Honda CX 500 Forum banner
1 - 3 of 3 Posts

·
Registered
Joined
·
1,556 Posts
Discussion Starter · #1 ·
I pulled the 10mm bolts out to drain the heads.

I am looking at pulling the engine so it seemed like the thing to do.

So no coolant came out. I pulled the thermostat and associated piping. Poured water in the holes in the heads and still no water has come out. The engine is not running and its history is unknown. It was bone dry when I got it.

The piping for the thermostat was full of crud. I am soaking it in CLR to try and clean it up.



How would you go about cleaning out the coolant passage ways?

Can I stick the straw from an aerosol spray can of some kind of cleaner in the there and fire away?

Can I stick a piece of small wire in there? I am concerned with doing damage with either a cleaner that can damage the gaskets or I do not know what else.
 

·
Super Moderator
Joined
·
23,060 Posts
I'd give the block drain holes a careful poking with a piece of wire or a welding rod or similar. The most vulnerable part there would be the threads.



The drains are probably blocked with scale.



Since you have removed the heads water neck elbows to allow an escape path you could also blow compressed air in through the drains to help clear the crud.



A really good flush with the garden hose should help also.



If a motor full of scale has been left with a dry coolant jacket for any period of time the scale can go rock hard so it might pay you to fill the coolant jacket with water and allow it to sit until next weekend before tackling it again. This may allow the scale to soften.



The idea of putting a solution of CLR into the coolant jacket is attractive but I tend to wonder if this will attack the head gaskets and 'O' rings. Maybe someone else can give you better advice on the advisability of the CLR as I don't know if it will attack the alloy block either though I tend to think it would be alright.



There are also proprietry cooling system cleaners, some of which must be compatible with alloy engines.
 

·
Registered
Joined
·
8,423 Posts
1 - 3 of 3 Posts
Top