My new Jinma

[3RRL]

Thanks for the replies, but I have a hunch the wiring is correct.
I'm wondering why the gauge started working after I re-assembled the thermostat housing? Then it quit working again?

 

[greg_g]

I'm wondering why the gauge started working after I re-assembled the thermostat housing? Then it quit working again?

"Sending unit" is actually a misnomer, it doesn't really send anything. One of those two sensors provides electrical ground for the temperature gauge. When the thermostat housing is separated from the block, you interrupt the path to ground (another argument against the use of teflon tape).

I know you don't want to hear this. But it still could be a wiring problem on the supply side. Alternatively, it could be a defective gauge - intermittent supply to the gauge - or an internal short in the sending unit.

As to how they work, they're essentially thermistors. Internal resistance (to ground) is influenced by the temperature of the coolant flowing over the brass tip. Externally, one side of the temperature gauge is fed a nominal 12 volts. The other side of the gauge is connected to this thermistor. The amount of internal resistance of the sensor determines the amount of the 12v supply that's permitted to pass through the gauge - to ground. That difference is reflected as needle movement.

//greg//

 

[Diamondpilot]

I was thinking the same thing as Greg. I had to replace my T-stat housing due to a crack. It was aluminum. I would try a test jumper from the sending unit to a better ground. With the housing being aluminum and there being a gasket and such it may not be getting a proper ground.

I am away from my tractor but if I remember correctly my sending unit is where your lower one is, not in the T-stat housing like you upper one.


Check the grounds and try a jumper from the sending unit to a better ground. It will be a quick easy check.

Chris

 

[Diamondpilot]

After re-reading all the post on this I would replace the T-stat no matter what. It will fail. I am away from my tractor like I said but I can get the part number for you on Friday. You can also take the T-stat to the parts store and match it up, thats what I did. I know the one I put in was a Stant Brand and 80C or there abouts. Prior to changing mine my tractor would never heat up, just stayed around 40C even if worked hard for 2-3 hours. That may be all your problem is. Just a bad T-stat and its not getting warm so there is nothing for the gauge to read.

Chris

 

[billbill1]

Rob, I bought an American temp gauge because I wanted it to read F instead of C. Mine has always ran right at 80 degrees C but I'm not smart enough to know what that means. The gauge I bought didn't come with metric fittings so I never installed it. Mine has the individual gauge instead of the cluster setup. The amp gauge quit after about a year and I replaced it with no problem. I think you could ohm your sending unit cold and see if you get a different reading as it warms up, It should change but I couldn't tell you how much. No change and I would guess that the sending unit isn't working but that would be pretty unlikely. Either not grounded or the gauge would be my guess.

 

[Diamondpilot]

Quick easy way to convert Celsius to Fahrenheit is to double the number and add 25. Example is 80C is 80x2=160+25=185F. This will get you in the ball park. It may be off 10 deg or so but all that really matters is keep the gauge out of the red.

Chris

 

[greg_g]

Quick easy way to convert Celsius to Fahrenheit is to double the number and add 25.

No Chris, that's a quick and easy way to get in trouble buying the wrong heat range. 80C is 176F.

F=(Cx1.8)+32

//greg//

 

[Diamondpilot]

I clearly stated it was meant to only get you in the ball park and could be off by as much as 10 deg. The guy mentioned he did not know how to read his Celsius gauge. My way will give him a quick idea as he is tractoring along without a bunch of complicated math or a calculator.

Chris

 

[greg_g]

I clearly stated it was meant to only get you in the ball park and could be off by as much as 10 deg.

My point exactly. The gentleman said he didn't know what 80C meant, and you basically told him it was 185 degrees. Sorry to step on your toes here, but that's just wrong. 80C is 176F. A 9 degree error like that could precipitate unnecessary troubleshooting as well as sending somebody off to the parts store for the wrong thermostat.

Besides that, now you've got us staying off topic from Rob's issue with two temperature sensors.

//greg//

 

[3RRL]

Well, I have learned a lot from your replies and I appreciate them all.
At least I'll know how to check it now. I'm thinking the sending unit for the temperature gauge is the one mounted below. Hope I'm right about that. I'm not sure about the one that is mounted on the radiator hose connection ... it might have something to do with EGR like Greg says? After testing it, I'll remove it and take off that Teflon tape to see if that makes a difference first...to see if it wasn't grounded properly.

