(s1) viscous clutch type


buyed but isn’t correct , i have no space between pulley and radiator fot this new type.
s1 2.8 '69 , what’s correct code for my engine ?




most times it is helpful to just consult the Parts Catalogue which you’ll find at https://www.jaguarclassicparts.com/uk/older-vehicle-info. You look at <XJ6 Ser 1> at and find C.28018 for non AC cars and RTC 1002 for AC cars. The parts catalogue doesn’t distinguish 4.2 and 2.8 litre engines with respect to viscous clutches.



75 XJ6L 4.2 auto (UK spec)

The S1 XJ VC is the same as 420/late MKX/420G

It might be possible to get that later VC fitted, but the space between rad and fan is about 5mm, and would also need rad moving forward to be able to initially fit it over the studs

A viscous coupler can also be remanafactured by a specialist

A viscous coupler can also be remanafactured by a specialist

Mean refuribish my unit or produce as new?. how can open this?

Easy pay for plug e play new o refurb unit c28018(s1) or c23693(420)
have you notice ?

2.5 centimeter difference i’m not able insert new unit.

Thank ’ you !

finally gained space working on radiator position…and used new viscous.

My viscous appear coming from 420,not longer avaible.

and hard to open without screws.


Hi Fred, I have 1972 XJ6 and I fitted a new Dayco viscous clutch - model number 115765. Works well about 10mm clearance to radiator at middle section. Archive has pictures. Paul

Thank’you Paul!

i have already resolved working on radiator side, but your code conversion Dayco 115765
is a little treasure information

Paul ,
have you size and weight about your dayco ??


Hi Fred, see other thread for sizes - straight from eBay advertising. Don’t know weight. Paul

Is the weight really of any importance, Paul…?

Either version is supposedly balanced and symmetric - and should offer no specific change of running load…?

xj6 85 Sov Europe (UK/NZ)

I agree, Frank. Not really relevant but Fred asked me. I reasoned any difference is marginal given the total rotating mass - fan etc. Paul