Need help on Engine oil

[otto B]

I have a 1985 BMW 325e with 76,000 miles. I am soon will do an oil change. I need some advice. I was told to use Liqui Moly Premium 5W-40 Synthetic Motor Oil (part number #2041) because its the best. The question is this the right oil? I ask because on Autohousaz says it fits my car but when i go to other websites it says it doesn’t. I need some help

[Jeffnhiscars]

The book says 20-50 and if you prefer synthetic M1 15-50 has the zddp our engines need. 5-40 is too thin especially in tx

[bluptgm3]

Where do you live? How are the temperatures?


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[otto B]

I live in El Paso texas. I keep on hearing to put 5-40

[otto B]

In a statement I found out in the link below, says: Based on modern oil chemistry, the best oil for the E30 is a 5W-40 Synthetic. Yes the booklet states to use 20-50 oil, but that was in that year 1985 timeframe. I think it will be ok to use 5W-40. I had a BMW Mechanic also recommend me the 5W-40.

https://www.e30zone.net/e30wiki/index.php/Oil

[Jeffnhiscars]

If you look enough you will find something to support virtually any opinion. 5-40 is too thin but it sounds like you had your mind already made up before you asked. Your car, your choice.

[otto B]

Oh no, I don't have my mind set up, that is why I ask for help, I want a recommendation from other E30 owners. I want to put the right oil on the car. So my other question what oil brand do you recomend because I have see that is very hard to get a Synthetic SAE 20W-50. In fact there are only few brands that I found see below.

I found this brands and type. What you all think:
Liqui Moly (20114) 20W-50 Touring High Tech motor oil
Royal purple SAE 20W-50

Castrol GTX high mileage 20-50
Amsoil Premium Protection 20W-50 Synthetic Motor Oil

[jclausen]

Then go for a 10w40

[KangstaE30]

Shell Rotella 15W-40 was recommended to me and works great (Texas), also inexpensive and widely available. Read up on the zddp jeff mentioned.

[superj]

I run rotella in the e30s also. its a great oil that you can get at Walmart. and I am in corpus so our temps are very similar

[Elvir]

Attachment 651834

[my1stE30]

this debate will never be solved .... it is something like do you prefer boxers or briefs ....
- each of the oils mentioned above are good and will work fine in your e30
- I have used synthetic Castrol Syntec 5W40 for years with no problems
- or you could use Castrol 15W50

[doctorx69]

i run rotella t6 5w-40 in my 2002 kia sedona and 92 gmc sonoma 4.3l. I got m1 15w-50 for the e30 but have wondered if i could just use the rotella. It is much cheaper and i have had great results from it in my other vehicles. Next time i do an oil change, i may just do that. So which? 5w-40 or 15w-40?

[superj]

run the same one you use in your Sonoma, would be my guess. I think that is the viscosity we run in the ones we have.

I almost put it in my Sonoma when I did the oil last week but since it was the first change I have done since I got it, I went with normal oil to start

[ELVA164]

You can probably run virtually anything and be completely fine.

That being said, I consulted BMW, Mobil, and the comprehensive list of oil test data at 540 rat's site and Mobil 1 0W-40 is the best combination of performance, durability, ZDDP, and price there is. Extremely high shear protection, ridiculous thermal breakdown resistance, very low cold start viscosity, plenty of hot viscosity, and readily available in Walmart.

- - - Updated - - -

FYI it's recommend to run above 1,000ppm ZDDP in these cars. If you can't find that data about a particular oil it's a bad sign.

[otto B]

That is good information, thanks. I thing it confuse me on high viscosity oils is that for example I was looking for the 20W-50 and a lot of oils it says that are for motorcycle.

[H.J. 1981]

The book says 20-50 and if you prefer synthetic M1 15-50 has the zddp our engines need. 5-40 is too thin especially in tx

I agree but i think 20w is a bit thick, though i am not familiar with e engines.

I use 15w50 from motul (4100 i think) winter or summer the engine loves it.

[Jeffnhiscars]

I agree but i think 20w is a bit thick, though i am not familiar with e engines.

I use 15w50 from motul (4100 i think) winter or summer the engine loves it.

Hes in Texas....nothing is too thick. The silliest part of this conversation is that unless you race, get your oil tested or put a couple of 100 thousand miles on your car you'll never know the difference. They all "sound fine" when you start them.

i met a Toyota mechanic who, rather than actually work on cars, he sat in the middle of the shop floor with a laptop and answered questions for all the other techs. I asked him how often I should change the oil in my Tacoma and his exact words were "every 5k if you want it to last 100k, every 3k if you want it to last 200k".

month to month or even year to year as long as you change it and its a reasonable weight, youll never know the difference.

[ArtHunter]

The truth is more likely that you will never know, if you use a reasonable oil, and change frequently.

20w50 is pretty extreme. If the engine tolerances we're designed for that viscosity, is one thing, but they would have to be pretty larger.

My suggestion would be to use real oil pressure gauge to see the hot pressure at higher RPM, with the 20w50, and the use an Xw40 type oil to compare, ensuring you are maintaining adequate oil pressure with the thinner oil.

Some guys are still trying to use really thick oil on the new BMW ultra tight rod bearing clearances. Almost guaranteed rod bearing failure.