried my leaf blower to clean my grill off when mowing those times...

Yep, check thermostat like he said. Especially if your tractor is older. Check your cap to, it may be bad. I've had my Chevelle do that once. Bad cap, gave wrong lbs cause broke, caused over heat. Whens the last time your coolant's been flushed, and replaced with new stuff ?

My bet is the system wasn't getting enough air, or the thermo, cap went bad.

 

[Gunfighter]

The first thing I'd check is the screen in front of the radiator, next is the fan belt slipping.
Other possibilities are stuck thermostat, collapsed water hose, water pump. You could
have a leak an were low on coolant. If you can look down into your radiator, check an see
if the passages are free from mineral deposits.

I'm sure there are many other reasons for over heating but this is my two cents worth...

 

[snowman]

Like the others have said, your screens were probably just clogged.

I keep a very close eye on the temperature gauge when mowing ever since I overheated mine (saw the gauge on "H" just as the coolant started spewing out).

I stop every half hour or saw to stretch my legs and clean the screens. Have never had an overheating problem since.

Note - don't have a JD - I have a Kubota, but problem is probably the same.

 

[Anonymous Poster]

After reading all your replies I have decided to buy a new thermostat and flush the cooling system while Iam at it, because I looked down into the raditor and saw corosion/and buildup. Can anyone recomend a good raditor cleaner, the kind you pour in and add water and let cycle thru the system??? Thanks to everyone that posted somtimes even us first year JD Ag Tech students need help.
Thanks again
Jonathan Pye

 

[Anonymous Poster]

Hi I just remembered somthing my dad had sugested could be wrong, that there could be a crack in the head or a blown head gasket which I have kinda a hard time beleiveing. Because most people say yanamar builds one heck of a good engine and this tractor only has about 390 Hrs on it. Please coment on this could this realy be the problem?
Thanks
Jonathan Pye

 

[grainger12002]

Be careful what you "dump"in the raditaor. Many times if you flush with cold water and run until it runs clean you will be fine. Many small radiators cant take any harsh chemicals. Disconnect the lower hose,pull out the t-stat,leave the radiator cap off and turn the garden hose on low in the top of the radiator,keep enough in the radiator tank as not to overheat,when it runs clear ,you are all set.New stat,new anti-freeze and give it a try. Keep us posted

 

[Anonymous Poster]

Thanks for the advice. I flushed the raditor on the 855 that I owned before the 955 I own now and used raditor cleaner made By Gunk I think, it seamed to be more like soap water not any thing real strong by any means. Iam not sure what to use here I kinda wanted to use more of a acid based cleaner because there seems to be alot of this white looking corosion in the raditor but of course I dont want to hurt any parts of the cooling system ether.

 

[kubmech]

Johnny, at the "shop", when I suspected a radiator of having alot of "deposits", I would remove it and send it to a radiator shop to have an acid flush. Always had good results. They usually pressure test it as well and can repair any minor leaks, or major, which could involve a recore which is still cheaper than a replacement. One of the biggest arguments for NOT flushing a cooling system with the products that are available while it's connected to the "system" was that you would open a "can of worms", any deposits that were currently preventing leaks in the head gasket or water pump would be flushed away and then the customer would be upset that, now, more work was required to straighten out the leaks that were not there when he brought it in. There is a valid argument there, However, I never completely agreed with the logic.........