Water Sludge - Grey Foam header Tank & Radiator

Found grey foam in my radiator when i removed the cap, further checking and the header tank was grey also,

Bike is a 6000 mile, Sept 08 (58) SDR...fully serviced every 12 months (just Done) no sign of any probs a month ago. Decided to do a proper clean and removed the panels and descovered the header tank had sludge settled in the bottom.

I have emptied the contents into my favorite receptical.......


and....


and...


The grey sludge has no body to it, it is best described as very fine grey powder.
The radiator and water pump housing has been removed and flushed and all is well, no oil in the water or water in the oil the only slightly interesting find is a hard deposit on the thermostat.



I have ordered a set of seals but as no sign oil in water or water in oil i am going to flush and reassemble, i will keep an eye on both header and rad for now.
A set of parts for the waterpump shaft / bearings and seals will be in a box on standby.

Only reason to post is just to inform and make people aware low milage well serviced is not exempt from minor hickups.

If i find any evidence of cause i will add to this post.

It may well be casting sand that has been on here a fair few times.

If it is, do as the link above suggests.

Obviously it's a bit hard to tell just from photos, but it looks like corrosion on the thermostat, which isn't right.

I noticed that your coolant doesn't look green enough to be the right dillution either, it should almost "glow".

The stats stainless steel, all shown was gently scraped off then the stat polished before re-fitting.
The fluid in the system was more concentrated but the header is as shown, i have never touched it only the dealer at service intervals.

How did u get the plug off the stat I've been trying to get mine off but it don't wanna move, looks like theres a slot to put a screw driver in and pull but the little fooker ain't moving

casting sand not properly cleaned... give the bike and engine a good flush out then top her back up and bleed on a steep angle.

lucky you caught it when you did.. could have worn out the water pump and most seals fairly quickly