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.