How much can I extend the change interval compared to "dino" oil? Every 7500 miles (12000km). I'm a first time synth oil user and alittle doubtful about 1/2 the number of oil changes :o
Here are some reason I found not to extend; Comments?
I do know is that although synthetic does last longer than dino oil, you still shouldn't extend the oil change intervals because of all the crap that builds up in the engine. Contaminants still collect and build up regardless of what kind of oil you put in your engine.
Although synthetic motor oils outperform conventional motor oils, extending the OEM's oil change interval is not recommended. The additives used in a synthetic motor are still depleted due to the by-products of an internal combustion engine and the oil needs to be changed as recommended.
Having changed the oil on MANY of the new cars with the 7500 mile recommended interval, I couldn't believe the condition of the oil at 7500 miles, the way it looked, the way it smelled and the way it came out of the drain hole. I wanted to add to my personal belief that 7500 miles was a bit too long so I had a customer that agreed to stop in every 1000 miles so that I could draw an oil sample. After sending in the samples at 1K intervals I now know that at the 4 to 5 K range the oil should have been changed.
I still change my oil every 4-5k, but it still comes out nice and golden. It's true that the oil still has the same effect as regular oil, but it's doesn't become as thick and burnt out as regular oil since synthetic oil is allot lighter grade..
At least that's what I think..
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whats the deal with synthetic? there are so many myths. Ive heard that you have to flush the engine before using syn. you cant mix reg. oil with syn.(whats with semi synthetic) and once you go with syn. you cant go back? Whats the story?
Just like conventional oils, synthetics have additives in them that eventually 'wear out' and stop doing their job. Likewise, the oil deteriorates over time, synthetics are less prone to failure due to heat or stress but its only designed to work for so long. I use synthetic and change my oil every 4k, if I had my car when it was newer, I would probably change it sooner.
I change my oil every 3,000 miles. I have since the car was new.
I used organic oil for the first 25,000 miles, then switched to synthetic. I have noticed no problems from the switch, and will be changing my oil soon, so I can check out the state of the used synthetic. It makes sense to me to use the most technologicaly advance oil for my new engine, I wouldn't care so much if I had a car that was built before reliable synthetic oil was introduced.
I never did an engine flush before I put synthetic. You'd have to do an engine flush and adjust your valves if you ever want to go back to regular oil.
I love my Mobil1 it's great...
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whats the deal with synthetic? there are so many myths. Ive heard that you have to flush the engine before using syn. you cant mix reg. oil with syn.(whats with semi synthetic) and once you go with syn. you cant go back? Whats the story?
From what I've heard you should only use syn from the get go. This is because syn is allot cleaner and if you use "dino" it leaves more deposites unlike syn. Also it is suppose to have a higher viscocity rating (work better @ higher temps) I'd assume that using syn at any point will stop the accumulation of deposites further.
You can mix syn and dino ever heard of valvoline dura blend?
50/50% I think and it is the only thing I ever put in my car.
One good way to tell if syn is right for you is pull out your dipstick any burnt oil on it? Start using syn or change your oil sooner because you engine is cooking your oil.
Flushing is a good thing I recommend everyone do when changing there oil.
Empty the pan and leave the filter, put the plug back in add a quart start your car and let it run for 10 sec. turn it off and then drain and change filter ect..
I don't see any harm of bouncing back and fourth besides the waste of money and defeating the purpose.
There's no need to do an engine flush...it's overrated unless your motor is VERY dirty. Syn oil can be changed 5-8k kms. I change mine every 5-6k kms and my oil is very black (02 SE V6). I do not share the same sentiment about flushing your engine by using 1 quart of oil for 10 sec. IMHO, you should not be running your vehicle w/ 1 quart of oil at anytime. There is not enough oil to run in your system and will eventually cause increased engine wear.
And no you don't have to adjust valves or anything, synthetic oil is 'compatible' w/ regular oil. Viscosity ratings are the same as dino oil however, it does have better fluidity under cold conditions. You can mix the two oils but as someone mentioned, you're defeating the purpose unless you cannot get any synth oil to top up or something.
Synthetic oil has better wear and breakdown properties as it is more stable and it is more fluid under cold conditions that dino oil. Dino oil turns to mollasses in very cold temps but synth oil retains its fluidity which decreases engine wear under startup.
Syn oil is much more expensive but for anyone w/ a turbo car, it's imperative. For turbos, 'coking' does not occur b/c synth oil turns to ash when it is 'fried'. Dino oil 'cokes' which is the sludgy, mucky deposity that occurs when the oil is overheated and ususually occurs on the turbo bearings when it is not cooled down. This over time can cause premature bearing failure in turbos and increases the risk of sludge deposits in the motor.
For breaking in your motor, you should use dino oil. Best thing is to use dino oil for the first couple of oil changes (ie. 1.5-3k, 2nd change 3k kms after), then use synthetic oil.
