the details are on a thread elsewhere and in the haynes book,but i must add,take the time and drop the rear panel off,its much easier to do it that way,and you will get all the mettalic sludge out.......look carefully,what looks like metal will be caked sludge,scrape out with a SOFT tool,that goes for the cover as well,best to put the cover in some petrol and go for a bacon roll/beer/whatever then get back to clean it properly.
also,you may need a new o ring,so get a gasket set before you do it,or your car may be off the road for a bit..
on a 126 thats been neglected,its the best ''feel good'' job you can do,and your engine/cooling will love you for it!!!
