Hi everyone,

So last Friday I noticed that my car was low on oil by THREE QUARTS!!! I've noticed no leaks, so I dumped in a quart of fluid to help oil stop burning, and added 2 quarts of mobil 1 synthetic (been on synthetic now for 6 months). Today, Five days later, down a full quart again!

Should I go back to regular since it's thicker/burns slower? I drive about 100 miles a day. Is this a sign of the motor going altogether? Please help!!!

 

I think you are asking the wrong question. Instead of "which oil to use in the engine that is burning oil?" you should be asking: "why is my engine going through so much oil?"

Does it puff bluish smoke at startup? how about open throttle?

 

No smoke...that's the weird thing.....

 

Then you have a leak somewhere. Oil does not evaporate inside the engine...

Rear oil seal, intake gaskets on the china wall, timing cover, fuel pump (if mechanical) or block off plate gasket, smog pump hole, all things to consider.

Do you have the smoge pump on your car?

 

A smog pump? I suppose so, being a CA car.....

 

If I did want to go back to regular oil though, would that be ok?

 

Oh its a cali car? then never mind on the smog. Your leak is elsewhere. Yes, changing to conventional oil is fine.

Either way, though, you need to find that leak. Does it drip anything anywhere?

 

the two are completely compatable. really you shouldnt even be calling them diffrent things.... ones just made from a high quality syn base, and the other from dyno juice...

you can pour in half a bottle of syn, and half of the cheapest crud they sell... it all works together without issue. heck, most "synthetics" are blended anyway.. lol (castrol comes to mind..)

in eithercase, you NEED to find where the oil is going. if its not burning (and you would notice one quart of oil burning) you have a leak somewhere..

 

What exactly was this "fluid"?

How many times have you changed the oil since first using synthetic? If the engine had significant time with petroleum-based oil (>50K), and/or didn't get the best maintainance, the crankcase most likely was coated with oil break-down products such as varnish and sludge. The synthetic tends to desolve and break up those deposits, dirtying the oil, making it less effective in sealing and therefore increasing the rate of consumption.

Wives tale. Misunderstanding of the differences. Mobil 1 has had a reputation over the years of leaking/consuming more, but that hasn't been an issue with the forumulations they've been using the last 5 years or so. At running temperatures, a 30 weight oil will be within a certain viscosity range, regardless whether synthetic or petroleum. Higher quality synthetics such as AMSOIL, Redline, and Mobil 1 actually burn at a higher temp, and therefore tend to be consumed less in the combustion process.

Knocking/rattling noises, loss of power, drastic reduction in fuel economy would be signs of the motor going altogether. Most likely you need to replace the valve stem seals and change the oil & filter.

 

I haven't found a leak so I'm going to take it in for an oil change and see if they can tell anything. The synthetic I've been changing about every 4k miles till now.....used to burn off a quart in between oil changes, which isn't that much. car has 172 k on it, motor maybe 45k or so.

 

My car used to burn a LOT of oil and I never actually saw smoke, 'course my exhaust dumped under the car....that played a big factor.

I would use some thicker oil, maybe some 20-50 unless you're in a really cold climate. That might help slow down the burning a little bit, hopefully. IF you are burning.

45k is NOT a lot of miles for a motor...... Sometimes the simplest solution can be the right one. Like a loose drainplug or improperly tightened filter.