M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: jpod999 on June 18, 2007, 10:14:02 PM
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The time has come to replace my oil. I am just about to hit 224,000 miles and would like to know what oil you guys would recommend to me.
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That would have to depend on where you are? Climate etc..
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I think i put 10w30 in my engine once i put the new head back on...but when i change it im probably going to put 40 in it instead.
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That would have to depend on where you are? Climate etc..
I live in the Bay Area. Right now it is dry and 90-100 degrees.
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I use Shell Rotella 5w40 in the gallon container. Can't beat $16/gal for a full synthetic. Diesel rating is another +. I live in the bay area.
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15-50 mobil 1
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10w40 or 15w50
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I use 15w50 Mobil 1, have used Castrol Syntec of the same weight previously...
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If you've alway run standard (non-synthetic) oil, stick with it, particularly with an engine with so many miles. Valvoline 20/50 -- or NAPA 20/50, which is the identical product.
This comes from Colorado's finest BMW shop, BimmerHaus, Broomfield. http://www.bimmerhaus.com. Owner Bob Tunnell has won a dozen National autocross titles and been to the road race SCCA runoffs -- all in BMWs. He won a Auto-X championship in a 1991 318is.
Gary
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15-50 mobil 1
+1 in Central Fl
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Ive done a lot of analysis on this, and perform oil analysis and similar functions quite often. As a chemical engineer Ive obtained a lot of knowledge about tribological topics pertaining to optimizing IC engine longevity.
Based upon my analysis for my drivign style and climate, I have found that rotella synthetic 5w-40 is the best. a 10w-30, short of redline with its ester base, will not provide enough viscosity at the bearings, evidenced by higher soft metal readings.
Mobil1 15w-50 is a great oil, but actually provides no added benefor for the most part over a decently formulated 40 wt oil.
Id run rotella or mobil1 5w-40 (both have superior diesel spec additive packages). Id also consider schaeffer's 9000 5w-40 if you can get it (or are willing to mail order it), it is a top notch oil as well.
If your engine leaks or develops a leak when moving to syn, the engine is telling you something. There are some fixes, includng seal cleaners and conditioners, but if it leaks and the car is worth keeping, you ought to be thankful that a leak formed so that you know that your car is in need of PM!
JMH
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so either 20w-50 non-synthetic or 5w-40 non-synthetic. That seems like the way to go?
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The chemistry of lube oils, as well as the shear stability of basestocks, has advanced so far that there really is little need for a 20w-50 oil to be used any more. There is something to be said about having enough viscosity at the bearings that we do not wear them prematurely, but once the chemistry of the metals and oil intertwine, and we have a decent lubricating boundary layer, anything else is just power loss.
I wouldnt say that you should use a 30wt, even one that is on the viscous/heavy end of the 30wt spectrum. However, IMO, unless you really thrash your engine in the desert heat all afternoon long, Id say that a 50wt oil is too much as well.
I have found via analysis that a 40wt oil is optimal for protection. It is a bit thinner at startup in a 5w- grade, and it merely sacrifices a little bit of unnecessary viscosity for better flow and cooling properties.
I also see no reason why not to use synthetic lubricants in any car worth keeping and running well.
5w-40 MUST be a synthetic oil, of at least group III (severely hydrtreated slack wax) spec, with some PAO and some ester mixed in, in order to meet the viscosity spread desired. Further, given its inherent use in heavy duty diesel engines, it must e EXTRA shear stable, so this limits the use of viscosity index improvers... that means thatr a syn base is more or less mandatory.
I would suggest to pick a 5w-40 oil and stick with it.
JMH
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From what I have read Deisel is best for older engines, at least regarding cam wear.
Many newer oils (which changed just after our cars were made) have less lubricating properties in them. Hot Rod or Popular Hot Rodding (I think) did a test on this because they were getting an abnormal amount of cam failure over the last few years.
I can try to dig up the issue, pretty interesting read, they found Shell Rotella T to be the best for older engines.
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So yes or no on synthetic? My car has never had synthetic before.
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So yes or no on synthetic? My car has never had synthetic before.
From what I have seen, it really makes little difference, I have noticed the lights come on about 1000 miles sooner is all. It did not really run much different.
