Radiator replacement

The author lost coolant, replaced the expansion tank without result, and then found coolant spilt into the crash limiter behind the grille and a dark patch in one corner. That pointed to the radiator. The 2007 guide is for people with some mechanical experience. He had the front clam off and, since it was off, replaced rusted fixings with stainless ones. To get the clam off, see the front clam removal guide.

1. Bonnet and undertray

1. Remove the bonnet to make things easier. Leave it closed but not locked and undo the six front bolts (four inside, two outside) with the 10 mm socket. Take its weight, open it, slide it towards the windscreen and put it somewhere safe.
2. Take off the front part of the undertray, which is easier with the car jacked up. Jack both sides and put an axle stand with a piece of wood under each jacking point. The tray is clipped into part of the chassis and held by five bolts with an 8 mm socket: three in the centre and one each side. See the jacking points guide.

These steps are optional. One owner did the job without removing the undertray and says it didn't get in the way. Another says you don't have to jack the car up unless the inner arch screws are hard to undo, in which case you jack it up to take the wheels off.

2. Remove the radiator housing screws

1. Four main bolts hold the radiator to the housing. Remove them with the 10 mm socket.
2. Ten screws hold the housing to the body: three at the front, three at the rear and two on each side. Remove the front three with a Phillips screwdriver. If they are rusted, drill the heads off.
3. The right-hand screw of the rear three is blocked by the ABS unit, and couldn't be reached from the rear. Unplug the cooling fan (the blue plug near the left-hand screw: press and pull apart) before undoing the rear ones.
4. On each side there are two more. The one at the rear has its head on the underside of the car, so it is easier with the undertray off. The last, a little further forward, also has to be removed from underneath.

The screws and clips are very weak steel that rusts, and the author had to drill out the heads and prise out the rusted C-clips. The threads on his three rear screws shredded, and with so little space he couldn't drill the heads out. The radiator can still be removed without removing the rear screws. Another owner fighting seized screws found that out too.

3. Drain the coolant

1. Drain into a bowl by taking off the passenger-side end radiator hose (the one with the bleed valve). A jubilee clip inside the housing holds the hose, and a flat-head screwdriver removes it. The coolant runs down the housing into the bowl.
2. Unscrew the expansion tank cap to let all the fluid out. Do it in stages, because the coolant flows very quickly with the cap open.

4. Take the old radiator out

1. Disconnect the other side: loosen the jubilee clip and pull off the feed hose.
2. Lift the front of the radiator housing and slide the old radiator out, feeding the fan's electrical plug through the housing so it comes out completely. Drain out any coolant left in it.
3. With the radiator out, take an angle grinder to the inside of the three rear screws and the C-clips to remove them. The author then replaced all ten C-clips with the 5 mm stainless ones.

The old radiator was leaking at the bottom left-hand corner and in the middle, and a previous owner had plugged a leak with a blue plug. Another owner says two of his standard radiators had that blue "plug" from brand new with no leaks, so it may not be a repair.

5. Move the fan across

1. The fan is riveted to the radiator, so drill the rivets out. Take off the foam cushions from either side too.
2. Rivet the fan onto the new radiator. The author thought about replacing the brackets but apart from surface rust they looked fine. He used the new 6 mm stainless C-clips in place of the four rusted ones on top of the radiator. Another owner cleaned and painted his brackets and used bolts and Nyloc nuts in place of pop rivets, to make it more secure.

6. Fit the new radiator

1. Stick the foam cushions on, lift the housing and slide the new radiator in, feeding the fan cable back through the back of the housing.
2. Reconnect the two hoses and tighten the jubilee clips.
3. Bolt the housing to the radiator with four of the new stainless M6 x 16 mm bolts. The Elise radiator's mounting holes are slightly offset from the VX one, but the housing has both sets, so the bolts go in the second set.
4. Plug the fan back in and refit the grommet.
5. Refit the ten housing screws and washers (stainless ones used), then refit the clam.

7. Fill and bleed

1. Close the bleed valve, take the cap off the header tank and fill to the max line. Refit and tighten the cap.
2. At the front of the car, open the bleed valve to let air out. When coolant reaches the valve, close it.
3. Back at the rear, top up to the max line again.
4. Leave the cap open for an hour so the air settles, then bleed it off with the valve. Repeat about another three times, until only fluid comes out of the valve.
5. Tighten the header tank cap and the bleed valve, then start the engine to let the water pump circulate the coolant.

On air in the heater matrix: the matrix inlet and outlet are on top of the matrix so the air rises out, and the author had no problem. The cooling system flush guide left open whether air needs bleeding at the radiator afterwards, so this bleed method may help. Other owners' bleeding methods and coolant advice are in Changing the coolant and bleeding the system.