Hi Rob, I have a 1999 Saab 9.5 station wagon. It only 4000 km on it when I purchased it in 2000. It is a 4 cylinder turbo and has always used regular engine oil, changed every 5000 km or so. I have been advised that I should switch to synthetic oil because of the high heat generated by the turbo. My car has 142,000 km on it and has generally been a good car.
Do you think I should use synthetic oil from now on or stay with regular oil?
Most of the time I use the car for around town trips.
Thanks, Helen
Switching over to synthetic motor oil is always a good idea. Engines using synthetics do not have to have their oil changed as often. This means more money in your wallet and less toxic waste to dispose of.
I’ve said this before: many vehicle owners change their oil too frequently.
The best part of switching to synthetic oil are the benefits for your engine. Your statement regarding the heat generated by a turbocharged engine is correct. Synthetic oils are very resistant to heat, which is highest around the bearings that support the turbocharger’s compressor/turbine section. These bearings are located very close to the exhaust gases that rotate the turbine and they rely heavily on a supply of oil to keep them lubricated and cooled. Exhaust gases are normally hot, and once a turbine is placed in the way of those gases trying to exit the engine, the heat generation is further increased due to this resistance.
“Regular” oils, if not changed very frequently, can “coke up.” That is, the oils turn to sludge and hard carbon deposits. If left unchecked, these substances will destroy the turbo bearings. Repairing these is a wallet-emptying exercise. Worse yet is the possibility of the coke and sludge making their way through the rest of the engine, wreaking havoc on the internal surfaces that rely on the same lubrication that is pumped to the turbo bearings.
Good on you Helen for your regularly scheduled maintenance. Using synthetic oil should add life to your Saab.
Do you have questions about auto maintenance? Send them to globedrive@globeandmail.com