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From what I have seen, it really makes little difference, I have noticed the lights come on about 1000 miles sooner is all. It did not really run much different.
Irrelevant. The lights in n E30 are not chemistry specific, and are more of a glorified startup and rev counter. Some of the new OLMs are syn vs. conventional oil tuned, but even them are not doing any real, active measuring of the fundamental properties of a base oil or its additive package.
JMH
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So yes or no on synthetic? My car has never had synthetic before.
Personally, I wouldnt worry about going to a syn oil. Ive converted a number of our cars at 160-230k miles, and hae not had issues.
If a leak forms, due to the syyn oil cleaning junk around seals that are compromised, guess what? you had a buildup of dirt in your engine, and the oil cleaned it. Is that bad? Does it mean that your seals were actually in GOOD condition? I think not. And, if there is junk around your seals, you can bet that there is impacted dirt around the rings too.
I would change to synthetic, and be glad if it shows a leak that you can then fix - its pointing out weakness in your system.
If you are really against syn oils, I would go with rotella 5w-40 synthetic, which is only a group III synthetic,m so it has less cleaning and seal swell chemistry, and thus has a lesser probability of causing any sort of an issue anyway.
If you want to be cheap and do nothing but pour oil in it, buy chevron delo 400 15w-40, and be done with it. This is the best of the conventional oils.
JMH
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Actually cleaning out build up can be bad - you are changing an existing operating property and as a result unexpected results can occur. Having said that I think high detergent oils are the way to go.
IMHO the difference between traditional and synthetics comes down to cost and service frequency. If you change your oil often there is nothing wrong with traditional oils and you will save money.
I use GTX in the 91 318 changed every 3K; Syntec since new in my MINI changed every 6K, and Syntec in my 325 every 6K. I use these intervals because they are 5 and 10K kilometers in the Great White North and thus easier to remember when to change.
A couple of additional benefits from synthetics are they do have longer shelf life which can be handy in low mileage vehicles, and the viscosity range is larger which also allows for less need for a change.
The M42 get GTX every 3K or 3 months and the viscosity is 20w50 in the summer and 10w40 in winter. These are the manual's temp dependent recommendations.
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I switched 3 cars from regular to synthetic oil at over 100k miles and never had any problems. I keep the synthetic oil in for 7.5k to 10k miles depending on oil consumption.
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Actually cleaning out build up can be bad - you are changing an existing operating property and as a result unexpected results can occur. Having said that I think high detergent oils are the way to go.
The results obtaned are never bad in terms of the engine - only good. The most common claim is the opening of a leak. The leak was always there, the issue with the seal was always there. It is merely a fact of the removal of sludge and dirt that the leak opened up. Is this bad? No, considering that this means that your engine was dirty and now is getting cleaner. By the way, your reccomendation of a high detercent oil is nearly the same. A strong detergent/dispersant package in a fully formulated motor oil will solve and remove/suspend junk just the same as a synthetic basestock. The rates of doing this may differ, but the phenomena is the same. Diesel oils, given their design to actively suspend soot, are what one would classify as a high detergent oil. None of the standard passenger car oils would be. Further, any so-called unexpected results (such as having a leak and running low/out of oil) are the result of poor PM/recordkeeping and check-ups of one's vehicles condition. This is a fault on the driver, not the oil or the machine.
IMHO the difference between traditional and synthetics comes down to cost and service frequency. If you change your oil often there is nothing wrong with traditional oils and you will save money.
Agreed. Other than some specific situations, it is poor economy to do 3 or even 5000 mile OCIs on syn oil.
I use GTX in the 91 318 changed every 3K; Syntec since new in my MINI changed every 6K, and Syntec in my 325 every 6K. I use these intervals because they are 5 and 10K kilometers in the Great White North and thus easier to remember when to change.
You coud liklely extend those rates, motor oil has come a long way, and it generally will hold up (syn that is) in excess of 7500 miles with negligible difference in wear rates from when new.
A couple of additional benefits from synthetics are they do have longer shelf life which can be handy in low mileage vehicles, and the viscosity range is larger which also allows for less need for a change.
