Question re engine oil and coolant

[Flyboy]

26 minutes ago, Tacet said:

Removing the big brass cap on the manifold can be tricky.  When I tried, with a 3/4" drive socket and some extra leverage, it got to the point where I thought there was a chance of tearing it out of the aluminium. So I gave it up.

 

It does seem to form a local high point that could trap air.  I considered drilling and tapping the cap to expel it - if not as a filling point.  But in the vent, it didn't cause any problems so either volume of trapped air was small or it was swept away when the water pump was running.

 

 

The Barrus manifold is cast iron and quite sturdy.  The brass plug has a parallel thread and has a fibre or copper washer.  If you don't fill the system from the manifold you will have big problems getting the air out.

[DannyC]

Just had a look at the brass plug. What kind of tool do I need to get it off?

 

Thanks again for all the advice.

[Flyboy]

45 minutes ago, DannyC said:

Just had a look at the brass plug. What kind of tool do I need to get it off?

 

Thanks again for all the advice.

A socket or ring spanner.  A large adjustable will work but make sure you tighten the jaws to get a good fit so as not to round it off,