[TR] TR3/TR4 block drain valve?

[Paul Willoughby]

How sturdy are the block drain valves?  The one on my TR4 is clogged.  I've 
been hesitant to remove it, fearing that it would crumble into pieces and 
screw up the threads.  Too many bad adventures with home plumbing have left 
me gun shy.

Paulw
64 TR4
56 TR3

----- Original Message ----- 
From: "Randall" <TR3driver at ca.rr.com>
To: "'William Brewer'" <wsb1960tr3a at att.net>; "'Triumphs'" <>
Sent: Friday, May 17, 2013 12:14 PM
Subject: Re: [TR] Fw: Recore vs Rodding Out TR3 Radiators


>      Do you have a hose part number for the Gates hose?

Gates 23511
 http://goo.gl/hOZTT

Apparently the same thing is available as AC Delco 31401
http://goo.gl/RxRtk

> I wonder it I should
> pull the head and check that out again?

If the block drain flows freely, then it's probably OK.  It's at the very
bottom of the water jacket, next to #4.

I'd probably leave it be as long as the drain can be opened up with some
prodding.

Used to be, you could buy a strong chemical flush that came in 2 parts.
There was a neutralizer to use after the flush, to stop the chemical action.
I couldn't find any, last time I went looking; but there are some recipes on
the Inet that might work.  IIRC the flush is oxalic acid (sometimes
available as "wood bleach" or "deck bleach") and the neutralizer is baking
soda or maybe washing soda.  The acid comes as a dry powder that must be
mixed with water before adding to your cooling system.

Oxalic acid is fairly potent stuff.  Be sure to keep it off your paint and
wear appropriate protection when handling it.  Have a hose handy for instant
flushing if it gets some place it shouldn't be.

-- Randall