235k mile BMW - different oil or stick with same?

Messages
7
Location
FL
Hello forum. I figured this would be the place to ask. I have a '98 740il with 235k miles on it, driven in FL, sees a good mix of highway and around town. I drive it pretty easy, but get on it at times. The V8s in these older BMWs run hot -- 100-110*C. Does city driving during the week and 500 mile round trip highway road trips on occasional weekends. Been in the family since 29k miles. I maintain everything myself. For years the well known euro shop in south FL used Castrol 20w-50 in it, so I continued with that when I got the car 8 years ago. I dropped down to 10w-40, when I spent time in CT in school, then switched back to 20w-50 when I moved back to FL. Reason for asking this is that I noticed with the my higher mileage that I "burn" about a quart every 3-4k miles. I just had to top up a quart to get back to full the other day after about 3500 miles. I change the oil every 7500 miles or so, which is half of the normal interval that the car says to do with the "oil lights" in the dash. I buy my oil at Walmart because they've got the best price. They were out of the conventional 20w-50 the other day so I start looking around and thinking about all the other oils there. I see Castrol High Mileage, Castrol Magnatec (blend), Castrol Edge (synthetic), Castrol Edge High Mileage, and I start thinking...should I at least be using a high mileage oil? My wife has a 540i (same engine as 740) that we got with low miles, and I started with Mobil 1 Full Synthetic European Formula in that car (0w-40 I believe). And that's all I've used in that. So just looking for advice. I'm leaning toward staying with Castrol in my car (for whatever reason), and maybe a high mileage oil? I thought I read somewhere it is not good to switch between dino oil and synthetic, but that was years ago. Can I (should I) go to a full synthetic? Thanks!
 
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16,548
Location
Upper Midwest
Buy the least expensive oil you can find that has actual Longlife-01 certification. For you that is likely Castrol 0W-40 at Walmart, same as it is for me. And if your engine is operating "hot" that is odd for that vintage of BMW. Most of them had large capacity cooling systems that didn't overheat. How is your thermostat? What about the aux cooling fan, is it working? Ignore the wive's tale about switching from conventional to synthetic.
 
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9,064
Location
Marshfield , MA
I ran my M 20s on supertech dino 20w50. Some leaked, some didn't. The Low oil level light. came on when the level was a qt low. I highly recommend you keep the low coolant level switch going too.I would continue with your 20w50 Castrol regimen. Just because old BMWs don't like to have their wah disturbed. Just continuous small fixes grin2
 
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Messages
16,548
Location
Upper Midwest
Originally Posted by andyd
I ran my M 20s on supertech dino 20w50. Some leaked, some didn't. The Low oil level light. came on when the level was a qt low. I highly recommend you keep the low coolant level switch going too.I would continue with your 20w50 Castrol regimen. Just because old BMWs don't like to have their wah disturbed. Just continuous small fixes grin2
What?
 

racer2086

Thread starter
Messages
7
Location
FL
Originally Posted by PimTac
Stay the course.
K that was my initial feeling, thanks.
Originally Posted by kschachn
Buy the least expensive oil you can find that has actual Longlife-01 certification. For you that is likely Castrol 0W-40 at Walmart, same as it is for me. And if your engine is operating "hot" that is odd for that vintage of BMW. Most of them had large capacity cooling systems that didn't overheat. How is your thermostat? What about the aux cooling fan, is it working? Ignore the wive's tale about switching from conventional to synthetic.
Doesn't LL01 certified oil have to be synthetic? I figured that's how it would be long life oil, but I'll look. My car is not operating hot. These M62 V8s run at 108-110*C. I put a cooler thermostat in, which gets me running at about 99-101*C, which is a lot better on all the plastic cooling components.
Originally Posted by andyd
I ran my M 20s on supertech dino 20w50. Some leaked, some didn't. The Low oil level light. came on when the level was a qt low. I highly recommend you keep the low coolant level switch going too.I would continue with your 20w50 Castrol regimen. Just because old BMWs don't like to have their wah disturbed. Just continuous small fixes grin2
Never had a low oil level light. Car holds 8 quarts of oil, and I check it enough to not let it drop too low. Can regular, "conventional" oil go 7500 miles before a change?
Originally Posted by Triple_Se7en
Your dash oil light does not tell you the life-span condition of your oil. Most newer vehicle OLMs are useless for important/integrity information also.
Right, this is why I just decided to split the typical interval in half. When half the lights are gone I'm usually at 7000-7500 miles. My concern now is whether the regular Castrol GTX can handle that or if I've been stupidly using an inferior oil.
 
