Oil pressure light and gauge show no pressure on start from cold

[Tipidave]

Hi all,

my 1147 Herald starts as normal but oil light stays on and oil pressure gauge does not register. I revved engine and let it run for 30 seconds or so without change. Turned engine off and checked a couple of things under bonnet. Note that there are some air bubbles in the clear oil pressure gauge line. Oil level good and condition of oil as new.  Restarted and both light and gauge respond normally.

first time I thought maybe it was a one off. It has now done the same thing last three days. Any ideas?

thanks in advance

 

 

 

[Guest]

As the electrics and the gauge share a common point - the oil pressure switch - it will be worth changing that as a first step.

[Pete Lewis]

bubbles in the gauge pipe are not a problem , if the pipe was black or metal you would never know 

have you done a recent oil change   what /whos filter did you use ???

Pete

[Nick Jones]

Pretty sure it’s a mechanical gauge Richard as he mentioned the tube.

Has the oil filter been changed recently? If you have a filter with no anti-drain valve (or the valve just plain doesn’t work) it drains completely while standing and takes ages to refill. Not good at all. I wouldn’t Rev it with no pressure!

Nick

Edit: I see Pete an I are thinking along the same lines.....

[Tipidave]

Thanks for suggestion. It seems that I need to stop engine, wait a few minutes and fire again and all indications are normal again. No not recent change. Maybe February? Use Rimmer bros for parts. Been fine all summer. Wonder if related to cold weather / viscosity Somehow?

[Pete Lewis]

so Nick and I  both feel the same   change the filter is a very cheap option and is the most likely culprit 

only takes a few minutes 

there's many posts on here about cold start oil drain back/ knock and some suggestions of alternative filters 

Pete

 

[Tipidave]

Thanks for the help.

i will be checking at the weekend 

👍

[Prince Brainier of Meccano]

Is it possible that the bubbles expand when the engine stops and push air back into the pump rotor causing an air lock?  Seems unlikely as after an oil change it self primes.  But under those conditions the filter is empty and the air in it can be easily compressed and let oil into the pump.  Then, why on a second start does it work?  Maybe it also puts enough drain back oil into the pump to make it seal better?   Perhaps bleed the air out of the line to the gauge?  Or make the T point down so the line is kept full, or something???

Be pleased to find out what it is when you do get a fix.

[Pete Lewis]

i think the small volume of air  bubbles in a 3mm tube is insignificant in this problem when youre looking for 1/2 litre of missing oil from the filter and pump body 

Pete