car engine oil extended change

Hi, My car (toyota petrol 1.3) does a smallish mileage in a year say
around 5000 miles, mainly
on fairly short distances around town. what would be the 'time' limit to
reasonably extend oil changes for economy reasons using a semi synthetic oil
?

I suspect a lot of people will immediately say don't economize in this way.
However some forty years ago I had a conversation with a professor of an
engineering college and he said engine oil does not degrade 'time wise' as
fast as most people think ( and importantly as the oil companies would wish
us to
believe). So by how much time could one reasonably delay an oil change with
modern oils?

jw 1111 wrote:

> Hi, My car (toyota petrol 1.3) does a smallish mileage in a year say
> around 5000 miles, mainly
> on fairly short distances around town. what would be the 'time' limit to
> reasonably extend oil changes for economy reasons using a semi synthetic
> oil ?
>
> I suspect a lot of people will immediately say don't economize in this
> way. However some forty years ago I had a conversation with a professor of
> an engineering college and he said engine oil does not degrade 'time wise'
> as fast as most people think ( and importantly as the oil companies would
> wish us to
> believe). So by how much time could one reasonably delay an oil change
> with modern oils?

I think oil and engine technology has changed somewhat over the past 40
years, so your conversation may not have much relevance :-)

I don't think the issue is one of time related degradation, more the
assumption that a car that does a low annual milage will mainly be doing a
lot of short trips. The problem then is that the oil is never sustained at
an elevated temperature, so contaminants remain in the oil. Of course, if
your low annual milage is done by virtue of only a few long trips it may
not be such a problem.

I have seen this, where a car doing a lot of short trips goes on a longer
journey. The oil level will be OK before leaving, but may drop below the
minimum during the trip as the the condensation boils off.

The rule of thumb for a car doing low annual milages is to halve the service
interval. In your case, I would at the very least do an oil and filter
change once a year. The cost of this when viewed against the total cost of
ownership is very small, especially if you are able to DIY it.

HTH

Chris

--
Remove prejudice to reply.

One of the big synthetic oil producers recommends this for 100%
synthetic oil (which is what I use):
12 months or 25,000 miles, change the filter and all the oil.
At the 6-month point, change the filter and the 1 quart of oil that
goes with it. This replenishes the additives that take care of things
like acids that form from combustion by-products.

Synthetics are also superb at hot and cold temp extremes.

I've been using it on my vehicles for years, typically about 25k miles
per year. I have kept the vehicles for over 200k miles.

"jw 1111" > wrote in message
...
> Hi, My car (toyota petrol 1.3) does a smallish mileage in a year say
> around 5000 miles, mainly
> on fairly short distances around town. what would be the 'time' limit to
> reasonably extend oil changes for economy reasons using a semi synthetic
oil
> ?

with this kind of small mileage you should at least do a 12month oil change,
if not 6 monthly; if you intend to keep the car for a fair time.

Tim..

jw 1111 > wrote

> My car (toyota petrol 1.3) does a smallish mileage in a year say around
> 5000 miles, mainly on fairly short distances around town. what would be
> the 'time' limit
> to reasonably extend oil changes for economy reasons using a semi
> synthetic oil ?

Dont bother changing it.

> I suspect a lot of people will immediately say don't economize in this
> way.

Yep, plenty dont have a clue about the basics.

> However some forty years ago I had a conversation with a professor of an
> engineering college and he said engine oil does not degrade 'time wise'
> as fast as most people think ( and importantly as the oil companies would
> wish us to believe).

He's right.

> So by how much time could one reasonably delay an oil change with modern
> oils?

Once every decade is more than you need.

"Rod Speed" > wrote in message
...
> jw 1111 > wrote
>
>> My car (toyota petrol 1.3) does a smallish mileage in a year say around
>> 5000 miles, mainly on fairly short distances around town. what would be
>> the 'time' limit
>> to reasonably extend oil changes for economy reasons using a semi
>> synthetic oil ?
>
> Dont bother changing it.
>
>> I suspect a lot of people will immediately say don't economize in this
>> way.
>
> Yep, plenty dont have a clue about the basics.
>
>> However some forty years ago I had a conversation with a professor of an
>> engineering college and he said engine oil does not degrade 'time wise'
>> as fast as most people think ( and importantly as the oil companies would
>> wish us to believe).
>
> He's right.
>
>> So by how much time could one reasonably delay an oil change with modern
>> oils?
>
> Once every decade is more than you need.

