Oil Change Interval for Synthetics

On Aug 20, 1:21 pm, The Doctor > wrote:
> Hi all, I'm thinking of changing my '90 Acura legend over to a
> synthetic oil product (Mobil 1 Amsoil..etc..suggestions?) and was
> wondering what intervals I can expect between changes. One person I
> was talking to said they can go to 25k. I don't know if I'd be
> comfortable with that, though. The car currently has only 88K on it
> now, but I put about 4k on it a month. Thanks for any input!

It is your car, and it is out of warranty. Do what you like with it.
Consider however that oil is the life of the engine. It inhibits wear
and friction,
it cools the engine to some degree, it disperses and neutralizes some
contaminants, etc etc.
It is literally the life blood of your engine.

You can change the oil yourself for less than about $20-25.
You probably spend more than on paper towels per month, according to
the Shamwow commercial. That is one dinner, a few drinks, a large
pizza,
or a movie for two...

Pick your battles. Is this something you really want to skimp on??

Synthetics are okay, but might lead to extra leakage or seepage on
your engine. It sometimes happens.

Hear what I am saying, amigo?

On Sat, 23 Aug 2008 17:58:52 -0700 (PDT), HLS >
wrote:


>
>Synthetics are okay, but might lead to extra leakage or seepage on
>your engine. It sometimes happens.
>

A few decades ago, my father installed a Chrysler-Nissan diesel engine
in a Plymouth station wagon -- He was experiencing difficulty getting
it started on cold winter mornings in New Jersey, so he switched to
Mobil 1 (which solved that) -- But he said he had to go around the
entire engine retightening all the pans and other parts of the oil
system because the Mobil 1 was now seeping out of places all over the
new engine.

Pete

On Aug 20, 2:21 pm, The Doctor > wrote:
> Hi all, I'm thinking of changing my '90 Acura legend over to a
> synthetic oil product (Mobil 1 Amsoil..etc..suggestions?) and was

(...)

I feel OK with 5K changes with Mobil 1.

Ashton Crusher wrote:
> On Thu, 21 Aug 2008 00:11:31 -0500, Brent P
> > wrote:
>
>> On 2008-08-21, Ashton Crusher > wrote:
>>
>>> European cars often go 15 to 25K on synthetics and you might be able
>>> to do so but it's a bigger stretch then I would be comfortable with. I
>>> have switched all my vehicles over to Mobile 1 and a 12,000 mi or 12
>>> month change interval. All of them had over 100K miles on them when I
>>> made the switch.
>> How often do you change the filter?
>
> Same interval. I've opened them up and there's nothing there. Now if
> it was some 1960's carbureted fume belcher with 100K on it, it would
> be a different story.

My '66 carubreted fume belcher does just fine on 7000 mile change
intervals using Shell RotellaT synthetic.

I'd worry a lot more about some modern under-designed dispose-a-car
econobox with an undersized oil filter, smallest possible oil pump for
lower parasitic loss, and undersized/overstressed bearings.

On 2008-08-25, Steve > wrote:
> Ashton Crusher wrote:
>> On Thu, 21 Aug 2008 00:11:31 -0500, Brent P
>> > wrote:
>>
>>> On 2008-08-21, Ashton Crusher > wrote:
>>>
>>>> European cars often go 15 to 25K on synthetics and you might be able
>>>> to do so but it's a bigger stretch then I would be comfortable with. I
>>>> have switched all my vehicles over to Mobile 1 and a 12,000 mi or 12
>>>> month change interval. All of them had over 100K miles on them when I
>>>> made the switch.
>>> How often do you change the filter?
>>
>> Same interval. I've opened them up and there's nothing there. Now if
>> it was some 1960's carbureted fume belcher with 100K on it, it would
>> be a different story.
>
> My '66 carubreted fume belcher does just fine on 7000 mile change
> intervals using Shell RotellaT synthetic.
>
> I'd worry a lot more about some modern under-designed dispose-a-car
> econobox with an undersized oil filter, smallest possible oil pump for
> lower parasitic loss, and undersized/overstressed bearings.

