Hi XT660Z owners

My first post, mostly been trawling. But now my trawling has produced no results.

Got a 2010 XT660Z with 16000km's a few months ago. Done about 7000km's on it and did a 350KM's offroad stint yesterday. Got home and started cleaning the bike for the next days use.

Found the coolant bottle cap/plug pushed out, but luckely not lost and I can see that all the water was pushed out as as well. The water was a brownish colour. Can see hot coolant stains on the adjacent coolant pipe.

I refilled with Motul coolant and drove 75km's to the office this morning. I can see water was pushed out again. It was a cold morning and it is winter here (South Africa), so it cant be from over heating.

Checked the oil and it is clean as I changed it 2500km's ago. Bike is sitting on 22600km's. Symptoms suggest head gasket, but not through to an oil channel, just a coolant channel. I am hoping that is not the case, perhaps an air lock or somehting.

Anyone experienced this...

Dean

Firstly - to XT660.com Dean.

Sorry to hear about your woes. Doesn't sound good?

However, looking on the bright side, cylinder head gasket failures are rare on the XT engine, in fact I don't think I've ever heard of one? One (cheap) thing to check is the radiator cap. There have been a few cases of dodgy ones in the past. Try a new one.

If the rad cap isn't holding pressure the coolant will boil at a much lower temperature than it should do in a pressurised system. Also if the cap isn't sealing properly the coolant system will be permanently venting to the expansion tank.

The brownish colour of the coolant is a worry as it would suggest to me that someone in the past has possibly added Rad Weld, Stop Leak, or some other quick fix additive to solve a leak or previous cooling issue.

Drain and flush all the old coolant out and refill. Then ride it and see if it turns brown again. If it doesn't, then you'll know that it was an additive causing the brown staining.

I hope it turns out to be something simple...

__________________

Hi Pleiades

Thanks for the welcome.

Checked everything again before I left the office yesterday and there was enough water in the expansion tank. Started the bike and left it idling till the fan came on. No water pushed out and the fan ran fine.

Went home last night and gave some stick doing mostly 140 kph on the way home. Checked the water level when I arrived and all was well.

Drove to the office again this morning and all was well again.

So...all I can think off is the expansion tank's cap/plug must have vibrated loose and dumped most of the water when offroad. Some of the roads were badly corrugated so lots of vibes.

Next thing will be to flush the system (was on the list, just not so soon) and make sure there is fresh coolant in there. And keep an eye on that plug/cap of the expansion tank...

Cheers...

Dean

Welcome mate.

__________________
Click here to join the XT Supporter's scheme

Mods that I have done to my XTX's

My 04 XTX
Stage 1 & 2 DNA filters / Kev fuel mod / snorkel mod / Drilled air box mod / Engine breather mod / Fork Spacer mod / 15w fork oil /
[
My 07 XTX
Raptor 700 cylinder 102mm / Modified Crank Case to take a 105mm Raptor Cylinder / 11:1 102mm JE Raptor piston / Stage 1 Raptor Hot Cam / Ported head / Colder Spark Plug / +2mm Throttle body / DNA stage 1 & 2 filters / Modified Air Box / Snorkel removed / Worry Brothers stage 2 filter cover / 6mm & 8mm Bolts Replaced with Titanium Bolts / Recovered seat in Black / O2 Eliminator /

My 09 XTX
59HP at the rear wheel / Stage 2 Raptor Hot Cam / DNA stage 3 Air Box / Carbon Can Exhausts / Modified Exhaust Link Pipes / PCIII With Custom Fuel Map / Wideband Commander O2 Data logger / LCD100 Dyno Jet display & fuel adjuster / 2500 OHM HT lead instead of a 10K OHM XT lead / Extra Coolant Cooler / Protaper Fat Bars / Tail Tidy With LED Tail Light / OKE Protection Knobs / LED indicators / AIS blocked / Modified rear sprocket rubbers / Rear Foot Pegs removed / 09 ECU With 02 Sensor Changed To A 06 ECU / Complete wiring harnes Changed from 09 to 04 / Home made LED resistor flasher / Hole drilled in the fuel tank filler neck to allow quicker filling / Modified Bar End Weights / Progressive front fork springs, 15W fork oil, forks lowered 25mm, used XTR rear links lowering the rear 20mm, rear spring one click stiffer / Changed front & rear guards from blue to black / 47T rear sprocket / Speedo Healer V4.0 / Kev throttle cam mod / Throttle grip mod / The new 2010 O2 sensor mod is out, works a treat, The new 2012 O2 Controller is out, PM me for details

Now ride a 2018 MT09SP ABS + TCS

My KTM 990 SMR Mod book. http://www.ktmsmt.com/viewtopic.php?f=13&t=4946

So...I thought the coolant issue was resolved. Severly mistaken!!

Got home yesterday and found coolant stains all over the righthand side of the engine and some residue on my boot. Decided to drain the coolant and replace with clean water to see what happens.

Got the sidecover off and decided to take the expansion tank off. I tried blowing air through the overflow pipe on the top of the expansion bottle and nothing... not letting air through. Traced the pipe to the where it
disappeared between the frame and the Givi crash bar. Tried pulling...stuck. Got sniff in the nose and decided to undo the bottom bracket of the crash bar.

Now this is what gets me rather hot under the collar...overflow pipe squashed inbetween the frame and the lower bracket, effectively cutting off the overflow completely.

Now that is why when the radiator pushes warm water into the expansion tank, it has nowhere to go and pushes the main cap/plug out.

Bright side - head gasket is fine and how much will a replacement overflow pipe really set me back. Got the bike with the crash bars, so the previous owner was obviously oblivious. Wondering about why the bike was sold at 16000 km's then...

Anyway...all's well that ends well

Cheers,

Dean

Gotta love a cheap easy fix.

Sent from my MB526 using Tapatalk 2

Nice one.

__________________