Right.. Last year I had a new engine in my polo because apparently oil wasn't getting to the top of the engine and did serious damage to it.. The oil light used to flash and it tap it's head off! Iv had no problems with the new engine but now the oil light is flashing again (yes there is the correct amount of oil in) it doesn't tap like before surly I won't have the same problem twice?! I had a new oil level sensor fitted when the engine was put in? Could it be that? Info would be much appreciated

I've just put this advice in for another thread, but here we go again for a fellow Yorkshireman!

Any loss of oil pressure should be checked by (temporarily) fitting an oil pressure gauge, this will eliminate (or otherwise) the possibility of the problem being down to the oil pressure sensor (it is a pressure sensor, by the way, NOT a level sensor).

It is quite possible that the sensor is causing the problem, but as you already know, serious damage can be done by ignoring what the oil light MIGHT be telling you.

I'm not sure what model you are running, but what I have said above, applies to just about any motor car.

If an oil pressure test does prove that the actual pressure is low, you may well have a claim against whoever sold you the new engine (assuming that it was reconditioned and not just second hand.)

Regards.

Ok thanks for your info ik try a new sensor and go from there

Here is what I found with a similar problem and the fix for the problem.

500+ miles since the fix and all is still OK.

Symptoms:

Oil light (and buzzer) comes during a journey at different times for different journeys.

Oil and filter have been changed and the oil pressure switch has been tested and found to be OK.

As the oil pressure is OK for parts of the journey (sometimes 1 hour+) even when the engine is up to temperature this rules out the oil pump.

This just leaves a few possibilities:-

a) Sticking pressure relief valve

b) Partially blocked pickup pipe with sludge causing a temporary blockage

c) Blockage in the oil pressure switch oil feed.

Possibility c) was easily tested by removing the oil pressure switch and using the air line to blow through the pipe work. There did not appear to be any blockage with air coming out from the crankcase breather. I thought this might clear a partial blockage in the pickup pipe as that would be the route of the air through to the sump.

After the above had been carried out it was about 1 week before the light came on again, this time at slow speed just as the car was moving off.

As possibility a) would mean a removal of the oil pump it was sensible to try possibility b) first.

This involves the removal of the sump and then removal of the oil pickup pipe.

Removal of the sump is relatively straightforward and does NOT require the removal of the exhaust or the drive shaft (as recommended in the VW service guide). In addition to normal tools you will need a long 5mm ball end Allen Key to get at the 2 sump bolts next to the flywheel and a 5mm Allen Key with a short leg (about 10mm) to get at the sump bolt behind the drive shaft.

Process is:-

Jack up and secure the car on axle stands (or use a lift if you have access to one), don’t forget to chock the rear wheels.

Drain the oil

Remove the plastic guard at the alternator belt end (prise off with a screwdriver)

Remove the flywheel blanking plate from the flywheel end (2 x 10mm bolts)

Unclip the wiring harness guide channel (clips onto 4 sump bolts)

Remove all the sump bolts (5 mm Allen Socket/Key/ball end Allen Key)

Using a rubber mallet to gently tap the sump pan to break the seal of the silicone (no gasket is used just silicone sealer)

Remove the sump and the oil pickup pipe can be removed by undoing the 4 x 10mm bolts. Take care with the gasket under the oil pickup pipe flange.

Once the sump had been removed the amount of sludge in the bottom of the sump could be seen and it was reasonably obvious that this could be the cause of the problem. The car has done 79K with a full service record which shows the oil and filter have been changed as per the service schedule.

The oil pickup pipe wire mesh sieve was also partially blocked with sludge and due to the design of the pickup pipe and wire mesh sieve with the metal shroud any sludge just gets compacted around the sides of the wire mesh sieve and cannot drop out of the shroud end. This results in a reduction of the available surface area of the wire mesh sieve and the increased chance of blockage with any sludge deposits in the sump (of which there were many)

I have many years of experience in building Race Engines and am a qualified Automotive Engineer so the following describes a modification that was made after the application of years of experience and knowledge of how lubrication systems work.

The modification was made to the end of the oil pickup pipe by removing the metal shroud. This has the effect of preventing sludge from building up and blocking the sides of the wire mesh sieve.

The shroud was cut using a hacksaw, with great care, and cutting through the metal shroud as far down as possible.

The resulting oil pickup pipe end would be less likely to clog up with sludge and would present a greater surface area of wire mesh sieve to allow oil to get to the pump

The distance between the end of the oil pickup pipe and the base of the sump is very little and the modification will allow a better flow of oil around the pickup pipe.

The before and after photos are shown below and illustrate the improvement.

Before

After

Comparing the modified oil pickup pipe with the original you can see the removal of the metal shroud and the reduced chance of clogging.

With the modified oil pickup pipe refitted, not forgetting the gasket, the sump can be refitted after cleaning and the application of silicone sealant (Loctite 5910 or similar).

Make sure the boltholes have silicone sealant all round.

Refit the flywheel blanking plate and the plastic guard at the Alternator belt side.

Refit the sump plug with a new copper washer.

Fill up with oil – 3.5 litres

Run and check for leaks.

Carry out an extended road test.

So far I have not had a recurrence of the problem and given the state of the oil pickup pipe and the sludge build up in the sump I am confident that with the modification carried out to the oil pickup pipe that this problem has been resolved.

I have no idea why VW have used this type of oil pickup pipe with the metal shroud that has such a small opening and which is positioned so close to the sump that it almost guarantees that any sludge will be picked up. The overall design just doesn’t work.

The size of the wire mesh sieve also seems to be very small and I did consider removing the existing wire mesh sieve and fitting a flexible wire mesh bag over the end of the pickup pipe.

I have seen many posts on various forums that go some way to solving the problem but hopefully this will help once you have exhausted the easier tests.

Edited 21 May, 201115 yr by gma