Complete and utter rubbish. Whilst the oil in itself doesn't degrade, the
contamination of the oil from the combustion process and condensation will
drastically shorten engine life, particularly when the detergents and
additives in the oil break down.

Hence we see engines completely ruined at 60,000km because of lack of oil
changes causing sludge buildup and accelerated wear.

Modern oils will protect your engine for 15,000km or 6 months.


Having said that, modern oils

Clockmeister > wrote:
> "Rod Speed" > wrote in message
> ...
>> jw 1111 > wrote
>>
>>> My car (toyota petrol 1.3) does a smallish mileage in a year say
>>> around 5000 miles, mainly on fairly short distances around town.
>>> what would be the 'time' limit
>>> to reasonably extend oil changes for economy reasons using a semi
>>> synthetic oil ?
>>
>> Dont bother changing it.
>>
>>> I suspect a lot of people will immediately say don't economize in
>>> this way.
>>
>> Yep, plenty dont have a clue about the basics.
>>
>>> However some forty years ago I had a conversation with a professor
>>> of an engineering college and he said engine oil does not degrade
>>> 'time wise' as fast as most people think ( and importantly as the
>>> oil companies would wish us to believe).
>>
>> He's right.
>>
>>> So by how much time could one reasonably delay an oil change with
>>> modern oils?
>>
>> Once every decade is more than you need.

> Complete and utter rubbish.

Have fun explaining how it worked fine for me.

> Whilst the oil in itself doesn't degrade, the contamination of the oil
> from the combustion process and condensation will drastically shorten
> engine life, particularly when
> the detergents and additives in the oil break down.

Yeah, yeah, nice theory, pity about the reality.

My engine has lasted fine for 30+ years.

> Hence we see engines completely ruined at 60,000km because of lack of oil
> changes causing sludge buildup and accelerated wear.

Nice theory, pity about the reality.

My engine has lasted fine for 30+ years.

> Modern oils will protect your engine for 15,000km or 6 months.

How odd that some manufacturers recommend 12 months.

You're furiously living in the past, child.

> Having said that, modern oils

"Rod Speed" > wrote in message
...
> Clockmeister > wrote:
>> "Rod Speed" > wrote in message
>> ...
>>> jw 1111 > wrote
>>>
>>>> My car (toyota petrol 1.3) does a smallish mileage in a year say
>>>> around 5000 miles, mainly on fairly short distances around town.
>>>> what would be the 'time' limit
>>>> to reasonably extend oil changes for economy reasons using a semi
>>>> synthetic oil ?
>>>
>>> Dont bother changing it.
>>>
>>>> I suspect a lot of people will immediately say don't economize in
>>>> this way.
>>>
>>> Yep, plenty dont have a clue about the basics.
>>>
>>>> However some forty years ago I had a conversation with a professor
>>>> of an engineering college and he said engine oil does not degrade
>>>> 'time wise' as fast as most people think ( and importantly as the
>>>> oil companies would wish us to believe).
>>>
>>> He's right.
>>>
>>>> So by how much time could one reasonably delay an oil change with
>>>> modern oils?
>>>
>>> Once every decade is more than you need.
>
>> Complete and utter rubbish.
>
> Have fun explaining how it worked fine for me.
>
>> Whilst the oil in itself doesn't degrade, the contamination of the oil
>> from the combustion process and condensation will drastically shorten
>> engine life, particularly when
>> the detergents and additives in the oil break down.
>
> Yeah, yeah, nice theory, pity about the reality.

You're out of touch with reality.

> My engine has lasted fine for 30+ years.

What your 30 year old engine has done is irrelevant when talking about
modern engines.

>> Hence we see engines completely ruined at 60,000km because of lack of oil
>> changes causing sludge buildup and accelerated wear.
>
> Nice theory, pity about the reality.

That is the reality. I work in the trade, you never have.

> My engine has lasted fine for 30+ years.

Irrelevant to what happens with modern engines.

>> Modern oils will protect your engine for 15,000km or 6 months.
>
> How odd that some manufacturers recommend 12 months.

Yep, typo on my part. 12 months or 15,000km.

> You're furiously living in the past, child.

You are completely out of touch with your 30 year nonsense.

Clockmeister > wrote
> Rod Speed > wrote
>> Clockmeister > wrote
>>> Rod Speed > wrote
>>>> jw 1111 > wrote

>>>>> My car (toyota petrol 1.3) does a smallish mileage in a year say
>>>>> around 5000 miles, mainly on fairly short distances around town. what
>>>>> would be the 'time' limit
>>>>> to reasonably extend oil changes for economy reasons using a semi
>>>>> synthetic oil ?

