another overheating problem

first I want to say thank you to all who have posted on hundred series overheating issues in the past. I have learned so much from everyone here on the subject.

with that said my 960 is running hot (230 and rising according to the IR therm at cyl head) while running a 5 foot bush hog in thick 3' tall weeds.

first question - is this just too much for this tractor??

second question

after checking the following

radiator - (new style 4 core)
water pump - new
thermostat - new (correctly installed IAW manual)
replaced muffler and manifold elbow with correct size
fan shroud - got one now
flushed cooling systems with vinegar (thanks old)
timing set with timing light
new coil
new points & condenser
set timing again
compression is acceptable with in 5 psi on all cyl

what else is there???

-Paul

I wouldn't think a 5 footer would be too much for a 960! Heck, an 8N should run a 5 ft.
Running lean maybe, or plugged water passages if the radiator was rusty?

My 640 pulls a 5' Howse brush hog with little problem. Doug

But are you cutting 3 ft high growth ?

If you put in a new radiator, it probably has only half of the cooling cores of the original radiator.
No, a 5ft brush hog is not to much for that tractor. We used to pull a 4 bottom 14" plow all day long without the 960 ever over heating, but the manifold would glow cherry red at night.

One of mine when I had the head off, I found a lot of rust had accumulated in the cooling passages especially around the last cylinder. You could try aggressively flushing with the water pump off, putting it in through where the coolant temp sensor threads in, using a fitting of the same thread. I think it is probably 3/8 pipe.

"radiator new style 4 core" Have you looked? Is it still clean?. Most "foreign built" tempreature guages read high .Should be able to touch lower hose without burning yourself.A 960 is 55 yearts old, Wonder how much rust and sand is in the block? Time to remove soft plugs and clean water jacket? Just some ideas.

Paul,

You mentioned that you now have a fan shroud. Is it installed on the tractor? They make a tremendous difference in cooling capacity.

Tom in TN

thanks for the responses

i will get into the fuel system Friday and flush the block through the temp sensor hole

-paul

Don't be too hasty to tear into the fuel system if it's running good Paul.
I mentioned it because it's just one thing that can cause over heating.
If you had to replace the radiator I would start with flushing the water jacket out good.

How's the fan belt? If it's slipping, fan & water pump won't move enough air & water under high loads.

it is installed on the tractor and did lower the
temp by 10 degrees under load

[M]y 960 is running hot (230 and rising according to the IR therm at cyl head) while running a 5 foot bush hog in thick 3' tall weeds.

Did you happen to check the radiator temp when the cylinder head was 230. If your coolant is moving through the radiator too quickly, you're loosing cooling capacity.

Wasn't there about 8 cores in the old rad???? I think I'd check that out very closely. Also make sure that coolant is actually moving through the rad.
That's probably th emain reason why I'm always gunshy about using a lot of this china knockoff parts.... you have no idea what you're getting other than it looks 'close' on the outside.

Rod

3 foot of thick or 3 foot of thin... if its thick.. then he is running the snot out of it, especially if the shredder is set low. also ground speed has a lot to do with it.

i agree with royse and some of the others.

a 5' mower is an easy swing for a 900.

IF you are mowing at a ground speed AND the tractor can maintain rpms at pto speed AND ground speed, and is not lugging, then you are not over taxing her. that said.. 3' steemy weeds cuts WAY easier than 3' lush weeds. I'd expect 3' lush weeds to be DOABLE with the correct ground speed, though yes.. it will be using all them 45 or so pto ponies... and WILL make alot of heat.

I can easilly see 2nd gear being used and none higher, if it is 3' lush. if it is 3' stemmy.. then 3rd gear is fine. i cut 3' stemmy in 3rd on a 950 weekly..

new rad... as others said.. some of them new rads have wimpy thin cores more like a car than a tractor.. they are very likely reduced cooling capacity.. and they plug easier.. so keep them clean... you should be able to see thru it.

deffinately make sure you have backflushed the block.. you wouldn't beleve the slude and sediment you can get out... it's worth it to knock out a few core plugs to facilitate this even.

in my 950 .. it was a salvage / parts machine.. it is built from whatever I had around.. and mostly whatever the previous owners had around. it has a smaller than oem import car rad.. if i run coolant any amount over the core.. it will push some out.. though not overheat.

lastly.. at auto stores you can buy a 'water wetter' coolant addative that improves the heat density / disipation capability of coolant. mostly it's simply a chemical thing dealing with molecular size, alkalinity, and surface tension.. but it DOES make some difference. invest in a bottle.. it's cheap. walmart carries it for sure.. that said.. run a proper coolant mix. remember.. straight ethylene glycol is actually worse than straight water .. so DO run a proper mix for your environment.

clean the rad often in thick stuff. when mowing my pasture i can load a radiator in 30m.. I will be mowing fine and then at about 20m it starts slowly coming up and by 30 I idle down and ride over to the well pump and hose her out while idling.. by the time I've hosed her out temp is normal and i get back to slashing.

soundguy

Do you have a radiator cap with the correct pressure rating for your cooling system and is it working properly?

Well ok, My 640 must be alright then. As I always suspected, I been over working the ol girl! The junk we've been cutting is 3 ft+ tall, lush, woody and full of chaff to clog the radiator! Lucky to go 30 mins. without hosing out the radiator.
All that and lugging it in the toughest stuff. I'm using a 5-1/2' tire driven 3 pt Sidewinder to reclaim 40 acs. of Pop's pasture
Thanks for the info Sounder!

Blindhawg,
Yep, thats about where I'm at too. We have a lot of blackberry around here. (east central Ohio) The large leaves get sucked up and cover the front of the Rad. Stops the cooling effect real fast. Can't see them because they are behind the grill but in front of the rad. Sometimes if I shut down and rap on the grill, enough stuff will fall out so I can keep going for a couple min. Then back to the water hose to get it finished off.
With the tractor running I hose off the bottom of the block and the oil filter until it starts to cool down. Then I shut it down and hose out the Rad. I took out an alternator once by getting water on it while the tractor was running. Will not do that again!!
Keith
Keith

yep.. if the rad chaffs up.. she sure will heat in 30m or less. i reclaimed some pasture similar to that on my 2000 4 cyl and could go, as said.. a max of 30m before cleaing and cooling down..

take it a bit easier and she will be good.