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95 bmw m3, 120k on it, can i switch to synthetic, and......

N nightkrawlerMember
hello everyone,
glad i stumbled upon this site, there is a wealth of knowledge here and some quite knowledgable people also. wondering if you guys can give me some guidance. i have a 1995 bmw m3, 3.0l, inline 6. it has 120k on it. the only history i know about this car is the following.

after some calls to the dealer i found that there was 1 service record found for the car. it was serviced in MD at a dealer there in 2001 and it had 5k on it at that time. so from 95 to 01 there were only 5k miles put on the car! the majority of the mileage was put on from 01 till present. i have to say though that if i didn't know the mileage and looked at the car, i would say it had about 30k on it. it is in very good shape, especially the interior.

now my questions. i want to switch to synthetic but i dont want to harm the engine. i spoke to the last owner and he told me he ran conventional in it but i dont think he had it very long. so i dont know what type of oil was used in it. i cahnged it when i got it and used conventional cause i did not know if i should switch yet. i posted this question on a bmw forum and suprisingly i think pretty much all the replys said, do it. there were even guys with more mileage on there cars than mine that switched to synth with no probs. i have heard a lot of horror storys of switching to synthetic after a lot of miles and having problems with seals leaking etc, same storys you guys have probably heard. but then some guys said that this was only the case with old engines with organic/paper type seals, and new engines would not be effected. they also said that synth is more prone to leaking past seals etc because the molecules of the synth are smaller than that of conventional.

anyway, on to my questions. 1)can i switch over to synthetic with the mileage i have on the car now? 2) if so, should i do a motor flush first before using the synthetic, and what do you recommend i use to flush it, seafoam, autorx, etc? 3)what brand/weight synth should i use? ie, mobile 1 0w-40 etc. also i live in PA and it gets pretty cold here in the winter so my next change, which will be soon. will be with an oil for winter driving. 4)additives, are there any good ones out there that actually do something besides screw up the chemistry of the oil you use them with. in the past the only additives i have used with any success were rislone, and restore.
5) oil change intervals, i have a current debate going on one bmw forum now about changing intervals. with conventional, i would always change it at 3k. what is a good interval to change synthetic? one note, those of you not familiar with the E36 3 series, changing the oil is super easy cause the motor uses a drop in canister filter which is located right on top in the front of the motor. so changing the filter without losing oil is not a problem at all.

please help me out if you guys can, cause im due to change it soon and i really want to use synthetic. but i dont want to hurt anything, what should i do? thanks, dave.
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M mgbv8Member
Number of good questions

Mobil answers can be found here

http://www.mobil1.com/index.jsp

These are probably reserved views as with oil changes apart from changing from Mineral. I've copied below ino from this site re change as a balance and perhaps auto rx a Lanolin ester may provide a gentlier cleaning process.

TheSynthtic life study is interesting from extending OCI may in fact be beneficial with filter and top ups the oil may last a lot longer than recommended. A fixed oil change interval is an insurance policy as not based on the use of individual car. Flexible oil changes based on use with current oil additives packages may extend even recommended changes to 30k miles and still be conservative.

The Synthetic Oil Study has some interesting conclusions

http://neptune.spacebears.com/cars/stories/mobil1.html
However there is concern over releasing any build up in engine

It is the ester that can cause problems when one changes from mineral to synthetic. Ester base oil used alongside PAO base oil in lubricant formulation has excellent natural detergency. In other words, it will clean up varnish on component surfaces as a result of thermal and oxidative degradation of the lubricant. When one switches from a typical mineral-based engine oil to a typical synthetic-based oil, the varnish layer will be removed by the ester in the synthetic oil and become suspended.

This suspended material can rapidly clog filters and can block oil flow passageways and lead to component starvation. The same is true for gearboxes and other industrial machines. So think twice about switching to synthetic oils in applications where the engine or other machine has been operating for some time with mineral oils. If you decide to make the switch, try to clean the system before making the change, then monitor it carefully once you start it up.
N nightkrawlerMember
one guy who replied to my post said after switching to synth, change the oil and filter at like 1500mi, then again at like 2000mi, then at regular intervals. i didn't get a chance to read the links you provided yet, girlfriend is nagging me to go eat dinner, but i will later. being that the car has 120k on it, not that it's unusual for a bmw to easily see that mileage. it runs like a bear, and i want to keep the motor protected so i can hopefully get another 120k out of it. i figured synthetic would be the way to go. so do you think if i used the autorx, and then say do this; switch to synthetic, as i said it's a 1 minute job to change the filter on this engine. so i was thinking maybe at say every 500mi, change the filter. and the whole oil early at maybe 1000mi, then again at 2000mi, or some schedule like that to be sure to get rid of the contaminents. what do you think of this idea?
T tallpaulMember
I thought the problems / horror stories about synth were from the old days and synth is different now and seals are different now. So I would think you could do it. The safe side is a blend. I see absolutely no issues in switching to a blend, like Valvoline Durablend, and trying for say 5000 mile oil changes, which maybe be good to support with an oil analysis. I can do 5000 on mine. In fact I did 4400 miles with 10w30 Maxlife in my motorhome and had a great used oil analysis. Maxlife is about 15% PAO synthetic, the rest dino. Great stuff though and supposed to clean up your engine over time. Gotta go, but will check back. Just remember I am no expert, just an interested oil freak.

