V12 oil pressure concern...?

[JIM BAUMANN]

Hello all


Enjoying the E-type-- and its all running sweet and lovely and smooth.

Oil pressure has been very healthy hitherto --around 80 psi indicated on gauge @ 3000 and much the same lower down as I recall....

Went for a small drive this evening ( beer fetching--the long way round)

anyhow--the oil light on dash suddenly started flickering when revs dropped to around 1500 or less...

went home immediately.
==============================================

Oil level is healthy and the car is oil and watertight now at last

Engine sound s as smooth as ever --with no apparent change in health as far as I can ascertain.

Do oil sender units ever malfunction?

Can the oil pump suddenly weaken/ fail

Or do I have a bigger problem on my hands..

I am having a 5 speed box and clutch fitted fitted in mid November...

so if here is a problem--then is the time to do it.

any thoughts?

Jim Baumann

( whose Friday night E-type Euphoria is a trifle dampened!!

[MarekH]

Dear Jim,

Fitr a mechanical gauge and see what the real oil pressure is. All electrical senders will always be subject to electrical problems, but not necessarily the senders themselves.

kind regards
Marek

[Alty Ian]

The sender units are notoriously unrealiable. I've been through loads of them. Just check the actual pressure before doing anything, it should be around 50psi at 2000rpm and can drop to about 25 when ticking over at 600 rpm. I dont believe that 80psi was right either btw.

[christopher storey]

Just a moment - what oil light on dash ? the only warning lights - certainly on the 6 cylinder cars - are the choke and brake warning lights, and the 3 in the speedometer which are for fuel, high beam and charging system ( there is an added complication in that the alternator light is in fact an oil pressure light on early 4.2s but we need not go into that ! )

[MarekH]

It's a series 3 car:- these have both a conventional electrical sender (for the usual gauge) and an oil pressure switch (for a light on the dash) mounted next to each other.

On early s3 cars, this was on the oil gallery above the left rear exhaust manifold and on all other cars was at the back of the "V" behind the throttle tower with an undrilled blanking plate at the older location.

With some ingenuity, you can probably remove and test the switch using a bicycle pump and an ohm meter, then substitute it with a mechanical gauge to test the elctrical unit in situ under running conditions.

If you suspect a blockage, you can also plumb in a standard 1/8npt fitting into the oil line and pump oil in under pressure using an insecticide sprayer - the oil light will go out and later you'll hear oil/air sqeeking through the ends of the cams as the sprayer unit runs out of oil. Doing this with the cam covers off also lets you see oil coming through all of the cam bearing caps. Having said that, it's the oil pressure at the main bearings that you are really concerned about as oil pressure at the cams can be much lower (15psi) and still so do its job.

kind regards
Marek

[JIM BAUMANN]

Thank you for all your expertise and positive and encouraging input--


PHEW !!

I took a shortcut -- rather than rely on experimentation with my own inexpert spannering....

I took my car down to SC Jaguars @ Netley...

en-route the needle mysteriously (!) regained itys usualpoistion twixt 60 and 80 psi.... nevertheless they checked oil pressure upper and lower gallery and pronounced engine in fine health-- did however clean the sender pipe(?) out in case of a bit of crud...

Me thinks a flush and another oilchange is imminently advisable-- just in case to try and clear out any bits of accumulated gunge anywhere ...


Thanks for all your answers

as ever-- indebted for support and advise


Jim Baumann