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16,548
Location
Upper Midwest
Originally Posted by racer2086
Doesn't LL01 certified oil have to be synthetic? I figured that's how it would be long life oil, but I'll look. My concern now is whether the regular Castrol GTX can handle that or if I've been stupidly using an inferior oil.
BMW would have specified a Longlife-98 oil, correct? That was superseded by Longlife-01, which continues today. I guess I'm a little unclear why one would not use the oil specified by the manufacturer, but would rather go by opinions found on an Internet board (even if you shorten the OCI). Not being mean, just asking. Castrol 0W-40 at Walmart is cheap enough even if you are determined to change it early and is one of the best oils on the market with a plethora of manufacturer approvals.
 

racer2086

Thread starter
Messages
7
Location
FL
Originally Posted by kschachn
Originally Posted by racer2086
Doesn't LL01 certified oil have to be synthetic? I figured that's how it would be long life oil, but I'll look. My concern now is whether the regular Castrol GTX can handle that or if I've been stupidly using an inferior oil.
BMW would have specified a Longlife-98 oil, correct? That was superseded by Longlife-01, which continues today. I guess I'm a little unclear why one would not use the oil specified by the manufacturer, but would rather go by opinions found on an Internet board (even if you shorten the OCI). Not being mean, just asking. Castrol 0W-40 at Walmart is cheap enough even if you are determined to change it early and is one of the best oils on the market with a plethora of manufacturer approvals.
I guess I just haven't looked lately. The stuff I'm using probably qualifies. BMW's LL oil back in the day was packaged in their own BMW bottles and you buy it at the dealer. BMW is way more strict about the oil in the M cars, as my dad's M3 needs the Castrol TWS 10w-60, which you can only buy at the dealer or online. In reading about the high mileage oils, it seems they're designed more for leaking engines, burn significant oil, or have noises, none of which really apply to me. So no worries about the high mileage oils. How about synthetic vs non? If money was no object, pretty much everyone would say just use the synthetic right? Bad to switch to that at high miles?
Originally Posted by SirTanon
Originally Posted by dave1251
Try some 15W40 HDEO.
Definitely worth consideration.
I have heard that 15w40 is some heavy duty stuff. I think they even sell that at my Costco.
 
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Messages
2,230
Location
Lyndhurst NJ
Keep doing what youre doing, it made it this far so youve gotta be doing something right. If youre worried, have the oil analyzed and see if theres anything to focus on. I think a quality 15/40 would work well, Shell t5 is on sale on amazon, 15$ for a gallon, semi syn. Have you had your vanos or timing chains redone at any point in its life?
 
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946
Location
Suomi
Originally Posted by kschachn
Originally Posted by racer2086
Doesn't LL01 certified oil have to be synthetic? I figured that's how it would be long life oil, but I'll look. My concern now is whether the regular Castrol GTX can handle that or if I've been stupidly using an inferior oil.
BMW would have specified a Longlife-98 oil, correct? That was superseded by Longlife-01, which continues today. I guess I'm a little unclear why one would not use the oil specified by the manufacturer, but would rather go by opinions found on an Internet board (even if you shorten the OCI). Not being mean, just asking. Castrol 0W-40 at Walmart is cheap enough even if you are determined to change it early and is one of the best oils on the market with a plethora of manufacturer approvals.
+1
 