Edit. If things go well with a blend then later move to synth, if still deemed necessary. I would consider Maxlife a bit of a blend too.
T tallpaulMember
From what I have heard, Mobil 1 is hard to beat, both qualitywise and pricewise. Often available at Walmart in the 5 qt just for under $20. Royal Purple will cost you more than that. I also have heard that Mobil 1 runs on the thinner side of grade. Some have done quite well throwing in a quart of the Mobil 1 15w50 with the rest such as 10w30.

I would think with Mobil 1 you could run 10w30 and get through winter fine. There also is Redline, but that is around $8 per quart. Advance Auto has it.

Redline is predominantly ester (Group V) synthetic. Mobil 1 is more PAO (Group IV). Those are true synthetics. The Group III, highly refined so-called synthetic is found in many other brands. They are pretty good if the price is right. For example, I got NAPA synthetic for $2.69 a quart on sale--excellent deal IMO. I am guessing it is Group III oil because the normal price is around $3.49 or so.

I have heard that synthetic can do some cleaning and that the first one or two oil changes may dirty up quicker. But if you run AutoRx and it does what they say it does, then you won't have to worry about that, and should not have to worry about the other synthetic horror stories.

For really long oil change intervals, a couple of used oil analyses are a good idea. ANA Labratories gives a good price break on 10 kits.
N nightkrawlerMember
i've learned so much about synth of the past few days, but still a bit confused on the groups, IV, V, etc. im assuming the lower the number, the less of an actual synth the oil is? if so, why would you want to use mobile over redline etc, except price? being that redline is V? mobile1 is what i'll probably end up going with, used to get the big jug of it at walmart for 20 bucks. and that 3.0l hogs up almost 7 quarts. pep boys want 5.99$ a quart for royal p!
T tallpaulMember
Royal purple may be great stuff, but pricy.

Groups I, II, II+, and III are all conventional (a.k.a., dino) oils. However, there was some deal where now Group III can be called synthetic. A good Group III will perform nearly as well as a Group IV. Group IV is true synthetic (PAO). I understand the Mobil 1 also includes some esters for solubility of additives. The combination is pretty good.

Redline is supposed to be mostly ester and it also is loaded with additives like higher ZDDP and a lot of molybdenum. All good stuff but especially the moly is pretty overkill. I like Redline and run it in trannies and rear ends, but too pricy for motor oil IMO. Seems more geared to high performance engines.

I think you can't go wrong with Mobil 1 if you are going synthetic. What grade do you run anyway?

If you AutoRx first make sure to use cheap dino. They want to avoid synthetic in the ARx treatment and especially the rinse. Some dinos will have synthetic in them, like Maxlife. Can call Frank at ARx for advice.

Also look at the Mobil website. A lot of discussion and FAQs on the synthetic. Helpful stuff.
T tallpaulMember
Well bear in mind I am not an expert, and am somewhat hesitant to recommend Redline as at the forums on Bobistheoilguy.com there is much discussion of Redline having certain higher wear numbers, but that could be due to it cleaning old stuff from inside the engine. MR. Terry Dyson is a strong supporter of Redline. He is an expert on motor oil and posts at the Oil Guy site and has an oil analysis interpretation business where he can tailor a oil program for your vehicle.

Visit the Redlineoil.com site and see what they say. The esters are the top oil for taking heat, they have superb cold flow, and are polar to adher to metal. All good qualities.

I'd say give the Redline a shot and use of oil analysis may be advised especially if you want to run long OCI of say 8 to 16 thousand miles. Remember the first couple batches of Redline will probably clean old stuff out, so a true analysis may not show up until the third run with it.

Redline is overkill, but hey we are not talking about that much money anyway, are we? Can get at Advance Auto, or order direct from Redline, or myoilshop.com is cheapest ($7) and happens to be in PA.

Have at it!

EDIT: Oh yeah, Group V is the ester and some other stuff. Higher yet is supposedly a Group VI (not sure if actual or proposed or what it woudl contain).
T tallpaulMember
Not exactly that easy as some have a mix and I an not an expert, but here goes:

Redline: Predominantly Group V esther
Mobil 1: Predominantly Group IV PAO with some ester
Most other brands synthetic is likely Group III.
You probably could find out more at the Oil Guy site though. Do a search over there on oil groups maybe.
Oh yeah, Amsoil I think may make some PAO, not sure what else. A few good Amsoil dealers at the Oil Guy site can help.
T tallpaulMember
Well AutoRx is highly regarded at the Oil Guy site and is said to really work. Yes I am trying it in my sludged pickup truck with 114,000 miles. No significant deviation from the instructions. The treatment oil blotters were especially dark compared to previous OCIs and the filter element after only 1500 miles was black. 1200 miles into rinse phase and now the oil looks pretty clean. Truck seemed to run a lot better about 500 miles into the rinse, but I also had been running Redline SI-1 Complete Fuel System Cleaner the last 3000 miles.

On my other vehicles I will see if synthetic will do the cleaning for me,

So you should be fine after the ARx treatment, so I would think. I ran a quart of Redline in my last 500 miles of the last OCI and the blotters for the next OCI were dark right from the first 500 mile blotter. So I think the Redline does clean. Which is better? Not sure.
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