Oil pressure

[Joes66]

Finally putting some longer journeys on my E and quick question on oil pressure
I've been using the car daily for a couple of weeks and went down to hailing Island the other day
Probably 60 odd miles there
Kind of went easy on the way down and no problems other than a blowing exhaust
On way back pushed it fairly hard for the last 20 miles or so
Question is
Start up cold with used oil rather than new oil I get about 50 psi
With about 40 psi idle
Once hot I get about 20-30 psi idle and 40 psi hot on a run holding steady
But after that hard run I came off the motorway to a stop and the oil pressure dropped to about 10 psi or slightly less at idle
It came back up to 40 psi once I got going again
I parked the car up for a bit and oil pressure after starting went back to about 20 psi hot
Does this seem odd or is it normal for an older engine
No noises other than a slight tapping from the top somewhere which it's always had
I have the standard guage and sender
4.2 engine
Joe

[mgcjag]

Hi Joe....standard electrical guage and sender will just give you an indication of pressure...they are often far from acurate.....the only way to tell exact oressure is with a wet guage.....Steve

[tinworm]

Yep Steves right - buy a nice glycerine filled gauge and test your actual pressure. The electric gauge is just a voltmeter really - you may have a bad connection.

Barrie

[christopher storey]

I doubt whether in this particular case it is a result of gauge inaccuracy , as on my mark IX with its Bourdon tube gauge the results are almost identical to yours - when very hot at idle I get 12 lbs/sq.in but it goes straight back up to 40 once off idle, and I have been told not to worry

[Joes66]

OK
Thought as much
Thx for replies
I will try a mechanical guage
Do they do a replacement one?
That looks the same?
Joe

[abowie]

Those numbers are fine.