Leaking "bolt" on BMC engine

S

SimonA

Well-Known Member
Joined
29 Nov 2004
Messages
1,936
Location
Northamptonshire
Visit site
Leaking \"bolt\" on BMC engine

I noticed a slow drip coming from a bolt near the exhaust on a BMC 1.5 diesel engine.

Is this likely to be an engine anode? It doesn't look like the bolt actually holds anything together.

I'll try and post a pic later.

Also it looks like the gasket is leaking on the section above. Being non technical I don't know what this part of the engine is, I'll try and explain. Looking from the gearbox end you have the air filter on the left, above this is a section of engine with the exhaust coming out of one end, the other end joins the heat exchanger. Along the top are 5 bolts and another anode. It has "Captain" stamped along the side.
 
Re: Leaking \"bolt\" on BMC engine

I'm not sure about your leaky bolt, however from your description of the leaking gasket! in the area of the air intake is an engine breather which lets internal pressure and smoke and sometimes little drops of oil out. These sometimes run down the side of the engine onto the bildge floor. if this sounds like your problem try puttng your hand/fingers under the air intake pipe between the filter and the block and you'll feel the little pipe, run your fingers along it and check for oil residue.
hope this helps
 
Re: Leaking \"bolt\" on BMC engine

Pic of another boat with the same engine. I'm talking about the area on the left behind the exhaust with the bolts along the top. What is this part called?

The bolt that is dripping water is on the side of this.

[image]http://www.thenorfolkbroads.net/phpBB3/download/file.php?id=1355&mode=view[/image]
 
Re: Leaking \"bolt\" on BMC engine

[ QUOTE ]
this is the exhaust heat exchanger jacket, i take it you leaks are all water?

[/ QUOTE ]

Yes, just water. And only a very small drip.
 
Re: Leaking \"bolt\" on BMC engine

Yes, that is the heat exchanger. I would guess the bolts along the top hold some sort of cover plate on. If the engine itself is not losing coolant, then the leak is raw water from the heat exchanger jacket, which may be quite badly corroded inside - or maybe the gasket seal has failed. If so it can probably be resealed with Blue Gasket Sealant from Halfords after cleaning up - assuming the gasket is still in 1 piece after you dismantle it! If not, and it is a paper gasket, you can get a sheet of gasket paper from a Motor factor, and by tracing round the part, make yourself a new one - unless you are lucky enough to be able to find a 'proper' one!
 
Re: Leaking \"bolt\" on BMC engine

I go with oldharry.
Manifold heat exchanger.
It looks as though the five top bolts hold on a plate covering the stack-tubes, from the look of the rust round the top. But it isn't a heat exchanger I have seen before. The common or garden type made by Bowman is aluminium and has end caps which come off to draw the stack pipes out for de-clogging. The early ones had metal caps, the later ones rubber.
The rubber end ones are still available at a price from Asap or AMC. Sods law has it that mine is one of the older ones.
Your bolt on the side is unlikely to be an anode... mine has no anodes and there is no mention in the workshop manual. Anodes are more usual on raw water cooled engines. Could it be a simple drain plug? If so a new copper washer, or re-annealed washer might fix.
 
Re: Leaking \"bolt\" on BMC engine

Thank you for the replies.

Here are some better images.

DSC00295-1.jpg
 
Re: Leaking \"bolt\" on BMC engine

Does the engine have a separate heat exchanger - the place you top up the water in?)
Pic looks like a water-cooled manifold. If so just needs a new gasket. The dripping bolt is likely to be a water drain and needs a new fibre washer.
 
Re: Leaking \"bolt\" on BMC engine

I agreem its just a water cooled manifold, which has a removeable top so you can clean them out. The gasket has either failed, or the manifold itself is corroded. The bolt is just a drain plug to drain the water out prior to winter layup to avoid damage from freezing.

These where used in the Newage BMC conversions, which were either raw water cooled or had a front mounted heat exchanger, bit similar to the setup on a perkins 4108.
 
Re: Leaking \"bolt\" on BMC engine

I do have a seperate heat exchanger on the front of the engine. This has a cap on the top for filling up with coolant.

So it looks like I need a new washer or core plug bolt and a new gasket. That doesn't sound too expensive. I have just spent £4300 on a new gearbox, prop, shaft seal and other bits!
 
Re: Leaking \"bolt\" on BMC engine

Bottom one is drain plug, as said top cover gasket needs replacing. Might be fun getting the bolts out... Probably the iron face is a bit corroded too. So sealant +gasket.
Andrew
 
You must log in or register to reply here.

Share this page

Top