I'd tend to agree with all that SE V6 posted. I've had my '89 Corolla GT-S since new and have been into maintaining it. The owner's manual says that under hypothetical ideal conditions you could go 16,000 kms (10,000 miles) between changes but anyone who operates in the real world should change it at 8000 kms. (5000 miles). Initially I changed it with conventional oil at no more than 8000 kms. I notice that Toyota now recommends oil changes every 5000 kms or 3000 miles, which is what I've been doing for a long time.
When my high order digit on the odometer turned 1 (i.e. 100,000 kms.) I switched to synthetic. Today it has over 350,000 and it doesn't burn oil. I did replace the oil pan last year because it had developed some pinholes. This gave me an opportunity to look inside. It was remarkably clean and varnish free, something that synthetic is famous for being.
There is no need for flushing when you switch to synthetic or vise versa. Flushing is good if you've gone too long between changes or if your engine has a lot of blowby and therefore contaminates the oil.
Another thing you hear is that synthetic will turn your car into a leaker. Well not necessarily. Here's what happens: You've been running conventional oil for a long time and your engine has seen a LOT of hot/cold cycles. As a result your gaskets are beginning to shear, but since there is a layer of sludge between the oil & gasket the leak never is detected unless the gaskets are truly punched. If you switch to synthetic it will actually begin to clear out the sludge and eventually oil will reach the bad gaskets and leak past. So don't swith if you've got an old, poorly maintained engine. I would think flushing the crankcase should cause the same thing.
I did switch to synthetic at 100,000 kms or 62,000 miles and never experienced any problems. I have run flush through it on occasion but I'm not crazy about having the flush residue left in the crankcase. Never drive the car with the flush it it or otherwise load the bearings! As for the synthetic oil change interval, I currently do it every 8000 kms., only because the oil get contaminated faster than when the engine was new & tight. With a good filter on a fresh, broken-in engine you could probably stretch the interval out considerably. Although synthetic lasts, the additives boil off & contaminants still are in suspension. Synthetic at least doesn't get thick like convetional oil in the cold and as a result it doesn't need the modifiers in it (that tend to boil off with wear). It is also more tenatious and will cling to parts better (remember this stuff if your car sits unused for a long time). My 50 cents worth...
In my daily driver I use a premium filter and any 100% synth that's on sale and change every 10k. The car is a '98 corolla, the manual recommends every 8k for mineral. I started putting synth in when the warranty ran out at 80k. The oil that comes out is always pretty clean after 10k. I just did the 120k change and I swear it gets cleaner each time. The car definitely gets better gas mileage on synth.
In my AE86 I probably change it every 3 months, or before lapping/racing which ever comes first. I only put 8-10k on the car each year, so I don't even watch the km.
"You'd have to do an engine flush and adjust your valves if you ever want to go back to regular oil. " ----Why, I would really love to hear the technical reasoning ..with references. Synth just reduces the rate at which the surfaces wear, why would this require a valve adjustment?
The leaky gasket myth (1owner pretty much summed it up). Another thing mineral oil does is cause rubbers and other materials used to make seals to swell.... so even if the gasket is completely shot it still seems to do the job (chances are if you've got alot of cake on your engine ...it's gonna eventually leak anyways). My new car already has 147k on it. I will immediately start using synth in it, if it begins to leak then I'll fix the gasket.. I'd rather know the gaskets are sound and run synth than just stick with mineral in the hope that it won't start to leak.
The big advantage to synthetic oil is it's uniformity, over 90% of off the shelf synthetics use the same base (as of this year that includes Mobil 1), so for a street car it doesn't matter what brand you use it's alot better for your engine than mineral. With the increase in gas mileage due to the reduce in friction, it pays for itself in fuel as well as with the life of the engine.
If you want to abuse your engine, go with Amsoil, Redline, Royal Purple or something similar, otherwise the cheap stuff is better than great, heck I use Tech2000 in the '98, at $18.50 for 4 litres it's a steal.
As for interval, that depends also on how you drive your car. If your really hard on it every 5k, if your a pretty average driver, stick to whatever your manual recommends, I figure I'm pretty easy on our commuter car, and it sees mostly highway driving, and I use a premium filter so I figure 10k is reasonable. My AE86 has a sticker under the hood that says every 16k for mineral!
For break-in, I'd change with cheapo mineral at 500, 1k, 2k, 5k, 10k, 15k, 20k, then I'd switch to synth. If I wanted to take the car to the track real quick, I'd probably make sure I put at least 5k on it with mineral and then switch to synth.
The car is a '98 corolla, the manual recommends every 8k for mineral.
I have a 99 and my manufacturer maintenance schedule says 2,500 miles for the first and second changes than 5,000 for the third change and repeats
2,500
5,000
10,000
12,500
15,000
20,000
Anybody else??????????????
I let mine go to 5,000 miles and the oil poured out fine but was blacker than Bob Marley's lungs.
Maybe I will go get one of those oil analysis kits.
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'89 Corolla GT-S (RIP 1989 - 2003 very sad!)
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