A friend has an N reg Fiesta (1.1 pushrod engine) which seems to have developed a lot of 'mayonnaise' inside the rocker cover. Deposits are even present on the dipstick. The car is used for short runs only and I realise this doesn't help.
Can anything be done to alleviate the problem. e.g. a blast down the motorway once a week to get the engine good and hot? Is there a breather pipe blocked somewhere? Finally, does the presence of 'mayonnaise' do any real harm? Many thanks for any responses.
Change the oil every 6 months, replace the breather cap and use the car more, if it doesn't warm up within a couple of miles replace the thermostat.
mrcheerful
Regular oil changes will help to an extent, but only real cure is a nice long drive on a regualar basis. Breather pipes can get blocked, but generally the mayo is soft enough that it'll evaporate out.
Myonnaise indicates water bin the oil. The oil emulsifies in the water and turns to mayonnaise.
It dcan indicate a blown gasket, some other seal or a crak in your cylinder head or elesewhere, gaskets are first priority.
The mayo may evaporate out, but only if the water entered the oil from such a place as the filling cap, or before you put it into the car.
Who let these goons loose on computers?
I often wonder???
as for harm, I don't know but thinking about what causes the mayonaisse; i.e. water in the oil then you'll do at least two things.
1- the 'mayonaisse' standing in the sump etc., when the car is parked, up will separate and you'll have precipitate water at the bottom, maybe leading to corrosion? 2- the lubrication properties of the oil will have changed and hence the car may be grinding away it's bits.Empty the sump, change the head gasket. Run the engine when empty of oil, for a short time and with the oil filler cap off and no dipstick (just a brief spell, no more than a minute or two - just to create some heat and boil off waters - the car'll get hot pretty quick - don't blow it up), refill with oil and check the dipstick again at a later date. You may have to do a couple of oil changes to flush it out, but it's unlikely.
Running it on substandard or no oil for too long will cause problems.
I used to get this in the 1.0 Kent engined Mk2 Fiesta, but only during the winter months. During the summer and autumn, all was ok, but during the winter the mayo would start to appear around the filler cap. It probably didn't help that I would drive under 5 miles at 5am on a cold winter morning and not getting the engine up to heat. Cured in the end by covering half the radiator during the winter with tin foil, engine finally got hot enough to drive the damp out.
PDH
The thermostat is in fact working? If it's not, on any longer runs, driven gently, the engine may not get to warm up at all.
DO NOT under any circumstances run the engine without oil in it, even for a few moments.
This seems to be a cure that's worse than the disease... Water absorbing oil, as is used in cars, will pick up any remaining water.
I'd consider getting it nice and hot, then draining the oil, while still hot. Do be careful not to burn yourself of course.
Freeing the sump bolt and retightening while cold is probably a good plan first so you don't struggle with it.
Billy H ( snipped-for-privacy@nanteshoward.nospam.f9.co.uk) gurgled happily, sounding much like they were saying :
To the OP - PLEASE, please, please, ignore this advice completely.
BillyH is a dangerous loon.
And that's exactly what I was told (by a repair shop) was the cause of the mayo build-up in my air-cooled VW back in the 60's when I was young and inexperienced, although I found the explanation puzzling at the time.
John
Perhaps you could tell us, as you're the one who seems to be arguing with the majority here? But just for you, here's an explanation of the 'mayo' problem, but I'm sure you'll find the standard textbook reply, and many years of trade experience totally wrong, after all, you seem to know better -
The mayo problem on these engines is a well known issue. It is caused by the water from the combustion process (which all petrols produce to some extent) entering the crankcase via the piston blow-by gases. On an engine that reguarly reaches operating temp for reasonable periods of time, it is not an issue, as the water stays as a vapour and gets drawn back into the engine via the positive crankcase ventilation system. But on vehicles only used for short journeys, where the engine never gets a chance to fully warm up, the water condenses on the inside of the engine (typically around the PCV fillter/gauze), where it mixes with the oil vapour, eventually emulsifying the oil, leading to the mayo that is commonly found inside the oil filler cap. The effect is more pronounced on the 1.1/1.3 endura engines, because the oil filler cap is also the crankcase vent, so the vapour is drawn to that area. I've seen other vehicles that have the mayo effect, but it's not as readily visible, due to the fact the filler cap is just that, and the mayo forms around the PCV filter/gauze, which isn't usually visible.
A headgasket failure can also cause mayo, but headgasket failures on these engines aren't very common. Combined with the fact the OP, didn't mention any coolant loss problem, I very much doubt the headgasket is a problem.
Where did he even say "sump"?
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