Foton 254 overheating.....in an odd way.

[amafrank]

Haven't posted for a while but I've been watching....

I've got a 2006 254 that I bought new. The electrical system really sucks and has since new but thats another story.... Right now the issue is overheating. The tractor starts and runs fine for quite a while when mowing. I've got a 60" chinese bushhog style mower deck and it has been running fine since I got the whole rig, until last year. I can mow for about half an hour and the temp keeps climbing slowly. When it hits 100C I shut down and let it cool or take the garden hose to the radiator til its back in the green. Last year the issue turned out to be the cap which wasn't sealing properly. It would allow water to leak out the overflow til the level dropped enough to start the temps rising. I replaced the cap last summer with a higher pressure unit and that seemed to work. Now I'm back at the same issue only I'm not losing water through a faulty cap....its just getting hot. I checked the thermostat when I replaced the cap and there wasn't one in it. I put in a 180deg thermostat and that seemed to help too. I checked it and it is still working. The tractor only has 175hours on it since new and has good oil pressure, starts easy and runs good. I'm wondering if the governor is allowing too much fuel into the system and making more power than the radiator can dissipate? I pulled the dipstick on the injection pump/governor and its full of fuel. I don't think thats proper as it had been running just fine prior to this with engine oil. I haven't had much mowing this year due to the drought in the midwest and no grass to mow. It was fine in the spring (the injection pump) but now its not.....I've had overheaters before and they usually get hot quick or else they run fine. This one takes a long time to get too hot and thats puzzling.
Any suggestions are appreciated.

Frank

 

[quicksandfarmer]

I'll give the worst-case scenario first: these engines very often blow head gaskets. The behavior you describe -- fluid leaking out of the overflow -- it typical. When the head gasket is leaking, combustion gases from the cylinder leak into the coolant at high pressure. This results in the coolant being pressurized, which causes the radiator cap to open. Head gasket leaks can be frustrating because they can be intermittent and the symptoms can seem illogical. Sometimes a head gasket will only leak when the engine is hot. If you can't hold a radiator fluid level suspect the head gasket.

Three times in my life I've had cooling system problems that defied diagnosis, and each time the problem turned out to be the head gasket.

If your cooling system is indeed sealed -- no head gasket problems -- then there isn't that much that can go wrong as long as there is a steady stream of hot coolant and cool air through your radiator. Is the water pump turning? The fan belts on these engines are cheap and tend to stretch. Is the radiator clean, both inside and out? When mowing I sometimes find I have to stop every 30 minutes to clean the chaff off the outside of the radiator.

 

[RonMar]

Well fuel dilution in the IP drive is not a good thing, I don't think it is related to the overheating. If you were dumping too much fuel, the engine would want to increase in RPM, and would smoke black... Fuel in the IP oil is bad though, and will mean you will probably need an IP sometime in the future...

SInce it sounds like it is not blowing fluid out the rad, I would go with a very through inspection of the radiator air passages first. The real fine dirt wil pack its way in there and take the edge off of cooling efficiency. The rad looks clean, but it really isn't. I use a long thin air pipe with a hole drilled in the side at the end(blows air perpendicular to the pipe) to blow dirt out with compressed air. This pipe is about 2' long, and I can slide it into small openings where the shroud on the back of the radiator meets the rad at the top corners. With this pipe I can reach 99% of the radiator's rear surface and am always surprised at how much dust blows out of a clean looking radiator. I have several layers of window screen wrapped around the original shield plate that slides into the slots in front of the radiator. Brushhogging is dirty buisness, and that mesh screen will clog with trash/chaff and need to be cleaned every 1/2-1 hour when mowing. Even with this screen catching a LOT of debris, the radiator still collects and cloggs with the fine dust carried thru the screen and eventually will need to be cleaned or the engine starts running hot. But since only dust can really get past the screen, it is real easy to blow out with the air pipe.

