What grade oil for high milage

I have two diesel turbo Vaux, a Zafira and an Astra estate 2ltr both done
90k miles. Should I use engine oil of a higher viscousity.
What grade would be best? Any ideas welcolme

 

Stcik with the original recommended oil, irrespective of mileage

 

Stcik with the original recommended oil, irrespective of mileage

As engines age, the bits inside loosen up - just like women.

Therefore, you need a thicker oil to stick to the bearings with their
now-wider clearances.

 

Do they "soften" too?

Just like men!

 

Hmmm...maybe I should get a thicker whip!

 

I don't think "Thicker" means what you seem to think it means - a "thicker"
oil (by which I guess you mean for example "use 20 - 50 instead of 10 - 40")
could leave our friend with oil that is simply too thick when cold, to start
circulating quickly enough - thus accelerating engine wear. The gap in the
clearances is taken up by the presure of the oil which I thnk would have
more to do with the condition of the oil pump once the engine is warmed-up.

Using a "thicker" oil on some Ford engines in particular could be a
disastrous thing to do.

 

I don't think "Thicker" means what you seem to think it means - a "thicker"

Yes, that is what I mean.

That is the problem. When an engine is hot, the oil gets thinner and the
pressure is reduced, and eventually the big-ends can be damaged. Starting
off with a thicker oil alleviates this problem.

Always take it easy with a cold, old engine!

They will quote a range - eg 10w40 to 20w50. As the engine ages or it is
used in hotter conditions, use a thicker oil.

I had an engine that had done just less than 70k. It was quoted as taking
10w40 to 20w50 so I put 10w40 in it. Was fine for 6 months until I took it
out on a long run on a hot day - and the big end went.

Used 15w40 in engine number 2...

 

Makhno [email protected] typed:

Bugger, and there was me thinking all along that's why Multigrade Oil was
invented.