Foton 254 : RPM Gauge and oil pressure sensor problems

[D0TC0M]

I take a page from the truckers playbook when it gets really cold here and hang an old towel over the front of the radiator only leaving an inch or two along the edges for air to pass thru the cooling fins. Keep an eye on the temp gauge untill you get the hang of how much is needed, What you want is to cover enough that the temp gauge reaches op temp and stays there without cycling(gulping cold fluid). The goal is a steady temp so the metal parts maintain a stabil size and some heat makes it into the engine oil. If it starts to creep up above the normal run point, you have too much covered, adjust accordingly. This happens to me in the summer when running the brushhog when the radiator screen gets clogged and restricts airflow. Then I have to stop and clean the radiator to get it back to a normal stable op temp. Properly covered in the winter, the tractor should warm up and behave the same as it does in the summer without the cover...

I tried the towel trick today and it almost made it to 40. It was noticeably warmer. My brother, who ran the tractor for my father, said the temp gauge used to go higher after about 20 minutes of plowing. I'm not overly concerned although I might order another thermostat when I place my next order.

 

[RonMar]

Cover more of the radiator or more layers or use something more windproof than a towel as the towel cloth will still pass some air. It should run at around 85C(190F) which is the thermostat temp that should be in it. Running a diesel cold is bad for it... You get incomplete combustion which fouls the valves, you get unburnt fuel which passes down along the cylinder walls. This bypassed fuel washes the oil off of the cylinders and causes the rings to wear faster. It also dilutes the lube oil and if rewarmed can cause vapors in the crankcase and possibly a crankcase explosion...

 

[D0TC0M]

I had used a shop rag to cover the whole rad before but this time I put a piece of plastic and completely covered the rad. This time under load the temps got up to 40c-60c with the heater fan on. As soon as I unload the engine it drop to below 40c. I touched the rad pipes and they weren't hot to the touch just to make sure the gauge might be off. I'm going to replace the thermostat, its 7 years old and its not expensive unless you really think its the nature of the beast.

 

[RonMar]

If it is really cold, the heater may be taking away all the heat the engine is making. Just to clarify, RPM does not equal load. performing work = load. These things put out 28HP continously at full output. Running a wood chipper fed steadily with large branches or a brushhog in heavy grass is a load. pushing even a heavy bucket of snow is not all that much load, and of course that small load is gone as soon as you pullaway from the snow to go get another scoop. A snow blower will be more steady a load, but is it bogging down the engine? no bog and black exhaust = not much load. Even then, unless you are doing a long driveway, the load is not sustained.

Did you try turning off the heater to see what happens? As a rule of thumb diesels adhere to the rule of thirds. 1/3 the fuel goes to making mechanical output, 1/3 goes out the exhaust as heat and the final 1/3 exits thru the cooling system. IF you can get an idea of how much fuel you have burnt in an hour, you can convert to BTU and divide by 3 to determine how much heat the engine has to dissipate in that hour. DO yo know the btu capacity of your heater? If you have a large heater, it may verrywell be covering the load generated heat. The heater output also bypasses the thermostat pathway so yor thermostat imay not even be opening. IF th engine is getting to 190F and the path to the radiator is being used, the upper radiator hose should be hot enough that you can only hold it a few seconds. My personal rule is about 5 seconds of hand/skin contact before discomfort = about 150F.

It could indeed be a stuck open thermostat, but you are kind of taking it out of the equation by blocking the radiator airflow. If it won't even reach rated temp with all the radiator air blocked, the heat is obviously going somewhere else