From Denmark, sludge concerns on a used SAAB

Dear Norris:

I have with great interest and some concern read your articles about oil sludge and the importance of low service intervals (Second Opinion, September 2005). I purchased a SAAB about a year ago, which has had quite irregular service intervals by its former owner.

My car is a 2000 SAAB 9-3i (130 HP) with 200,000 km on the clock. Service intervals with the former owner range from 20,000 and up to about 30,000 km (except 1 service). I did notice this when I bought the car, but I wasn't too concerned, partly because the car was obviously used mainly for longer journeys, thus eliminating the short journeys/many cold starts problem - plus I got the car at a good price. The manufacturer recommends 20,000 km service intervals.

I was not aware of the oil sludge problem before, and my question now is: Is there a higher risk now for engine failure due to too long service intervals in the past? Is there anything I can do to prevent or minimize this risk? I use full synthetic oil and high quality filters. I have until now kept service intervals at 20,000 km, but will reduce that to 10,000 km.

Kind regards,

PH
Copenhagen, Denmark

Dear PH ,

Thanks for reading. You are correct to point out the interval issue, and I agree that there is concern for SAAB owners of this model. Much of what I talk about here comes from daily experience on 9-3 and 9-5 models in the year range of 1998 to 2003 for the US market.

I used to believe the American 3-month/3,000 mile interval until recently. Many hours of experimenting with various kind of oils and testing used engine oil with my blotter test method have taught me otherwise. I have discovered that the cheaper the oil - the faster it breaks down into sludge, with obvious indication on the test sample.

I now know that high quality oil can go as far as 6 to 8,000 miles in a properly operating turbocharged gasoline car engine. The key phrase is properly operating.

Most of the problems with SAAB sludge come into play when the PCV system is malfunctioning or leaking, and it will fail—if not now, then eventually. PCV system repairs are a fact of life for these cars. Check with the local dealer and your local mechanic for the latest update/repair kit for your market area and install it promptly.

Then, field test the oil using a blotter method to monitor sludge content in the crankcase. It only takes 15 minutes and costs very little, and anyone can do it. Results are less accurate than mailing a fluid sample to an expensive lab, but a field test is all you really need. Go to http://schleeter.com/car_documents.htm and take a look at the Engine Oil Test Kits I am offering.

Finally, if sludge is present or begins to develop, it can usually (when not severe) be corrected by using a solvent flush and/or detergent additive extender and very short service interval on the oil filter—but only while watching the oil test and judging future intervals on your own. If tests continue to be unsatisfactory, the engine must be disassembled and cleaned by hand.

If severe sludge is present and the car is driven (even for a short time) when the "oil pressure" warning light blinks at idle (even once) or is lit for any length of time.....game over, turn it off before the engine is hurt and tow it home.

Think of the oil pressure and oiling system as your #1 maintenance concern because sludge and oiling system problems are a real wallet-smasher if it gets to that.

Another hint for good maintenance on your oiling system. Check for a leaking oil pressure switch by peeking behind the starter. Look for a single yellow wire attached to the switch. Is it leaking? Does the oil warning light function? These switches are well-known for leaking and should be replaced promptly when needed.

(Attention! If anyone knows of a better quality (than OE) oil pressure switch for this car, please let me know and I will share this information with every one and post a link to the seller once verified.

I hope this helps and happy trails,

~Norris Schleeter

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