Block drain tap

[Davemate]

After rolling up a the auto solo with what looked like a steam powered saloon my radiator is being re-cored,the chap at the repairers said "it's blocked and it's got a few holes in it"
As I was taking the rad out last night I had a very quick look for the drain tap on the block and I couldn't see it,as the wife has had a move round in the living room I currently can't get to my workshop manual so I find myself in the embarrassing position of asking
Where's the coolant drain plug on a 2.5 block ?

[Davemate]

Can it be got at without removing inlet/exhaust manifold and or starter motor ?

[junkuser]

Plugs are more practical than taps.
Taps usually block and or jam after not being used for a long time and in any case have to be removed to poke wire in the hole to check the waterways.
Easy enough to remove bottom radiator hose to remove most of the water from the cooling system, if the water is not too hot.

Polished taps look nice for show though.

[junkuser]

Most of the water from the block and head.
Drains the block and head. Removing the radiator cap to allow air in is handy to remember though.
Just a bit cautious about saying completely. Some may be remaining due to angle of engine possible blockages in block.

Many, if not most, modern cars have no block drain Iain.

[Davemate]

Thanks chaps

[Nick Jones]

Be prepared for nothing to come out when you remove it.  On the saloon, the angle of the engine means that the drain is at pretty much the lowest point and all the crud collects there and sets like cement.  May need to be poked with something and you may have to poke quite hard.....

Nick

[Jonny-Jimbo]

Is it a good idea to remove the starter motor too so you don't cover it in cruddy water? Thinking of doing a flush out on my 2.5 engine before RBRR as I haven't flushed the block out properly.

[Davemate]

Ummmm standard starter 6-3-1 manifold,so removing starter isn't easy

[TedTaylor]

Shouldn't think that water going over the starter motor would be a problem - they are very well sealed anyway and they get loads of water over them in their location at the bottom of the engine anyway.  If really worried simply throw a cloth or some plastic over the motor to keep the water off.

As Nick says be ready to have to break through a load of crud collected in the block behind the plug.  With luck a drill held in something like a tap wrench should do it unless the accumulation is really bad.  Then there is the problem of your exhaust .........

MUT

[josh18]

Ha, I never knew there was a drain plug on the block. Ive always just removed the bottom radiator hose too.
I would be reluctant to touch any plugs etc on the block in case it breaks or strips out or something. I reckon a good flush out with a garden hose would clean the block out well enough.
Cheers

[TedTaylor]

Quoted from josh18

I reckon a good flush out with a garden hose would clean the block out well enough.
Cheers

The problem is that a fine 'silt' primarily of tiny rust particles etc. circulates in the cooling system water and accumulates in the block which can settle into odd corners, especially the bottom of the water jacket of the block and to a lesser extent the head.  As this 'silt' over times settles it can become pretty hard.

When you strip a block you can also see rust that has accumulated around the water passages sometimes partly blocking them.  

While flushing with fresh water can clear much of the fine silt it cannot clear it all or it and the rust.  A flushing agent dissolves most of this rust but for the accumulation of silt in deep recesses even the flushing agent cannot always work effectively though most will get removed.

MUT

[GT6 M]

wen dooing me olde new engine,
could see loadsa crap,barnicles and groths inside the wter jackets.

so filled it up wid Phosphoric acid,aboot 20% worth mix, heed as well

left it bubbling away for a week,   wid occaisional scraping wida long  screwdriver to shift stuff.  there were some pile o sheite kem oot of
it when emptied,
And, alott of nice smoothish shiney steel when finnished.

Acid was v v black

M

[Tim Bancroft]

Seriously, one of the issues with the Triumph six cylinder engine is that crud does collect in the water jacket on the exhaust side of the engine. Its a complete and utter sod to get it all out. Pop out all the core plugs and have a good go.

Marcus' solution seems a good un!