Messages
5,729
Location
North Texas
Originally Posted by racer2086
Hello forum. I figured this would be the place to ask. I have a '98 740il with 235k miles on it, driven in FL, sees a good mix of highway and around town. I drive it pretty easy, but get on it at times. The V8s in these older BMWs run hot -- 100-110*C. Does city driving during the week and 500 mile round trip highway road trips on occasional weekends. Been in the family since 29k miles. I maintain everything myself. For years the well known euro shop in south FL used Castrol 20w-50 in it, so I continued with that when I got the car 8 years ago. I dropped down to 10w-40, when I spent time in CT in school, then switched back to 20w-50 when I moved back to FL. Reason for asking this is that I noticed with the my higher mileage that I "burn" about a quart every 3-4k miles. I just had to top up a quart to get back to full the other day after about 3500 miles. I change the oil every 7500 miles or so, which is half of the normal interval that the car says to do with the "oil lights" in the dash. I buy my oil at Walmart because they've got the best price. They were out of the conventional 20w-50 the other day so I start looking around and thinking about all the other oils there. I see Castrol High Mileage, Castrol Magnatec (blend), Castrol Edge (synthetic), Castrol Edge High Mileage, and I start thinking...should I at least be using a high mileage oil? My wife has a 540i (same engine as 740) that we got with low miles, and I started with Mobil 1 Full Synthetic European Formula in that car (0w-40 I believe). And that's all I've used in that. So just looking for advice. I'm leaning toward staying with Castrol in my car (for whatever reason), and maybe a high mileage oil? I thought I read somewhere it is not good to switch between dino oil and synthetic, but that was years ago. Can I (should I) go to a full synthetic? Thanks!
Keep on truckin. My mother in law has 95 5 series with the V8 with 16K original miles, lol.
 
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4,672
Location
MN
Originally Posted by racer2086
How about synthetic vs non? If money was no object, pretty much everyone would say just use the synthetic right? Bad to switch to that at high miles?
Actually, I recommend an HTHS 3.5 to 3.9 range oil, matching BMW LL-01's recommendation for those engines. A High Mileage full synthetic is what I'd use to keep those seals flexible going forward, preventing future leaks. Either Mobil1 High Mileage 10w30 (HTHS 3.5) or Mobil1 High Mileage 10w40 (HTHS 3.9) would be what I'd use. If you drive hard, very fast, as in track conditions, then definitely the 10w40, otherwise the 10w30 would be better here for normal driving. Since you said you shop at Walmart, it's easy to get. For engines like that over 15 years old, you'll do fine using any modern synthetic from a reputable company with about the right rheology ranges BMW calls for. Definitely an HTHS 3.5-3.9 engine there. ... And High Mileage oils mostly just add in something to prevent seal leaks, as time & heat can age them a bit.
 
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Messages
10,254
Location
MA
Yeah, I don't know about all the other oils mentioned but some of them were diesel oils and I think several of them mentioned don't have any BMW certifications. I'd second the recommendation for Castrol 0w40. Meets lots of specs. Some say it's even better than Mobil 1 0w40 as they have their MB 229.5 spec but no LL-01 spec. Castrol has both. Buy an oil that meets BMW specs. There's no special magic oil out there that would be better that doesn't meet spec.
 
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13,195
Location
Maricopa Arizona
Originally Posted by Wolf359
Yeah, I don't know about all the other oils mentioned but some of them were diesel oils and I think several of them mentioned don't have any BMW certifications. I'd second the recommendation for Castrol 0w40. Meets lots of specs. Some say it's even better than Mobil 1 0w40 as they have their MB 229.5 spec but no LL-01 spec. Castrol has both. Buy an oil that meets BMW specs. There's no special magic oil out there that would be better that doesn't meet spec.
BMW with 235K miles primarly on 20W50 and your concerned about BMW certs. Let me put you at easy if the HTHS is 3.5 or close to it at a minimum longevity will not be affected. German car owners have been using HDEO in their engines long before I became a member and stated engines are still running. Check out the BMW, Mercedes, and Porsche on Google using HDEO.
 
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1,877
Location
Crawfordville FL
The 20w-50 conventional will run 7500 miles The Castrol 0w-40 is the "correct" oil If you go with the M1 10w-40 route, they run rebates twice a year. $12 back on a 5qt jug, buying at Walmart it comes out around $13 for a 5qt jug of syn. M1 has a good 0w-40 HDEO 15w-40 or 5w-40 would also work fine. Penzoil also runs rebates, and they have a full syn 0w-40 euro oil available at Walmart. If the consumption bothers you I would try different oils until I found the one that seems to slow the consumption. Nothing wrong with keeping your same regimen. That amount of consumption is pretty low considering the mileage. Might be worth checking the PCV valve if it has one, when the internal spring weakens manifold vacuum can pull oil mist from the crankcase straight into the intake.
 

CT8

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15,396
Location
Idaho
It sounds like you have done everything right ! I don;t know if changing what works is a good idea.
 
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