ToolManRick
Silver Member
Bingo! The cooling system would be defective if it ever reached operating temperature without a thermostat, unless there's really something else wrong or it's 160 degrees F outside. /forums/images/graemlins/smile.gif
Harrygoodwrench
Gold Member
I have to side with Bruce, & Toolman on this one. The engine should run cooler with the thermostat removed providing the rest of the cooling system is functional. The only purpose for a theromstat is to allow engine to achieve operating temperature asap and maintain it there for maximum efficiency by modulating the flow. This results in max power output & effiency, longer engine life, etc.
I have worked on hundreds upon hundreds of gas & diesel engines of road design, stationary units as well as marine design and although their cooling sysems may differ they all do the same thing. A tractor is much easier in design.
BTW, the main purpose of the bypass hose system is to permit coolant flow between the block and the suction side of the water pump when the thermostat is closed to provide uniform warming of the block during warm-up. True there are some that may circulate it thru a heater core then the radiator as the bypass but that is only primarilly for the passenger heat.
In my opine removing the thermostat will make the engine run cooler assuming all systems are working properly.
I believe the poster having the overheating concern has a problem in another area. Some areas of concern: clogged radiator fins(maybe internal passages), block/head cooling passages sludged up, defective water pump as in impeller bad or belt slipping. Hose collapsing(lower radiator hose)Head gasket leaking some combustion gases into coolant, radiator cap, intake or exhaust restriction, timing, airflow over radiator. These are just some areas that I thought of quickly at the moment and there may be others. Always check the easy first I always say.
I would first suggest to the poster to verify with a known temp gauge what the temp really is.
I have worked on hundreds upon hundreds of gas & diesel engines of road design, stationary units as well as marine design and although their cooling sysems may differ they all do the same thing. A tractor is much easier in design.
BTW, the main purpose of the bypass hose system is to permit coolant flow between the block and the suction side of the water pump when the thermostat is closed to provide uniform warming of the block during warm-up. True there are some that may circulate it thru a heater core then the radiator as the bypass but that is only primarilly for the passenger heat.
In my opine removing the thermostat will make the engine run cooler assuming all systems are working properly.
I believe the poster having the overheating concern has a problem in another area. Some areas of concern: clogged radiator fins(maybe internal passages), block/head cooling passages sludged up, defective water pump as in impeller bad or belt slipping. Hose collapsing(lower radiator hose)Head gasket leaking some combustion gases into coolant, radiator cap, intake or exhaust restriction, timing, airflow over radiator. These are just some areas that I thought of quickly at the moment and there may be others. Always check the easy first I always say.
I would first suggest to the poster to verify with a known temp gauge what the temp really is.
greg_g
Super Member
- Joined
- Dec 18, 2003
- Messages
- 6,126
- Location
- Western Kentucky
- Tractor
- JD3720 Cab, 300X loader with 4-in-1 bucket
</font><font color="blue" class="small">( the main purpose of the bypass hose system is to permit coolant flow between the block and the suction side of the water pump when the thermostat is closed to provide uniform warming of the block during warm-up)</font>
I stand corrected Harry. I was considering the bypass hose from the wrong side, and see now that there's no circulation path through the radiator available when the thermostat is closed.
//greg//
I stand corrected Harry. I was considering the bypass hose from the wrong side, and see now that there's no circulation path through the radiator available when the thermostat is closed.
//greg//
Harrygoodwrench
Gold Member
Greg, others,
I must differ. What you see during warm up with thermostat installed and closed is turbulance due to the water pump impeller attemting to circulate the coolant. The by-pass in effect is only designed to allow circulation of coolant while thermostat is closed.
Many engines will actually overheat if not "burped" or vented after refilling the cooling system. Thats why some manufacturers provide a vent hole(very small drilled hole or a jiggle pin) in the thermostat face to provide circulation to vent air.
Of course the thermostat is necessary as we all will agree but a engine will run cooler with out one which is not desirable due to we want all metals to expand to operating temperture so maximum efficiency can be achieved.
I have run many an engine at part throttle RPM for quite a while( 1/2 hour) after rebuild with a heat enchanger consisting of nothing more than a water pump pipe connected to the water pump inlet and the discharge was dumped overboard and the engine and engine would run cool. It was the increased coolant flow that caused the decreased temperture as Hbaird stated in a earlier post.
I am not trying to prove anyone incorrect I am only trying to inform those interested in the purpose and design and reason of such components. Simply put, if you slow down the media flow then heat transfer will decrease. Its simple physics.
With all said, if the gentlemans concern still exists with the thermostat removed his problem lies elsewhere and not with the thermostat. Most likely I would assume would be clogged/plugged radiator tubes.
As I said, I respect all here but am trying to help a poster solve his problem.
I must differ. What you see during warm up with thermostat installed and closed is turbulance due to the water pump impeller attemting to circulate the coolant. The by-pass in effect is only designed to allow circulation of coolant while thermostat is closed.
Many engines will actually overheat if not "burped" or vented after refilling the cooling system. Thats why some manufacturers provide a vent hole(very small drilled hole or a jiggle pin) in the thermostat face to provide circulation to vent air.
Of course the thermostat is necessary as we all will agree but a engine will run cooler with out one which is not desirable due to we want all metals to expand to operating temperture so maximum efficiency can be achieved.
I have run many an engine at part throttle RPM for quite a while( 1/2 hour) after rebuild with a heat enchanger consisting of nothing more than a water pump pipe connected to the water pump inlet and the discharge was dumped overboard and the engine and engine would run cool. It was the increased coolant flow that caused the decreased temperture as Hbaird stated in a earlier post.
