Extended Oil Intervals

[DragonKnight]

Check this out:

http://neptune.spacebears.com/cars/stories/oil-life.html

Seems like these fellas are trying to see how long it takes to break down synthetic oil before an oil change is needed. The only 'flaw' in this study is that the oil is sorta replenished whenever they take a sample out for testing. But they take that into consideration when they finished up their study on Mobil 1. They're currently working on Amsoil which has a 25,000 mile or 1 year change interval on 'normally driven' cars.

rich-c

[ren28]

Very interesting link!

[mrazntre]

hehehhehe... "normally driven"

[BigLew]

Seems like these fellas are trying to see how long it takes to break down synthetic oil before an oil change is needed. The only 'flaw' in this study is that the oil is sorta replenished whenever they take a sample out for testing.
rich-cYeah but at the same time most cars burn a little oil and you'd have to add oil if you went that long of an interval without changing. I burn a around 1/2 a qt every 1000 or so miles which is normal for my car, so if I went 25,000 without a complete change then I'd have added at least 10 qts. of fresh oil in this timespan.

[mrazntre]

burning 1/2 a qt of oil seems to be a bit much. what kind of car you runnin?

[BigLew]

Honda Prelude VTEC, trust me it's normal.

[Arex]

I too have a VTEC Prelude and started noticing that it's been burning a decent amount of oil since I hit the 90k mile mark. I've been using Mobile 1 synthetic since after about 10k miles. I even switched to the thicker stuff since reaching about 110k miles in the hopes it'd burn less, but it just keeps on drinking the stuff up. Because I'm lazy and an irresponsible car owner (as opposed to having read the Mobile 1 article), I've pretty much just been going service intervals (7,500 miles) between oil changes. It guess, given that I'm often topping off, I can go even longer! Interesting read.

RX

[>:^|]

That's funny; my Honda is 14 years old and doesn't burn oil at all. I change the oil every 3,000 miles or so. A friend in the Netherlands has the same car but his service manual recommends 7,500 miles.

My old American car used to burn about a quart a month so I never changed the oil, just the oil filter. :wink:

[BigLew]

I too have a VTEC Prelude and started noticing that it's been burning a decent amount of oil since I hit the 90k mile mark. I've been using Mobile 1 synthetic since after about 10k miles. I even switched to the thicker stuff since reaching about 110k miles in the hopes it'd burn less, but it just keeps on drinking the stuff up. Because I'm lazy and an irresponsible car owner (as opposed to having read the Mobile 1 article), I've pretty much just been going service intervals (7,500 miles) between oil changes. It guess, given that I'm often topping off, I can go even longer! Interesting read.

RXIf you haven't done so you might wanna have your oil seals checked next time you have a t-belt change. Also oil consumption will correlate in how often you engage VTEC.

That's funny; my Honda is 14 years old and doesn't burn oil at all. I change the oil every 3,000 miles or so. A friend in the Netherlands has the same car but his service manual recommends 7,500 miles.

My old American car used to burn about a quart a month so I never changed the oil, just the oil filter. :wink:Most VTEC Honda engines are known for burning characteristics.

[537]

Arex and BigLew, have you guys ever done a compression test and a leakdown test?

[deez nuts]

should i switch to synthetic too?

i heard nothing but good things about it. there's gotta be a catch.

[mrazntre]

should i switch to synthetic too?

i heard nothing but good things about it. there's gotta be a catch.

yea, it's like $4.XX dollars a quart as opposed to dino oils at like $1.29 to $2.19 a bottle.
Syns are usually more slippery than dino oils with better breakdown.


contrary to popular belief, some motors are actually engineered to take synthetic oil. some are just based off dino oils. Most motors, regardless of design, can take synthetic oil. I don't specifically know which motors can't, but there are always exceptions.

i use synthetic.

[BigLew]

Arex and BigLew, have you guys ever done a compression test and a leakdown test?Yes and in my situation I am fine. Again this is normal for VTEC engines.

Well preludes at least and my comp is 210 across the board.

[mrazntre]

how about leakdown?

comp test figure can vary due to 1) strong starter 2)strong battery 3) carbon buildup on valves

[BigLew]

Leakdown was fine too, you know if you guys don't believe me you can look it up or even call a Honda dealership and they'll tell you the same.

[mrazntre]

1) It ain't that serious

2) I don't trust dealerships

[DragonKnight]

I wouldn't trust the dealerships. But if your local Honda community (or message board) says its a normal thing, then it should be cool. I know my Celica GT-S is suppose to burn oil the same way. Might be a 'lift' thing due to the characteristics of these particular engines.

Unfortunately my DSM is a different story. Need to do a headgasket swap and a leakdown to see if the rings are shot on cylinder four.

[Beat180]

There's a proviso to Amsoil, you gotta replace the filters at regular intervals. Personally I use mobil 1 since it's about the cost of other base IV oils, has pretty good stability at high temps. Redline, Royal Purple, Motul are all base V and are so stable they don't need extra stabilizers. However the last 3 I've listed cost a bundle and aren't really worth it unless you're going to the track and seriously taking laps. I use mobil 1 personally because of the detergent package that is included with it. It cleans a bit better than other oils I've used.

Motors that are using syn right off the bat: BMW, Porsche, Mercedes for sure. Reason I know is because their dealerships are supposed to use Mobil 1 cuz of some contract between them and Mobil. I think corvettes and vipers also come stock with syn oils in them. Specific makers I'm not too sure of though.

[mrazntre]

Contrary to popular belief, there are motors that are specifically designed to run synthetic oils (whereas others are built to dino oil specs and later on are tested to see whether or not the syn oils will work). This is the case with Subaru.

I think that the main issue is whether or not the synthetic oil is too wet/slippery for the internal engine components. Thin oil will not be able to adequately lube engine parts and such and might cause engine failure. However, I think this can be "made up" using thicker weight oil.

btw: I'm also using Mobil1 because frankly, it's popular, relatively cheap and readily attainable - Walmart, Costco, and only a few molecules from being a pure synthetic (heh!).