Oil pressure following oil change.

Steve Welton · Joined: 17 Oct 2013 Posts: 105

When I changed the engine oil on my 3.5 L last year I was alarmed at the length of time it took for the oil pressure to register on the gauge after restarting. This year I thought I would whip out the plugs and spin the engine until such time as oil pressure shows on gauge but no joy!! Any thoughts or ideas?

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

You can use a pre-oiler to pressurize the system and purge all the air. Or do it manually by connecting into one of the oil lines and pumping oil in.

Steve Welton · Joined: 17 Oct 2013 Posts: 105

Well I don't quite get it. Surely it would be in the Technical Manual.
Which oil line would I need to pump oil into?

Chris Card · Guest

I had a similar problem with my 4.5L. It was caused by air trapped in the pipe to the gauge. At idle, I disconnected the gauge and purged the air from the pipe. Oil will also flow so you must have a cloth and container to catch the oil before it gets on the upholstery.

Chris

Mark Taxis · Posted: Tue Nov 21, 2017 7:15 am Post subject:

I am not familiar with the Derby oil system, but on my Mk6 after an oil change I always ¾ fill the oil filter bowl before starting the engine, oil pressure seems to come up reasonably quickly
_________________
Mark Taxis
Sunshine Coast
Queensland 4560

Christopher Carnley · Posted: Tue Nov 21, 2017 8:37 am Post subject:

This is a Derby 4 1/4 (3 1/2 almost identical) with my own version of the full flow, before plating.
The original oil supply would run vertically from the lower feed pipe to the crankcase feed into the main gallery.

The oil pump, a high capacity one in this case is slung low right.
and the rockers.

Any idea of pre-filling is a non-starter as the oil runs back.

Steve, Have you checked the screen in the sump for blockages and coud the pump be worn? Worn crankshaft bearings may also be the problem.

Mark, There never was a production external filter except on the last MR/MX series.

Charging pressure from a start in a worn engone is very slow.

Now running and gone !!!!

Steve Welton · Joined: 17 Oct 2013 Posts: 105

Thanks for the responses! Reassuring to know its not just my car!
I have not checked the screen in the sump for blockages but the pump is not worn and crankshaft bearings are good. The engine is in fine condition with little wear..

Richardson Masten · Joined: 01 Jan 1970 Posts: 49 Location: California, USA

What about a “pre-oiler”? That way the oil pressure would be up before one presses the starter button.