Hello again,

where do this deposits come from an how can I remove them?


If I scratch with the screwdriver it peels off.

Best regards M.

Baked on oil residue - very, very common - on cars that have been neglected by missed oil and filter changes.

Basically combustion products that bypass the piston rings contaminate the engine oil. These are held in suspension in the oil ad will adhere to, and bake on to hot surfaces. Eventually this "crud" will build up, produce what you see, and also block the engine breather system (which compounds the problem).
The oil filter is designed to remove contaminants from the oil, but if this is not regularly changed it is bypassed.

No easy way to remove it other than a strip down and rebuild, cleaning each component.

This is what is should look like!



Mac

Low oil, dirty oil, overheating.

I'd take off the sump plug, get a bottle of parrafin - brush the valve gear with the solvent, until all clean. Flush with rest of parrafin (comes out of sump hole).

Let engine dry of parrafin fo 30 mins, fill oil. ---->

thanks for your answers!

Best regards.
M.

CBA wrote:Low oil, dirty oil, overheating.

I'd take off the sump plug, get a bottle of parrafin - brush the valve gear with the solvent, until all clean. Flush with rest of parrafin (comes out of sump hole).

Let engine dry of parrafin fo 30 mins, fill oil. ---->

Agreed - you'll get 90% off that way (and of course much easier than a dismantle and re-build). I generally find "white spirit" (turpentine substitute) as effective as paraffin, and easier to find cheaply.

Me, being finicky, would say that this sort of grunge usually goes hand in hand with heavy carbonisation of the valve stems which won't wash off without strip down.

If you go for the above method - fill with fresh oil (any cheap 10w-40) and filter, run thoroughly hot, drain the oil and refill with fresh (quality) oil, use for a couple of hundred mls., finally change the oil again and fit another new oil filter.

Mac.

I like to use turbo diesel oil as that has a lot of detergents in it and is good at washing out crap.

The worry with heavy carbon build up is the oil ways getting blocked. Best thing to do is stick to good quality oil and change every 3000 miles or 6 months whichever comes soonest. As always use a Volvo filter at every change

I also find that synthetic oil doesn't breakdown as much and gradually cleans the engine, starts better too.

We've all seen this before

Getting the rocker cover gasket perfect, and the inlet manifold (and due to the close placement of the exhaust ports) and exhaust manifold.

Leaks either side will allow dirt into (and oil out of) the engine.

My(the) 1.4 is suffering this minute from a leaky rocker cover, it's turned my oil from honey to sludge in a week.


Just as important as the gaskets are the pipes, vacuum - all of them. perfect seals throughout = engine stays clean.