I have for sale a 2001 XC70 wagon. Great condition. All wheel drive with good tires. nice leather interior. NC and rust free car.

What little sludge this does break up, will likely plug the oil pump pickup screen.
Pull the pan to clean properly.
when you see the amount of crud in the pan and how solid it is, you will understand.

R/R of the pan is not that bad, it is the remove of the crud that takes time.

Agree with Ignatz. Drop the pan. Clean with Zep Industrial cleaner, or take to a local garage with a parts washer. Clean the block and replace the plastic vent box. Remove the Banjo bolt and clean with Zep and air. Tip to remove and install the banjo bolt: first remove the P/S and ALT. I don't remov...

In my experience with Coil over Plugs, COP failure is caused by excessive plug gap. this can be the plug gap at the tip and also inside the plug at the built in resistor.
so, If your COP(s) fail, always replace the spark plugs. New COP(s) with worn/defective plugs are doomed to fail again.

Service the CC vent system, completely.
Remove the engine oil sump and clean.
Remove the oil pickup tube and clean.

the sludge is too thick/hard to be removed with a flush.

Wasting your time and money. Remove the pan. See my post on this with pictures.

It has been my experience that to truly know the amount of Sludge in an engine, you must remove the engine oil pan. you will find a lot of stuff in the pan. Clean the pan, clean the oil pickup sump and reinstall all. R&R the pan is not too bad. it is the cleaning that takes some work. Zep indust...

I agree with rspi. Pack fun stuff.
But be prepared as best you can. a Good Paper map. cell service can be spotty. Tire plugger, flats are common.
check the age of your battery, should be a sticker on the top or side. how old is the Alt? maybe a new VR/brush assy.

Depends on the condition and how it was maintained. In BC, have the car carefully inspected for rust damage. Volvo cars have a great body rust treatment system. the better EU cars have similar, but the Volvo treatment is near to the best. A good technician can inspect the car BEFORE you buy and give...

you can weld the pan, if it is just cracked. But, the pan MUST be removed from the engine, completely cleaned first. there are tools/techniques to weld aluminum.
Please don't attempt to weld the pan while on the car.