Oil Pressure Warning light on - no need to panic !!

[marshman]

Went to the TR International multi club event at Malvern at the weekend. My wife (was) volunteered to drive the Sprint and follow me up in my Warwick GT. Got up there OK - left at 5 AM Friday to miss the worst of the jams on the M25. On the way back we got onto the M25 and were in slow moving traffic in the roadworks near J10 when she started to flash the headlights and gesticulate !! Thinking the Warwick was spewing liquids on the road I found a gap in the cones and we pulled over. Turns out the oil pressure light on the Sprint had started to flicker and the come on brightly. Had a look, turned off the engine, popped the bonnet to look expecting to see something amiss. The engine wasn't hot, no oil anywhere, lots of oil on the dipstick. So started it up and gave it a rev. Engine sound sweet - top end rattle as always - but no knocking, temp gauge was steady at its usual 1/3rd mark, so said we have only got around another 100 miles to go lets carry on. Providing the engine doesn't make any loud knocking noises or get hot it'll be fine!! My intuition said it was a fault pressure switch.

We continued and made it home, oil light on all the way. Checked it out today, firstly removing and cleaning the switch and checking with a multimeter. It seemed to work ok when a thin screw driver was pushed up the hole, switching "off" when the plunger was pushed, but when refitted the light was still on. Then temporarily fitted an oil pressure gauge and started it up again and a cold idle pressure of around 35 psi. A quick rev pushed the pressure to a tad over 50 psi before the PRV could be seen to be doing its thing.

So conclusion is knackered switch. A new one is on order and I can breath easily again. We did just over 450 miles, used no oil and a lot less fuel than I was anticipating. Not worked out an exact MPG as I need to brim the tank again but was surprised at how much the gauge says is left in the tank..

Didn't realise how much oil runs out of the transfer housing when the switch is removed, nice puddle of oil under the car and on the rear of the subframe !

[xvivalve]

How come I can never meet a woman who takes notice of dashboard lights??? I'd say she's a keeper!

I was actually with Susie driving in her 1850 once and I noticed it was running very hot; she responded "It'll be alright" to my request to pull over and I'm convinced she'd have driven it until it stopped!

[Matt Cotton]

That is a relief! Glad it is easily sorted!

I had the opposite recently with my Sprint... plenty of nasty noises and when I checked my oil pressure it was in single figures - enough for the light to go out.. but only just!
It transpired I had the wrong PRV in my pump - the spring and certainly the shuttle were incorrect for the pump. I replaced the pump with a NOS one and the pressure was back up to normal levels...

Unfortunately, the grey/metallic slurry in the sump and the scoring on the crank suggested the damage had been done... so off to Mad Mart the block went and is soon to return all refreshed.

Had I known the oil pressure was this low I would have investigated far sooner - I think a permanent gauge will be a sensible addition!

BW

MC