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Discussion Starter #1
SO pretty much every season I have to buy an expansion tank. This last one lasted me three hundred miles....I mean really? I am starting to realize my Ducati is the most unreliable machine I own..and almost the most taken care of with the least amount of miles. Honestly losing faith considering there is no fix for these little things...only compromises. Seems the only real fix is to get a metal one..but that makes it near impossible to check the level without removing the tank. :kaioken: Anyone else have any insight?
 

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-.- old news.
Get an aluminum tank from motowheels.
And don't be too lazy about checking your fuel level by open the cap lol
 

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Coolant level

And from what I see, the tank needs to come off to do that.
I gotta remove the air intakes on my 848 to get access to the radiator when I had to refill as well.
One of the flaws about Ducati since their design is compact so they use every space they get.
There's a space small enough for me to look at the levels but I feel you.
It's PITA
 

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Your problem is most likely the blow-off system. The cap has a spring in it and that whole thing gets gummed up. You've gotta make sure its free-flowing, otherwise you'll blow up the expansion tank. I had only ONE expansion tank failure over three years and it was on a tank which was from the 90's, it was simply worn out. But on customers bikes, I see the problem all the time, I use to keep spare tanks in my garage just to deal with these issues.

Needless to say, you've gotta go through the whole system and insure its working. I bet there is a very small issue you haven't discovered yet. The new tanks are far less brittle and I've never seen one go bad.
 

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The pressure in the cooling system is controlled by the pressure relief valve in the coolant expansion tank cap. If pressure is excessive, the valve spring preload is overcome and the valve opens allowing coolant to flow into the auxiliary holding tank located between the cylinders. If the relief valve is defective or the flow path to the holding tank is blocked (check the hole in the cap's rubber washer) the pressure can exceed the design allowable.
That said, the problem with cracked coolant expansion tanks first started with the 916 and continues today. A leak develops at the tank's mold line (parallel to the fork tube) and appears to be caused by fatigue from thermal cycling and vibration.
The main reason that a Ducati superbike coolant tank cracks is that the tank expands as it get hot but there’s not enough clearance around it to allow free expansion in all directions. In particular, there is a rubber grommet that holds the tank in place and presses it tightly against the frame. Because the grommet is somewhat oversized, it causes the hot plastic tank to be compressed by the frame and receive vibration transmitted through the frame.

The solution to the problem is when you install the replacement tank, trim the rubber grommet to compensate for this design flaw.
 

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Discussion Starter #7
FYI we went through the cooling system the first time it happened. And yes, I also have already trimmed the rubber grommets. I will look at the cap. And a guy here in town goes through one every two years...but doesn't ride a often a I do
 

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..but that makes it near impossible to check the level without removing the tank. :kaioken: Anyone else have any insight?
I have a metal one on my bike.
I can tap the sides of the aluminum tank to tell where the fluid level is.

I've never had any problems with low coolant levels since I installed the aluminum tank.

-M
 
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