Boxer owners ?

I found that I lost coolant with .9 Bar. However, the expansion tank "balloons" when using the 1.1 Bar. I have had two expansion tanks balloon with 1.1 Bar, and numerous other owners have commented on it. Seems to be a design flaw.

Jim S.

 

1.1 bar is what my cap reads.

Drew

 

One would think, wouldn't they. However, the internal surface area of the header tank, and its large flat surface (relative to the cylindrical shape of a hose) lends itself to "expansion." I have seen these tanks expand on several Boxers, not to speak of two of my own. I replaced my tank with a brand new one (as it was leaking), and within a few miles of initial use the new tank had expanded. Take a close look at yours to see if it is distorted.

Jim S.

 

I would think the lower the pressure the better it would be on all your hoses and expansion tank. I don't believe adding pressure increases anything but the boiling point which can give you a safety margin if you are running straight water with no anti freeze and are close to 212 degrees.

 

I have a 308QV and just ordered a new radiator cap from Algar. My old cap was rated at 0.9 bar, and the new one was rated at 1.1 bar. I called Algar and they told me that the .9 bar cap had been replaced and "updated" with the 1.1 bar cap by Ferrari. So as of today, the 1.1 bar cap is the OEM cap for the cars.

Ken

 

Frank,

My cap is stamped 1.1 and I haven't had any cooling problems at all.

 

Walt - while the coolant at the transducer may not be at 212 degrees, the water flowing past the combustion-area may be at a higher temperature. The system is closed, thus the pressure is uniform throughout. As mentioned, this raises the boiling temperature (pressure being an independent variable, along with molar concentration of antifreeze as an independent variable). Thus, the greater the system pressure, the less likely is local boiling. The downside to much greater pressure is hose integrity, propensity for leaking, and water pump efficiency.

I have heard that the factory had called for 1.1 Bar caps to replace the .9 Bar caps. My experience of venting at normal operating temperature supports this recommendation. The only downside has been the ballooning of the expansion tank.

Jim S.

 

I agree with what you are saying. That is why I said the lower presure the better IMO. This would possibly make it necessary to keep the anti freeze up a bit. When I was a kid and my Firebird had a radiator leak I would run without a cap at all to keep from pushing the water/anti freeze mix out and never once overheated. I did have to add water to make up for evaporation.
Walt

 

The difference between 1.1 bar and .9 is almost 2 psi and when you figure the surface area of the expansion tank that is quite an increase. The boiling boint of water only (no antifreeze) goes up from about 245 degrees at .9 Bar to about 251 degrees at 1.1
I don't see the advantage of increasing the pressure but I'm sure Ferrari has a good reason.