Shelf life is about the same for all oils. The issue is generally additives falling out of sollution in time. In that regard, conventional oils are actually better... But this is a virtue that is analyzed in years, and even in seldomly used cars, years is not a good duration for oil changes, due to the buildu of moisture. One place where syn oils are more stable is in terms of 'shear stability', or the reduction of viscosity with respect to use. Syn oils need little to no viscosity index improvers, so they stay in grade much easier. Syn oils are the best in this regard, HD diesel oils, such as the key 15w-40 oils and 5w-40 oils from the manufacturers are the next best, with standard engine oils last in the hierarchy, and still often showing issues.
The M42 get GTX every 3K or 3 months and the viscosity is 20w50 in the summer and 10w40 in winter. These are the manual's temp dependent recommendations.
Thats a fine choice - that said, motor oils have come a long way from API SG and 1991 chemistries. Though people like to make blanket statements about why the world is moving to lighter oils, please consider that everyone, BMW included has moved to lighter oils over time. It is not because there has been a significant change in tolerances and build quality in engines, changes in metalurgy, fuel economy, etc. While all of these things are good concepts, and partially true, the key thing to realize is that whether via requirement push or technology pull, the chemistries have improved so much so that a significantly lighter, more stable oil can be put into a significantly more power dense machine with all other things (build quality, toplerances, etc.) equal. This is thanks to the advancement in the shear stability, oxidative stability and enhanced performance of the additives put into fully formulated motor oils.
I hope this helps and is informative.
JMH
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I switched 3 cars from regular to synthetic oil at over 100k miles and never had any problems. I keep the synthetic oil in for 7.5k to 10k miles depending on oil consumption.
Of our nine cars, ranging from plymouth to MB, 120 hp at full boost diesel to 320 hp twin turbo cars, they all run syn and none leak or have any consumption. We have converted four at over 160k miles (one of them was done at exactly 200k), and the rest at over 60k miles, none showing any problems.
Yours is proof that a lot of the syn oil issues are wive's tales for well maintained machines. And, some that see consumption also see it go away to zero after 5-10k miles.
JMH
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Castro Magnatech
GTX 5-40
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The results obtaned are never bad in terms of the engine - only good. ... ... Further, any so-called unexpected results (such as having a leak and running low/out of oil) are the result of poor PM/recordkeeping and check-ups of one's vehicles condition. This is a fault on the driver, not the oil or the machine.
I really don't know if a change to synthetic is likely to cause leaks, but being conservative, gradual change is better than sudden change :rolleyes: In my case I'm already leaking - lower timing case (more of an ooze), given the profile gasket is one of the risk points in the M42, I'm not going to change to synthetic until I've been in there and replaced the gaskets and inspected the profile gasket.
The goal is to extend life and avoid expensive maintenance, sometimes that includes doing things that are not theoretically optimum ie my service intervals are easy to remember rather than the most efficient.
...that said, motor oils have come a long way from API SG and 1991 chemistries. ... I hope this helps and is informative.
JMH
Indeed... ...it is. For me the cost benefit means synthetic for the new dino for the old. This saves me about $50CDN a year so in 200 years I can afford a new MM engine! :)
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I really don't know if a change to synthetic is likely to cause leaks, but being conservative, gradual change is better than sudden change :rolleyes:
We always changed the oil early the first syn fill, but didnt do anything else... worked fine. On my MB, which I changed at 200k, I did so 50/50 the first time.
I'd agree with the desire to go it slow, and take the precautions in the name of being careful and economical, etc.
cheers!
Best,
JMH
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Alright, so I think I am going to go pick up some 5w-40 synthetic today. Hopefully I get no leaks.
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I'm about to follow in your tracks, hope to hear of the results soon.
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I'm about to follow in your tracks, hope to hear of the results soon.
LOL I went to Carquest yesterday and they didn't have any 5W-40 at all. Gonna have to head to Napa now.
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This should be interesting! I thought it was not a great idea to switch to synthetic once the engine reaches 100k and dyno oil was used through its life?
Let us know if the motor does quiet down some also!
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Alright well change of plans. I was away for the weekend and my dad got a case of regular 10w-30 in the meantime. So I put that in today...sorry to the people that wanted to see the results of my swap to synthetic.
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My car had 180,000 miles when I bought it and I didn't know what it had in it all that time. I switched it to synthetic and everything has been ok for the last 11,000 miles.