1949 MK6 - oil pressure

mcneillian · Posted: Sat Jul 01, 2023 3:13 pm Post subject: 1949 MK6 - oil pressure

As a new member I would like some advice re the oil pressure on my MK6.The car has 81k on the clock and I am running it on xl 30 mineral oil. The car is still fitted with a bypass filter. The pressure when cold is 20 psi at idle, as the engine warms up the pressure drops to 5 psi at idle and increases to 20 psi when rpm is increased. I have replaced the oil pressure relief valve springs and plungers, these readings were taken with test gauge. I used a test gauge, as initially I thought the car gauge was faulty, but the readings are the same. Any comments would be appreciated.

Regards
Ian McNeill

John Murch · Posted: Sun Jul 02, 2023 2:51 pm Post subject:

I hope you will get some replies from current owners; it is a long time since I had a Mk VI, but the handbook says that 4 or 5psi at idle when hot is normal (and much higher when cold) which should rise to circa 25psi at normal cruising speeds.
So if when thoroughly hot you maintain 20 it doesn’t sound too bad to me.

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

Your pressures are fine, but you'd be better off with a multigrade oil.

Martin Webster · Posted: Tue Jul 04, 2023 9:46 pm Post subject:

Ian, The oil pressure should be 20/25 psi when warm. You may consider having the oil filter system converted to a full flow system for more effective filtration. There are several options available. Bin the 30 grade oil and use a decent 20/50 multi grade oil instead.. Don't bother with synthetic as there is little or no advantage with a Mk VI engine.
Martin.

Stephen Blakey · Posted: Mon Jul 10, 2023 9:21 pm Post subject:

I agree with all that.

The word on the street is that classic engines like a lot of Zinc, in the form of ZDDP, mainly to reduce wear of the cams and followers. 600 ppm seems to be the minimum recommended but there are plenty that go higher than that. You won't get it in a modern oil as it contaminates oxygen sensors.

e.g.; this stuff (that's a link to some oil on ebay. The forum couldn't cope with me posting the raw link, for some reason.)

Christopher Carnley · Posted: Tue Jul 11, 2023 9:39 am Post subject:

It does not matter what you use, the cam lobes are worn below the case hardening and the tappets are condensation corrosion b--------d.

mcneillian · Posted: Sat Jul 15, 2023 12:08 pm Post subject: 1949 MK6 - oil pressure

Many thanks for all the replies I will take these onboard regards Ian McNeill

mcneillian · Posted: Sat Jul 15, 2023 12:11 pm Post subject: 1949 MK6 - oil pressure

Many thanks for all the replies. I will take these onboard. Regards
Ian McNeill

mcneillian · Posted: Wed Jul 19, 2023 12:32 pm Post subject: 1949 MK6 - oil pressure

Many thanks for all the replies I will act on the suggestions regards Ian McNeill