# Motor oil for 73 2002



## joebenda (Apr 24, 2017)

This is my 3rd 2002. Prior 2 cars I ran with synthetic oil with no issues. The shop I have been taking it to says I should use a conventional motor oil because of oil leaks. Any opinoins ?


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## rubberduck (Mar 30, 2015)

Hi Joebenda,

I would recommend a conventional mineral-oil of type 15W40 for these old engines (unless you live in a very cold region). You might need to change it a little more often (always change the filter too), but i think it's worth the effort. Never had engine problems with an old BMW using that type of oil (always used Gastrol GTX but that doesn't matter). I once used a synthetic oil which had another level of viscosity and the engine started leaking, so i changed again after two weeks 

greetings from germany
Phil


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## Autoputzer (Mar 16, 2014)

Early synthetic oils (circa 1970's) would cause rubber seals to shrink or swell. That problem was quickly solved. Rubberduck's bad experience had two variables: synthetic and different viscosity. Back in the 1970's, the only Mobil 1 available was 5W-20. That stuff would leak out of a car that was designed not to leak on 10W-40.

It's possible that existing leaks in an engine have been plugged up by sludge from conventional oil degrading. Modern synthetics can actually dissolve and disperse sludge. So, it's possible (not necessarily probable) that a synthetic could unplug a leak plugged by sludge. It's possible that chunks of sludge could be broken loose and clog the oil pick-up screen or oil filter.

If the engine's reasonably clean, pick a good synthetic, but one that has the viscosity index required in the car's owners manual. You'd probably be all right if the synthetic has a lower "W" index (e.g. a 0W-40 synthetic instead of 10W-40). That old engine's bearings are designed to operate with whatever viscosity listed for that engine. Modern cars' bearings are designed to operate on lower viscosities.

Several synthetic brands offer a "high-mileage" versions of the oil. These oils have an additive that causes hard, shrunken seals to soften up and swell. They're good for curing small leaks from rubber seals.


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## joebenda (Apr 24, 2017)

Thanks for the advice. Maybe a synthetic blend Liqumoly has one that is sold by Bavarian Autosport.


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## thumper600 (Sep 24, 2014)

*what type of oil?*

Old school chart of oil to use. Temperature dependent. In my 1977 and 1978 e21 320I's I always used conventional oil, whatever was on sale. Usually I could get Castrol or Valvoline for 89 cents a quart and would run 10W40 in the summer and 5W30 in the winter. I still have oodles of engine parts. (Most of which interchange freely with the 2002 engine parts). If you want them you're more then welcome to them


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## Autoputzer (Mar 16, 2014)

thumper600 said:


> Old school chart of oil to use. Temperature dependent. In my 1977 and 1978 e21 320I's I always used conventional oil, whatever was on sale. Usually I could get Castrol or Valvoline for 89 cents a quart and would run 10W40 in the summer and 5W30 in the winter. I still have oodles of engine parts. (Most of which interchange freely with the 2002 engine parts). If you want them you're more then welcome to them


Modern engines (not from the 1970's) have much lower bearing clearances. In these engines, a SAE 10 (or SAE 10W...) would cause real problems at -18C (~0 F). It would take too long for the cold oil to get where it needs to be. There's also a chance of rupturing the oil filter element.


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## joebenda (Apr 24, 2017)

Thanks for the reply. I am gonna use some 10 40 Liquimoly synthetic blend. We live in Oregon and it does not get very cold, beside I wont be driving much in wet weather. I will ask my mechanic about the engiine parts. I understand that the alternator on a 320i may be a nice upgrade and should be interchangable.


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## thumper600 (Sep 24, 2014)

Herr Putzer, (great name by the way, I'll wager you know what "Putzer" is in the German language, and then to combine that with car...... priceless), I thought the question was about a BMW model 2002, not build year 2002 and I believe, if memory serves correctly, those cars stopped being produced in 1976 and replaced by the e21 320i series. And Joe, when you talk to your mechanic ask about 5w30 too because I'll bet regardless of how cold it gets there'll be a couple of days that'll just make you itch to taker her out of the garage. As for the parts, be sure he knows I also have a Tii head that I bolted to the 320 block, worked great, slightly higher compression, and a couple of iron standard motor blocks. I'll go check the shed and see what I have and forward.


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## Autoputzer (Mar 16, 2014)

thumper600 said:


> Herr Putzer, (great name by the way, I'll wager you know what "Putzer" is in the German language, and then to combine that with car...... priceless), I thought the question was about a BMW model 2002, not build year 2002 and I believe, if memory serves correctly, those cars stopped being replaced in 1976 and were replaced by the 320i series. And Joe, when you talk to your mechanic ask about 5w30 too because I'll bet regardless of how cold it gets there'll be a couple of days that'll just make you itch to taker her out of the garage. As for the parts, be sure he knows I also have a Tii head that I bolted to the 320 block, worked great, slightly higher compression, and a couple of iron standard motor blocks. I'll go check the shed and see what I have and forward.


Yeah, I suspect BMW's from the 1970's required something along the line of a 10W-40. It's the last number that's important when the car's warmed up. Old cars had larger bearing clearances, and needed a higher viscosity oil to keep oil pressure (and oil) in the bearings.

The W number is important for cold start-up's, the lower the better. Petroleum oil gets is multi-viscosity properties (having a W and non-W rating) from additives called "viscosity improvers" (VI's). VI's get more viscous as they get hotter. But, VI's are unstable and break down. So, a petroleum 10W-40 eventually becomes a 10W-30, 10W-20, and then a 10W-10. The larger the difference between the W number and the non-W number, the more unstable a petroleum oil would be. Synthetic oil is naturally multi-viscosity. So they need fewer or sometimes no VI's. So, a 0W-40 synthetic, widely available, would stay a 0W-40 for a long time.

When I married Frau Putzer, somebody asked her what my hobbies were. Hunting? Fishing?Golf?

She said "It's the damnedesst thing. His only hobbies seem to be accounting and washing cars. But, I'm pretty sure we won't have to work as Walmart greeters when we get old, and it's sure nice driving a clean car."

In Yiddish, "putz" means to play or act ineffectively. "Auto" means "self." In German "Autoputzer" means "car washer." But, in Yiddish, it sort of means... well... one who plays with himself..


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