3515ch thermostat

[denjen]

GM, hope everybody is doing well. I did do some searching around this; but thought I would throw it out here. I have ~75 hrs on the tractor and originally noticed the temp would go up to the 1st mark and drop to cold and would fluctuate a bit; but never getting up to 1st mark. I don't have a way to manually check the temp; but the engine was luke warm to the touch after running at higher rpms for ~1hr tilling.

The engine was so cool that you could take the radiator cap off, no steam or boiling over happened.

The dealer sent mechanic down and replaced the thermostat. At this point the temp was reading at the 1st mark or bit higher, since then appeared to hold it there while flail mowing. Last weekend hooked the tiller up and noticed it did the same thing dropping down to cold. I then hooked the mower back up to do some mowing and it was back up to around 1st mark and holding. I tried AC on/off with no difference.

One question I have for y'all is where is your normal temp running, I was wondering if it shouldn't be closer to the mid mark. I talked with the dealer and he is doing some researching and going to get back to me. I did see the posts about troubleshooting temp sensor; but have to wonder if that is it since the engine really doesn't to get that hot.

Thoughts are appreciated!

 

[ptsg]

Found an older picture of mine. This is where it stays once it's warmed up. Even under load, it won't go above that. It did went above once but I had the radiator full of chaff, which I cleaned right away.

Now, I do believe the dash is slightly different on the Cab version.

 

[LouNY]

Mine runs close to mid scale most of the time, under heavy load it will go a bit higher.

 

[ericm979]

Most cars these days don't have a real temp gauge. It's really a three state idiot light with a damper to make it move slow so it looks like a gauge. The middle "ok" stage will have the needle in the same position over a wide temp range, like 180-220 degrees F. I've verified this on a couple vehicles that I ran additional OBD2 gauges on. The real temp does vary in operation but since it does not go outside the "ok" stage the needle never moves once it's warmed up.

My 3725's gauge needle sits at that same place when it's warmed up, and never changes. I wonder if it's also a three stage idiot light. Too bad it doesn't support OBD2 so I can read the sensor directly.

 

[denjen]

Thank guys!

I was wondering about that, I wonder if it might be a lower temp thermostat that was put in. I need to get me a temperature gun to least get ball park numbers. Will keep y'all updated.

 

[Slowpoke Slim]

Mine runs about the same as ptsg's. Only time it ever went over mid range was mowing in hot weather with chaff in my radiator fins. Blew that out and continued mowing and the temp went back down to slightly below the mid line.

It does take it a while to warm up all the way in winter though, lol. But it does get there.

 

[denjen]

Ok, update, I flail mowed for ~1hr and you can see what the temp gauge looks like, also after mowing I held my hand on the radiator for about 20 seconds and was not tremendously hot. Dealer thought it might be temp sensor, I guess it could be but to me it still seems like a thermostat which his mechanic said he did replace. I wonder if they might have put a lower rated thermostat in. Dealer will get back to me. You can see how the gauge fluctuated.

 

[ptsg]

A lower temp thermostat would mean that the temp gauge would just sit slightly under the mid mark. It wouldn't cause the temp gauge to fluctuate like that. Once it gets to operating temp, it should just sit there.

I'm also wondering about the temp gauge sensor or wire acting up.

 

[LouNY]

Can you reach your upper radiator hose were it leaves the thermostat housing without getting tangled in the fan or belt.
If so see how hot it is there.
Also I see your tractor is a 3515CH does the CH stand for cab and heater?
If so check the temperature of the heater hose leaving the engine.
Or if you have an oil cooler/heater in the base of the oil filter you can check the temperature there also.

 

[K5lwq]

I would look closely at the sensor wires. I bad connection would create the symptoms you are seeing.

On mine, it has two sensors. One by the thermostat housing and one on the heater hose. They installed the heater hose on mine after hooking up the sensor so it is in a bind. I plan on fixing this when I do the 50 hr service. The wire should route over the hose not under. See picture.