Oil Warning Light

[Z3MCJez]

Sigma 125 engine.

 

Changed the oil and filter last weekend. Filled to broadly right level, ran until warm and then filled to max level.

 

At Mallory yesterday, the warning light is flickering at high revs. Could be a failed sensor (pressure is fine, water temperature was fine) but seems strange that it happened immediately after I changed the oil.

 

I've used 5W30 fully synthetic - previously it had 5W30 part-synthetic. Could this make a difference? Anything else that I could have done wrong?

 

Jez

 

Build Photos

[Mick Day]

As long as the oil you are using is to the appropriate API grade, probably SL or SM, then the oil will be OK whether semi or fully synthetic. However be aware that certain (most?) synthetics are not proper synthetics.

 

If the OP gauge is reading OK suspect a failed WL sensor.

 

The WL sensor may be adjustable & that adjustment may have "slipped". If adjustable it can be adjusted with a small allen key.

[Willie.]

I'd be inclined to trust the warning light before the gauge. The gauges tend to be damped and give an average figure over a second or two, rather than a live reading like the light.

 

Any problem with oil pressure is serious, so I always check the metal bits, before worrying about electrical. If you're happy the pump etc is ok, then you can test electrial quite happily, without worrying your big ends are going to end up coating the sump.

 

My first check would be to drop the sump and look at the pick up pipe. Flickering at high rpm is a sign of a partially blocked pickup pipe. At low rpm, the pump is getting enough through, but at high rpm, there is a restriction which doesn't let enough oil through to keep up with the pump...and you get low pressure.

 

If you establish that its not the pickup pipe, and there is nothing floating about in the sump/crankcase (Maybe a bit of sealant if the sump is fitted with "instant gasket"), then look at electrical.

 

Hope you get it sorted.

 

Willie

 

 

[CageyH]

At high revs, the pump is pumping a large quantity of oil. Are you sure there is the right quantity in it? Too much oil may lead to windage and pick up problems.

 

Only dead fish go with the flow....!

[Z3MCJez]

Will check the grade, but am 99% sure it'll be the right one.

 

If the pump had gone completely, I assume I'd have zero oil pressure (here's my novice bit!). Is there an easy way to test it's running properly? I'll also check that the sensor hasn't moved.

 

Cagey - are you saying that having too much oil could lead to the oil light problem? I am right on max, but it's not dead flat where it's measured. I've always been from the too much rather than too little, but then I've not run any of my cars hard like I do with the Caterham.

 

A quick google search on windage suggests the symptoms I've got. I assume this is bad news generally (I.e. possible big end risk) and that I should find a dead level place to measure and let some oil out if it's over the limit. Any way of doing that without making a complete mess? As the oil is almost brand new, seems wasteful to chuck it all out.

 

Jez

 

Build Photos

[Mick Day]

Having had a few WL sensors fail I'd be more inclined to check that 1st before thinking oil pump failure or blocked pick-up. However I have seen this happen when a Zetec sump was grounded pushing into the pick-up & partially blocking the flow. Wouldn't do any harm to drop the sump & check.

 

However is it possible to temporarily fit a manual OP gauge just to check? A local garage should be able to do a quick check for piece of mind.

 

Another thought is have you fitted the correct filter? Some OEM filters have valves inside but some pattern filters don't.

[Willie.]

Jez,

 

I would doubt if you've overfilled it, if its on the max line, but I have never looked at the Sigma install, so I'm no guru.

 

I usually check my oil level with the engine running, as a fairly substanial volume of oil is held in oilways, the head, the pump and so on, when the engine is running...which drain into the sump when the engine is off.

 

Windage can also occurr when "wind" from the crank is frothing up the oil in the sump. I would be surpised if the Sigma doesn't have some form of baffle/windage plate to combat this. However, even without that type of windage, the oil is bring flung out of the big ends and mains at 8000rpm, so its bound to be picking up bits of air as its flung all over the place.

 

My problem with the windage theory is that I don't think you would actually see tiny bits of air in the oil as low pressure. Even if you did, the air wouldn't just dissappear as soon as you dropped the revs a bit, so the light should flicker for a while.

 

If the Sigma has hydraulic tappets, you would likely hear windage aerated oil as ticky tappets.

 

It could be electrical intereferance...or it could be something more sinister. Does the pickup pipe have sufficient clearance below it in the sump, or is it quite close to the bottom of the sump; causing a restriction at high flow?

 

By the way, what revs are high revs? 8000rpm?

 

Willie

[CageyH]

I would be tempted to change the sensor.

 

Windage leads to aeration, which leads to pump cavitation which causes low oil pressure. If the level is correct, I doubt this is the problem (having thought about it).

 

Only dead fish go with the flow....!

[Willie.]

Windage leads to aeration, which leads to pump cavitation which causes low oil pressure

 

Cagey, I'm going to tell Peter Charmichael on you 😬

 

 

Willie

[CageyH]

😳

 

 

 

 

 

 

 

 

 

Only dead fish go with the flow....!

[Martin J]

Where is the oil pressure warning light? I have the same sigma 125 as you Jez & I thought the gauge was the only indication of oil pressure? The bottom of the rev counter has the ign light & brake fluid light (lights up when you push the test switch) is the remaining third the oil pressure warning? No mention of this in the manual

[Willie.]

Who's betting Jez has mistaken the shift light as an oil pressure warning light?

