Before using this site please read the site disclaimer. Also please note that any links provided may be part of an affiliate programme (viz. eBay, Amazon) which helps support the site as I will earn a commission when visitors make a qualifying purchase.
There are four places that the front camshaft holder can leak oil through on the mechanical fan models; the O-ring around the steel collar, the oil seal around the camshaft, the oil seal around the tacho peg or just through the gasket itself. This guide doesn't cover replacing the tacho peg seal (6x14.5x5mm, incidentally) - that will be written another time. The electric fan models have an aluminium plug where the front camshaft oil seal sits as the camshaft does not extend past the holder; in practice this doesn't seem to be a source of leaks.
For the sake of this writeup we will refer to the manual fan models as the 500s and the electric fan models as 650s. A 500 camshaft holder removed:
It's a good idea at this point to give it a thorough degrease and scrub - if you have had an oil leak there's probably old oil and dirt caught up in it and you might as well clean it out now. Try not to get any rubbish into the tacho drive gear area. A parts brush is handy for this sort of thing (eBay US, eBay AU, eBay UK).
On a 500 model there is an oil seal surrounding the protruding camshaft nose - pry it out with something soft:
Beneath it you can see the tacho drive gear:
Note the channel for oil to pass through; if you're cutting your own gaskets make sure to replicate the channel in the stock gasket. It provides an oil pathway to the tacho drive gear. It's a good idea not to use silicone sealant on the camshaft holder gasket (or try to replace the gasket entirely with sealant) in case this hole becomes blocked.
A curiosity - anyone know which company this symbol belongs to? It's on the rear side.
Anyhow, back to the oil seal. 650 engine owners skip to the gasket, 500 engines read on. Now that the old one has been removed make sure that the surface it sits on is clean and grab your new seal:
The oil seal is part number 91201-415-013 (eBay US, eBay UK, eBay AU, and original part number was 91201-415-003) and is 17x28x7mm.
This side faces inwards - towards the motor:
Use a socket or something similar - hard and round - to press in the new seal:
Pressed in:
The gasket is part number 12230-415-306 and is generally available online (eBay US, eBay AU, eBay UK).
Thoroughly clean the surface it sits on - both the block side and the camshaft holder side. A gasket scraper can help here (eBay US, eBay AU, eBay UK), though be careful not to mar the soft aluminium surfaces. While you're cleaning check that the little hole isn't gunked up with hard crud:
Place the gasket:
Make sure it doesn't cover the little hole we checked - once upon a time we opened up a motor with a gasket which blocked it - probably a home made gasket:
Next, locate the collar/dowel that sits between the block and camshaft holder - it lives just below the camshaft:
The collar or dowel is part number 15155-300-000 (eBay US, eBay UK, eBay AU) and the O-ring is part number 91301-268-020 (eBay US, eBay AU, eBay UK) - 13.6x2.4mm. The temperatures in this location are enough that you might consider using a Viton O-ring.
Clean away the junk in the block and camshaft holder on either side of where the collar sits:
Clean up the collar - should just be a case of wiping off old oil residue - and place the new O-ring around it:
Insert it back into the block (block surface hasn't been cleaned in this photo, yours should be at this stage!):
Excluding replacing the tacho drive seal, you're now ready to do the next step - reinstall the camshaft holder/tacho drive.
In 2019 the server has had to double in capacity to support the growing site... please consider dropping the site a donation to help cover the costs! Check out our Patreon for support options, buy a shirt, buy our apps, use my NordVPN affiliate link to sign up to their service or donate via Paypal:
| Paypal $5 link ->> | |
| Paypal $10 link ->> |