Oil light flicker

[MMMC]

Hi

I know this will have been asked before but my search wasn't very successful. My oil warning light has started to flicker after the engine has been working hard and is at idle. It doesn't flicker when its working - just on idle after its been hot. Any clues? What is the normal oil pressure for a warm engine at idle? cheers

 

[TheBusDriver]

Oil pressure should be roughly 10 psi for every 1000 rpms.

The oil pressure sender should only come on at a very low psi like 4-5 if I remember right.

2 cheap things to try are:

1. Replace the oil pump cover. On high mileage motors the gears wear a groove into the cover causing low pressure.

2. Replace your oil pressure sender. It may be on its way out.

If neither of those solutions work, you can put in a slightly thicker weight oil and start saving up for a rebuild. If you replace the bearings now before the motor quits it will make for a much cheaper rebuild.

 

[MMMC]

Hi mate - thanks for your response.

I did have an issue of the fuel dumping into the engine the other week and I replaced the oil...I changed the oil again last night so it may be that the fuel was contaminated...I'm going on a big run at the weekend so will keep an eye on it.

I just use Morris's SAE30 so any other suggestions appreacited.

 

[bobley]

The petrol leak will certainly "thin" the oil and reduce the pressure. As far as service fill oils goes I cant see any harm in using a more modern 15W40 multigrade like Castrol GTX Magnetec. Dont use a modern long life oil though as the detergents will probably scrub the muck out of all the nooks and crannies which will do more harm than good.

 

[noddy]

Had this type of problem with my old engine, tuned out to be worn gear ends and cover plate had deep scores in it.

For the cost of a new oil pump I wouldn't mess around, get a new one in as soon as.

 

[Trikky2]

As suggested - use 15/40 or 20/50. If you still get the problem then try replacing the sender before doing anything more expensive.

 

[MMMC]

cheers chaps. Will look at a 15/40 oil.

 

[ProfessorWheeto]

Make sure its 15/40 MINERAL otherwise you'll kill the engine. Semi or Full synthetic are a big no no.

My old beetle has this problem and was actually worse on the expensive stuff. As I change the oil often (as your meant to) I just shove the cheap stuff in carplan or halfords own brand.

Is the van using any oil?

 

[MMMC]

Make sure its 15/40 MINERAL otherwise you'll kill the engine. Semi or Full synthetic are a big no no.

My old beetle has this problem and was actually worse on the expensive stuff. As I change the oil often (as your meant to) I just shove the cheap stuff in carplan or halfords own brand.

Is the van using any oil?

The van isn't burner oil really just the normal bit of smoke like with any vdubs. What did you do to your bug to solve the problem? To be honest if I just blip the accelerator the light goes out anyway...

 

[noddy]

Does it do this from cold or only when hot?

I still think is sounds like a worn oil pump.
Pumps are only about 25 quid and new gaskets about 5 quid, just the hassle of having to pull the bottom pulley off, loosen case bolts around pump, getting pump out can be a pig even with a puller.

Another though is one of the oil pressure regulator plungers in the base of the engine case could be sticking open or be worn, this would cause lower oil pressure.

Also is you engine tick over set at 850 rpm, oil light comes on some time at low tick over speeds.

 

[MMMC]

Yep the engine only does it while hot and as soon as it cools a bit there is no trouble. The tick over is OK. It dosn't happen all the time. What I may do is replace the oil pressure switch as suggested and go from there...I 'll update once I've sorted.... cheers for your advice

 

[noddy]

Hi MMMC

dont over tighten the pressure switch its on a tapered thread, it its overtightened the case can split.

 

[ProfessorWheeto]

The van isn't burner oil really just the normal bit of smoke like with any vdubs. What did you do to your bug to solve the problem? To be honest if I just blip the accelerator the light goes out anyway...

If you put any throttle on it'll kill the light as your making the pump work slightly faster and building the pressure.

With my bug it was a combination of things, incorrectly set timing and carb (causing hot running) stupid monza 4 tip exhaust and even more stupid chrome firewall! B+Ps were pretty shot though, if you pulled the oil breather pipe off it was puffing smoke like a steam train.