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1999 Outback Wagon 2.5L
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2 Posts
Discussion Starter · #1 ·
I've got a 99 outback with 65,000 miles. I have had it for about 4 months and put 7000 miles on it. I just did a seafoam treatment to it running 1/3 in through the vacuum line that goes to the pcv valve, 1/3 in the oil and 1/3 in the fuel. I put both the oil and fuel in and then put the vacuum line in a bottle and allowed it to directly draw from there. Immediately after I changed the oil with 3 quarts 5w-30 1 quart Lucas oil no slip leak fix heavy weight stuff. Now I have a pretty loud knock at low RPM/idle and Coming down from high rpm. Prior to this the car went through a lot of oil but I kept an eye on it adding as needed. Any thoughts on what this might be?
 

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OBW H6 VDC, Tribeca, XT6
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12,385 Posts
If it goes away or gets quieter as the engine warms up - it's piston slap.

The timing tensioner can slap - and it's so loud it does sound like rod knock. pull the drivers side timing cover (3 10mm bolts, that's it) to get a glimpse of it. Run the engine with the covers off - you'll see it slapping around. Replace with a new one immediately - interference engine so if it slips you'll have bent valves. Ebay kits are a great low cost alternative with all new pulleys, tensioner, and belt.

Or it's rod knock. with that amount of oil loss it's very possible it was run low before you bought it and damaged the internal bearings.
 
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