I change out the mobil 1 at ~7K. not so much that I don't trust the oil
or the engine running clean, but I don't trust that the filter does it's
job much longer than that. The V8 is clearly a strong engine, so that's
not an issue. I have thought about just replacing the filter and going
with longer drain intervals. But what's the point if I am going to under
there and get dirty to change the filter anyway? Might as well change
the oil too.

On the winter beater I used for a couple years I did do a filter only
change or two. But that car leaked enough oil that it was kind of
'self-changing'. At times I mixed the mobil 1 I drained from the '97
with some new walmart oil to top it off. Didn't do any harm.

"Brent P" > wrote in message
...
> On 2008-08-25, Steve > wrote:
>> Ashton Crusher wrote:
>>> On Thu, 21 Aug 2008 00:11:31 -0500, Brent P
>>> > wrote:
>>>
>>>> On 2008-08-21, Ashton Crusher > wrote:
>>>>
>>>>> European cars often go 15 to 25K on synthetics and you might be
>>>>> able
>>>>> to do so but it's a bigger stretch then I would be comfortable
>>>>> with. I
>>>>> have switched all my vehicles over to Mobile 1 and a 12,000 mi
>>>>> or 12
>>>>> month change interval. All of them had over 100K miles on them
>>>>> when I
>>>>> made the switch.
>>>> How often do you change the filter?
>>>
>>> Same interval. I've opened them up and there's nothing there.
>>> Now if
>>> it was some 1960's carbureted fume belcher with 100K on it, it
>>> would
>>> be a different story.
>>
>> My '66 carubreted fume belcher does just fine on 7000 mile change
>> intervals using Shell RotellaT synthetic.
>>
>> I'd worry a lot more about some modern under-designed dispose-a-car
>> econobox with an undersized oil filter, smallest possible oil pump
>> for
>> lower parasitic loss, and undersized/overstressed bearings.
>
> I change out the mobil 1 at ~7K. not so much that I don't trust the
> oil
> or the engine running clean, but I don't trust that the filter does
> it's
> job much longer than that. The V8 is clearly a strong engine, so
> that's
> not an issue. I have thought about just replacing the filter and
> going
> with longer drain intervals. But what's the point if I am going to
> under
> there and get dirty to change the filter anyway? Might as well
> change
> the oil too.

Have you ever actually tried to figure out if the filter is anywhere
near capacity? In the past GM used to let filters go twice as long as
the oil (15,000 miles in the not so far past). I assume they had
reasons for doing so. And GM always specified tiny filters (by
comparison to Ford or Chrysler). I've cut numerous filters open, and
usually find nothing of note. The only time I found anything
disturbing was when I cut the SO's new RAV4 filter open at the first
oil change. There were some significant pieces of metal in that
filter, but after subsequent changes, I've found nothing. I always
change my filter when I change the oil, but I am not sure it makes any
sense to change the filter unless you change the oil. I've always
wanted to try and figure out how much "stuff" the filter collected,
but haven't come up with a good method yet. The empty filter weight is
easy to measure, but it is hard to measure the weight of a used filter
because they are difficult to fully drain, and because the oil soaked
filter media weighs more than the dry media. I've considered. filling
a new filter with oil and weighing that. Then, emptying and refilling
the same filter with clean oil when removed after use and weighing it
again. In theory this could give me a reasonable idea of how much
"stuff" the filter has collected. Of course what I really want to know
is the efficiency and flow capacity of the used filter. It is entirely
possible that a used filter is actually a more efficient filter than a
new filter, as long as it is not so contaminated that the bypass
opens.

Ed

On 2008-08-25, C. E. White > wrote:

> Have you ever actually tried to figure out if the filter is anywhere
> near capacity?

No. I've just used rules of thumb of my own creation. The factory
recommended interval is 5000 miles, so I take that, add about 50%... and
that's the max I work with. For all I know it could last 14,000 miles
but I have no real way of measuring that. For a $3 part and a total
investment of ~$30 for the whole oil change, I play it safe.

