Perkins 4-108 info?

[BruceS]

I've very recently come into ownership of the Perkins 4-108 engine that has the oil/water heat exchanger in front of the motor.
I've also got the full manual in paper format.
There is no mention of what is the correct 'radiator' cap, the relief pressure of it or whether it is a recovery cap or not. (Overflow surge bottle etc)
Would anyone be able to advise?
I've also found the block drain tap (coolant) is leaking and despite attempts, it still weeps.
Would anyone know what thread & size it may be so I can get one before I remove it?

[Dynamo1181]

7#s on the cap.
A

[BruceS]

Thankyou.
Does yours have a recovery bottle or just an 'overflow'?

[Dynamo1181]

The 7# cap is standard. I added my own recovery bottle, so that I seldom remove the cap except to flush the system. When I added the bottle, I kept the original cap in place. Works fine.
A

[CSY Man]

buy the caps at NAPA for $8 or from Perkins at 3 times the price. Around 7 pounds of pressure.
I also added my own bottle to recycle the fluid that sometimes are being spit out.

[BruceS]

Yes mine has a fairly new cap on it & it is a 7lb one.
Usually a recovery cap has a rubber seal down in the bottom of the neck as well as on the very top. The one I have has the seal down but not on top. Just a brass to metal seal. As my recovery bottle is well down in the bilge I suspect it's sucking air long before it recovers coolant. I'll try raising the overflow bottle & if that doesn't work I'll look for a proper recovery cap.
The 'official' 4-108 manual specifies the coolant level to be 1" below the neck so keeping the header tank full doesn't appear to be essential.
No one game to comment on the thread size & pitch for the engine drain tap on the side of the block under the exhaust manifold??