Further to the discovery that my new viscous coupling had failed very quickly, I have discovered something rather strange.
The supplier has sent me another one, but before fitting it I examined it, the failed one and the 2 x Mk1 viscous couplings I have. The crankshaft washer that holds the viscous in place is, on my car, 40mm OD. The new Mk2 couplings are made so that the rubber seal is proud of the centre bush/bearing race, therefore this washer squashes the rubber seal, leading to the seizure/failure. On the Mk1 couplings I have, the centre bush/bearing race extends further so the washer presses on this, allowing the coupling to work properly.
I have acquired a replacement washer. This is 30mm OD and fits within the radius of the seal. This is now fitted and seems Ok although I have only done a short test run.
The large washer has always been fitted within my ownership (18 years, 60k miles) with no problems. Are there any other owners there with Mk1 couplings/fans? If so, could you look at the washer on yours and check the OD? I need to know if mine is a 'one-off', possibly fitted by some DPO, or if there are others there who may suffer the same fate if changing to a Mk2 coupling/fan arrangement. Mk1 couplings are not available new.
Dave
The supplier has sent me another one, but before fitting it I examined it, the failed one and the 2 x Mk1 viscous couplings I have. The crankshaft washer that holds the viscous in place is, on my car, 40mm OD. The new Mk2 couplings are made so that the rubber seal is proud of the centre bush/bearing race, therefore this washer squashes the rubber seal, leading to the seizure/failure. On the Mk1 couplings I have, the centre bush/bearing race extends further so the washer presses on this, allowing the coupling to work properly.
I have acquired a replacement washer. This is 30mm OD and fits within the radius of the seal. This is now fitted and seems Ok although I have only done a short test run.
The large washer has always been fitted within my ownership (18 years, 60k miles) with no problems. Are there any other owners there with Mk1 couplings/fans? If so, could you look at the washer on yours and check the OD? I need to know if mine is a 'one-off', possibly fitted by some DPO, or if there are others there who may suffer the same fate if changing to a Mk2 coupling/fan arrangement. Mk1 couplings are not available new.
Dave