How does very short OCI's hurt an engine?

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I do not change oil more frequently than 3 mo./3K mi.; however, I am curious if there is any truth to potential harm in changing your oil in very short intervals. I've read this in a few differnt places, including some somewhat respectable Porsche forums.

I have read that if you do not leave the oil in long enough, that it it not allowed to "neutralize" as it should over time -which to me implies that somehow fresh oil is not ideal. Does this have any true basis (i.e. pH?) or is this just misinformation? Thanks in advance for your opinions as I am somewhat baffled by this idea...
 
I have also read it....right on this forum....that changing your oil too early is not beneficial to your engine.

It seems that the posters, who stand by letting the oil run for some time, feel that the quality oils of today need a break in time before the additive package can really begin to do it's work in cleaning and protection an engine.

I don't know if there is any truth to this....so please don't shoot the messenger. I have seen it posted on this site, as a warning, for people who change their oil too soon and not giving the oil a chance to break in and the add pack to start cleaning.
 
I have no idea how 'new' oil could be bad for an engine. Sounds crazy to me. Changing too early would just be a waste of money but to actually be bad for your engine? I've never read that anywhere.
 
Most people adjust oil change intervals to suit the driving habits and shorter drain intervals act as a means to that end and are used for "cleaning " the engine of sludge/varnish.
 
lighter molecules in the oil evaporate first. thus continual fresh oil could gum the pcv. this is probably bull, but I've heard it and other bull on BITOG.

also, some of the additive chemistry can be time/temperature/pressure dependent. Thus takes a while for anti-wear and friction modifiers to properly seat. Thus might be getting your best performance later in an OCI. Will miss out on the oils best AW & AF if you dump too soon, and thus will always be running on half-baked oil (no pun).
 
Increased wear from dry starts. I've always gotten a pretty nasty sound for a couple seconds before oil pressure builds.
 
Every time you change the oil, you open up the engine to possible contamination. Plus, you run the risk of doubling up a sealing gasket on the filter, stripping a thread, overfilling, underfilling, replacing a good product with one that is defective, having the car fall off the jackstand, starting the car by accident when the oil is drained. There is plenty of discussion on this site about how long oil will last and it is definitely not 3,000 miles - it's far longer. Changing more often that needed accomplishes nothing. A maintained engine will essentially never fail because of oil, and in general, the car will fall apart before the engine does.
 
Originally Posted By: meangreen01
Increased wear from dry starts. I've always gotten a pretty nasty sound for a couple seconds before oil pressure builds.


Not if you fill the filter before installing... I haven't installed a dry filter in 40+ years...
 
Originally Posted By: TomYoung
..having the car fall off the jackstand, starting the car by accident when the oil is drained...


I have the heavy plastic ramps from Wallies. I scare myself to death every time I drive up on them. Also, one of these days, as I get older, I can see myself starting the car with everything drained.

Here's an old favorite from web site (edited for brevity).

Woman changing oil - drive up to Jiffy Lube, sit and relax. Pay $30.

Man changing the oil -
(1) Wait until Saturday, drive to auto parts store and buy a case of oil, filter, kitty litter, hand cleaner and a scented tree, write a check for $50.00
(2) Stop by liquor store and buy a case of beer, write a check for $20.00, drive home.
(3) Open a beer and drink it.
(4) Spend 30 minutes looking for jack stands. Jack car up.
(6) In frustration, open another beer and drink it.
(7) Place drain pan under engine.
(8) Look for 9/16 box end wrench.
(9) Give up and use crescent wrench.
(10) Drop drain plug in pan of hot oil: splash hot oil on face and arms in process. Cuss.
(11) Crawl out from under car to wipe hot oil off of face and arms. Throw kitty litter on spilled oil.
(12) Have another beer while watching oil drain.
(13) Spend 30 minutes looking for oil filter wrench.
(15) Crawl out from under car with dripping oil filter splashing oil everywhere from holes. Cleverly hide old oil filter among trash in trash can to avoid environmental penalties.
(22) Install new oil filter making sure to apply a thin coat of oil to gasket surface.
(23) Dump first quart of fresh oil into engine.
(24) Remember drain plug from step 11.
(25) Hurry to find drain plug in drain pan.
(26) Remember that the used oil is buried in a hole in the back yard along with drain plug.
(28) Shovel out hole and sift oily mud for drain plug. Re-shovel oily patch of ground and avoid environmental penalties. Wash drain plug in lawnmower gas.
(29) Discover that first quart of fresh oil is now on the floor. Throw kitty litter on oil spill.
(30) Drink beer.
(31) Crawl under car getting kitty litter into eyes. Wipe eyes with oily rag used to clean drain plug. Slip with stupid crescent wrench tightening drain plug and bang knuckles on frame.
(32) Bang head on floorboards in reaction to step 31.
(33) Begin cussing fit.
(34) Throw stupid crescent wrench.
(36) Beer.
(37) Clean up hands and forehead and bandage as required to stop blood flow.
(38) Beer.
(40) Dump in five fresh quarts of oil.
(42) Lower car from jack stands.
(43) Accidentally crush remaining case of new motor oil.
(44) Move car back to apply more kitty litter to fresh oil spilled during steps 23 - 43.
(45) Beer.
(46) Test drive car.
(47) Get pulled over: arrested for driving under the influence.
(48) Car gets impounded.
(49) Call loving wife, make bail.
(50) 12 hours later, get car from impound yard.

Money Spent
Parts: $50.00
DUI: $2500.00
Impound fee: $75.00
Bail: $1500.00
Beer: $40.00
Total: $4165.00 -- But you know the job was done right!
 
crackmeup2.gif
 
sorry, I shouldn't have edited out step 18 - it was needed in the story -

(18) Sunday: Skip church because "I gotta finish the oil change." Drag pan full of old oil out from underneath car. Cleverly dump oil in hole in back yard instead of taking it to recycle.
(19) Throw kitty litter on oil spilled during step 18.
 
Originally Posted By: dparm
Changing it after 50 miles might not be smart, but I can't see a 3K OCI being WORSE than a 5K OCI.


Depends on if that 50 miles was 1/4 mile at a time.
 
Purportedly, the detergent package competes with the anti-wear package for metal surface area (front row seats so to speak) so possibly you coukd be wearing your engine out faster with too frequent an oil change. GM and ford have published papers on this very subject. Another reason why in many race oils formulated for highly stressed engines the detergent package is reduced. what does this mean on the road with a passenger car, I dont know - guess a 10% hit in service life? Conversely you would think having clean ring grooves would help service life, maybe its a wash?
 
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I know quite a few people that change the oil at 2k miles. Of course they get horrified when they find out I change the oil at 7.5k or 9k or whatever. And they usually buy new cars when the "old" ones are barely broken in at 120k
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. I'm going to be buying those cars, and I need to know if I need to persuade them to change the oil less frequently
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