Reasons for Mayo in the oil.

Post by **Defender110** » Thu Jan 27, 2011 12:02 pm

I'm with you on this Ken just condensation. 36,000 in 22 years the engine oil has never had a chance to get up to working temperature to remove any condensation everytime it is started just adding more each time.
It'll take more than one oil change and 500 miles to flush it all out.

Mike E (uk) · Post by **Mike E (uk)** » Thu Jan 27, 2011 7:55 pm

I reduced my mayo by switching to semi synthetic oil, but as the others have said, if it only collects in the filler cap, I would not worry about it.

I still get some mayo, but I wash the filler with a hose when ever I think of it, and it has been much the same for the last 10 years.

Almost certainly just condensation in your case too. The filler pipes on the top of the engine don't get warm, so any moisture gathers there.

I replaced my metal filler cap insert with one of those stainless steel kettle anti scale pads, and it is much easier to clean.

My engine has done about 100,000.

I would fit a proper engine temperature gauge anyway-I think it is the most important gauge on any engine. All the others you do not really need (if it wasn't for the wretched speed traps).

Mike

Rich · Post by **Rich** » Thu Jan 27, 2011 11:22 pm

I've been chatting to a mate of mine who is a mechanic. He had a look and suggested a breather problem.

He said to clean out the pipe work by the oil filler, bung some engine flush in to clean every thing out and change the oil and filter again.

Mike E (uk) · Post by **Mike E (uk)** » Thu Jan 27, 2011 11:32 pm

yes- I did that, and it made no difference at all!

Mike

Philip Chidlow · Post by **Philip Chidlow** » Fri Jan 28, 2011 12:21 am

In my experience, flushing an old engine causes more problems than it solves.

rmattila · Post by **rmattila** » Fri Jan 28, 2011 3:33 pm

This is a continuous topic of discussion in Finland: some cars have this problem every time it gets the slightest bit chilly (below -15 C or so), and unfortunately BX is among those. A special windshield is fitted during the winter time in front of the radiator grill, the steel wool stuff was removed from the oil filler cap early on by the official instructions by the importer, short trips in cold weather are avoided, and a heated discussion is going on about which oil to use in winter time. Breather pipes are being insulated. Some even use special electric heaters in the breather pipes.

Still, a number of BX:s vomit their oil through the dipstick every winter due to freezing of the breathers and a design error in the dipstick guide tube (too long: reaches below the oil surface).

I use an electric engine heater and let the car idle for a few minutes before getting on the road when it's cold, and have thus far avoided these problems.

Mike E (uk) · Post by **Mike E (uk)** » Fri Jan 28, 2011 6:02 pm

In the winter I used to put a large about A4 sized sheet of aluminium behind the rad, it seemed to keep the temperature up, simply by reducing the cold wind over the engine.

Then we had lots of mild winters, I did not use the sheet and now I have lost it.

It may have helped reduce the mayo problem, and it is a good idea to help the motor keep warm.

Mike

kiwi · Post by **kiwi** » Fri Jan 28, 2011 6:10 pm

For some reason my BXs do not seem to suffer that mayo problem here. Altitude, humidity, mild winters maybe?

Post by **Defender110** » Fri Jan 28, 2011 7:27 pm

Mike E (uk) wrote:In the winter I used to put a large about A4 sized sheet of aluminium behind the rad, it seemed to keep the temperature up, simply by reducing the cold wind over the engine.

Then we had lots of mild winters, I did not use the sheet and now I have lost it.

It may have helped reduce the mayo problem, and it is a good idea to help the motor keep warm.

Mike

Mike

I have some ally sheet off cuts if you want me to send you an A4 sized piece?

Post by **docchevron** » Fri Jan 28, 2011 8:21 pm

rmattila wrote: every time it gets the slightest bit chilly (below -15 C or so),

Blimey, i consider +15°C a "bit chilly"
-15 is sodding freezing!

rmattila · Post by **rmattila** » Fri Jan 28, 2011 8:32 pm

docchevron wrote:
rmattila wrote: every time it gets the slightest bit chilly (below -15 C or so),
Blimey, i consider +15°C a "bit chilly"
-15 is sodding freezing!

Yeah, well, as you probably have noticed, English is not my first language - having trouble with these slight nuances..

Post by **Defender110** » Sat Jan 29, 2011 12:47 am

rmattila wrote: Yeah, well, as you probably have noticed, English is not my first language -

No I hadn't noticed, your English is excellent.

Post by **docchevron** » Sat Jan 29, 2011 1:34 am

I guessed from links and location! But yeah, your English is very much better than many English people.

It was merely a joke, and a bit of a point to the winter, that to me at least, feel like it's lasted for 19 years solid now. Very very bored of the cold.

rmattila · Post by **rmattila** » Sat Jan 29, 2011 4:22 am

docchevron wrote:It was merely a joke,

Mine too: although it occasionally falls below -30 °C here, I consider -15 bloody cold as well.. The mayo problems start way earlier (around -5 °C or so), and BX is notorious for the nasty habit of shooting the oil out through crankshaft seals or dipstick tube. Not as bad as ,say, early C5:s, but something of a continuous topic for discussion anyway.

Cleaning of the breather pipes, windshield in the front, good-quality oils and insulation if needed all help to reduce the condensation/freezing problem. And letting the engine get thoroughly warm every now and then.

And the dipstick guide tube should really have been designed so that if/when the breather blockage occurs, it's only the pressure, not the oil that escapes through it. Cutting it a bit shorter at the lower end helps.

citronut · Post by **citronut** » Sat Jan 29, 2011 8:03 am

first thing i would check is the crank case breather is all in tgood order,

hose's and both filter's the one in your photo and the one inside the filler kneck, the pipe between the bottom of the filler kneck quite offten becomes kinked over which blocks the breather,

the other thing which can cause the mayo is cheap engine oil,

regards malcolm