Testarossa radiator cap, 0.9 or 1.1 bar?

I'm still using the stock 0.9 bar cap (101499) on my TR without issue. My guess would be that F went to the 1.1 bar cap (137644) on 308QV as a way to address customer complaints about excessive overflow discharge (when the real problem was the 308QV cooling system just being somewhat marginal). Interestingly, the 328 original design documents still call for the 0.9 bar cap. If someone's got a copy of that Service Bulletin for updating the 308QV cap to 1.1 bar, please post -- would like to see their state "reason" and which models it applies to.

 

Probably not, but I have no information. I noticed on the RA website that the 1.1 cap is substituted for the 0.9 cap, and the same on the eurosparesUK website (137644 replaces 101499), but they offer a 101499/C at 0.9 bar that looks like the stock 0.9 cap. Are you having a specific problem?

 

For what it's worth, I replaced my original 0.9 with a 1.1 cap several years ago and haven't had any problems. I do take my TR up to redline from time to time. I found, as Steve noted, the replacement parts on the "big" Ferrari parts sites all list the current replacement part as the 1.1 cap.

 

Less than 3psi difference should not damage anything. If it leaks with an extra 3psi, the seal is already a problem.

How hot does your car run?

Based on water:
1.9 bar boils at 245deg F
2.1 bar boils at 251deg F

Likely either cap would work fine for preventing boil over or more importantly, hot spot cavitation/steam pockets.

Just an opinion.... I’d stay with the 0.9bar cap unless running in hot ‘iffy’ conditions, or if availability is problematic. No biggie either way.

 

No problems with using 1.1 on mine for years. FWIW

Jeff Pintler
89 348tb, 86TR, 99 360 3-pedal