Another XC70 question.... sludging of oil...???

As mentioned previously, seriously considering the purchase of a 2000 XC
70..... 149,000 km on it....BUT

Just spoke with the previous owner (now at a lot) who described having had
"oil sludge scraped out of the oil pan and LOTS of cleaner flushed through
the engine" several services ago. I understand that "sludging" can lead to
catastrophic (read:replace engine) failures...?

Is there anything I/mechanic can check pre-purchase to assess the risk of
this?

Thanks,

Kevin

 

Since sludging is purely a function of infrequent oil changes, you can
see the evidence of neglect by removing the oil filler cap and looking
both at the bottom of the cap and into the cam tray. You will see the
evidence of sludge, varish and carbon build up. In order for oil to
sludge it must be hot. Oil temps in excess of 200 degrees F will cause
dino oil to smoke and thicken. On daily drivers this usually occurs long
after its useful life as a lubricant has expired. Since all engines use
some oil, pushing the change interval means that the volume of remaining
oil in the crankcase becomes less and less as time goes on. Since there
is less oil, its contribution to engine cooling becomes less adequate
and the oil runs hotter as the volume decreases, hence the sludge. If
the volume gets low enough there is not enough free flowing lubricant to
protect the bearing surfaces and the engine seizes.

I've seen high mileage (150K miles +) white motors that get regular
synthetic oil changes that look and run as if they were brand new: not a
speck of varnish under the cam cover, no deposits on the backs of the
valves, no grainy carbon junk in the pcv, no lifter noise; just a
perfect example of what regular oil changes with synthetic oil can mean
to the longevity of a motor.

Bob

 

Bob,

Thanks for the (extremely helpful) info..... previous owner bought vehicle
at 100,000km, and suspected it was abused/overused by original purchaser.
Will check out areas you described... am better armed now...

Kevin

 

Hope you checked the mileage as well ,seems like a lazy service schedule and
using dino oil .Use quality oil it works out the extra cost is offset by the
longer service life .

 

What evidence do you have that more expensive oil is of "better quality"
and doesn't just have more advertising?

What evidence do you have that more expensive oil extends service life?

I always use dealer service with ordinary oil or changed my own oil
using ordinary oil and never had any service life problems with the
engine. This ordinary oil always met the specs that Volvo published.