Engine oil mythology debunked, and ZDP content

[paulfarber]

Couple of important points:

MODERN engines have 5000-7000mile oil change interval. 3000 miles changes was a Jiffy lube jingle. The *only* time a manufacturer specifies less and 5k is forr 'extreme duty' use. No, that ain't your car.

TO the mechanic that says the oil is dirty.... um, its not the color that matters, but the amount of esters and additives left in the oil. Color? Really?

Bypass filters are GREAT at what they do. Most cars with full flow filters will open the bypass valve at about 3kPRM and above... that means NO FILTERING from your full flow filter becuase the bypass valve is open and bypassing the entire filter. That's good how???

Non-Detergent oil is still misunderstood. Do people really thing that as soon as the oil hits the pan the dirt immediately falls out of suspension and sticks to the pan? No. It still happily circulating in your oil. When your engine STOPS is when it falls out of suspension. A bypass filter will still filter all your oil every 8-10 minutes. Thats much better than NO filtering.

 

[mobileauto2000]

I have a customer that changes his oil every 2500 miles.
1965 ford pickup 312 175000 miles. These engines were worn out at 90000.
1990 chevy pickup 350 236000 Still going. Not unheard of for the year.
1974 chevy nova 6 cyl 350000 before rebuild.
1975 chevy nova 6 cyl 300000 when sold
1995 dodge caravan 290000 last time in my shop. still runs like new, no oil consumption.

I know this will be random scraps of paper to some. but all these vehicles have had the same 2500 mile oil changes, owned by the same guy. You can make the argument that its maybe not cost effective if you do not plan to keep your car forever. But if you are like me and do. Nothing helps more than regular 3000 mile oil changes in older cars 5000 in newer cars. And if most of you driving is around town in short trips it is 'extreme duty' no matter what some people say.

PS Draind the Gl 5 out of my deuce trans and went with 40w. don't have to fight the syncro's into 2nd any more. I know seat of the pants opinion but that is how Po- fessional mechanics test drive-ability problem

 

[emr]

short and sweet, detergent oil in an engine that has a filter and non in an engine that does not, true as it was and is today, period. lighter oil in a tighter tolerance engine and a thicker in a looser bigger/older engine, true today as it ever was, the easy set of true rules for oil, All oil... ALL oil is mixable, oh yes it is... ANY oil is better than no oil to get home or out of harms way or the woods...

 

[paulfarber]

If an engine is getting regular oil changes that means its getting MAINTAINED. Most modern car engine manufacturer will state that that oil change interval is less than 5k, only in 'severe duty' do you get the 3k number.. and they never define 'severe duty' precisely.

Ask any Fleet operator what their oil change interval is. Most don't have one. Its done by oil analysis. They will change FILTERS ever X miles, but only adding oil to top it back off. And a diesel in a tractor is seeing a much harder life than any car. A $20 analysis is cheaper than at $100-$150 oil change.

I'm sure there are many motors out there with 300K miles and still running and only gets oil when the 'oil' light flashes in the turns.

And unless you have receipts, I don't believe it. Sorry. Prove it, then you have my attention.

 

[mobileauto2000]

I knew you would argue the point. To start i was talkin' cars not heavy trucks. Now How many cars do you maintain. How many engines do you rebuild a year, Swap, Major repairs? What are your credentials. How many years have you owned a repair shop? Number of cars you see a year? I don't know, maybe you are quantified to be an expert. But i don't think so.

 

[paulfarber]

I completely agree that a well maintained engine will last.

You seem to insist that the 'jiffy lube' 3000 mile oil change is the key.

If that were the case then every motor would last 300k+ miles at 3k oil change intervals. We both know that is not the case.

If I change my oil every 1500 miles will it last 600k?

If I add Lucas oil will it last even longer

 

[mobileauto2000]

I'm still waiting for your credentials.

 

[ShearerLegal]

With apologies for resurrecting an old thread, I thought some of you might be interested in my experience with synthetic oil. in 1997 I purchased a brand spankin new land rover Defender 90 and a 100k mile extended warranty. At the first oil change I started using Amsoil synthetic and changed the oil roughly every 3-6 thousand miles with either Amsoil or Mobile 1 synthetic. At 99k miles, I took it to the dealership and they replaced the exhaust valves under warranty. One day after work, I stopped by the dealership to check on the vehicle. A very excited service tech came up to me and asked if the black D90 was my vehicle. He asked me to come look at the engine with the heads off. Upon looking at the engine, each cylinder bore still had the cross-hatch pattern from the factory. There was no bore wear. The guys working there were astounded by this. Just my experience. I have no affiliation with any oil companies.

 

[mobileauto2000]

Have a 99 dodge ram 1500 with a 360, 98000 miles on it in my shop now. Guy just runs dino oil and changes it when he feels like it. heads are off for head gaskets. Still has hone marks on cylinder walls too. Has more to do with improved steel used in the blocks than the oil used. If only dodge would redesign their heads so they would not crack.

 

[SCSG-G4]

My 93 Corolla goes in every 5000 miles for servicing, next time it will get another new timing belt (every 60K). It does burn a quart about every 1000 miles, but still gets 35 MPG in town and better than 37 on the road. Dern batteries don't hold up, I had to replace the third one last year. Folder with all the service/repair tickets is about 2 inches thick now. Oh yeah, 358623 miles so far.