> In the past GM used to let filters go twice as long as
> the oil (15,000 miles in the not so far past). I assume they had
> reasons for doing so. And GM always specified tiny filters (by
> comparison to Ford or Chrysler). I've cut numerous filters open, and
> usually find nothing of note. The only time I found anything
> disturbing was when I cut the SO's new RAV4 filter open at the first
> oil change. There were some significant pieces of metal in that
> filter, but after subsequent changes, I've found nothing. I always
> change my filter when I change the oil, but I am not sure it makes any
> sense to change the filter unless you change the oil. I've always
> wanted to try and figure out how much "stuff" the filter collected,
> but haven't come up with a good method yet. The empty filter weight is
> easy to measure, but it is hard to measure the weight of a used filter
> because they are difficult to fully drain, and because the oil soaked
> filter media weighs more than the dry media. I've considered. filling
> a new filter with oil and weighing that. Then, emptying and refilling
> the same filter with clean oil when removed after use and weighing it
> again. In theory this could give me a reasonable idea of how much
> "stuff" the filter has collected. Of course what I really want to know
> is the efficiency and flow capacity of the used filter. It is entirely
> possible that a used filter is actually a more efficient filter than a
> new filter, as long as it is not so contaminated that the bypass
> opens.

Same here. If I had some way where I could *know* how the filter flowed
and what it filtered out after X miles I would trust it more. Instead
it's a 3 dollar part that was supposed to be changed every 5000 miles. I
figure there is a generous factor of safety involved, but is it 50%
more? 100%? 500%? No clue.

"Brent P" > wrote in message
. ..
> On 2008-08-25, C. E. White > wrote:
>
>> Have you ever actually tried to figure out if the filter is
>> anywhere
>> near capacity?
>
> No. I've just used rules of thumb of my own creation. The factory
> recommended interval is 5000 miles, so I take that, add about 50%...
> and
> that's the max I work with. For all I know it could last 14,000
> miles
> but I have no real way of measuring that. For a $3 part and a total
> investment of ~$30 for the whole oil change, I play it safe.

But in Europe, the same filter (with possibly different oil) is
allowed to go 10k miles.....

Ed

On 2008-08-25, C. E. White > wrote:
>
> "Brent P" > wrote in message
> . ..
>> On 2008-08-25, C. E. White > wrote:
>>
>>> Have you ever actually tried to figure out if the filter is
>>> anywhere
>>> near capacity?
>>
>> No. I've just used rules of thumb of my own creation. The factory
>> recommended interval is 5000 miles, so I take that, add about 50%...
>> and
>> that's the max I work with. For all I know it could last 14,000
>> miles
>> but I have no real way of measuring that. For a $3 part and a total
>> investment of ~$30 for the whole oil change, I play it safe.
>
> But in Europe, the same filter (with possibly different oil) is
> allowed to go 10k miles.....

In my case I don't think Ford offers the 4.6L V8 or the FL820S filter in
europe. (not that some don't get there anyway)

That said, each model should be checked to make sure it really is the
same filter being used in europe. If it is, that would be sticking with
OEM filters. (wouldn't trust another brand not to have shot for the US
reccomended service interval) I would be comfortable with such a long
interval in that case.

Brent P wrote:

>
> I change out the mobil 1 at ~7K. not so much that I don't trust the oil
> or the engine running clean, but I don't trust that the filter does it's
> job much longer than that.

That's a big part of it. Large engines such as those in over-the-road
trucks keep the same fill oil for unbelievably long times- many 10s of
thousands of miles. But there are two big differences between them and
passenger cars:

1) they have multi-stage filtration systems with much larger and more
effective filters which are changed more often than the oil itself, and
2) they have oil capacities measured in tens of gallons, which means
that the oil passes through the engine many fewer times per thousand
miles than is the case in an automobile engine that only holds maybe 6
quarts.