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Radiator pressure cap-`1965 Veloce Spider

2K views 16 replies 8 participants last post by  AlfistiSA 
#1 ·
I cannot find the pressure rating for my radiator cap in the literature I have. Can anyone point me in the right direction or tell me the pressure rating?
 
#4 · (Edited)
Thanks gents-7 PSI it is. My radiator cap is not marked with the pressure rating. I have a Stant radiator testing kit and I tested my radiator starting at 8 PSI and found the pressure drops to 6 PSI after about 40 seconds. This occurs in the following: all plugs in, all plugs out, then sequentially removing one plug at a time. Same results in all cases; perhaps I have not gotten a good seal between the testor and the neck of the filler cap.

I am still searching for an answer (or answers) to why I note traces of oil on a paper towel inserted into the coolant via the filler neck. In answer to divons question, my best guess as to the amount of oil I recover each time is 2 or 3 drops. I rebuilt the engine about 500 miles ago; could this be some residual oil that got into the cooling system?

All thoughts most welcome.

Ciao.
 
#5 ·
#9 ·
Agreed on Evans does not sell water! Mixed reviews on whether or not it works to keep pressure lower in a radiator, thereby extending a radiator's life. I went through plastic BMW radiators about every 80K miles, but the Alfa has a REAL radiator.

I think I will drain the coolant, flush and refill to see if the problem was residual oil in the cooling system after the engine rebuild. Easiest of the possible remedies, and I am getting old and tired.

Ciao
 
#16 ·
Nope, you're right 330, it was sodium bicarbonate in the manual, not carbonate: I misremembered. Won't do much for oil, though.

A bit of Dawn in water works fine as a flush: do a search on the BB. It's gentle and will remove oil residue. Won't foam up significantly if you fill the cooling system completely...if there's no air there's no way to form bubbles.

Regardless, you don't drive it like that: you just run it for a bit to flush out the oil, and then flush it a few times to get all the soap out.
 
#17 ·
Depends who built the motor, old school said to oil the head gasket well to allow it to 'slip' or 'settle' into position when being squeezed under torque conditions. Not necessarily for Alfa, I remember watching many side valve vintage engines as well as an MGB engines being rebuilt like this.

Might account for traces of oil in the coolant ?? If so then flushing with Dawn will remove it - if the oil reoccurs then you know the problem is deeper seated...

Aye
Greig
 
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