Oil surge

[englishmaninwales]

Oh dear! I suffered a brief oil surge today. 1966 S3 with an standard wet sump.

Some spirited driving and took two right handers at speed, heard the brief clatter from the engine, and saw the oil pressure gauge at zero. I was able to dip the clutch and pressure returned immediately. Engine clatter and low pressure for 2 - 3 seconds maybe.

Stopped the car and to my utter shame found the oil level low, 2/3 down the 'fill' on the dipstick.

Engine now appears fine with no new noises and oil pressure hot is unchanged, 25 psi at tickover, 40 psi on open road.

Prior to this engine has been in fine health with good compressions, oil pressure, cold and hot starting. It was rebuilt about 20 years ago but has only covered 6k miles in that time.

My feeling is that I should pull the engine and inspect the bearing and crank. Little to lose in doing that, and I bet it all will look fine, but if I don't take a look fate will dictate a catastrophic failure later on and I will be even more angry with myself.

What's your experiences with oil surge and damage with these engines?
Malcolm

[robertverhey]

I've suffered a bit of the old oil surge/needle plummeting to zero on Kent engines over the years....usually on hard cornering (right?) when the oil level has been a bit low. No damage was done, so unless your clattering continues or your oil pressure is low I wouldn't go pulling things apart just yet

My kids drove one of our Audi A3s around for a few days before asking me to investigate a "loud rattling noise" in the engine.... Oh yes and "a big yellow oil can symbol on the dash"! It had dumped all it's oil courtesy of a blown o ring on the oil cooler adaptor (an Audi weak point). But it was fine, new o ring and fill the oil, off we go!

Robert

[rgh0]

Hi Malcom

Loss of oil pressure on right hand bends is common especially if the oil level is a little low. If oil pressure is OK and no further noises from the engine then you have probably not done any damage in the brief period of no oil pressure. You can pull the sump to check the bearings if you want to be extra sure, but a subsequent catastrophic failure is unlikely. If the crank or big end bearings were going to seize or catastrophically fail they would have at the time of the incident I think ( been there, done that, got the avatar to prove it ).

cheers
Rohan

[StressCraxx]

Agree with Rohan, it's happened to me too, but with no damage.

If you are concerned, you can do a "patch test" to detect metal in your oil.

Drive the car til the oil is good and warm, pull the dipstick and put a drop or three of oil on a piece of clean white paper. Let the oil stand for a few minutes on the paper and spread out. Look at the paper under a bright light or sunlight and look for specks or sparkles of metal. You and also do this with some oil drained from the sump.

Porsche mechanics used to perform this test on the early Speedster engines with the Hirth roller bearing crankshaft every race!

A sign of damage to rod bearings is an increasing knock under load and the knock goes away when you lift off the throttle. You will likely not see a loss of oil pressure from a rod bearing, only a main bearing.

Regards,
Dan

[englishmaninwales]

Thanks for this advice. I'll do a patch testand if ok just run it and see how it behaves.