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MG TD TF 1500 - Sludge

This is what drips out of my breather pipe. I scraped this out of the bottom of the pipe. (The oil on the dip stick looks fine and clean.)

To my inexperienced eye it looks like water and oil that has been whipped up into a mayonnaise consistence.

Any ideas on what's going on in my engine?


Mort 50 TD

No clue, but it looks disgusting! Maybe pull the rocker cover and see if there is any gunk under there?
George Butz

Condensation build up? PJ
Paul S Jennings

it is definitely an oil water mixture..i am with PJ on this one..condensation mixing with the oil fumes in your breather system. regards, tom
tm peterson

Hi Mort,
I agree with PJ & Tom. I've seen it in the past, seems like happens if the engine has not run long enough, for several times, to get up to, and stay at, operating temp for a while.
54 TF "Emma"
A W Parker

It is moisture mixing with the oil blow by and congealing into that mayonnaise mess. Open your rocker cover, you may see the same in there.

In the original design, the scarfed bottom of the pipe sits in the airstream while moving and draws crankcase vapor out, along with moisture. The vent air in comes from the rocker cover hose going to the air cleaner element. The amount of ventilation is controlled by the size of the orifice in the air cleaner vent. You seem to be drawing in more air then needed which is adding moisture to the crankcase. Try putting an orifice in the line going to the rocker cover, and make sure your pipe is oriented right side up so the air is being drawn out by venturi, not pushed in by ram air pressure. i.e. the slant should angle up towards the rear of the car.

Don't run a rocker cover without a vent as ironically, no vent can cause the exact same problem, especially on engines which are well sealed (i.e. no oil leaks).

hope this helps,
Dave Braun

What you say makes sense.
I had the valve cover off yesterday to check on the head bolts and the area is pristine. No sludge, just clean oil.
The dip stick is the same way.

This past winter, before I did work on the engine, I had a lot of blow by and a lot of discharge from the breather but it was oil and not sludge. It was splashing the undercarriage so I put a rubber hose on the end of the breather in an attempt to lower the exit point and hopefully not mess the bottom up. I probably changed the angle at the bottom and messed up the aerodynamics. By the way it was not effective. I still got a mess underneath.

Although some have advised against it, I mocked up a PCV system and now the breather goes through an oil separator and to a PCV and into the intake manifold of the supercharger. The attempt here was to lower my crankcase pressure.

My concern with this posting was the source of the sludge. If it was internally generated than I would eventually plug up my breather to PCV line. If the sludge is from the ram effect (external) than my current set up will eliminate that concern.

In the photo you see the oil scrubber between the PCV and the side cover and a second oil scrubber between the valve cover and the air filter. If this works i will come up with something more permanent.

Then future mayonnaise will come from the grocery store only.
Thanks, Mort

Mort 50 TD

If the blower is pushing 6-8psi of positive pressure into the intake manifold, does the suction exist to make the PCV system work? Just head scratching.

J K Chapin

I am no expert but this is what I understand.

To start with remember that the PCV is a one way valve.

The intake manifold can be positive or negative pressure. At idle and at cruising level it is negative. The blower kicks in on demand. While accelerating either shifting or when cruising and you step on the gas. Then the manifold is positive.

Now the effect this has on the crankcase. When the intake manifold is under negative pressure (most of the time) the PCV is open and the vacuum sucks fumes out of the crankcase thus lowering its internal pressure. When the intake manifold is under positive pressure the PCV is closed and there is no effect on the crankcase pressure.

The benefits are:
1-The reduced crankcase pressure tends to lower the amount of seepage of oil through the seals and gaskets.
2-The oil scrubbers are collecting the discharged oil rather than polluting the atmosphere, my engine compartment and my undercarriage.
3-When properly fitted the oil can return to the sump.
4-If it works it will make Mort and Mobius happy.

Mort 50 TD

Mort, thanks for the explanation. I was assuming (you know what that does) that a blower was always pushing enough air into the system to create positive pressure. I guess I've looked at clouds (and now blowers) from both sides now and I really don't ...

You guys are great for responding nicely and informatively to DQs.

J K Chapin

dave, are you sure about the "air vent in comes from the hose off the air cleaner"? how would the inside of the rocker cover be at a lower pressure than the rocker cover which is open to the crankcase? how would air being drawn through the air/oil bath have pressure above the rocker cover? thank you. regards, tom
tm peterson

Mort, I am curious how your sludge issue was solved. Could you comment on this? Thanks, Huib
Huib Bruijstens

This thread was discussed between 11/06/2014 and 29/03/2016

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