Author Topic: Oil type question? (Read 8161 times)

Travis · « **on:** October 10, 2011, 05:56:11 PM »

So i went to autozone today to pick up oil for my 91 318is. I was gunna get 10w 40 synthetic but the guy said once u put synthetic in it u always have to use synthetic after the switch, is this correct? The only reason i was gunna get synthetic in the first place is becuase the auto zone guys said thts all i should use in the m42, but heres the kicker, they didnt have any oil filters for synthetic. Wat the hell? I also dnt kno if the previous owner used synthetic or not, any way to tell? Summers here get to about 95F and winters get to 35F any sugestions on oil?

91 e30m42 · « **Reply #1 on:** October 11, 2011, 11:50:01 AM »

i would go to the dealership for the oil filter they are the same price 14 bucks and the synthetic oil wont damage the filter it will still do the same job if not better to filter the oil ive been doing synthetic oil and the mahler filter since i bought the car and the motor enjoys it all the time no problem at all ...... i usually use mobile one full syn 10w30 or 10w40 or royal purple 10w40 i like them both but its up to you to decide your oil depending on weather, driving style, e.t.c

xxlbimmer · « **Reply #2 on:** October 11, 2011, 03:25:20 PM »

Your guy at Autozone is an IDIOT! You can switch back after you put synthetic oil in, I don't know why you would, but you can. There is no special filter for synthetic oil.
There is so much misinformation regarding synthetic oils. There are numerous papers available online etc regarding synthetics. Check with ASE, Mobil, RedLine, Amsoil, BMW, GM etc etc. The vast majority of auto manufacturers utilize synthetic solely. Far superior protection, longevity, resistance to breakdown, less apt to failure under high heat situations, and more.
I would definitely use synthetic, with a Mahle or Wix filter.
Just my 2 cents. Your milage may vary. Limited to stock on hand. One coupon per customer. Not to be used in conjunction with any other offers. This is offer may expire at any time. Dealer to retain any rebates or incentives.

Nelson_40 · « **Reply #3 on:** October 11, 2011, 09:29:05 PM »

Quote from: Travis;107328

I was gunna get 10w 40 synthetic but the guy said once u put synthetic in it u always have to use synthetic after the switch, is this correct?

This is complete baloney!!! You can use either conventional, synthetic oils or a blend and switch back and forth as much as you like. As long as you use quality oil with a grade appropriate to the application and usage you will be fine. As far as synthetic vs. conventional many are a blend of each other anyway so don't fret too much. But if you have the extra to spend and like to drive your car hard or go a bit longer between changes synthetic is probably a better idea.

Quote from: Travis;107328

The only reason i was gunna get synthetic in the first place is becuase the auto zone guys said thts all i should use in the m42, but heres the kicker, they didnt have any oil filters for synthetic. Wat the hell?

I have never heard of filters for specifically for synthetic or conventional oils. Most are a fiber/cloth/paper membrane and do the same things, remove particulates from your oil to keep your engine nice and shiny inside.

Quote from: Travis;107328

I also dnt kno if the previous owner used synthetic or not, any way to tell? Summers here get to about 95F and winters get to 35F any sugestions on oil?

A decent way to check to see if conventional oil has been used for a long period of time is to look at the bottom of the oil fill cap for brownish deposits which can indicate a car that has not run conventional exclusively. But on the other hand most every M42 has run conventional at some point, so it is nothing to worry about. As far as grades of oil people tend to prefer 0w-40, 10w-40, I tend to run the former.

In future be very skeptical of what people at local auto stores say, often they know nothing about your vehicle or they have been told to pitch certain products. If you do want to lean more, which is always good, http://www.bobistheoilguy.com/ is about the best oil knowledge base on the web.

DesktopDave · « **Reply #4 on:** October 12, 2011, 07:09:40 AM »

Synthetic is an excellent choice. No need for a special filter. I use synthetics to extend my oil changes around 10k miles, no increase in wear from what tests I've done. I would not suggest that for everyone, but it works for me.

