Dave,
OK, whatever the problem is; it's going to have to come out. Unless it's a loose drain plug - you might get lucky
(It's a lot easier with the bumper off but that would create it's own mini-saga - trust me!)
To remove rad;
1) Take off the plastic undertray - held with 4 6mm. bolts that have small heads - mine were rusted to buggery so I ground them off.
2) Undo hose clips and pull hoses out of the way
3) Undo the bolts on the rad mount - see pic - there's a lot of them and some are difficult to get at and are small, too. I have a small cheap socket set that allowed access to the more difficult buggers. This is a good time to practise all your swear words and wonder why Lotus engineered this in such a perverse way. Leave a couple of the bigger ones in place until last as the rad will now want to drop on your head
4) Remove rad, wring coolant out of your clothes!
5) Choices;
a) if its the core you can get them recored - try any local Serck dealer - if you get stuck try Heathrow rads (I work near there so I can drop it off / collect it for you)
b) if its the drain plug - stripped thread - degrease with meths and Araldite in place with classic Araldite - mine has been in Le Mans traffic james in searing heat witohut a problem
c) if its the side tanks, then put out a wanted add (I may have a fairly decent rad if you get stuck) or you can get an entire one in aluminium made by those jolly nice chaps at Alisport (£350+vat) - they'll need your old one as a template. [T'other Dave has suggested getting side tanks fabricated in ally - seems a reasonable price yet another option]
6) Optional - replace the fans - these are Renault van fans - not that expensive - complete with cowls. There's a thread about that (I have not replaced mine - yet)
7) In true Haynes manual style - Refitting is the reversal of removal
I chopped up a scouring pad to replace the knackered sponge bits on the rad mounting pins. Top tip - hoick the rad up into position and secure with tie wraps round the lower pins and the inverted y-yoke so you can fiddle with the rad mounts and the many bolts. You can leave these in place afterwards.
While you're at it - I'd recommend replacing the hoses - they're quite accessible with the rad out.
HTH
Jim
PM me for more info or contact by phone - I'm in Wokingham so can drop by to help if you want...
