Morris Minor Owners Club

What is the cause of sludge?

In other words, can it just be down to old oil?

Onne

flush the engine that cured mine.

I was told sludge was old oil and condesation that emulsified the oil (white sludge)

Just what I wanted to hear. Smells like old oil anyway.

but then the car has been stoof for 2 years, and they probably didn't put it away with clean fresh oil.

I'll buy some engine oil flush to get rid of the sludge, and then some nice fresh 20W50

Or just use diesel engine oil for 500 miles or so. Much kinder than an intensive flush.

what does that do then?

Diesel engine oil has more detergents to clear sludge, which accumalates more readily in a diesel engine. For the same reason they shouldn't be used all the time in a petrol engine ( detergents can dislodge crud that actually helps compression), they also work as a flush for a short period of time.

I will try that. What is the thickest diesel oil you can get?

15w40 probably, I should think that would be fine.

Ok, will give that a go, thanks for the tip

When I took the sump off the engine that is going in Sophie there was a thick layer probably 10mm of sludge in the bottom. I had to scrape it out. The worryiing bit was that underneath the sludge were several bits of metal. So I would suggest a magnetic sump plug or magnet on the oil filter would be a good idea.

Diesel oil may not be a great idea - it may (as mentioned above) remove deposits that are helping to seal up the pistons and rings !! I would suggest just an oil and filter change - using cheap ASDA 20W50 oil - and then change both again after 500/1000 miles running. In fact - I use the ASDA oil all the time - in both Minor and Mini - not given me any problems at all over the last 6+ years. There should NOT be any metal in a Minor sump - this is a problem with Minis where bits get chipped off the gears which run in the sump (hence they have magnetic plugs) - but there is no way metal bits can appear in Minor oil - unless very serious engine damage is happening!!

Is the ASDA oil better now that the price has gone up? ;-)

I also noticed B&Q do a cheap 20w50 and this one has an API rating.

when I said " bits of metal" I meant filings not pieces of metal!

bmcecosse wrote:I would suggest just an oil and filter change - using cheap ASDA 20W50 oil - and then change both again after 500/1000 miles running. In fact - I use the ASDA oil all the time - in both Minor and Mini - not given me any problems at all over the last 6+ years

This can be done perfectly in any old car (execpt the high performance cars). Why? Because modern cheap and low additive oil is better than the top level oils when your car was new. Your cars engine is designed on using low quality oil according to modern standards.

Erik

What is the cause of sludge?

Some of it is also down to the engine running too cold in the winter thats why blanking part of the radiator off can be useful, different oils can suffer in different amounts, when I was younger the 2 main oils were Duckhams 20w50 and Castrol GTX 20w50 and in the winter months the Duckhams oil always sludged up the rocker box with mayonaise to a certain extend but the Castrol oil rarely did and I was told it was because there was a certain amount of vegetable content in the Duckhams, but wether that was true or not I dont know.

Exactly - and i'm sure the ASDA oil is still the same oil - just the price has gone up - it was ridiculously cheap before.

Ok, I will try that out, and blank the rad off a bit. Get it a bit hotter inside too!

Better just to fit an 88 degree thermostat - and if not doing any traffic work the fan can be removed too.

88 one is already fitted. I have done lots of very short trips though.

Lets hope it changes on my short trip to London