Coolant spilling out of Resevoir

Scoofy · Post by **Scoofy** » 25 Apr 2009 10:05

When ridden harder than I normally ride (eg reving up to say 8000rpm) my Corsaro starts pissing coolant out of the resevoir, and I really mean pissing out. It goes all over the tank, engine and me.

Does anyone have any thoughts why this is occurring. The resevoir is definitely not overfilled. I know this from the amount of coolant that has been lost as well as the amount I have removed. Is the engine overheating? If so, what would cause that to happen? Could the thermostat be faulty? Could there be an air pocket in the flow of the coolant?

Any thoughts greatly appreciated.

Note that I am taking the bike into the shop next week for investigation and hopefully resolution, but it does not sound like they have any experience of a bike doing this.

Cheers
Darren

twisty · Post by **twisty** » 25 Apr 2009 18:23

normally when coolant boils over the header tank it's indicative of a blown head gasket or water not circulating properly, but for your sake i hope i'm wrong.
A blocked thermostat will stop the water circulating but is probably the easiest to check.

Peter V · Post by **Peter V** » 25 Apr 2009 19:55

twisty wrote:normally when coolant boils over the header tank it's indicative of a blown head gasket or water not circulating properly, but for your sake i hope i'm wrong.
A blocked thermostat will stop the water circulating but is probably the easiest to check.

There where several owners in the Netherlands who had that problem, there where some updates for it under warranty, beeing a different reservoir and a modification or replacement of your cilinderhead(s). Cant remember exactly

MMC 1200 2006

Scoofy · Post by **Scoofy** » 21 May 2009 09:56

Update:

Bike has been at the dealer and they have done the following:
- replaced all clamps on all coolant hoses (appears the standard factory hoses aren't too reliable) as the system was just not holding pressure
- checked water pump to ensure the impellor was not loose on the shaft
- done a test on the coolant for carbon monoxide, this came back fine
- pressure tested the system and this is also now fine

Problem - bike is still blowing coolant out the reservoir.

Dealer has now decided that its time to take the head off and take a look. Just have to wait and see what they find.

Post by **morini_tom** » 21 May 2009 12:44

Weren't there problems with the radiator cap on some early corsaros? If you have a faulty cap which isn't allowing the system to pressurise you could get the described water feature. And this probably wouldn't show up if your dealer pressure tested by screwing his kit onto the radiator in place of the cap. I'd be looking to try a different cap before I had a head off, particularly if the coolant looks and was tested to be uncontaminated...

Scoofy · Post by **Scoofy** » 22 May 2009 10:48

Thanks Tom.

I should have mentioned that the radiator cap had already been replaced as the very first attempt to see if that was the root cause of the spilling coolant.

Spoke to the Dealer today, and they have removed the head of the rear cycliner and found nothing. However, when the removed the head of the front cycliner they have found that the gasket was leaking. Based on when the coolant was overflowing (ie only after being riden harder than usual, eg around 7,000 rpm), my guess is that the leak was relatively minor and with gases only finding their way into the coolant at the higher pressure and temperature. I am also guessing that when the did the carbon monoxide test on the coolant, they weren't reving the engine as hard, and hence no gases were escaping into the coolant to cause the test to show positive.

Either way, I am glad that the root cause has now been identified and is being fixed. On the other hand, I am really disappointed to have this problem occur on my 2008 Corsaro that had only done around 3,000km when this problem first started to appear.

Thanks to those who provided reponses with their opinions around the probable cause.