This week I decided that it was time to change the engine oil on my 1968 Saab Sonett V4. Here's a quick step by step guide in case you wonder how to change oil on your Sonett.
The first thing you need to do is to decide which oil to use. I did some research and found that many Saab V4 owners use and recommend the Castrol GTX oil. According to the car's manual the car is to have 10w-40 oil. So I decided to get the semi-syntetic Castrol GTX 10w-40. My advice is to use a quality brand oil and either 15w-40 or 10w-40. You will need under 4 liters.
The next thing you need is a skrew-on oil filter. You can get a genuine Saab filter or a replacement filter. I got a Bosch filter from a local workshop. Here's a list of some possible filters:
Bosch P 7005
Mann Filter W 712/80
Saab 9144445
There are many many other manufacturers to choose from. Be sure that the filter you get has an outer diameter of 76 mm. There are filters out there that the reference charts say will fit that are over 90 mm, but they are too big to fit a Sonett!
The last thing you need to get is a M14 x 1.5 drain plug washer/crusher/gasket/seal or whatever you call it. It should be made of copper, have an inner diameter of 14 mm and an outer diameter of about 20 mm. The thickness may vary, but I guess 1.5 mm is fine.
Now you got all the parts you need. But you will also need a few tools. To remove the drain plug you will need a socket wrench/ratchet and a 19 mm female socket. To remove the oil filter you may need a strap-type oil filter wrench.
Now we are ready to change the motor oil!
First drive the car for 15-20 minutes to get the oil heated up so that it gets thin and flows easy. The oil drain plug is located on the right side of the oil pan at the front of the car and is easy accessible. You don't really need to lift the car or park over a grease pit. Possition your oil tray, which should take at least 4 liters, under the drain. Unscrew the 19 mm drain plug with your socket wrench. Let the oil flow into the tray. Leave the tray under the car and the drain plug out for a while to empty as much as possible of the old oil. In the mean time you can unscrew the oil filter, which is located on the right side of the engine. You may need a strap-type wrench to loosen it. Remember that the oil filter is also filled with oil, so position a smal tray under the oil filter. The filter takes approx 0.3 liters of oil.
Okay, so now the car is drained of oil. Time to get som new oil into the engine! First replace the oil copper washer/crusher with the new one and then screw the drain plug back into the oil pan. I do not know what torque to use, it doesn't even say in the Saab genuine workshop handbook, so you will have to use your feel. It's better to tighten it some more later if you see a small leak, than to overtighten it! Take the new oil filter, dip your index finger in the new oil and lubricate the rubber seal on the oil filter by using the oil on your finger. Screw the oil filter to the engine. When the rubber seal and the engine are in contact, continue screwing the filter half a turn. Then the filter should be tightened enough, but remember to check for oil leak later.
Now fill the engine with oil. The oil filler plug can be found on the top left side of the engine. Fill approx. 3 liters, let the oil sink into the engine and then check the level. Keep on filling untill the oil is over the min mark. Go for a drive, let the oil sink and then check the level again. Top off untill the oil is almost on the max mark. The engine with a new oil filter takes 3.3 liters to reach the max mark. Also remember to check for possible leaks from the drain plug and oil filter. If neccessary, tighten the drain plug and/or filter.
Some people say that today's modern oils miss some addidatives that are important for old engines. Zinc is often mentioned. If you want, you can get a zinc addidative like ZDDPlus.
Finally a word on the drain plug. Your car may use a different plug, i.e. a plug that needs another tool than mentioned here to be removed. Over the years Saab changed drain plugs and also previous owners may also have changed the drain plug. So check your drain plug and make sure your got the proper tool before you start!
