2010 TXC 250 overheating. Suggested diagnostic step appreciated

My 2010 TXC 250 has started running hot over the past 4 or 5 rides. I have trailtech computer with coolant temp sensor and the coolant temp was running between 180F in the open roads to 220F ish when riding tighter slower areas, with the fan cycling when needed.

Now it runs between 225F in the open roads and 240 in the tight stuff. Obviously running at those temps, the fan is always on. I don't suspect the temp sensor because the fan doesn't actually come on until the coolant hits 200F, the problem is, once it goes above 200, it stays there.

I boiled it over on a hill climb the other day, and again riding some single track yesterday. I let the bike cool down to about 185F and intentionally stayed on the fireroads riding mid to low RPM at high speed to keep air flowing across the fins, and sure enough, within a couple of minutes it was up over 200F again stabilizing around 221F.

I should also mention that it isn't extremely warm yet, so the ambient temp shouldn't be a factor.

Here are some specifics:

1. Running Engine Ice (always have, even when the bike was operating at normal temperatures.
2. DRC Silicone Hoses
3. FMF 4.1 with Powerbomb (new this season without adjusting ECU Map. Race ECU installed. Possibly running lean?)
4. recently changed from using 10w-50 castrol to 0w-40 mobil 1 oil.
5. Bike is running great. Idle's better than ever, starts instanlty on starter, hot or cold. Always starts 1st or second kick on kicker.
6. Oil not milky on change
7. seems to be losing a very small amount of coolant each ride, but no sign of leak.
8. Had a crash a few weeks ago that slightly crushed some of the bottom inner most fins on the Right rad. but rads look good overall ( I will try to post a picture when I get home.)

I've been reading through posts all day, and have seen a few possibilities. I've got a new rad cap and some XF coolant on the way. I've also read some examples of leaking head gaskets, but who knows.

At this point, I'm just looking for some diagnostic tips to make sure I eliminate the simple things before jumping to worst case scenario.

Thanks in advance to anyone who chimes in.

Check to make sure the waterpump impeller is tight.

Fingers crossed it's that simple. I'll find out tomorrow.

The cap seems ok- 'cause at those temps you should burp some coolant.

Do the '10 TXCs have a thermostat? I ask because it sounds look you don't have full flow of the coolant (or maybe even convection only? bad impeller?) and a bad thermostat that only opens partially would be a suspect too.

Pop the cap off (bike not hot yet) and run the engine so you can watch the coolant flow by.

good luck.

Well, problem is officially diagnosed. Not only was the nut on the impellor loose, it wasnt there at all. I found it lodged in the thermostat!

The coolant is dark, cloudy, and has a lot of aluminum particles in it. Judging by all the scouring on the pump housing and impellor, it's shed quite a bit of material. I'm going to replace the entire pump mechanism to be safe.

Here's some pics of the result of the nut coming off.

Would anyone have a picture of what the inner mounting surface of the impellor should look like? as it is now, it doesn't sit on the shaft at all. Either there's something missing, or it's been bored out by the shaft.

Ouch! The next time I have that cover off I'll loctite the nut in place.

Cavery- congratulations.

BTW, seems like there is an upgraded or high-flow impeller available (maybe by one of the site sponsors even: ZTR? 7602?) that you might consider. And it probably goes without saying , but I can't help it... change the seal also.

I would also take the radiators off and give 'em a good flushing. Just in case there are some nooks & crannies where aluminum can hide, out of the main water flow. OTOH, it's probably not a huge deal- not much the aluminum dust can hurt.

Toss the thermostat maybe?

Run with tap water for the first hour to help detect any oil leaks. You may have "stuff" in your cooling system so don't panic if you see something floating by. Flush & fill with tap water until you can ride for 15+ mins without seeing residue. A drop of laundry detergent (a drop, not a squirt) will help emulsify any oil already in your system, but it will make it harder to see if new oil from the engine is entering the cooling system.

...and then flush & add your coolant- you're probably never going to have any cooling problems again.

Thanks for the tip Shovelhead, I appreciate the advice. I know there was a Husky hi flow impeller kit, but it was only for the pre X-lite engines. I haven't found an aftermarket one, but I'll look again just in case. I have already sourced a set of silicone TC250 hoses to delete the thermostat.

Everything here up north is closed for Canada day, so I'll be calling the local husky shops tomorrow to see if I can get the parts I need locally. If not, I'll be calling Hall's.

Oh- ...Canada. <grin- happy Canada Day>

I just got back from "downtown" (pop. 2500) and they're already setting up booths etc for July 4th. I'm saying this because if you don't get everything done by Thursday, it might be a while- at least here in the States.

Silicone hoses- I've been thinking about this myself. OTOH, in one of the big box stores (Home Depot, Lowes, maybe Canadian Tire) someone found a nice copper/bronze "Y" or "T" that worked very well as a direct replacement for the thermostat.

[weird: I was looking at the Wikipedia pg for CT... about 1/2 down is a pic of copper Tees]

good luck.

Anyone know if the impeller from a 2012+ redhead 250 will fit on a 2010? I know the pump itself is redesigned, but the impellor shaft has the same part number. I figure if the shaft is the same, it may work? It looks like the 2012+ impellor has the nut attached to it. Either that or they come as a kit.

Here's a picture of my Engine Ice coolant. All of the grey is aluminum particles.

All of the parts are ordered. Everything was in stock at the supplier, so I should have it all mid next week. I'm out of commission for this weekend though. Give me a chance to do some other maintenance I've been putting off. Time to service/change the Steering, linkage, & wheel bearings.

^I don't know if you're dealing with Rob Lang for your Husky stuff, but if not, keep him in mind. He keeps a good supply of Husky parts in stock.

Very knowledgeable and a very nice guy.

http://langsoffroad.com/

Thanks Andrew,

I do usually deal with Lang's, and you are correct, Rob is a great guy and definitely knows his Huskies. Has been a great source on info since I bought the bike. Unfortunately, he shut down for the rest of the week for the Canada day holiday, and he's not back until next week, so I ordered the parts from Mark at Quad Expert http://www.quadexpert.com/ near Ottawa. Also a good knowledgeable Husky operation that still supports the Italian bikes.

Unfortunately here in Toronto, both of the best dealers are hours away, doesn't matter if I go east or west . The only localish dealer is current KTM Husky only.

No problem. Just wanted to make sure you were aware of him.

And, yeah, I'm in the same Husky void as you. About 1hr 40 min to Rob's shop.

I mentioned that he should relocate to Niagara, but he didn't seem interested.