jinma 254 overheating

[rkevis]

Jinma 254 200 hours Overheats after one hour running a 5' bush hog.
I have cleaned the screen ,cleaned and flushed the system,installed antifreeze, tightened the fan belt , changed the radiator cap , removed the thermostat.
It will run a chipper , and move dirt with the front loader with no overheating .
What else can I do?

[red]

Rkevis-
Have you changed your fan belt? Remember someone who actually replaced their head because of overheating/ blown heat gaskets and the problem ended up being fan related. Similar situation too, cause run the machine for about an hour before overheating. Fan was slipping on the belt . Easy check that may save you a lot of aggravation.
Have you also cleaned out your radiator (from the outside)? Need to be able to see daylight thru it. Do not use a pressure washer lots of people use compressed air and blow it out from the backside towards the battery. A few guys (think Rob) use a furnace filter adapted to replace the metal screen that is in front of the radiator. Good Luck -Ed

[GuglioLS]

Rkevis,

I see this is your very first post, welcome to CTW, bummer to here of the overheating troubles. Red has some good advise, it does not take much to clog a radiator, make 100% sure there is ZERO debris, or caked dust clogging the cooling fins. If none of that pans out, maybe check to see if the water pump is actually circulating the coolant. Since you removed the thermostat, with a cold engine, remove the radiator cap, start the engine, look inside the radiator to see if coolant is circulating. maybe the water pump is out? Check your oil to make sure there is no coolant mixed in the oil, it will be a brown foamy oil after it as run for a few minutes. Maybe the head gasket is already blown? Did you ever re-torque the head bolts? How about injector timing? what does the exhaust look like? How hard do you push it brush cutting meaning what RPM's? Air filter? is it clogged? a clogged air filter will make it overheat. Oh and do you have an IR temp gun? Measure the temp at the top of the radiator and at the bottom. Try flushing out the cooling system, maybe the internal radiator tubes are restricted or clogged?

Good luck with it - please follow up with your findings.


Larry

[biggkidd]

Hi Guys,

Another thought for you without the thermostat it may be moving through the block to fast to cool right. I had a similar problem with race cars. The system needs some restriction to work right. When we had to run with no Tstat we took an old one and removed the center and put the plate back in. Which slowed the flow down enough to work.

Good luck.
Kidd

[jaroban]

This is my first post on this forum also . I have the same tractor with the same problem. I have to remove the radiator and clean it out (on the outside) at least once a year. It gets small seeds and other trash that clog it up when brush cutting. I did add a fine screen in front of the radiator with some success. Robby

[Ronmar]

I use a an old aluminum arrow shaft with the nock removed(has a smooth rounded aluminum point). I drilled a 1/8" hole right above where the nock was glued on and I put this onto my air blow gun. This blows air at a 90 degree angle from the point. On my radiator, the fairings on the rear have small openings at the top corners. These openings are just big enough to slide this arrow shaft blow gun extension into. From the top corners, I can reach the entire rear surface of the radiator and blow debris out the front with compressed air.

A easy way to check how clogged the air passages might be is to use a small droplight, or a minimaglite with the lens assembly unscrewed and just the bare bulb shining. In a darkened garage, or at night, carefully work the light bulb past the fan blades and look for the light from the front with the screen removed. You will have to move the light around to assess the state of clog, but this will tell you how much junk is in the passages.

By the way, what exactly are you calling an overheat? Is the gauge in the red? Is the radiator boiling over? Do you have a radiator catch can/expansion tank? What is the outside airtemp? An IR themometer is handy for determining gauge accuracy, and if the radiator is dissipating heat(should be cooler on the bottom).

Sometimes a leaking headgasket can be mistaken for an overheat condition by injecting hot combustion gas into the coling system. this hot gas rises up to the temp sensor and causes it to read high, and the added pressure causes the radiator pressure cap to vent foam and liquid. If you have a catch can, the oil that comes with this combustion gas will leave an oily sheen and a scum ring in the can.

Ron

[rkevis]

I will try to clean the radiator as you suggest.
The guage will run into the red, and fluid will run out the overflow.
I am in Hawaii outside temperatures are 75-85.
If the headgasket is leaking hot combustion gas into the cooling fluid , could you see it ? I have noticed what looks like fizzing in the top of the radiator.
I will collect some of the overflow and check for oil.
thanks

[GuglioLS]

I have noticed what looks like fizzing in the top of the radiator

That statement appears to be a leaking head gasket. Did you ever re-torque the head bolts? It may be too late for that now, but maybe worth a try? If it were mine I would replace the head gasket and be done with it. It's not not really all that hard to do, one day to a weekend at most.

To verify that fizzing are exhaust gases, look at the bubble frequency, have someone rev the engine, if the bubbles increase, it's a sure sign the gasket is leaking.

Did you ever drain the engine oil to see if there is coolant in it?

Larry

[rkevis]

Anyone know the torque setting for the head bolts?

[3RRL]

If you have cleaned out your radiator and it overheats while brush hogging, there's a really good chance your air filter needs to be cleaned also. A clogged air filter will cause overheating just as much as a clogged radiator.

Check for the "fizzling" like Larry suggested by revving your engine up and down when it is hot. If the "fizzling" gets worse as the revs go up, it's a sure sign of a blown head gasket or head leak of some sort.

Regarding the torque figures for the Jinma, my wife printed out this comprehensive maintenance manual for her 284 Jinma. It's got lots of good information in it.
JINMA MANUAL
Look on page 34, item #4.
Suggested in THAT manual is 95 to 105 ft/lbs. and NOT to loosen the bolts up, only tighten them to the specs. That's what we use on her Jinma anyway.

I'm not sure what other guys feel about that, but some loosen the bolt first and then re-torque to spec. Some guys loosen the bolts, take it out and clean and lube slightly, then re-torque. It's up to you what you want to do, but in any case, if you're going to remove the bolt or loosen it first, I would only do ONE at a time that way. Your goal is to be sure the torque is correct, or at least where it's supposed to be. Some guys feel if you loosen them all up you could run into trouble.
Rob-

[rkevis]

It seems like maybe I have fixed the problem.
I sat and watched the open radiator for twenty minutes using a stick to accelerate the throttle. No fizz. Some bubbles but they are from rapid circulation.
I made a blower from 1/2" copper pipe with a cap on one end and a hole drilled in the side . A lot of dust came out.I blew it from inside and outside . I put a fluorescent drop light behind and its cleaner. The temperature now hovers just above 80C.
What would I do without you guys ?
Stay in the dark all alone!
thanks

[GuglioLS]

Whew, what a relief that must have been, here I am suggesting to replace the head gasket and turns out simple. Glad you took the time to observe the coolant flow and make that "magic wand" to wave it over the radiator fins. Sounds like a cool gadget. Did you solder on a quick connect air hose coupling? I think you should post some pics of your invention so I can admire and copy it. So.... when are you going to test your tractor out with some heavy mowing?

Larry