Upgrading The Radiator And Cooling Fan On A 1969 Mgb Roadster
In all the 18+ years of ownership of our 1969 MGB Roadster it has never overheated, but a minor leak from the radiator in 2016 necessitated its change so I decided it was the right time to upgrade the cooling system in preparation for the next 18 years.
While checking on prices for a new radiator I came across a company in The Netherlands offering an aluminium radiator for not much more than a standard one, so ordering was a no brainer. Fortunately I ordered this about one month before the British voted to leave the EU and the Pound plummeted against the Euro.
As the whole cooling system had to come apart I thought I would also replace the engine driven radiator fan with an electric one. I have fitted Kenlowe fans to my cars in the past and while they worked perfectly well I had two issues with them. Firstly fitting with their universal fitting kit was never that accurate and always looked a bit untidy and secondly the sensor was an odd bulb arrangement which fitted in the head of the radiator and slotted into an extra seal, which I found difficult to make watertight.
This time I opted for a Revotec fan as it fixed both these problems. Each fan comes with a laser cut aluminium frame which fits onto long bolts in place of the normal ones and the sensor is embedded into a special section of aluminium tube which along with two short hoses replaces the normal convoluted top hose. The Revotec came complete with a good set of instructions and all necessary wires, connectors, and even a set of cable ties to tidy up the wiring.
Inevitably my work involved in replacing the cooling system doesn't stop there as while this was removed from the engine compartment I cleaned it up as much as possible. The radiator surround and expansion tank, I had previously fitted, were removed and painted with black Smoothrite and the water pump hub in yellow. The inner wings were cleaned, a few areas touched in and all polished. I replaced the lower radiator hose, crankcase breather and oil cooler grommets at the same time while I had easy access.
Everything was installed relatively smoothly and with no problems. I wired in the fan and controller loosely to make sure everything worked properly, before I committed to cutting the wires to size and fixing it as tidily as possible.
The MGB all fired up first time and amazingly there were no leaks from anywhere. The controller worked well and after allowing the engine to heat up and the fan cut in OK. It took a few cycles to set it at about the right operating temperature. A good road test in varied conditions also proved successful, still without leaking. The Revotec works really well generating a huge airflow which cools the radiator very quickly and cuts in and out smoothly. My only criticism of Revotec is that nowhere in the instructions did it say what ampage fuse was needed to the fan supply. A quick Google search found this on the Revotec website. So why on earth don't they include it in the printed instructions?
In theory removing the engine driven fan should also release a few extra bhp but no-one ever said how much. But as the MGB was originally only 95 bhp, and presumably over the years this has dropped a bit, even only a few bhp could make a 5% difference although there wasn't any noticeable difference during my road test.
The new aluminium radiator and Revotec fan should serve the car well for a long time and it gave me the excuse to clean up the engine bay.