Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
Oil Related Engine Cleaning
- Thread starter ChrisD46
- Start date
- Status
Once again Pandora's Box has been opened, and hopefully the bashing doesn't start, but here goes. Moderate sludge heavy varnish: I'd add a pint of MMO 1,000-1,500 miles before you plan on changing the current fill. At that point I would drain the oil, change the filter, and replace one qt. of oil with a qt. of MMO and run it for 4,000 miles during the winter OCI. Keep an eye on the oil level and top it up if needed with oil and a 20% mix of MMO, or just oil. Dino oil would be fine, althought MMO mixes with synthetic oil as well.
You'll get plenty of different responses. I had a Chrysler 2.7 sludge monster. To keep it from getting dirtier I would add a pint of MMO 500 miles before it's 3000 mile oil change. I ran PP or Maxlife the entire time I had it.
PP for a few 3000 mile oil changes should clean things up without over thinking it.
PP for a few 3000 mile oil changes should clean things up without over thinking it.
Some say diesel oil works, others say a good Dino like Pennzoil yellow bottomless or Valvoline white bottle works, some day mobil1 works, others swear marvel mystery oil works....
Honest answer, I've done ALL of them in a sludged up varnished motor. When pulling the valve cover 40k miles later it looked exactly the same as it did before. Maybe it got stuff out of the bottom end...maybe not.
Pennzoil yellow bottle in the specced weight sounds like a good idea to me. I wouldn't expect miracles...merely that it wont get worse.
If at any point you get any leaks from crud being cleaned out... I'm a firm believer in maxlife. I developed a massive oil leak back in August, two oil changes of maxlife and now it doesn't leak at all.
Honest answer, I've done ALL of them in a sludged up varnished motor. When pulling the valve cover 40k miles later it looked exactly the same as it did before. Maybe it got stuff out of the bottom end...maybe not.
Pennzoil yellow bottle in the specced weight sounds like a good idea to me. I wouldn't expect miracles...merely that it wont get worse.
If at any point you get any leaks from crud being cleaned out... I'm a firm believer in maxlife. I developed a massive oil leak back in August, two oil changes of maxlife and now it doesn't leak at all.
Originally Posted By: ChrisD46
Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
1 Full Quart can of Kreen, and 6 quarts of Rotella T6 5w-40.
Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
1 Full Quart can of Kreen, and 6 quarts of Rotella T6 5w-40.
Originally Posted By: ChrisD46
Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
Did you pull the valve cover to determine the sludge and varnish?
I would run PP for 5K oil changes. Forget the snake oil.
Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
Did you pull the valve cover to determine the sludge and varnish?
I would run PP for 5K oil changes. Forget the snake oil.
Originally Posted By: Donald
Originally Posted By: ChrisD46
Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
Did you pull the valve cover to determine the sludge and varnish?
I would run PP for 5K oil changes. Forget the snake oil.
+1 best to do a few shorter OCI's and if able cut the oil filter open and see if it's catching anything out of the norm .
Use of cleaners to me is playing with fire as you always risk loosening too much build up and creating a problem that otherwise wouldn't likely would never have happened .
Originally Posted By: ChrisD46
Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
Did you pull the valve cover to determine the sludge and varnish?
I would run PP for 5K oil changes. Forget the snake oil.
+1 best to do a few shorter OCI's and if able cut the oil filter open and see if it's catching anything out of the norm .
Use of cleaners to me is playing with fire as you always risk loosening too much build up and creating a problem that otherwise wouldn't likely would never have happened .
Go with a quality synthetic like M1 5-30. Here is a link from XM.
http://www.mobiloil.com/USA-English/MotorOil/Synthetics/Mobil_1_Sludge_Protection.aspx
http://www.mobiloil.com/USA-English/MotorOil/Synthetics/Mobil_1_Sludge_Protection.aspx
fyi I have a 2002 trailblazer. did try Kreen in the oil and if you have the famous GM piston slap it might get worse, mine sure did. the truck runs fine but noticeably louder with piston slap when the engine temp gauge is below 150 degrees. case of it is not broke don't fix it. inside the filler hole looks very clean as I had used M1 5-30 in it for years. suppose I got caught up in the Kreen craze. I know the piston slap is nothing to worry about but it sounds terrible. I would think PP or M1 for a few ocis and see what happens.
I vote PYB for first OCI, with ~15% MMO added. I prefer to "bump" the grade of the oil when using MMO. Keep an eye on level and top off as necessary. If your feeling flush (pun intended), then AAP has the QSUD deal right now. Depending on how the current oil coming out looks I'd judge the OCI off of that. Seeing chunks and glops in the drain? then maybe only 500miles. Just real dark, then probably 3000-5000 depending on how fast your adding up the miles. Make sure the engine sees some good solid warm ups and highway runs, short tripping isn't likely to help the oil/additive do their best job cleaning.
From there I'd let the experimental evidence guide the process. On the second time might only use the MMO for top off if near the end of the oci. I'd even consider LubroMoly Motor Flush 500ml as per instructions. I have not used Kreen, but it does have a decent following here, so if your inclined, then why not. Shortish regular OCI's with quality oil and properly applied additives are a prudent plan in a case such as this.
I've also been intrigued by the Amsoil detergent flush product.
From there I'd let the experimental evidence guide the process. On the second time might only use the MMO for top off if near the end of the oci. I'd even consider LubroMoly Motor Flush 500ml as per instructions. I have not used Kreen, but it does have a decent following here, so if your inclined, then why not. Shortish regular OCI's with quality oil and properly applied additives are a prudent plan in a case such as this.