 

[amafrank]

I don't think its the head gasket though I could be mistaken. I don't get any fizz out of the radiator, no oil in the water and no water in the oil. I will have a look and see what I can find though. I've checked the radiator as well as I can for plugged cooling fins and they appear to be pretty clear. I haven't had the front screen plugged for some time though I have on occasion had to remove and clean it. I normally clean the rad pretty well when that happens. Right now I can see water flowing through the rad when I take the garden hose and run it from front to back. I don't see any plugged fins and water won't flow where air will not.(at least not a normal pressure). I can see where the black smoke and higher revs would result from excess fuel so I guess thats not the answer. I'll get the wrenches out and retorque the headbolts and see if that helps overheating. I'll try to find a schematic of the IP and see if there is a seal I can replace to keep fuel out of the governor section....maybe thats an unrelated leak.

Thanks for the suggestions

Frank

 

[Bob Rooks]

There are no seals in the barrel and plunger assemblies, they are a lapped fit and lubricated by the fuel. You have one or more bad plunger assemblies, but unfortunately they are not sold separately. Besides, you would need a test stand to set and calibrate them anyway. Test stands run around $20k for a good used one. You are looking at a new injection pump/governor assembly for around $450.00. Suggest you change oil frequently until you get a new pump assembly as this will lessen your chances of contaminating the engine lube oil through the pump shaft seal. The injection pump and governor share a common sump.

It would also help a lot to give the cooling system a good chemical flush and use a coolant designed for diesel engine service such as Final Charge Antifreeze Home Page or equivalent.

Let me suggest that you drop down one gear and try mowing again. Example: #2 L to #1 H. You might be slightly lugging the engine.

 

[zonta223]

I did what you did flushed the radiator with water through the fins and I was sure it was clean........Then I had to take it off for another non connected job and sat it it a bath of water. Came back next day and could not believe how much junk had come out of the radiator fins which I thought was clean. If all else fails it may pay you to remove the radiator, soak it then flush it out with your hose.

 

[greg_g]

x2, remove the radiator for a thorough cleaning inside and out. The 180 degree thermostat is ok, but a little higher than factory. I've had 4 Chinese tractors, and they all came with either 72C or 80C thermostats. But the higher pressure cap should be replaced. This is a low pressure system - about 0.3 bar - which translates to about 4.35 psi. If you put a conventional (15psi) cap on there, you're straining the seams of the cooling system. Don't be surprised to see the radiator seals and/or hoses and/or water pump seeping. Some owners who didn't realize this actually put sealant in to try and stop the weeping, which only served to clog the system up even worse. If you can't get the proper cap from a Chinese tractor dealer, go to NAPA and get a 7 psi tractor cap. It's almost certainly better than what you have on there now.

I strongly recommend a thorough cooling system cleaning and go back to a low pressure cap.

//greg//

 

[Diamondpilot]

Your rad is dirty. Take it off and have it cleaned or do it yourself. While you have it off get the proper 4 psi cap for it. Your HP cap is too much for the system.

While you have it apart flush the system and install the proper coolant and check the basics like the belt tension, ect.

Chris

 

[RonMar]

Guess I should ask a basic question also. Is your fan shroud in place? Without a fan shroud the fan cannot produce a low pressure area behind the entire radiator surface and will not pull air thru ALL the air passages. Removing a fan shroud disables a large precentage of your radiators cooling capacity...

Flowing water thru the fins won't clean them as well as the compressed air. The water just flows past the wedged in fine dirt... Running water at enough velocity to dislodge the dirt risks bending the fins. The compressed air has enough velocity to create enough turbulence to dislodge the dirt, but not enough mass to bend the fins. Soaking it in a tank of soapy water would give the water enough time to soak in and dislodge the dirt. Give it a shot of air from the backside, I think you will be surprised at what comes out of a "clean" radiator.

Oh, and FWIW my 2005 jinma 284 was delivered from china with a 13 PSI radiator cap...

 

[Bob Rooks]

I agree with RonMar on the radiator cap. 13 - 15 psi is fine. The higher pressure keeps the boiling point lower. ~10 psi difference shouldn't have any effect on the radiator, hoses, pump seal, or any gaskets. Cooling systems are typically hydro tested to 30 psig. If you don't have a coolant recovery system in place, I suggest you install one.