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Up Topic C1 Information / Repairs - Faults & Fixes / Thermometer warning light...but not normal problems
- - By Filbert Date 22.10.18 15:50
Hi all,

I am having an issue that I haven't encountered before - I wonder if any of you have, and can maybe shed some light on it.

My temperature warning light went on a few weeks ago - and I did the usual checks regarding coolant and looking for leaks, etc. Took it into the garage who replaced the sensor. This didn't fix the problem, so they looked at the head gasket, thermostat and the pump..all seemed to be ok.

They have just phoned to say that there was a leak from a long pipe, that was spraying out hot mist under pressure and that seems to be the issue (?). They tried a fix that didn't work so have ordered a replacement part from BMW. One of the mechanics at the garage is ex-BMW and is very experienced with C1's, so I am happy that the problem is what they say it is.

But I've not come across this issue previously and I'm not entirely sure which bit of the bike he's talking about - any ideas??!

Oh, and front forks are knackered - I've posted on the classifieds, but if anyone has any knocking around...!!!
Parent - - By aware Date 22.10.18 16:04
Can happen that a hose gets punctured but you would experience coolant loss. Just besides the headlight there is the radiator cap and there you should have really much coolant to fill in such a case. Did you ever check there?
Parent - By Filbert Date 22.10.18 16:23
Yes, I did, thanks.

As with all of the issues that inevitably happen with the bike, I looked on here first to utilise the experience of others (who are all much more mechanically minded than me!). 

There was coolant loss from the expansion tank, but couldn't find a leak in the usual places - which is why I took it in to the garage
Parent - - By jeb Date 22.10.18 16:23
the pipes that run from the radiator down to the engine are  metal not rubber.     they can corrode and cause these symptoms.    I had this happen to one of my C1s
Parent - By Filbert Date 22.10.18 16:26
I think this is what might have happened.

Not something I've encountered before, tbh
Parent - - By alunt Date 22.10.18 16:23
I once found one of the alloy (?) pipes with a tiny pin hole in it, invisible to the naked eye, but just kept producing a drop of water every few seconds. It was under all the bodywork going between the engine compartment and the radiator. I wrapped self amalgamating tape round it and the repair has been perfect ever since.
Parent - By Filbert Date 22.10.18 16:27
This might be what happened - the garage tried a fix but decided to replace.
Parent - - By leonm Date 22.10.18 17:31
why do you say that the front forks are knackered?
Parent - - By Filbert Date 22.10.18 17:49
Mechanic said they were - I haven't been in to look yet
Parent - - By Filbert Date 06.11.18 19:46
An update - if it helps anyone...

The metal water pipe (hose?) that looks a bit like a chopper handlebar shape had a small crack in it that leaked when under pressure, but was ok when not.

This seemed to be causing the temp light to come on around when things heated up and the fan cut in.

Replacement was purchased pretty inexpensively, but it cost me rather a large amount in labour as it was a bit of a fecker to access and replace.

Parent - - By aware Date 06.11.18 20:02
Good that you finally sorted this out.
Parent - By Filbert Date 08.11.18 06:02
Nearly £300...
Parent - - By rockstedy Date 07.11.18 22:21 Edited 07.11.18 22:26
Replacing one of these alloy pipes won’t be easy. Have you locate exactly where crack is- it may be worth to try soldier it before replacing. Possibly using some self sealing plumber repair tape+metal clamp may work as well as epoxy pipe repair kit. Usually these pipes cause problems/leaks in scooters involved in accidents, proper drop.
Parent - - By Filbert Date 08.11.18 06:08
They tried a fix, but weren't very happy with it. I can carry out minimal repairs, so this was way out of my league.

The pipe has already been replaced at the garage - had to take a chunk of it it apart to access it, so it wasn't a particularly fun fix.

Mechanic said that he could see quite a bit of general wear and tear to things like the wiring loom, etc when he had the panels off.

I have a second bike that I have been keeping in case I need a donor bike. I might give the garage a rebuild project to see if they can make one decent machine out of two ageing ones... 
Parent - By rockstedy Date 09.11.18 22:43
There is some areas where wires/pipes are more likely to wear ( moving parts under dash board and engine area). It may be worth to keep better bike and use worst as source of parts when good one breaks.
Parent - - By Nightman Date 21.11.18 23:21
This sounds suspiciously like the problem I had. Water temp light came on riding into town so I took it to be looked at (always act on warning lights). No leak, fault with engine or thermo could be found but coolant was found to be low with no obvious leak. Never had an issue with coolant before. Ever. The coolant was topped up which produced the desired effect of no warning light even when riding for a while. The thing is, where did my coolant go? Was told to keep an eye on things and bring it back if (and probably when) the light comes on. This whole 'fine leak' pipe issue sounds like it could be the culprit to the water loss. Will keep you posted on any developments...
Parent - By alunt Date 22.11.18 16:50
Check for drips after riding it on a dry day, when it’s up to temperature, they could come from anywhere between the engine and the radiator.

If you don’t see any drips, take the dipstick out and look at the oil on it. If it’s cloudy or light coloured it could mean that coolant is leaking past the body of the water pump. This is different from the usual water pump leak which drips out of the reveal hole. If in doubt, shine a torch through the dipstick hole and look at the colour of the oil. I had this problem and found that the outside of the water pump was corroded. It explained the mysterious loss of coolant without any sign of drips.
Parent - - By leonm Date 22.11.18 16:59
where did the coolant go: the bottle behind the seat squab should be up to full mark indicating proper operation. slow loss over time is normal. what happens is that a topped up radiator will expell a small amount of water via the radiator cap as the engine heats up along  a rubber tube to the expansion bottle.  when the engine cools down, the cooling system draws a vacuum and "pulls" the expelled water from the bottle back into the system. check your coolant level once a week and top up, either at the rad. cap (more convenient) or at the bottle (better  indicator)
i would guess that  a cup of coolant loss per 500mi  is acceptable.
Parent - By Nightman Date 26.11.18 16:22
Love you guys. The pool of knowledge is just great. I've been keeping an eye on things with nothing to report as of yet. So fingers crossed we haven't got any major issues here. I did think of the oil/water check as I had this problem with an old car of mine (the gasket was shot). As for a dry day to check for any drips? Oh you guys crack me up! Chance would be a fine thing. Seems to have been wet every day for as long as I can remember, with it looking like staying that way for a while yet. :)
Up Topic C1 Information / Repairs - Faults & Fixes / Thermometer warning light...but not normal problems

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