I decided to change the moth-eaten radiator on my Sptifire 1500, in an attempt to lessen the overheating. But, when I removed the drain plug in the engine block, nothing drained out. As I found a good deal of crud in some of the hoses, I dont take that as a good sign!
Is it likely that there are blockages inside engine as well?
If so, is there a relatively easy way of flushing it out?
Take the take the bottom rad hose off and the plug out the block, plus heater hoses as a start. Alternate a garden hose on each (rubber gloves this weather!) until everything seems to run freely/clear. A good prod may be required in the engine plug with some thin wire to get it started. The heater should be flushed back and forth in a similar way. I then chuck some holts speedflush in, top up with water and take for a good drive, longer than it says on the tin anyway. Then drain, refill, run, empty etc until happy all clear, fill with 50% antifreeze and good to go!
Location-Brighton, East Sussex Foxy is here, 1500od tax exempt Toledo. Now has the decent engine back in Spitfire Zetec project is started work progressing slooooowly
Get a welding rod or a bit of coathanger and clear out the block drain plug till water runs clear, the back of the engine block is where all the crap gathers.
I remember being wrong once before Laurence Cochrane Newtownards Northern Ireland. 1972 Gt6 2600EFI The Mutt. Some original parts fitted, Not many ! Early PI motor overbored to 2.6. Lightened & balanced, ported chambered, cam'd 6-3-1 manifold.† Running on DTA engine management system incorperating the PI throttle bodies fitted with electronic injectors and throttle position sensor. 0-60 4.7s & 7000rpm. Seriously annoys owners of modern stuff ! (particularly coz its a heap)† 2500 S box with competition 28% od. 3.63 diff with a quaife in it,† innit ! Rotoflex based rear but with a swing spring fitted & sliding shafts.(swing spring rotoflex without rotoflex's). Koni's front Spax rear. Hydraulic handbrake. Citroen xantia discs 11,1/4 in dia under Morris Garages 15 in Maestro alloys.
Ditto the above. I had to renew a hose on the GT6 today, so took the opportunity for some backflushing. Got a good initial flow from the block hole, but a poke around there soon released some crud which would have otherwise hindered proper cooling.
"They may be drinkers Robin, but they're also human beings"
Make sure you thoroughly flush out the hose that exits from the top of the heater valve. When I took mine off I found it absolutely full of a wierd kind of minerally green crystal jelly like substance. I don't know what it was or what caused it but it was blocking the entire pipe solid! The pic below looks is a 1cm long cross section of the hose and as you can see it's entirely blocked apart from where I poked a tiny screwdriver through it!
'73 Stag, '77 2500S for sale, '71 Spit-sold (UK) Club Member
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I was about to flush mine and clean out, etc. but then I thought. Hang on, it doesn't leak, it doesn't overheat (even in 35'c up some serious hills in Wales) and it doesn't freeze. Should I be messing with it? In the end, I figured any slodge in the rad was brobably blocking rad leaks so didn't bother!!
The trouble with doing nothing is that silt builds up in the radiator and heater matrix over time. If you flush it out regularly it dosen't get time to build up and solidify in such quantities as to cause a problem. If you leave it until you actually have a problem you may well find any chance to flush it out has gone and you're in new radiator territory!