4.2 coupe - oil & filter change advice....................

[david340]

Just contemplating carrying out an engine oil and filter change on my newly acquired 75 4.2 coupe.

Ive not had much to do with the cannister / element style oil filters and it looks to be quite tricky to gain access to.

I've read up in the Haynes manual about removing the air cleaner etc. Just wondered if anyone had a few tips i.e. is it easier to access the filter from above or below, should I do the job with the car jacked up on on the ground, and what really needs to come off to gain proper access to it.

Ive looked at the exploded diagram of the filter assembly - im a bit concerned about getting all the spring, washers, plate etc in the correct order - I take it they go between the filter element and the filter casing and the other end of the element just sits against the filter housing on the engine, with a new seal carefully installed ?

Is it worth unscrewing the pressure relief valve and cleaning that up too, or is it best left alone ?

As an alternative - ive seen the "spin on" conversions.

Just been doing some research. Looking on the sc parts website for example. They do an "adaptor" that screws onto the existing filter housing on the block and enables the use of a spin on filter. Cost is £34.

Also a company called Flexolite to a variety of adaptor conversions including one suitable for the 4.2 xk - at £46

There are more comprehensive kits that incorporate a completely new housing - any thoughts on these items as that could be a good option for me.

Finally - the age old question i suppose - what do you guys suggest oil wise. A 20/50 such as halfords or a more modern 10/40. I live in the uk and will cover about 3k miles max each year.

I want to learn how to do the oil / filter at home as I intend to treat the car to regular oil and filter changes. the car has covered 45,000 only from new so i'd like to preserve the car !

Any hints & tips greatly appreciated !

Also, if anyone is interested - or for the purposes of the club mag - I can photograph the process and document it.

Regards.

Dave

[CliveRothwell]

Hi
Spin on oil filters are easier to use.

If you use any other oil other than 20/50, it will simply leak every where due to the tolerances of the engine being so much "looser" than a newer engine. I use halfords 20/50 in my 3.4 series 3 XJ6 and renew the oil and filter every year / 3000 miles. If you are careful, you can just get at the filter from above but ensure you have the ground fully projected from oil spillage, ensuring you clean any spilt oil off the subframe. Good luck

Clive

[CliveRothwell]

and......jack the car up and use Axle stands. Don't mess with the oil pressure switch unless you have to.

[stuarthardy]

I'm not so sure about the tolerances idea but definitely use a 20/50 on the older engines. I use Castrol GTX 20/50 in my 420 Sovereign with 58000 miles on it.

Castrol also do a high mileage oil for older engines, which might be worth considering.

Personally, I would stick with the canister type oil filter. The spin on ones don't filter as much oil due to the reduced flow through them. Drop in filters are cheap enough although I agree that they can be messy to remove (so too can spin on filters if they're positioned awkwardly). Do you have the exploded view of the assembly order for the filter and seals?

Regards

[david340]

Thanks gents.

As a result of my research and enquiries ive ordered a spin on filter / adaptor kit from SC parts.

Im going to change the oil for Halfords 20/50 classic oil. I have some left over in my garage from my Triumph.

I understand that there are perhaps more upmarket oils, but im looking at probably changing the oil and filter again after about 1000 miles. The existing oil is very black in appearance and in reality has probably been in the car a year or two, so a "flush through" with some fresh oil for a thousand miles then change again can't do any harm.

I dont intend using any actual flusing agents or oils as I might end up dislodging something and causing more problems !!

Will keep you posted on how good the filter conversion kit is !!

[david340]

Update as follows.........................

Gathered together all the bits - or so I thought as id been sent the incorrect conversion kit which appeared about half the diameter it should be !

Having looked at the kits im not overly impressed with them or confident having one on the car so im going to revert to keeping the original cannister set up.

Keen to get some fresh oil in the engine I left the filter intact as I couldnt source a new element locally and dropped the oil, leaving it plenty of time to drain - re filled with Halfords 20/50.

What I will to in about 1000 miles is drop the oil again and change the filter - treating it like a flush really which wont do any harm.

Oil pressure at approx 2500 on the rev counter is indicated at just below 40psi on the gauge - to be fair im not convinced the gauge is actually accurate - it takes about 30 secs after start up to register correctly. Oil light (now ive put a bulb in it) goes out and stays out as it should, no flickering etc.

[stuarthardy]

Oil pressure gauges in Jaguars are notorious for incorrect readings. i would say that yours is probably fine.

Regards