 

May I be the first to give him a good ribbing if he has 😬

 

Willie

[Normans_Ghost]

Apart from the fact that unless Jez has fitted an oil pressure warning light there appears not to be one the correct procedure would be to connect a manual gauge to check that the dash gauge is about right. If it is and the gauge was reading OK then there would appear to be no problem.

 

If the dash gauge proves to be wildly out and the car is still under warranty then return it to CC for checking and rectification.

 

If, however, the flickering light was a shift light we should just keep quiet and allow the thread to fall into oblivion.

 

(some hopes)

 

^{Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here}

You and your seven toThe French Blatting Company Limited

[Windy Corner]

My Manual doesn't mention an oil warning light (but its a Sigma 150) but then I haven't got the brake fluid light either ????

 

R

 

Roadsport SV 1.6 Sigma 150

in Viper Blue here

[Martin J]

On my sigma powered car, if you push the sprung loaded brake test switch as well as the switch itself lighting up, a section of the light at the base of the rev counter to the side of the ignition light also lights up. Has your car had the updated rev counter fitted that was meant to sort out the innaccurate fuel gauge?

Caterham sent me a replacement gauge sometime ago but I still don't really trust the gauge.

I would be interested to know if there is some sort of shift light fitted but it seems unlikely. I'm not prepared to rev the nuts off the engine just to find out!

[Z3MCJez]

A couple of clarifications from my first post!

 

It's the oil level warning light that is flickering - the one in the speedo. I don't have an oil pressure warning light - I have a gauge - that was reading as normal. I don't have shift lights 😬 (Although they'd be nice, if the Academy allowed them!)

 

On the more serious responses ( ) Mick - I've definitely got the right filter (supplied by Caterham). However, I've had to replace a bent engine mount, so I've clearly hit something. I had an eventful day at Brands and while I don't remember any serious "clunk" a full inspection did find the damage. Now the sump itself is not showing any damage, but I wonder if I've partially blocked the pickup (or indeed, damaged the sensor). I may well have not noticed it during the remainder of the event, as I was too pre-occupied, although I did notice it on track at Mallory.

 

I assume the sensor just screws in somewhere?

 

Jez

 

PS Martin - I have a wildly inaccurate fuel gauge too. Never got a replacement - was told that TADTS.

PPS Opposite Lock - red line is at 6,800 in the Sigma 125

 

Build Photos

[Gridgway]

In that case does anyone know hpw the oil level warning system works on the sigma in a caterham? Are you really sure it's got one? Sounds far too sophisticated for a caterham to me!

 

Graham

[Mick Day]

It's the oil level warning light that is flickering

Please, please, please check with CC what warning lights you have. Although modern Fords may have oil level warning lights (probably only tell you when the level is well low)I would not have thought this would have been carried over to a Caterham installation.

 

If you've broken an engine mount by whacking the sump then I would want to check all is OK inside.

 

On a K series OP & WL sensors are rather vulnerable but not to sure where they are fitted on a Ford.

[Z3MCJez]

*redface*

 

^{It's the brake fluid level warning light}

 

I feel like a bit of an 🙆🏻. I called Caterham Midlands who have put me straight. Thanks for the nudge Mick - being a man, I don't like to ask for advice on the phone. I'll leave this thread open for a day for people to tell me I'm an idiot

 

In my defence, the actual level is not below the minimum, but then I do know that I've lost some brake fluid as I have new rear calipers ready to fit to cure the problem.

 

There is no oil level warning light, as was suggested earlier. Tuesday was the first time I'd driven it hard since changing the oil, so I immediately assumed that I'd screwed that up. Incidentally, the owners handbook doesn't have a description of all the warning lights.

 

🙆🏻 🙆🏻 🙆🏻

 

Jez

 

Build Photos

[myothercarsa2cv]

A lesser man would have claimed that it was a one off CC test mule

 

Never mind, Jez

 

John

_________________________

 

myothercarsa2cv

Bugsy: '82 2cv6 (Back on the road!!! 😬)

Talloulah aka Feargal: '08 1.6K Classic (Imitating an imitation 7!)

[tbird]

Jez your an idiot 😳 😬

But I would like to know which of us haven't been that same idiot in the past

 

glad its sorted 😬 😬 😬

[Normans_Ghost]

Jez, don't worry about it. I usually post my stupidity so everyone can have a laugh.

 

I assumed you had fitted an oil pressure warning light. It's well worth doing. And not difficult to do. I have a large warning light running off a 35psi switch. The light is directly in front of me and the ignition gets cut as soon as it comes on (other than when staitionary).

 

 

 

^{Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here}

You and your seven toThe French Blatting Company Limited

[Willie.]

Jez, don't worry about closing this thread...we'd just start a new one for you in ChitChat

 

You did just make my day though, and even if you do feel a wolly...be thankful you're not ringing up CC asking how much new big end bearings cost.

 

Willie

p.s. Muppet *tongue* 😬

[Martin J]

Ah Ha the mystery is solved!

Just top up the master cylinder with some DOT4 & you'll be fine.

 

Martin

[Roadsport06]

Z3MCJez, are you loosing brake fluid? I remember reading that CC had a dodgy batch of calipers recently that were leaking (you will need to do a search on here). It might be worth a look around to check you aren't loosing brake fluid.

 

BRG and Yellow nose now with added brooklands