2013 TE310R cooling/coolant issue

I haven't had any issues with my 2013 TE310R re cooling, even in the hot summer weather. I was riding on Saturday, doing lots of slow, technical trails (what I always ride, so no different), and I started smelling coolant (riders behind me said they were smelling coolant as well), and saw some steam coming from the left side of the bike. Luckily, the trail ended at a gravel road with an easy out to the road and a short ride home. I found a very small hole in the short coolant hose that goes from the water pump to the thermostat. I wouldn't leak until the bike was hot.

I don't think I heard the fan on, going up this last trail - it's typical that the fan may come on riding these trails. I looked back at my GoPro footage from a bit earlier in the day and pretty sure I can hear the fan running when I stopped at some other locations, but when I stopped this last time, and saw the steam, smelled the coolant, the fan was NOT running.

I ran power directly to the fan and it runs. So, I'm thinking the thermoswitch (fan switch - inline in the coolant hose on the right radiator). I'd read somewhere on CH that if you disconnect the thermoswitch that should turn the fan on. My fan doesn't come on, engine running, with the thermoswitch wire unplugged. Fuses are good (pretty sure the fan fuse is on (at least) the headlight circuit and the light is working, plus the 3 fuses all look good.

After putting a replacement hose (automotive hose for now, will order the correct hose) on, I ran the bike (10-15 mins) to get it nice and warm, to test the hose, and the fan. I have an IR temp gun and I'm seeing about 200F on the coolant hose going to the top of the left radiator, but only about 170 on the right side hose that goes to the top of the right rad. The coolant temp switch itself, seemed to be about 195F. I let it idle a few minutes longer, then started seeing coolant coming out of the overflow hose. Fan was still not running. So, I turned off the bike at that point.

First thing I'm thinking is to replace the thermoswitch. It seemed odd the temp difference between the right and left side, made me start wondering if the thermostat was working? It's relatively expensive, so I don't want to just start throwing parts at the problem.

Any thoughts?

I could just wire up a manual switch on the fan, but likely will forget to turn it on, and would rather fix the source of the problem.

You had a hole in a hose.... but you seem unduly concerned about the fan. I'm pretty sure you solved your problem (except for the cause of the hole)

You're right- on our bikes it's a thermoswitch. Pretty reliable. On earlier xlites, it's a sensor and the ECU turns on the fan.

I haven't had a working fan in 3 years and 6500 miles (out of 4 years and 8000 miles). I think you're fine.

Well, the coolant puking out of the overflow is to be expected if you just re-filled the radiator.

The fan on my 2010 TE-250 never came on. I just took it off.
The fan on my 2012 TXC 310 runs all the time in tight woods.
Go figure?

30 degree difference in the rad temps does not seem odd to me.

I once had a stiff branch knock the bottom hose off my radiator in the woods.
Thankfully my camelback was full and I could top off the rad.

I had to replace the thermo switch on my 2013 TXC310 as the fan stopped working. One rad warmer than the other is fairly normal as it flows across having been cooled some in the first.

I'll have to look up the wiring in the service manual. I'm curious if the fan is run off a relay - maybe the relay is bad. I think of the fan because I look back at my videos from the day and can hear the fan running on another trail, then have the steam and coolant leaking out and no fan running on this last trail. Plus, I assumed that the fan would kick on before it started to boil over - it was topped up right to the top, but I thought that pressure was what caused coolant to come out of the overflow, not volume of coolant? (although more coolant leaves less room for expansion, and I guess therefore more quickly gets to the rad cap allowing some coolant to exit the overflow tube.

This has me thinking as well - that hose is right below the bottom of the gas tank and has a 'mesh' protective hose over it. The hole was just a pinhole, but about where the end of the metal tube from the water pump would end, so maybe a bit of lateral pressure on the hose at that point eventually causing it to start to tear through. For now, I just put in a piece of automotive coolant hose that I had - it didn't quite have the same bend in it, but close enough that it's not pinching the hose. I will still order the Husky replacement hose and protective cover. I started thinking: if the fan (switch, relay) failed and allowed the coolant to get hotter than normal, that may have created more pressure and heat than that hose is normally exposed to, and a small potential defect might have turned into a hole.

I am still concerned about the fan, as I normally hear it come on at least a few times during a ride - lots of slower, technical riding, so not a lot of airflow through the radiators.

Next ride, I might just carry a small bottle of extra coolant with me, just in case - I know you can just put water in, but it's a good idea to flush and replace as soon as possible after putting regular water into the cooling system, putting premixed coolant in would save me that hassle.

Seems like this may be your issue for the hole. I posted this early '13 when noted it. http://www.cafehusky.com/threads/radiator-hose-a-tight-fit.31649/#post-293396

I also have a fan that exhibits the same issues and has since I changed to ZT Coolant V1 and silicone hoses.

Thinking of getting the silicone hoses. My hose was close to the bolt heads, but that wasn't where the hole was. I did add some rubber washers to the tank posts, but am thinking about adding a few more.

You can test the fan switch. It's a normally open switch. Hook a multimeter across it set for ohms it will be open circuit at room temp. Then heat it in a pan of water with the leads connected and it should close before the water boils. I was pretty sure mine was bad so I just heated it with a torch in the air and it never closed but that may damage a switch that's good if you heat it too much. They're not too expensive or hard to replace. you can also test the rest of the circuit by putting a jumper across the plug that goes on that sremp sensor and starting the bike. If the fan turns on everything else is good.

So, I jumpered the wires going to the fan thermoswitch and the fan comes on. So, I ordered a new fan thermoswitch - wasn't expensive, and not hard to replace, but at this point, still waiting for it to arrive. I did put a Tusk 2.0Bar rad cap (with built-in temp gauge) on - so I can monitor the temps easily. Haven't had a chance to test ride it. I'll probably ride it before replacing the fan switch, and watch the temps. Worst case, I have a spare fan switch, just in case. If I get bored, I can do the boiling water test and see if the switch is working or not. FSM says on at 97C (+/-3) and off at 92C (+/-3).