Expansion tank cap Euro 85 GTBQV

Michael DB · Sep 9, 2024

I noticed a dribble under the overflow pipe from the expansion tank. To me that is usually overfilled, but it took about 1 pint to get it to 60mm from surface to the top of the neck.

The cap is rated at 0.7, whereas the OM shows it should be 0.9. In addition the cap has a rubber seal directly under the cap. This seems common but surely negates the purpose of it. The seal needs to be at the bottom of the neck where the spring loaded part of the cap pushes against it. It also makes putting the cap on/off needlessly difficult.

Simple answer is a new cap but it's done 3k miles in 6 months to get like that.....

Comments welcome!

Freddie328 · Sep 9, 2024

I think the purpose of the rubber seal directly under the cap is to prevent fluid spurting out through the underside of the cap, rather than going down the overflow pipe in the event of the spring lifting.
I'm using a 0.9 bar cap, I believe this was later uprated to 1.1 bar in accordance with recommendations from Ferrari. O.7 bar sounds very light, but your car is slightly different to mine.
Wit the 0.9 bar cap, tank level 60mm from base of tank cap neck, I get an occasional dribble when the car runs in prolonged traffic, when its hot. Not enough to need topping up between fluid change.

Michael DB · Sep 9, 2024

Thanks. Think I’ll get a 0.9 cap!

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Expansion tank cap Euro 85 GTBQV

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