tuner-automotive Posted March 30, 2007 Share Posted March 30, 2007 I recently bought a 97 Legacy 2.2l w/132k miles. When I bought it , it had a slight piston slap that went away once the car was warm. The previous owner was using 10w30 dino oil. I wanted to switch all the fluids to full synthetic and started by swapping the oil to Mobil 1 5w30. Now the slight slap is a prominent slap that never really goes away. Im thinking the 5w30 is much to lite and I should run a heavier oil. I usually use Chevron Dello 15w40 in older cars and am thinking of going to it in this case but dont know about doing so since i have run Synthetic in the car now. Ive heard that you shouldnt change back to dino after going to syn. Ive only ran the synthetic for about 5-700 miles. Also, is the Mobil 1 15w40 full syn gonna be as good as the Dello 15w40? Thanx Quote Link to comment Share on other sites More sharing options...
cookie Posted March 30, 2007 Share Posted March 30, 2007 I've done several oil swaps with mine and it gives very good oil reports from Blackstone. I got it with 10-30 dino, tried 10-30 Mobil 1 and it did not help my piston slap. I tried Mobil 1 15-50 and it did quiet the slap a bit. now I'm running Havoline 5-30 which is pretty quiet when new and gets louder as it ages. Modern oils are pretty compatible and some folks mix thier own syn with some dino. Quote Link to comment Share on other sites More sharing options...
subaruplatt Posted March 30, 2007 Share Posted March 30, 2007 The most sensible rule I ever heard and I can confirm it with anecdotal evidence,is, Never switch to another brand of synthetic back to back as sometimes the differing additive packages will react. So always run dino oil in between as synthetic oils and dino oils are for the most part compatible, I went from syntec to mobil and I developed a stuck lifter (VW( tick tick.......) Fixed it with two doses of a bardohl oil additive that appeared to be graphite and kerosene in nature. And I finally settled on amsol as my synthetic of choice. Still on the fence if I will start the new Subaru on it or not. It has about 8000 miles on it now so pretty soon I Know it would be safe. Kind like the way it warms up so quickly in the winter, synthetic might make it take for ever. Quote Link to comment Share on other sites More sharing options...
nipper Posted March 30, 2007 Share Posted March 30, 2007 Switching from Dino to Synthetic is ok. What may happen is if you had any seals that were going to leak, it would accelerate the process. Switching back from Syn to Dino is more risky, again because it tends to tends to make the seals more likely to leak. It wont harm the engine mechanically. nipper Quote Link to comment Share on other sites More sharing options...
tuner-automotive Posted March 30, 2007 Author Share Posted March 30, 2007 Well Im thinking of using the Dello 15w40 since I only have 500 miles or so on the syntheic oil. The seals shouldnt have been under the usage of the synthetics long enough to cause problems . At least thats my way of thinking. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.