I've also been intrigued by the Amsoil detergent flush product.
OVERKILL
$100 Site Donor 2021
Just use a good oil at reasonable intervals and make sure your PCV system is healthy, as that's likely the cause of the sludge in the first place.
I'd recommend M1 5w-30 or M1 0w-40, the latter only because it has a more robust additive package and might do a bit more cleaning.
I'd recommend M1 5w-30 or M1 0w-40, the latter only because it has a more robust additive package and might do a bit more cleaning.
Lots and lots of opinions on this topic. Take a look at Mobil1 High Mileage. It seems to have more cleaning agents than regular M1. As for OCI, Mobil suggests a few 3-5,000 mile initial oil changes when introducing M1 HM to a vehicle that may have been neglected or that has an uncertain maintenance history.
Yes , this '02 TB has a little over 80K miles on it with an uncertain maintenance history . The oil cap had some crud on it and looking down the fill hole was a bit cruddy looking as well . I believe 9% ~ 10% MMO added to the new conventional oil the dealer put in it will provide a slow , conservative clean for the next 1500 miles or so ...Vehicle sees Interstate runs of 25 miles one way to work and back four days a week so getting temp up is not a problem . After that , begin using fills of PP or M1 < 5K OCI's and see how the cleaning progresses (with PCV valve system serviced or replaced) and hope I'm moving in the right direction to get this engine cleaned up !
Originally Posted By: demarpaint
Once again Pandora's Box has been opened, and hopefully the bashing doesn't start, but here goes. Moderate sludge heavy varnish: I'd add a pint of MMO 1,000-1,500 miles before you plan on changing the current fill. At that point I would drain the oil, change the filter, and replace one qt. of oil with a qt. of MMO and run it for 4,000 miles during the winter OCI. Keep an eye on the oil level and top it up if needed with oil and a 20% mix of MMO, or just oil. Dino oil would be fine, althought MMO mixes with synthetic oil as well.
This method gets my vote.
Originally Posted By: Donald
Originally Posted By: ChrisD46
Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
Did you pull the valve cover to determine the sludge and varnish?
I would run PP for 5K oil changes. Forget the snake oil.
Since when is mmo snake oil. It contains chemicals known to dissolve deposits,which is what he's looking for.
Kreen is a great product to for this condition as well, or is it snake oil too.
Let me guess. Only products you approve of aren't snake oil,right?
Once again Pandora's Box has been opened, and hopefully the bashing doesn't start, but here goes. Moderate sludge heavy varnish: I'd add a pint of MMO 1,000-1,500 miles before you plan on changing the current fill. At that point I would drain the oil, change the filter, and replace one qt. of oil with a qt. of MMO and run it for 4,000 miles during the winter OCI. Keep an eye on the oil level and top it up if needed with oil and a 20% mix of MMO, or just oil. Dino oil would be fine, althought MMO mixes with synthetic oil as well.
This method gets my vote.
Originally Posted By: Donald
Originally Posted By: ChrisD46
Just bought a used '02 Trailblazer with the 4.2L 6 cylinder in it and 7 qrt oil capacity . My question is : The engine has moderate sludge and heavy varnish - would it be better for the first few OCI's to use conventional oil with up to 20% MMO OR a good synthetic oil for cleaning ? How to judge how many miles to go for the first few OCI's ?
Did you pull the valve cover to determine the sludge and varnish?
I would run PP for 5K oil changes. Forget the snake oil.
Since when is mmo snake oil. It contains chemicals known to dissolve deposits,which is what he's looking for.
Kreen is a great product to for this condition as well, or is it snake oil too.
Let me guess. Only products you approve of aren't snake oil,right?
I believe in MMO.
Slow and steady wins the race here. MMO works, just use it in moderation and be patient. Cleaning with oil alone is an even longer project. Maxlife or one of the Pennzoils would be a good choice.
problem is some cleaners knock too much stuff loose then you have a real problem or a busted engine due to an oil gally getting plugged .
Some of you guys just don't seem to get that and I have seen it happen a few times when I pulled wrenches so that's why I'm not one to recommend starting a regime of additives on an unknown engine , best to run as is and just do some shorter OCI's and observe what is happening for a while . Doing that is not going to cause any problem or change the state the engine is in at this point anyway so why the urgency ??!
Some of you guys just don't seem to get that and I have seen it happen a few times when I pulled wrenches so that's why I'm not one to recommend starting a regime of additives on an unknown engine , best to run as is and just do some shorter OCI's and observe what is happening for a while . Doing that is not going to cause any problem or change the state the engine is in at this point anyway so why the urgency ??!
Originally Posted By: demarpaint
I'd add a pint of MMO 1,000-1,500 miles before you plan on changing
Don't use additives.
They simply aren't needed, especially since oils already have additives.
The synthetic oil will remove the sludge All By Itself without assistance. Just make sure to change it at 1000, then 3000 miles (to remove the loosened-up sludge from the pan).
I'd add a pint of MMO 1,000-1,500 miles before you plan on changing
Don't use additives.
They simply aren't needed, especially since oils already have additives.
The synthetic oil will remove the sludge All By Itself without assistance. Just make sure to change it at 1000, then 3000 miles (to remove the loosened-up sludge from the pan).
- Status
