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Engine water jacket drain plug


Brian Sculpher
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Has anyone had a similar problem - having removed the engine block water drain plug (1974 TR6 North American spec engine and  ancillaries) 

I  am unable to drain any water from the block, check hole for silt  build up with inspection camera although unable to see clearly  inside.

The car was rebuilt circa 2018, assume they overlooked the block was clear - any suggestion how I may resolve safely?
 

Best regards BRIAN

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Hello Pete,

Thanks for your prompt post - however I have already had a good poke around with a stiff wire to no avail.

My concerns being more long term, although I have no current overheating problems, I would feel more comfortable with being able to drain - any other suggestions?

Thanks BRIAN

 

 

 

 

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ive always used cheap washing soda as a flushing agent 

a couple of good cup full into the rad and run it for a couple of days , then seriously flush out might release some deposits .

it can disolve alloys so dont leave in for ever  !!! or thermo hsg might suffer .

works better than any £££ stuff thats available 

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Brian,

I couldn’t clear my drain plug, Initially very worrying, mine was blocked with  black casting sand that had been there since original manufacture! No chance of getting it out through the drain hole. It might be possible with the head off. 

I found a map of the cooling jacket and the drain plug sits in a cavity to the side and slightly lower than the main cooling circuit. No wonder this cul-de-sac fills with crud. 

But as said mine’s been blocked for 45 years with casting sand and I’m not alone, other owners have the same issue. 

The soda flush certainly cleans out the main water ways, but if the drain is still blocked it’s not a great problem, you just can’t drain from the drain plug!

Doug

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15 minutes ago, dougbgt6 said:

Brian,

I couldn’t clear my drain plug, Initially very worrying, mine was blocked with  black casting sand that had been there since original manufacture! No chance of getting it out through the drain hole. It might be possible with the head off. 

I found a map of the cooling jacket and the drain plug sits in a cavity to the side and slightly lower than the main cooling circuit. No wonder this cul-de-sac fills with crud. 

But as said mine’s been blocked for 45 years with casting sand and I’m not alone, other owners have the same issue. 

The soda flush certainly cleans out the main water ways, but if the drain is still blocked it’s not a great problem, you just can’t drain from the drain plug!

Doug

If poking through the drain plug hole with stiff wire doesn't get the coolant flowing, the only certain way is to remove the cylinder head. A lot of sediment builds up in the waterways around cylinders 5 and 6, furthest from the water pump. With the head off, the sediment can be attacked with a screwdriver and flushed away with water.

Nigel

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I had the same issue-- the drain was blocked. Though the blockage was pretty hard, I did manage to chip it all out.  I believe it is left over casting sand from the foundry.  Part of the casting core.  A fairly common occurrence, apparently.

Ed

SDC12613a.JPG

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Thank you for everyone’s posts, I now believe the best route is to leave well alone as with my constant persistence may well uncover new problems I didn’t have before.

I recall my father saying on many occasions if the car is going well and general maintenance is maintained leave well alone.

Many thanks to all Brian

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6 minutes ago, Brian Sculpher said:

Thank you for everyone’s posts, I now believe the best route is to leave well alone as with my constant persistence may well uncover new problems I didn’t have before.

I recall my father saying on many occasions if the car is going well and general maintenance is maintained leave well alone.

Many thanks to all Brian

Honestly, you really should make an attempt  to clear the blockage. 

A bit of wire coat hanger poked around may well get things moving. Then keep at it. I have used a bit of steel cable (actually handbrake cable, but anything similar) in a battery drill, poked in the hoke and jiggled about while spinning, and changing direction of rotation. The more muck you get out, the better. Then flush the engine thoroughly with a hosepipe, most hoses off at one end. Push teh pipe up against the drainhole, flush the heater both directions a few times, and via teh various other waterways around teh engine. Reconnect everything, then I run with some form of radflush to get even more stuff cleaned out. (I like speedflush as it is quick!)

You want the waterways as clean as possible to prevent future problems. 

Once happy, and teh radflush is drained, teh system flushed to get rid of that, fill 50:50 with blue antifreeze, all good for a few years

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I had similar with a 1500 block and had to resort to using a long  3/16" twist drill, mounted in a cordless drill, inserted down into and through the water passage from the top face of the block above the the drain hole. This removed loads of black matter and rust and once it had broken through it was much easier to poke upwards though the drain hole to widen the passageway as thescrapman says above . This obviously can only be done with the head removed though.  If you can get a jet-washer lance in there it helps move things along.

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