Oil light is flickering

[Gert_8]

Hi Guys. I noticed my oil light is flickering. There's plenty of oil, so that's not the problem.

Any ideas on the fix please.

TIA.

[Grrrmachine]

Which engine?

Oil sensors on an M20 can get sticky with age. Removal and soaking in petrol is good for freeing them up.

[Gert_8]

Hi Grrr. Yes m20. Point me to the right Wiki please.

Thanks mate.

[jimbom30cab]

Yes it could be the

1. Duff switch
2. Switch not earthing properly
3. Supply wire earthing slightly if it is caught or chaffing

It's such a simple circuit that it must be one of the above

[Grrrmachine]

Just realised - you're talking about the oil PRESSURE light, not the oil LEVEL one It's the level one that gums up.

The Pressure light comes from a sender with a single wire. It's in the block under the exhaust. That one wire runs to the front of the engine, over the pulleys and back around to the intake manifold, and along its route it gets worn, trapped and frayed. It the sheath has broken at any point, it'll be grounding on the block which will make your light flicker.

You'll have to trace the path of that wire, but I bet a point it's come loose and been worn by the pulley.

[gromgsxr]

Is Light flickering when the engine Is running cuts that could be a bad thing

[jimbom30cab]

It's unlikely the engine will run for very long with a flickering light, they come on at about 0.2 psi which is basically zero and your white metal bearings would be wiped in seconds.

If you open the filler cap with it running and see oil peeing everywhere in side it has plenty of pressure.

[B7]

No ones asked when it's happening. If it's happening when he engines cold then yes, could be wiring fault.

But heres my thoughts:

We are seeing the highest temps for a long time. Therefore the engine temp is higher and the oil is thinner.

Flickering oil light on tickover when the engines hot is a classic sign of botttom end wear and the light flickering in high temps is just the start.

I used to see it a lot on Stags and have also seen it on M20s.

You can put a new pump in which may sort the issue short term but once the wears setting in, it's a bottom end reuild is what it really needs.

Sorry! I hope it's not!

[Gert_8]

Hi guys. Light flickering when engine is cold, ticking over. Thanks Grrr, I'll trace the wire and see if it's damaged.

Thanks.

[jimbom30cab]

And check the switch is well connected to the block so you have a good earth

[Grrrmachine]

Hmmm, if it flickers only on cold tickover then it may be working fine, and you've either got a very thick oil in there, or an ailing oil pump that can't lift cold thick oil.

[Gert_8]

Hahah. I'll be bringing it home tomorrow, so it will get a run. I'll post up to let you know whether the light stays on or goes off, once warmed up.

[Gert_8]

Hahah. I'll be bringing it home tomorrow, so it will get a run. I'll post up to let you know whether the light stays on or goes off, once warmed up.

The weight of the child in the boot can affect the oil warning light, PM Pete he'll set you straight.

Hahah. I've already spoken to him, he said you had the same problem.

[reggid]

i had this and it was dodgey sensor

[Gert_8]

The engines fairly decent and been looked after from what I can see, but you never know. I hope it's just the sender or a dodgy connection.

Thanks.

[Gert_8]

Update. Drove car home. It was warmed up nicely. Oil lamp light didn't flicker at all, so I suspect it's a grumbling connection. If the weather remains nice, I'll take it on a longer run and see if it flickers again when it's hot.

Many thanks for your replies guys.

[Brianmoooore]

No 'grumbling connection' or poor earth will make the oil light come on. The only thing that will make it come on, other than a dud switch or a clapped engine, is the single wire from the switch shorting to earth, usually around the front of the engine, where it gets hot and the insulation gets brittle.

[Gert_8]

No 'grumbling connection' or poor earth will make the oil light come on. The only thing that will make it come on, other than a dud switch or a clapped engine, is the single wire from the switch shorting to earth, usually around the front of the engine, where it gets hot and the insulation gets brittle.

Have you got a pic of this location Brian ?

[Brianmoooore]

If I had a pic., it would take me the rest of the night to work out how to upload it!
Just follow the wire from the switch.

[Gert_8]

I've got nothing but admiration for you guys that know your way around an engine, but, regrettably, I don't.

I would like to be better than I am. Anyone able to direct me to this single wire and switch please? Images are always good, but if these aren't available easy markers on the engine, in terms of pointing out where this wire is, would be appreciated..

Thanks guys.

[Grrrmachine]

Gert, get your head under the engine and look under the exhaust manifold. There should only be one wire coming out of the engine there. That's the wire you need.

I presume you do know which one the exhaust manifold is

[Gert_8]

Gert, get your head under the engine and look under the exhaust manifold. There should only be one wire coming out of the engine there. That's the wire you need.

I presume you do know which one the exhaust manifold is

Thanks Grrr. Don't laugh, but it's on this side...right? /

[Brianmoooore]

As above, but don't confuse it with the crank position sensor, which is mounted on a bracket right at the front of the engine on that side, and has a single thick cable coming from it. Oil pressure switch is about a quarter of the way back.
Be careful that you don't dislodge the crank sensor cable, and the cable from the sensor on #6 plug lead, from the guide behind the water pump pulley which prevents them from being savaged by said pulley.

[FinalD]

I thought I had a pic of the cable running over the front of the engine but I can't see one in my web folder.

That is the correct side, below the exhaust there should be a small wire coming from the block/sump, this runs up below the water pump (and front radiator hoses), along the front of the block, back round to under the big round diagnostic port thing and plugs into a wire there.

[Gert_8]

Thanks Guys, I'll check it out tonight.

[Gert_8]

Right, Is this the lead I'm looking for, guys? It's very close to the oil filter..?

The first pick shows it connecting to the lower block, and the second pic shows were the lead ends.....on a screw?





Thanks guys.

[Grrrmachine]

Yep, that's the one. It doesn't end on that screw, but snakes around the front of the engine and disappears into the mass of wires under the intake manifold.

From your pics it looks in good condition, but check for chafing around the pulley and belts in your second pic.

[Gert_8]

Excellent. Thanks Grrr. I appreciate your help guys.

Now, if the problem is not with this wire, what is the problem, fix required and how much do you think that would cost. I'm hoping not to take this route, of course, but just want to be mentally prepared...