Chris, I will be at my property this weekend, but would sure appreciate if you could get that cross reference for the T stat. For me to take it out and drive to the nearest Napa will be a half day trip, at least. That will be the next move, to replace it if I'm still not getting a good reading on the gauge.

Oh, for conversions, I use this Josh Madison free download.
It is fast and easy ... it's free too.
Josh Madison Converter

 

[bluechip]

Rob, you can disconnect one or the other and see which affects the gage reading.... I have not seen the 2 sending unit setup, but have not bought any Yangdong engines in a couple years.... OH and is it Yangdong or Laidong that you have?

 

[Diamondpilot]

Chris, I will be at my property this weekend, but would sure appreciate if you could get that cross reference for the T stat. For me to take it out and drive to the nearest Napa will be a half day trip, at least. That will be the next move, to replace it if I'm still not getting a good reading on the gauge.


Josh Madison Converter

Rob I will look it up and post it as soon as I get home. I know I tore the top off the box and stapled it to the operators manual so it will be a quick look up.

Chris

 

[3RRL]

Chris, thanks ... much apreciated.

Chip, I will have to ask Loretta what motor it is.

 

[studor]

I think the tsat xref when I looked it up is a Gates 33508 for 180 degrees and a 33509 for 195 degrees. Worth a double check though cause I have not put mine in yet.

 

[Diamondpilot]

Rob, got home and looked it up right away. The one I used on my 2003 254/284 is a Stant 45358. It says its a 180 deg F/82 deg C T-stat. Hope this helps. By the way I have the Yangdong Model Y385 Engine.

Chris

 

[Mrs3RRL]

is it Yangdong or Laidong that you have?

Hi Chip - it says it's made by AnHui QuanChai Engine Co., Ltd. And the plate says it's a YT-QC385T-1-A-Y (but the book just says QC385T).

 

[EddieWalker]

Hi Loretta !!!!!!!

Somehow I missed this thread until just now. So even though I've seen your tractor in person, and can attest to how nice it is, Congratulations on your new tractor!!!! From what I was able to see on it, you have a very nice tractor that's going to be a wonderful workhorse for you.

Has Rob been able to get any more done on your grapple? I'm looking forward to reading the posts on it and seeing the improvements he makes in the disign over the one on his tractor.

Eddie

 

[bluechip]

Ah, Quanchai, that explains why it looks somewhat different to what I have seen in the past. So now Jinma is building 200 series tractors with at least 3 different engine manufacturers... that will keep the parts guys hopping. According to the EPA site, this engine is certified, like Yangdong, without any "emissions system" so that leaves the extra temp sensor a bit of a mystery.

 

[3RRL]

With all the help I got here, I was able to get the temp gauge to consistently read.
Here is a picture of it reading about 75C with the motor running at the max rpm. BTW, the motor runs great!



What I did...
First, you saw that I had taken the T stat out before and replaced it, noting that the gauge read the temperature for a brief moment. So I figured the gauge was OK and so was the T stat. That's not to say I won't change it out later though. Anyway, I removed both sensors and touched each to ground and determined that the one on top was the one sending to the temp gauge. The other sensor did nothing I could determine?

The other interesting thing was when I grounded the top sensor to it's port in the radiator hose mount... even after removing the Teflon tape ... it did not send any signal to the temp gauge. However, when I touched it to ground on the water pump side, the temp gauge flickered. So the radiator hose mount is sort of insulated via the gasket I guess. In any case, it did not provide a proper ground.

Next, I saw that all (most) of the sensors were installed in the lower port, not in the bolt on part that connects to the radiator hose. That's why I ground the sensor to that port in the first place. I ended up switching the sensors. I put the one that did nothing into the top port, and the the one that's connected to the temp gauge into the bottom port. The threads were clean and I used a small amount of thread sealant. Then fired up the Jinma.

After a few minutes, the temperature started to rise on the gauge. After warming up we let her run at high rpm and she heated up to about 75C or so, as you can see in the photo above. That T stat in there is a 78C one so I thought it was close enough. Then we shut it down a couple time to see it the gauge continued to work and it did. So I think that's the end of the temp gauge problem.
Thanks for all your help.

 

[3RRL]

I have another question about this engine.
What is this sensor for and what does it do? Is it the EGR or something?