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Hello, I know this subject has been raised on previous occasions but I'm not clear as to the exact amount of oil to put into the engine WITH an oil filter change.

The manual says 7.5 ltrs but a number of threads on this site says the maximum is 6.5ltrs and just reaches the bottom of the hatch markings on the dipstick. Can anyone clarify please.

Many thanks,

Neil

Hi Neil
My Jaguar service manual (fourth edition, E121/5) specifies 6.25 litres for a refill and 7.5 litres in total. However, it is not completely clear what the word refill means - with or without the volume of oil in the filter - although the service manual also specifies that the filter should be drained at each oil change. I read this as the engine holds a total of 7.5 litres when filled from dry after a rebuild, but there are 0.75 litres that do not drain when the sump plug and filter housing are removed. I may be wrong.....
What I actually do is to drain the system, including the filter, and then pour in fresh oil until the level reaches the hatched section of the dipstick.
Perhaps we should have a ballot??
Best wishes, David

Thank you david I will follow you advice. I have a second question. The gearbox/overdrive has been leaking. It was suggested that the oil be replaced with a thicker grade and I was advised to buy SAE 40. One or two friends have expressed surpise that I have been advised to use a straight SAE 40 rather that a Hypoid oil. Can you comment on this . Many Thanks

Neil

Nooooooooooo! Only use engine oil! The overdrive probably won't cope with anything thicker.

Terry

Terry is correct, the gearbox and overdrive should be filled with engine oil. If the unit is leaking, there are only two solutions: accept the leak, or fix it.
Best wishes, David

Hello Terry,

as a matter of interest my Triumph has the same 'A' type overdrive as my MK 2 but that uses ep90 oil in the gearbox, the same as the differential.

Alec

Interesting thread this. To add to the discussion:-

My 420 service manual specifies EP90 gear oil be used for gearbox and overdrive unit. 420 uses a Laycock De Normanville overdrive unit with 4 speed full forward synchro gearbox.

The manual stresses the importance of maintaining oil level in the gearbox as this will damage the overdrive if level falls too low. Also, to drain the overdrive unit (and clean filter and magnets) at same time as gearbox (every 12000 miles), otherwise old oil gets left behind.

Personally, I doubt that engine oil would have the shear strength for gearbox use. Certainly not for 12000 miles use.

Regards
Stuart

Hi guys
Murky water, this is!! The Mk2 manual definitely specifies engine oil for gearbox/overdrive. That Jaguar, and other manufacturers, who use the same gearbox and/or overdrive unit specify different oils suggests to me that it is the presence of oil, rather than the specific grade, that may be more important. I have certainly seen non-functional overdrive units resuscitated by an oil top-up. An EP80 or 90 oil makes sense for a gearbox, and I can't see a good reason why it should not be good for an overdrive too. Interestingly, Jaguar specified EP90 oil for the XJ6 MOD gearbox, which is the same box and overdrive as the Mk2 as far as I can tell. Perhaps Jaguar found out the hard way what Stuart's intuition tells him......
Best wishes, David

I ran a Triumph Vitesse MK 2 with a Laycock overdrive unit for many years. Both the gearbox and overdrive ran in EP90 which is as previously suggested rather better at resisting molecular oil shear due to the mechanical action of the gear train.

Mike Kennedy.

Hello all,

I note in this months magazine, Ken Jenkins recommended EP 90, for an E.Type, same gearbox overdrive?

Alec

The factory manual for the Mk10 and 420G specify EP90, as does the Haynes for XJ6 - they all use the same gearbox and overdrive?

I think the consensus is EP90 then. For info, E types were never fitted with overdrives ex factory. There isn't room for one in the transmission tunnel.

I would never recommend using engine oil in a gearbox, it just isn't strong enough to take the loads between the gear teeth for any length of time.

Regards
Stuart

Hello Stuart,

Nobody ever told Alec Issigonis about that!

Alec

Agreed!

Remember that idler gear bearing that used to break up on A series engines, eventually leading to a damaged housing and complete collapse of the gear and bearing. Regret to say I used to put STP in those engines and the gear train then used to survive reasonably well. I imagine that the STP beefed up oil shear resistance and that might have helped with longevity issues.

Additives must be carefully used in conjunction with modern synthetic oils. Mixing the two products can cause more problems than it solves.

It is a definate No No as regards use in overdrive gearboxes.

Mike

The A35 and Morris Minors (another one of Mr Issigoni's) I owned all had/should have had straight 30 engine oil in their gearboxes. SAAB 900s (the classic shape) should also have engine oil - if they have EP90 the gearchange becomes almost impossible.

Anyway, my S type has hypoid in its gearbox....