XJS Oil Change Should I Replace the Sump Plug Washer?
 

I'm about to do an Oil Change on my XJS V12 and was wondering if I should use a New Sump Plug Washer or just put it back as it was.

OB
I only change the washer if it starts to leak, which it has not so far in about 6 oil changes. But they only cost pence from (eg) D Manners. In the olden days you used to get a new washer with the filter, no more, sadly.
Greg

Hi Greg

Thanks, I will do it your way.

Last night I changed the Oil on my Merc and had hell of a job in undoing the filter, even though I had a 'Chain Wrench Thingy'

With a 2ft Breaker Bar on the end, which almost destroyed the Old Filter in the process.

But the plug was dead easy to get to, without even having to Jack up the Car.

So I've only put the New Filter on Hand Tight.

OB,

It may be that the V12 sump and washer is more robust and long-lived than the 4 litre, so I'll bow to those who are more experienced on that engine. Personally I would always change the sump washer if I undid the sump plug but that's maybe because a lot of engines use crush washers which never seal effectively the second time.

Whatever you choose, be prudent when tightening. The 6-cylinder sump is particularly prone to cracking at the plug boss through over-tightening, which can be a VERY expensive result. Maybe the V12 is ok in this respect?

I've done all my oil changes for the last few years using a compressor-driven suction container and drained the oil through the dipstick. On most cars, I've also extracted more oil that way than through the sump plug. It's also avoided me disturbing the plug with its attendant risks.

Paul

Hi Paul

That is making me nervous! so I will have to be very careful not to over tighten the plug but thank you for that very good advice.

If you have the copper washer type gasket, "they" say that it will work-harden after being tightened which will make it more prone to leaking if reused. Copper is easy to anneal though which returns it to the soft state - it just needs to be heated good and hot then allowed to cool - I just hold it over the kitchen stove on a piece of stiff wire. Check for damage first - gouges, ridges etc - and clean the soot up after. This has worked for me so far when I didn't have a replacement washer.

My Toyota Land Cruiser has a plug washer of aluminum with thin rubber bonded to both sides. It works very well on that vehicle and they only cost about US$0.10 each. Has anyone tried this type with the V12? And if so where were they sourced?

Eric

Eric
In the Uk they are called Dowty Washers, if this is what you had in mind:
Dowty Washers | eBay

They provide a fantastic seal. They are also called hydraulic bonded sealing washers, and they are used in all sorts of extremely high pressure applications, such as JCB hydraulic connectors etc etc. A bit over specified for a sump maybe, but they work really well and reliably.
Greg

I've been using the same oil plug & washer on both the the XJ-S & VDP sdn for years. I use a little aviation sealer on the plug threads when changing oil. Wash (the plug not the washer if it has a rubber seal ) off the old sealer in lacquer thinner, reseal threads, do not over tighten the plug . Never had a drop/leak at the pan drain plug.
Lawrence

Hi Greg

Thanks

Any idea what Size Dowty Washers I would need and are they better than the OEM Type?

Great Advice

Many Thanks

I am pretty sure it is 5/8 UNC the sump plug.
Greg

Cheers Greg

Thanks.

Greg - those Dowty washers look similar, but on the ones I have for the Cruiser the rubber completely covers both faces of the aluminum washer.

Regarding the size, I seem to remember reading that it's 16mm? Never actually measured my plug though. Thats only a few thousandth of an inch difference in size, but I doubt the threads would be interchangeable. Not an issue at all unless you need a new plug for some reason, washer ought to work either way.

Hope this helps, Eric