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Cylinder Block Drain


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Just re-fitted my radiator to the 4A after a repair at Serck in Peterborough and some nice new hoses for the heater after the steering column had been chafing them. During the process thought I would check the block drain and as expected nothing came out. I have looked at every post I could find on the matter but not really found a good tip for unblocking apart from taking the head off !!

 

The initial deposit was soft cheesy rust, but so far by using copper wire, cable ties and syringing I cannot get any water to flow through even though I can insert wire/ties about 2" into the block. Is a flushing product the answer or does anyone have another good suggestion. I would very much appreciate any advice.

 

 

Rod

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Hi Rod,

I made up a threaded connector which goes onto a hose pipe and screws into the block,

I took the hoses off the radiator, then turned the water on.

Then i took the hoses off the heater pipes, then using a piece of 15mm copper pipe connected to the hosepipe blasted water down each one until water ran out of the block drain..

 

hope this makes sense!

 

Steve

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Important to note that pressure flushing the block in situ or poking it with bits of wire etc. has a tendency to release bits of old casting sand from dark crervices that havent been disturbed since the block was originally cast .... so care is needed and very careful cleaning down afterwards to ensure that none of this very abrasive stuff remains in the engine. The upshot of getting this wrong is wrecked bearings (and possibly worse) after a few hundred miles.

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Hi Rod,

that end of the block where the drain tap is sited is the elephants graveyard of rust. Even a good poking may not free the solid lump above your access.

If this is the case then the next step is head off and poke down the water ways.

If that doesn't shift it, then pots out and do a thorough job.

 

Roger

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Dear All

 

Thanks for your replies on this topic but unfortunately nothing has worked. Filled the system up with water but left the drain plug out for several days. Just a slight and insignificant seepage resulted. Since I am not into taking the head off right now I guess I will refill and carry on as before and hope. Nothing significant has happened in the last few years although I avoid traffic jams and high revs !.

 

Your advice well received Roger and will follow it ultimately. Still looking for suitable ground to re-bury elephants.

 

 

Rod

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Hi Rod,

In days of old we used to fill the cooling system with a mixture of water and caustic soda and run the car for a week or so before draining and flushing the system. You'd be very surprised at all the rubbish that came out of the cooling system.

It might be worth a try?

Tom.

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Thanks Tom

 

Any ideas on a safe concentration for such a procedure. I mean for the engine, I am aware of human hazard issues during handling.

 

 

Rod

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Bear in mind that caustic soda makes a fairly efficient job of dissolving aluminium components, generating quite a wallop of hydrogen gas as it does so . . . . .

 

One South Downs Group member blew himself, his garage door and its frame across the garden many years ago, result of being careless with caustic soda and aluminium - the TR didn't exactly benefit either. Both his home and car insurers refused the claims, incidentally. Expensive error.

 

Cheers,

 

Alec

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Hi Rod,

when poking with the wire try and bend it upwards as that is where the water is and the thinnest layer of rust (you knew that, didn't you).

If the car was going OK before being nosey then I would live with it until a convenient time to get the head off.

 

I find thick garden fence straining wire is good for this type of thing.

 

Roger

Edited by RogerH
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I'd be more inclined to use citric acid (10% solution). Run the engine for an hour then drain and refill with bicarb solution to neutralise remaining acid. Drain again, flush with water then refill with your chosen antifreeze mixture.

 

Citric acid is used in commercial descalers, also works well in kettles etc.

 

Mike

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The cavity between the drain and number 4 liner on my engine was packed solid with crud. I cant imagine any amount of poking or flushing would have made any impression on it. It did yield to medium force and a screwdriver but the sediment had set up pretty good.

 

Stan

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Not sure citric acid will do much as 1: it is a weak acid and 2: this is a mixture of scale and rust.

Formic acid would be the way to go if you can get hold of it, it wont corrode aluminium and is safer than sodium hydroxide. Even this would require many treatments to remove the amount of accumulated crud.

I am with the head off brigade and even then you need heavy duty flushing in a confined space.......remember those large ear syringing plungers and wide bore needles, they work a treat. Again not easily available

John

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I personally would stay away from caustic for this type of app, citric is to weak. In theory formic would eventually work, but really you need flushing as much as, more than, chemical reaction. When I needed to do this years ago for ancient 40s field find engine I found repeated goes with Fernox central heating flusher.to be effective and have been using it ever since.

 

Mike

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Thanks Mike (and all the others who contributed ). Looking at the Fernox website I see there are several products such as DS40, F3 and F5. From the data sheets, the pH of F3 and F5 is around neutral but DS 40 is very acidic ( pH 2 ). Which one do you use and any thoughts on conc.

 

Your experience would be appreciated.

 

 

Rod

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Hello Rod,

 

I have a bad overheating problem with my TR6 and put domestic central heating descaler in the system. My plumber assures me it will not eat anything it shouldn't so I put in the whole bottle (4 bedroom house size) and topped it up with water. It has loosened quite a lot of crud and it now overheats more slowly but I suspect that the collection around the back cylinders is still there.

 

To my complete surprise I was able to save my badly rusted petrol tank, which I was sure was a write-off, by using Bilt-Hamber's DEOX-C. As the alternative is to strip the engine I feel I have nothing to lose so I'll now flush the system and fill it with full strength DEOX which will hopefully do the trick.

 

With luck I'll be on the road and drivin' cool in a week.

 

I guess if all else fails you'll have to take the liners out and chisel the rust out but sadly I don't have that option - good luck with yours.

 

Willie

 

 

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Fernox / heating descaler. Same difference.

I used the neutral pH one, its on sale in all the sheds, conc was a generous inteprtation of the the suggested mix. (The amounts involved are much smaller than a house). I'm not sure taht over strength will be that beneficial with this type of stuff. In any case the car will be hotter than your average central heating which will speed thigns up handily. Repeated apps with mains water back rinse to get a good velocity through the system did the trick for me.

 

Mike

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