Is it harmful to mix synthetic and natural motor oil? on 2003 BMW 530i

Have both 530i and 323ix. "fULL SERVE" attendant put 2 quarts of 10-30 natural in the 323 without asking. Will oit do any damage to the engine?

by in North Reading, MA on January 19, 2012
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1 answer 1 comment
ANSWER by , January 20, 2012
NO, BUT If it was that low, you've likely exceeded the time factor or miles for the oil and it needs changed anyway. Unless you have a significant leak, I can't imagine being 2 qts low. If it were mine, I'd change it ASAP. I used syn-oil in my 1999 323i and it never leaked, but would use < 1 qt. by the time I changed at 10k miles intervals. KIA at 235k miles and still running great. My now newer 530xi does not loose a drop up to 8k miles between changes on BMW approved Syn-Oil with 68K miles on the odometer.
COMMENT by , January 20, 2012
Thx. Yes, it was due for a change --to synthetic, about 10K between changes -- 125K on the odo. Doesn't burn, but it uses oil. Similar situation with 160 hp aircraft engines I fly -- oil is really the lowest type of insurance. Thx.