K - Cooling System
The car had the original radiator refurbished by Marston Radiators in Reading, cost £100. Nothing much wrong with it, but done for good measure as part of the rebuild. There was one repair concerning the cooling fans frames, as one corner had come unstuck from the rad and had to be re-attached.
Mods:
| Cooling Fans |
| Fan Override |
| Water Pump fixing |
Cooling Fans:
The original design may have been all that was available in 1978, but by modern standards it is the biggest pile of junk on the car! Being a 503 it had two fans for the air con and they both had different motors and various bodges to repair the rusted mess of a framework. Throw the whole assembly in the bin and start again. This will also save a lot of weight and thereby substantially reduce the stress and loading on the radiator unit.
With the original frame repaired it was incredibly easy to fit two new plastic fans which are light, reliable and efficient. These were bought from Merlin Motorsport at Castle Combe and can be made to run in either direction so that they can be attached to either side of the rad. In the Elite it makes sense to attach them to the engine side, and on a 503 this is the only way due to the air con rad. The fans are set up to pull air through the rad from the front and exhaust it out through the bonnet vent.
To fix them in place I cut two lengths of 1" x 1" aluminium angle which were attached to the original fan frame using the original captive nuts in each corner. The fans fit exactly between the angle frames and are secured with 6mm nuts and bolts that bolt through the angle frame and into the recesses on the fan units. Both fans are wired to work together at all times using the standard Lotus wiring.
Fan Override:
During the rebuild I had to re-wire most of the loom in the engine bay, including the replacement of the relays down in the front offside corner of the bay. This gave me the opportunity to add an extra circuit that allows me to switch on the fans from the dashboard manually. I know a lot of people have done this so it seems a good idea. And it is, except that on a car with air con (mine) it is really a waste of time because every time you switch on the air con the fans are turned on automatically. In my case I didn't realise this until after I had done the wiring. This was because my car was wired wrong and the air con circuit was incorrect. The wiring diagram on the Lotus Manual is also wrong! Note that the air con switch works by moving the temperature lever and works regardless of whether the the air con system is installed or not. Also note that cars without air con only have one cooling fan, and my mod would work on either car.
Water Pump fixing:
There is one hex head bolt that is extremely difficult to access when the cam pulleys are fitted. I have replaced this bolt with a hex socket head bolt which is much easier to tighten ot remove with an allen key.
Esprit Engines: My car is fitted with an S3 Esprit engine and the only mod I had to make here was to replace the esprit water pump with the Elite unit because they are quite different.