For our resident "Oilman"

At the risk of boring everybody else, my problem is as follows: -

In my 1989 E34 520i, pots 2,4 and 6 are letting oil in via one of the Valves.  I have come to the conclusion that it is Valves not Rings because the plugs are fouled-up on one side only.  If it was the rings, I would expect a more even fouling.

To mend the problem is a “Head off” situation, which will cost me more than I paid for the car…..I am happy to clean the plugs and replace them every 3 months.

The plug fouling is the classic “Brown and crusty, with traces of black and wet”.

I have tried Wynns stop leak, to see if the neoprene seals needed cheering up – to no avail.

I have been trying a thicker oil (20w50) to see if that slowed down the oil leakage.  Apparently to no avail.

So, what if I try a very thin oil, say 0w50.  My reasoning here is that the thinner stuff may have more chance of burning off.  Good plan bad plan?  What other tips could you think of, just to reduce the problem.

Tanks in advance.

Thanks for fast response!

Great minds.....

I too find it very odd and too much of a coincidence that it's only those three pots.  The other three are perfect by the way.

Because of the odd selection of pots, and the fact that leads 2,4,6 are on the same side of the Dizzy cap, I changed the leads, the Cap and the Rotor arm...months ago. So I've now ruled that out......but, what else could cause a mis-fire?  How can this be checked? (Note 1)

The tickover does sound a little ropey, but I was putting that down to age/mileage.  It was awful on tick-over until 3 weeks ago when I drowned the ICV in carb cleaner.

Mileage...just this week passed the 150K.  Oil pressure light flickers on tick-over, but hardly noticeable in daylight.  Oil light goes away as soon as revs are given.

(Note 1.)  If that answer is a main dealer/ decent garage check-up....who in South Wales does the collective rekmend?

I am suddenly growing confident that we (You team) can bottom this!!

Yep, cheers.

My mind is now bent on the fact that it is a timing / ignition problem.  But I will check the Mazda RX8 oil out.  BTW, it's a 1100cc engine, that gives WORSE mpg than my old 520i.  !!!!!!!!

More info on my car, mpg is still as per handbook, the coil is old...but if that was iffy, then all 6 pots would give an iffy bang, not just my problematic 3. Yes/ no?

The pulse sensor (As I call it) is on lead 6.  That correct...or does it make no difference?

Ok, here comes the surprise, I own an RX8 as my daily driver (ex BMW man) and the recommended oil is a semi-synthetic Ford spec 5w-30.

The reasons for this are simple:

The engine burns oil like hell (1 litre per 1000 miles)

The engine is very uncomplicated

5w-30 is a good "all year round oil"

The oil is in the engine for such a short space of time that it doesn't have time to thermally breakdown!

The fact of the matter is that you could try something thinner, say a decent 5w-40 and see if it works but I'm no mechanic so I'm unsure if your problems are terminal or not.

Cheers

Simon

Actually practically no torque at all, but a nice high power figure, around about 200bhp for the low model and 240 for the high if memory serves :)

Think they still get less than 20mpg though!

GT6-M3 wrote: Actually practically no torque at all, but a nice high power figure, around about 200bhp for the low model and 240 for the high if memory serves :) Think they still get less than 20mpg though!

You're right, I have the "high" power model and my MPG's are between 18 and 24.

There have been many discussions on "torque", all I can say is test drive one, they are great fun if you use the gears and the revs properly. It also handles extremely well.

Would I buy a 300bhp on? Yes please!

Cheers

Simon

ermmmm

That's what happened to me, test drove it and was addicted.

The sound of the buzzer at 9500 rpm is like a drug!

Cheers, Simon

I am still trying to bottom this fault.

Fellow car nut here at work also thinks this is an ignition / timing problem as opposed to a Cylinder/valve guide leak of oil.

He asked if there was two Fuel rails - one feeding pots 1-5-3 and one feeding 6-2-4.  Is there?

What else is/could be specifically related to pots 6-2-4?

Would a new ignition chip in the ECU do any good?  If so, what is the exact part description/number?

Throttle body - as my ICV was gummed up, it follows that the interior of the throttle body will be too.  I can only get at the side where the large intake pipe is - and obviously a bit of the inside with the butterfly open.  I want to remove the T.Body and give it a good squirt with carb cleaner - but the Haynes (Joke book) suggests that I have to remove the water hoses from the throttle body.  I can't see any such, nor do I understand why there should be such???  What are they talking about?  Is removing the T.Body as simple as the 4 nuts (Plus the associtated Air-lines and Elec. Connections)?

Looking forward to responses.

Old shape! wrote: I want to remove the T.Body and give it a good squirt with carb cleaner - but the Haynes (Joke book) suggests that I have to remove the water hoses from the throttle body.  I can't see any such, nor do I understand why there should be such???  What are they talking about?  Is removing the T.Body as simple as the 4 nuts (Plus the associtated Air-lines and Elec. Connections)? Looking forward to responses.

The throttle body on my engine has cooling water running through it. I didn't realise until I tried to remove one of the hoses. Doh!

I managed to remove my throttle body and clean it without disconnecting these two water hoses.

No idea why the throttle body has cooling water running through it. 

Back to the oil in cylinder problem.

I had a long chat with a BMW mechanic (Retired - so knows a bit more than todays "Plug it in and see what the computer says") mechanics.  He suggested the only thing to do to cheer up the car, and prevent me scraping and wire-brushing plugs on a weekly basis was to put hotter plugs in the cylinders affected.  After a few weeks delay (Waiting for NGK to find a source in the UK that had some of the correct type) I telephoned Champion Technical, their hotter version of the N9Yc is the N12Yc.  They have been in the car since Friday 19th Nov. and since then I've clocked up 510 miles.  The plugs are fouled up, but nowhere near as bad as they would have been with N9Yc's.  After 500 miles with 9's, I would be starting to misfire as the gap was breached with crusty-brown unburnt oil!  So, I am beginning to succeed.

Nowthen, I may try an even hotter plug to see if the whole of the depositing oil can be burnt off.  Has anybody seen a Hotter (With Champion it's a higher number) plug than a 12 in the shops?

Do we have a resident Spark plug expert as well as an oil expert?