DDK - Die Deutschen Klassiker

The last couple of times I've started my car after a stop of 8 hours or more the oil going back into the tank sounds like someone throwing it in from 50 feet.. It's always gurgled a bit, but this is loud. There are no oil leaks, no foam in the tank, oil level is fine, oil pressure normal.

Someone please give a simple and cheap explanation...

It's a 72 so the tank noise is more in the cabin than normal.

Hmmm, sounds interesting ... with the checks that you've done, I just can't think what that could be.

Are there any baffles in tank that could have moved? Could the tank have shifted so that it's touching somewhere new to transmit the noise? Is the thickness of the oil O.K.? (No petrol contamination). Have you noticed a fifty foot high pipe going in to tank that wasn't there before? Kinked oil pipe so that it's squirted in?

That's it: proof indeed that I really have no idea: looking foward to hearing what it turns out to be though

Have you recently changed the battery in your hearing aid?

Bob

I never hear my oil. Sounds like there could be a constriction somewhere. at idle on the flat the oil gushes across the top of the grilled insert to my tank but dioesn't make a noise. Something to do with the changes to your induction system? I've been following the megasquirt thread with interest, shame its way over my head.

Not very constructive, but I'm with Bob, are you sure its not titinus?

I'm really hoping that my advancing titinus will drown it out soon...

All the pipes look fine, I'll check the tank hasn't come loose, but it really sound like it's in the car with me...

After 30 seconds or so it's all normal, I thinking maybe all the oil has drained out of the tank over night and the excess noise is it being thrown into an empty tin? I need to look at the oil circuit and see what normally retains it, I guess it's the oil pump, so let's be hoping that isn't about to fail...

Can't see the pressure pump failing as like you say you've got good pressure, longshot... could it be the thermostat sticking on hot? i.e not closing and letting all the oil into the crankcase when the engine cools? havent got an oil system diagram handy to verify the oil system though, from memory the t/stat is after the pressure pump, which might blow that theory, certainly an odd one

Also isnt there a safety valve (not the pressure relief valve) between the pressure pump and thermostat that dumps oil into the crankcase?

Gary: I also wondered whether it was wet-sumping: strange if it was this that it seems to have happened over a short period of time though .

If your oil level gauge is working O.K. you could double check to see how quickly the level comes up. Is it smoking any more on startup? What about a temporary full length dipstick: are you near anyone else so you could use a long dipstick in another car as a comparison. Don't know if you could get one in, and all the way down or not: might give a clue.

I always suspected that my car put an extra couple of litres in the sump overnight: no real evidence, just the time it took for the oil level to reach its normal running stage.

Hi,

Did you find the cause?

Mine did this today when it was started, it has been sitting for a week or so. There was also distinctly blue smoke which cleared up about the same time as the noise stopped.

Neil

Hi, Nope still not found the cause, I tried topping the oil level up, but still the same.. no idea

I going to pull the engine out in a couple of weeks as the other minor mechanical noise is eating at my brain and needs to be discovered. I'll take a look at the oil system whilst it's out.

I've been thinking that potentially the scavenge pump isn't drawing the oil cleanly from the sump when there is a lot of oil in there (like when it's been left overnight) so maybe the gasket on the pickup tube is drawing air making the oil return to the tank 'pulse' hence the noise.

Well, over a year and 10K miles on and it's still doing it

So whatever it is it's not terminal for the engine, but I really would like to understand it as it is a little disturbing

With the influx of specialists on the forum maybe someone can help?

Gary could it be coming from the oil filter rather than the tank? I think there is a relief valve as part of the unit which could be causing it...just an idea

Hi,

Not long after our previous posts about this the oil pipe from the engine to filter console fell off!

I fitted a new pipe and also stripped/cleaned the console as there was a small oil leak from the o ring round the blanking part where the oil thermostat would go. This was difficult to find as it would run along the chassis rail and then appear where the engine bay sealing rubbers meet, it would then blow backward onto the rubber/metal joint of the pipe going to the oil tank! I also fitted a new filter.

Afterwards I have had no noise so I’ve fixed it but can’t tell you exactly what it was.

Regards

Neil

Thanks Neil and Brendan

I've changed the oil since this all started, but it is due another change this Xmas.

I'll clean out the filter console this time around as I also have a small leak from this area! I guess this means I have to tackle the the big fittings in the wheel arch get the console off the body. Can't quite see why this would cause the noise, but I will wait and see!

Can someone confirm that my marked up oil circuit is correct for a '72 without oil cooler? Red implys the pipes are not there and blue is were I expect a revised routing without cooler: