Should I change the oil and/or filter?

[Tobygot]

Hi, I posted a couple of weeks ago about a '99 Saturn SW2 that I bought w/ 270k on it. I changed the oil and put in Mobil 5000 10w/30 w/ 20% MMO. When I dumped out the old oil that came in the car at Autozone, there was chunks of sludge left behind on their steel grate.
So now I've been running Mobil w/ MMO for 200 miles.
Today I did an MMO piston soak. I'm not sure what I did wrong but I tried to crank it over 7 or 8 times and very little came spitting out and I could still see fluid in there. I put in the spark plugs and rolled it in neutral for about 30 feet (I'm not sure if the pistons move when the car is rolling and not turned on). Then I fired it up and drove it for about 30 miles. For the first 20 miles the car would stutter a little.
From what I've read, after a MMO piston soak, you have to change your oil immediately.
I now have 200 miles on the Mobil/MMO mix and the oil is barely tinted. I thought it would be black by now.
In 200 miles I have added 2 quarts w/ 20% MMO, (the car takes 4 quarts w/ and oil change).
Maybe the car just wasn't getting hot enough. I changed the coolant and thermostat yesterday and it was only warming up to about the 1/4 mark. Now it warms up to 3/8 and will continue up to 1/2 w/ a minute or two of idling.
From what I read on the Saturn forum the way it's acting now is normal and the car only warming to the 1/4 mark is from a stuck open thermostat.
So maybe the car wasn't getting hot enough to the MMO to work?
Should I change my oil or just the filter, even if it looks really clean?
Should I run a bottle of AMSOIL flush?
I think AutoRX would be too expensive for this car. I would have to buy about 10 bottles to get through the entire treatment and I only paid $300 for this car.

 

[5sfe91]

If you have more than 20% percent MMO in the oil i'd change it.
Then just run a normal OCI and right before you change the oil next time just do a Motor flush like Gunk Motor flush pour it in run the car for 5-10 min. drain and that should get some cleaning done.

 

[yaris0128]

Originally Posted By: 5sfe91
If you have more than 20% percent MMO in the oil i'd change it.
Then just run a normal OCI and right before you change the oil next time just do a Motor flush like Gunk Motor flush pour it in run the car for 5-10 min. drain and that should get some cleaning done.

+1 Also if you can afford it, use PP or PU. That stuff will work some wonders for a slugger.

 

[Spyder7]

That little was ejected means that it mostly likely drained past the rings and right down into the oil pan. It is recommended to change the oil after the piston soak, especially if you already have a full dose in the crankcase.

For the next soak I would skip the crankcase dosing, and instead monitor the soak more closely; you want to ensure the rings remain wet throughout the soak, so if its working its way past the rings, its not getting the time it needs to do its thing and you will have to continue to add it to keep the rings wet. Then eject it and change the oil.

Keeping in mind that its draining into the oil pan, you should factor that and the fact that its going to be changed afterward into the oil you use and how much you put in during the pre-soak OC. If your sump capacity is 4 quarts, I'd add only 3 quarts in the pre-soak OC, using something cheap but still up to spec (like Supertech) and measure the oil level once the soak is finished. Then top to full, drive a short distance (maybe 50 miles), and change it out.

The oil in this type of application is mainly being used as a flush oil, so there is no need to buy anything more expensive than Supertech, or to begin the soak with anything more than just 3 quarts of oil in a 4 quart sump and no additive beyond what is used for the piston soak.

-Spyder

 

[demarpaint]

I'd do one more piston soak before you change the oil. Rolling the car in neutral doesn't turn the engine over the transmission is disengaged from the engine so the pistons are not moving. If there is a main damper pulley on that engine get a breaker bar, put the tranny in neutral with the emergency brake on so the car won't roll while you are working on it, and move the engine via the bolt on the damper pulley. If you can't do that just turn the key and let the starter do it, it makes more of a mess.

Remove the plugs, add the MMO, let the engine sit overnight, turn the bolt or starter in the morning, and refill the cylinders with MMO, and let it sit. I'd do this over a 2 day period. When you are done crank the engine with the starter to eject any remaining MMO and put the plugs in, go for a short drive change the oil and filter.

Then add a pint of MMO to the new oil and drive 3000 miles, and change it again. Top up with oil mixed with about 10-20% of MMO.


As a side note, if you used more than 25% MMO in total change the oil and filter skip the piston soak. Replace one pint of oil with a pint of MMO and drive 3000 miles and change the oil. In the future do a piston soak just before you plan on changing your oil.

MMO is not a fast flush agent so running a car for a few minutes with it in the sump is like taking a 5 second shower and washing 2 of your toes. It needs time to work. HTH

 

[mechtech2]

f you are going to soak the pistons with 100% MMO, then give it a chance.
More than an hour - as long as you can.
Rough running is expected immediately afterwards.
It sounds like some good has already been accomplished.
Maybe try another MMO flush, but a good cleaning oil should be on your list.