>>>> Dont bother changing it.

>>>>> I suspect a lot of people will immediately say don't economize in
>>>>> this way.

>>>> Yep, plenty dont have a clue about the basics.

>>>>> However some forty years ago I had a conversation with a professor
>>>>> of an engineering college and he said engine oil does not degrade
>>>>> 'time wise' as fast as most people think ( and importantly as the
>>>>> oil companies would wish us to believe).

>>>> He's right.

>>>>> So by how much time could one reasonably delay an oil change with
>>>>> modern oils?

>>>> Once every decade is more than you need.

>>> Complete and utter rubbish.

>> Have fun explaining how it worked fine for me.

>>> Whilst the oil in itself doesn't degrade, the contamination of the oil
>>> from the combustion process and condensation will drastically shorten
>>> engine life, particularly when
>>> the detergents and additives in the oil break down.

>> Yeah, yeah, nice theory, pity about the reality.

> You're out of touch with reality.

You wouldnt know what reality was if it bit you on your lard arse, child.

>> My engine has lasted fine for 30+ years.

> What your 30 year old engine has done is irrelevant when talking about
> modern engines.

Never ever could bull**** its way out of a wet paper bag.

Nothing has changed with car engines over that time that
has any relevance whatever to oil change frequency.

The only significant change is that its not computer controlled
and that makes no difference to the behaviour of the oil.

>>> Hence we see engines completely ruined at 60,000km because of lack of
>>> oil changes causing sludge buildup and accelerated wear.

>> Nice theory, pity about the reality.

> That is the reality.

No it isnt.

> I work in the trade,

You just crash cars. Doesnt count.

> you never have.

You cant even manage the basics with electricity either, child.

>> My engine has lasted fine for 30+ years.

> Irrelevant to what happens with modern engines.

Never ever could bull**** its way out of a wet paper bag.

Nothing has changed with car engines over that time that
has any relevance whatever to oil change frequency.

The only significant change is that its not computer controlled
and that makes no difference to the behaviour of the oil.

>>> Modern oils will protect your engine for 15,000km or 6 months.

>> How odd that some manufacturers recommend 12 months.

> Yep, typo on my part. 12 months or 15,000km.

That aint a typo, thats you desperately attempting
to bull**** your way out of your predicament and
fooling absolutely no one at all, as always.

>> You're furiously living in the past, child.

> You are completely out of touch with your 30 year nonsense.

Never ever could bull**** its way out of a wet paper bag.

Nothing has changed with car engines over that time that
has any relevance whatever to oil change frequency.

The only significant change is that its not computer controlled
and that makes no difference to the behaviour of the oil.

On Sat, 04 Mar 2006 08:56:01 GMT, "jw 1111"
> wrote:

>Hi, My car (toyota petrol 1.3) does a smallish mileage in a year say
>around 5000 miles, mainly
>on fairly short distances around town. what would be the 'time' limit to
>reasonably extend oil changes for economy reasons using a semi synthetic oil
>?
>
>I suspect a lot of people will immediately say don't economize in this way.
>However some forty years ago I had a conversation with a professor of an
>engineering college and he said engine oil does not degrade 'time wise' as
>fast as most people think ( and importantly as the oil companies would wish
>us to
>believe). So by how much time could one reasonably delay an oil change with
>modern oils?

Your problem has to do with oil contamination not mileage or
oxidation. If you don't get the oil up to engine temp ( somewhat over
the boiling point of water for the oil, but I've never measured it ),
condensates will accumulate in the oil. Gasoline, water vapor, who
knows what from crankcase fumes. Pretty soon, if you never let your
engine run long enough to boil off these volatile condensates, you've
got acidic crap pumping through your engine that is going to dilute
the lubricity and other wear-resistant characteristics of the oil,
which will lead to early engine death.

So you have to change your oil just as often as anyone else, but for
the contamination reason. You'll have pea soup in the oil sump
eventually, or worse, gunk that will clog the minute oil galleries
that lube the piston bearings and piston pin ( I call it the pin...the
rod that the head pivots on ).

Say at least every 6 months, every 4 months would be better.

Otoh, I'm using full synthetic, and am going by miles not time...5,000
miles change filter and add oil to bring up to full mark on oil stick
( say just less than a full quart for the filter ). And at 10K miles
a complete oil and filter swap.

For me, that means a new filter and somewhat less than a full quart at
25,250 miles, regardless of how long it takes me to get to that
mileage. Then at 30,250, I change ALL the oil and put on a new filter
again.

YMMV
HTH

Lg