91 e30m42 · « **Reply #5 on:** October 12, 2011, 01:28:34 PM »

Quote from: DesktopDave;107379

Synthetic is an excellent choice. No need for a special filter. I use synthetics to extend my oil changes around 10k miles, no increase in wear from what tests I've done. I would not suggest that for everyone, but it works for me.

same here i also heard that once you go synthetics you cant go back ... but that doesnt matter to me cause ill spend the extra money to get my motor to perform better. $40 bucks for oil and filter is not bad for the performance synthetic will give your motor... i used to change every 5k untill i went to a car show and talk to some mobile 1 techs and told me im just wasting my oil since they perform well up to 15k but recommended i do it between 7-10k depending on driving style... ive always used synthetics in all my cars preferably mobile 1 as it does better work than other oils especially in heat control as mobile doesnt heat up as quick as castrol or royal purple

Travis · « **Reply #6 on:** October 13, 2011, 10:05:03 PM »

Thanx guys, dnt think il be goin to autozone to much anymore, overpriced and undereducated. My oil looks brand new but its been sittin in the car for like 4 years, the car wasnt run tht much and when it was it was only idling or quick 5 min trips around the naiborhood, do u think i should change it, the oil lights not on but its been sittin for so long tht its probably still a good idea to change it or do u think tht would jus b wasting oil?

DesktopDave · « **Reply #7 on:** October 14, 2011, 07:29:28 AM »

Definitely change it. Oil itself won't go bad, but the detergents will oxidize. $40 of oil is cheap insurance.

My opinion on synthetics is not to expect any massive improvement. I'll bet you see only 2-3% total improvement if you replace all the conventional oils. For instance, I've changed to synthetic ATF and gear oil in my car as well and I've seen about 1 mpg improvement overall. The car does seem sprightlier, but it leaks more. I'm considering organic oil next...

BTW, forgot to ad that when extending your oil change intervals with synthetic, be sure to change the oil filter at the usual intervals, 3-5K miles. If not, the element can plug and ALL your oil gets bypassed...unfiltered!

If you really want to know what's going on in the motor, get used oil analysis. They're cheap (~$40), but you will absolutely know what's going on with your motor. Blackstone is a good choice, there are others as well. They'll even send you a free sample kit. Getting a good, competent opinion instead of the claptrap you hear (from people like me:D) on websites is worthwhile.

Nelson_40 · « **Reply #8 on:** October 14, 2011, 10:48:49 AM »

Quote from: Travis;107438

Thanx guys, dnt think il be goin to autozone to much anymore, overpriced and undereducated. My oil looks brand new but its been sittin in the car for like 4 years, the car wasnt run tht much and when it was it was only idling or quick 5 min trips around the naiborhood, do u think i should change it, the oil lights not on but its been sittin for so long tht its probably still a good idea to change it or do u think tht would jus b wasting oil?

If you have an Advance Auto locally they are running a decent promotion if you buy $100 in goods you get $20 off and a $50 off coupon for a later purchase of $100. Even if they do not have the brand/grade of oil you want in stock you can order it online and pick it up at the store. I am not saying they are a good store or anything like that, but it's a good deal if you want to stock up for two oil changes. I think the promotion ends at close of business 10/15. Whatever you do, definitely change your oil and filter.

91 e30m42 · « **Reply #9 on:** October 14, 2011, 11:16:33 AM »

Yea Autozone wouldnt be a good place to go for info the one by my house has a lady that brings her kid to work they are not certified techs so info they give is based on what they hear...i still go to them just because they are walking distance from me...

91 e30m42 · « **Reply #10 on:** October 14, 2011, 11:18:38 AM »

Quote from: Travis;107438

My oil looks brand new but its been sittin in the car for like 4 years, the car wasnt run tht much and when it was it was only idling or quick 5 min trips around the naiborhood,

i would also recommend doing a fuel treatment as well if you havent used the car as much as well

Travis · « **Reply #11 on:** October 18, 2011, 12:30:58 PM »

What kind of fuel treatment do you think i should do, becuase the engine does run kinda rough

91 e30m42 · « **Reply #12 on:** October 18, 2011, 02:08:52 PM »

just some good quality fuel injector cleaner... i do it every other month or so depending on driving habit... usually techron fuel injector cleaner before a full fill up from chevron... you should use all of the old gas in your tank just to start fresh.. also would clean your ICV valve, intake plenium and throttle body.. with some good throttle body cleaner as it may have some oil deposits there that can help smooth the idle a bit as it did with mine.. i also added a oil catch can to further keep my intake clean

Travis · « **Reply #13 on:** November 03, 2011, 05:45:34 PM »

so i was taking off my alternator and i took my intake setup off to reach it, and i decided to look at my filter to see if it was dirty, and u know what i found in my airbox? A freakin mouses nest. Now tht its cleaned out mybe she'll run a little smoother lol. and thnx for the tip man, i cleaned my throttle body and now theres much better throttle response

91 e30m42 · « **Reply #14 on:** November 04, 2011, 02:49:39 PM »

lol so thats where jerry hid better tell tom... good to hear it smoothed out your idle and throttle response... without a catch can and alot of spirited driving you may have to take it apart again to clean as for i used to do till i added a catch can... some silicone hoses would be a good upgrade as well