On 09/13/2009 04:34 PM, Leftie wrote:
> jim beam wrote:
>> On 09/13/2009 03:39 AM, Leftie wrote:
>>> jim beam wrote:
>>>> Leftie wrote:
>>>>> Elle wrote:
>>>>>> On Sep 11, 8:41 pm, jim beam <m...@privacy.net> wrote:
>>>>>>> here's something to consider - an old "trick of the trade" is to use
>>>>>>> some of that crappy "stop oil consumption" additive when a dealer
>>>>>>> sells
>>>>>>> a known dud car. it works fine for a while, then, once a few months
>>>>>>> have gone by and it's no longer a quick come-back, it breaks down
>>>>>>> and
>>>>>>> oil consumption rises again.
>>>>>>
>>>>>> I was not aware that such additives existed but I can certainly
>>>>>> believe this is what happened and I got sold a car with a way worn
>>>>>> engine. This may be a lesson of used car buying, even with a clean
>>>>>> title and second owner status. Worst case I guess I may live with the
>>>>>> oil consumption and then at some point chase down an engine to swap
>>>>>> in.
>>>>>>
>>>>>> I will keep this thread updated.
>>>>>
>>>>>
>>>>> There are two types of additives to lower oil consumption. One swells
>>>>> the valve seals; if you did the seal replacement right then you can
>>>>> rule that out. The other kind thickens the oil to slow blow-by past
>>>>> the rings. That would have been removed not long after the oil
>>>>> change. You can do a simple test to see if it's worn rings: pull all
>>>>> the plugs and the air filter, then run a compression test with the
>>>>> throttle wide open. If you have worn rings OR valves, the compression
>>>>> will be low. Then squirt about a tablespoon of higher-weight oil like
>>>>> SAE 80 or 90 into each cylinder and repeat the test. If the
>>>>> compression shoots up, you have worn rings. It if only rises slightly
>>>>> or not at all it's worn valves.
>>>>
>>>> valves don't affect oil consumption.
>>>
>>>
>>> Valve seals do, however. I was assuming that worn valves would be leaky
>>> as well, but maybe not.
>>
>> read the thread - they've been replaced already.
>
> Read my reply again: "One swells the valve seals; if you did the seal
> replacement right then you can rule that out." Ah, usenet...

why raise it at all if the o.p. had already ruled it out? [rhetorical]
read the thread!