Need to know what motor oil is best for my 2000 volvo s80 with 150k

Replace your water pump.

I believe it's every 80k. Just do it if you don't know when it was done last , these are non-tolerence motors and you will do damage to the valves if you break the belt in motion.

Are you sure the gauge is reading correct? You also didn't mention how many miles the vehicle has. If it's less than 150k I would doubt the motor it worn out, (excessive bearing clearance would cause poor oil pressure even with high volume pump). Chevy's have a lot of issues in the dash with the motors that make the individual gauges work. I would check the oil pressure with a manual gauge. If you don't have the skills to do this yourself, a qualified shop wouldn't charge much to do it. If you find that the gauge is incorrect, there is a guy in MN that rebuilds the instrument cluster for $65 with all new stepper motors (the motors that work the gauges) and replacement of all the bulbs, plus gives it a lifetime guarantee. www.speedometerrepairguy.com.

5w30 is best, if you are over 150k then you may want to add a bit (half a bottle) of Lucas oil treatment.

ENGINE OIL

You will need to use a 10W-30 grade engine oil, such as any of the following Mobil products.
"Fully synthetic" oils are more expensive. Conventional oils or syn blend engine oils are fine for the vehicle but need to be changed more frequently.

Mobil 1 Extended Performance 10W-30
fully synthetic motor oil ;
Mobil 1 High Mileage 10W-30
fully synthetic motor oil;
Mobil 1 10W-30
fully synthetic motor oil;



Mobil Clean 7500 10W-30
synthetic blend motor oil ;
Mobil Clean High Mileage 10W-30
a conventional motor oil;
Mobil Clean 5000 10W-30
a conventional motor oil .

To repair your cluster you can google a company called XeMoDex, or you can find a *same year* S80 in the junk yard and take the cluster from that and hope it's ok.

The thing is that the car will generally show whatever the highest mileage is - whether it's in your car's computer or in the new cluster. If your car has 100K miles and the junk yard cluster has 150K miles, it will show 150K miles.

The best oil for Audi 1.9 TDI is CASTROL 0W30 SLX Longlife II (TDI Pump Nozzle) VW Norm 506.01 . This oil is issued by Castrol special for TDI - Pumpe Duse (Pump Nozzle) engine as longlife oil (50,000 km service interval, or two years).
Also a normal service oil (15,000 kmservice interval, or one year) is Castrol TXT 5W40, and Castrol EDGE 5W30, for TDI Pump Nozzle engines, VW Norm 505.01.

I would recomend "SJ" Weight = 5W-30(Quaker state)

The spanner symbol usually pops up at the recommended service interval for the engine.
A. standard service would include change of Engine oil, oil filter, air filter and possibly plugs.
All other major components and fluids should be checked at this point too, and replaced if needed.
Oil and filters is the minimum to ensure trouble free motoring.

you need a oil filter wrench.