S2 Renault Engine - No Oil Pressure

[Taggart]

Any advice would be appreciated please.
Car has been in garage for a couple of months. Started it up this week for a quick Christmas / New Year run out.
Started OK but absolutely no oil pressure!
Gave it a slight rev but pressure will not build up - verified by rattle off the bearings.
Immediate thoughts are drop the sump and remove oil strainer to check for debris blockage, then remove oil pump and relief valve to check over. Car had 55-60 psi when last used. It is original non-crossflow engine.
Anything else you can suggest before I proceed? Can I take the sump off with the engine / transmission in situ ?

Mark Gilfedder   

[dakazman]

    For Renault… l What type oil pressure sender? Can you loosen the sender and verify no oil pressure while cranking?
Do you know how to remove and install a distributor? If so remove it.
Drain oil into a clean drain pan, ( if you have a paint filter ,strain it ), then pour it down into the distributor hole, the object is to let it lube the shaft into oil pump. Save about a quart for the head since it may be dry from running before.
Reinstall distributor and start engine.
 Success?
Dakazman
 

[GavinT]

Sounds like you're on the right track. This is a very unusual situation.

I'm pretty sure you can get the oil pump out with the engine in situ. I recall you may need to jiggle the sump a little due to the surroundings.
You should be able to measure the pump rotor clearances before taking it out, if that's needed.

[jbcollier]

Sounds like your pump has lost its prime, the pressure relief valve is stuck open, or the oil pump drive has failed.  The first is the most likely.  Since it is an original engine and it rattles without pressure, most probably the pump is worn allowing the oil in the pump to drain and the pump to lose its prime.

You can get it running by removing the oil filter and using a large syringe to force oil backwards into the pump.  This will restore its prime and allow it to work again.  You could also just fit a new pump, properly prepped, and you are off to the races again.  However, if the engine is truly original and virginal, the gods are sending you a sign that it is time for a proper overhaul.

[Taggart]

Thank you for the advice.
I took the oil filter off and injected oil down the centre piece. Oil pressure came back to normal as soon as I started her up.

Not sure why this has happened- the filter is MAHLE OC11 which does not appear to have any non-return mechanism. It could be as JB suggests that after 59K miles and 55 years the engine is due a full overhaul. Not sure if there is anybody left in UK capable of doing the job properly.     

[richyb66]

Salv Sacco in Wolverhampton is your man for Renault engine work.

[jbcollier]

It may not be "worn out", just in need of attention.  The bearing material is a bit fragile and does not like long exposure to acids in used oil.  If it sat for a long time with used oil, the bearing material can be eaten away. The rattly bearings on start up are potentially a sign of that.  Easy to check though, just drop the pan and inspect a rod bearing or two.  If the crank looks good, nothing on the crank that will catch on a finger nail, you could just fit new rod bearings -- check a main as well if the rods are bad.

We once had a VW Beetle come in after tens years sitting with old oil.  Every bearing was down to bare copper with not a mark on the crank or the copper.  The bearing coatings had just been eaten away over time.