I am not trying to prove anyone incorrect I am only trying to inform those interested in the purpose and design and reason of such components. Simply put, if you slow down the media flow then heat transfer will decrease. Its simple physics.
With all said, if the gentlemans concern still exists with the thermostat removed his problem lies elsewhere and not with the thermostat. Most likely I would assume would be clogged/plugged radiator tubes.
As I said, I respect all here but am trying to help a poster solve his problem.
Latest Update. Went to the farm an mowed.
Changed the oil, adjusted the shroud again.
Still runs hot. I was able to mow with the hood up, but as the day got towards noon and heated up, I had to stop when I went in the red and cool off. The furnace filter is really catching a lot of stuff. Maybe my field is just too much on the first cutting.
I didn't mention, but about six months ago I lost the belt without knowing and it boiled over while idling and I wasn't with the tractor. It was hard to start before then, I would think because it was still breaking in, but now it starts easy.
I don't know if I possibly damaged something when it overheated?
I still need to try the radiator cap, but after that I'm out of ideas.
TJ
Changed the oil, adjusted the shroud again.
Still runs hot. I was able to mow with the hood up, but as the day got towards noon and heated up, I had to stop when I went in the red and cool off. The furnace filter is really catching a lot of stuff. Maybe my field is just too much on the first cutting.
I didn't mention, but about six months ago I lost the belt without knowing and it boiled over while idling and I wasn't with the tractor. It was hard to start before then, I would think because it was still breaking in, but now it starts easy.
I don't know if I possibly damaged something when it overheated?
I still need to try the radiator cap, but after that I'm out of ideas.
TJ
greg_g
Super Member
- Joined
- Dec 18, 2003
- Messages
- 6,126
- Location
- Western Kentucky
- Tractor
- JD3720 Cab, 300X loader with 4-in-1 bucket
</font><font color="blue" class="small">( still need to try the radiator cap, but after that I'm out of ideas. )</font>
Sounds like you haven't gotten around to removing the radiator for a proper cleaning either. Ain't no way you can tell by looking at an installed Jinma radiator to see whether or not your air gun or water hose did any good.
//greg//
Sounds like you haven't gotten around to removing the radiator for a proper cleaning either. Ain't no way you can tell by looking at an installed Jinma radiator to see whether or not your air gun or water hose did any good.
//greg//
pasturesnew
Member
- Joined
- May 29, 2005
- Messages
- 30
Good morning,
For what it is worth:
I'm running a new 254T, cutting bramble scrub and tall grass on steep slopes. It has been 28-35C in the shade and I am having to use 4x4 and low 1st or 2nd to keep it safe.
The only time the temp guage goes above 80-90 is when that radiator screen gets blocked - and then the temp rises very quickly unless I do something about it immediately.
I carry a small auto vacuum with me, powered from the cigar lighter. Takes about two minutes to pop the hood, take out and tap the screen, vacuum the radiator and put it all back again. I leave the engine running if it has got above 90 - if that screen is blocked, it will not cool down sufficiently for a safe shutdown. With the cleaned screen, by the time I am back in the seat the temp has dropped to 80 and of we go again. Also, I always give it another clean with the shop vac before putting it away.
Not an elegant solution, but hope it may help.
For what it is worth:
I'm running a new 254T, cutting bramble scrub and tall grass on steep slopes. It has been 28-35C in the shade and I am having to use 4x4 and low 1st or 2nd to keep it safe.
The only time the temp guage goes above 80-90 is when that radiator screen gets blocked - and then the temp rises very quickly unless I do something about it immediately.
I carry a small auto vacuum with me, powered from the cigar lighter. Takes about two minutes to pop the hood, take out and tap the screen, vacuum the radiator and put it all back again. I leave the engine running if it has got above 90 - if that screen is blocked, it will not cool down sufficiently for a safe shutdown. With the cleaned screen, by the time I am back in the seat the temp has dropped to 80 and of we go again. Also, I always give it another clean with the shop vac before putting it away.
Not an elegant solution, but hope it may help.
bluechip
Veteran Member
I didn't carefully read this whole thread to see if anyone suggested this, but a bad head gasket could cause overheating. Especially if the engine got very hot when the belt broke. We have a liquid that changes color with CO but you MAY be able to see if you are getting bubbles in your coolant before you get to 100C (boiling).
Somthing is not right here...
Somthing is not right here...
Wayne_Freeman
Gold Member
Bluechip is right about the head gasket causing overheating. I had this happen on my first Jinma. It would slowly run hot and all the suggested fixes recommended here did no good in solving the problem. The symptom for this however is you slowly lose liquid in the radiator. To diagnose this problem simply fill the radiator, leave the cap off, start the engine and observe the liquid for any sign of bubbles. If it bubbles you have a leak in the head gasket! When you pull the head and observe the gasket footprint the area that has leaked will be obvious. Performing this fix would probably require a 102 mechanic. A 101 mechanic like me would have a 50/50 chance of doing it right the first time in my opinion!
I don's see how I could look for bubbles in the radiator. The circulation is so great with the engine running that I wouldn't be able to see any bubbles. I guess that's because I took the t/stat out. I thought about the head gasket also, hoping that it wouldn't come to that. I'll look for the CO detector fluid and a radiator cap. Thanks for all your help. I only get to my tractor on the weekends so I won't be able to give you an update until Saturaday night or so...
TJ
TJ