Best detergant oil

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Mar 18, 2008
Got a GM 5.7 with about 225,000, but its needs a good cleaning. Currently what is the best detergant oil on the shelf? I dont want to get real aggressive, the previous owner was using oreilly store brand oil, not sure how it stacks up. Im sure its not bad, but prob not the best either. I dont expect expect miracles but anything that can help clean it up will be good. Have seen a lot pointing to pennzoil? Never been a big fan cause it seemed like it used to and sludge real bad, but I guess thats changed. Ran a 3.8 since new with mobil 1 and at 160k it looked like new inside, almost like it was fresh from machine shop.
pennzoil ultra cleans really really good i have seen it myself its not cheap and i dont know if it will be good in a high mileage engine that may leak but i have seen it work wonders..In the past i always used the correct weight dino oil with a quart of mmo and had good results also
If its really dirty inside, any high detergent oil that you choose won't do much, and if it will, its going to take 20,000 miles of extremely short intervals of 2-3k and even then, I'm still skeptical. If the engine is a bit dirty, it needs an aggressive cleanup now. There's no point in slowly doing it because by the time you get any kind of result, years will pass and you'll be selling the car by then. Haha. I suggest a good high mileage oil and a good cleaner (there are many, just pick one or even try em all) and do 500 mile intervals at full strength for a couple thousand miles to help remove as much loose built up stuff as possible and call it a day. At that mileage, there's no point in trying to get a spotless engine. I say you get it running good and enjoy it.
Use Pennzoil Yellow bottle conventional, but replace 1 quart with Marvel Mystery oil. Run this for 3000. Do it again with a fresh filter. That should clean things up a bit.
I just got the truck on the cheap, needed a tranny and intake gaskets. Noticed when doing the intake that it was pretty dirty under the valve cover and intake, But in reality prob more than I could expect to clean up. Im not gonna worry about it too much, just thought any little bit might help. Any thoughts on valvoline? Woudl it be a toss up between any of these 3 conventional oils, mobil, pennzoil or valvoline? Do the high mileage oils really make a difference? Any thoughts on store brands, NAPA, Oreilly, Advance Auto etc? Or should I just see whats on sale when i need it?
First, congrats on your first post(though registered for a while?) welcome As to your decisions/questions: High Mileage oils are typically formulated to keep more crud in suspension, but over the course of normal oil change intervals(3,000-6,000 etc)...not your current COA(course of action) most likely. Also, in order to help seals before they completely fail(if you have leaks, worth a try!) Elaborate on 'pretty dirty under the valve cover'? Caked on layers of thick/hard crud or gunk? OR more like slimy varnish/grainy carbon deposits w/ discoloration everywhere BUT you can still see where the metal parts are well enough just covered in nasty crud(not caked on mind you!)? If it's caked on/hardened patches best to manually clean first. Too risky to clean with chemicals aggressively first, most would agree. Though, not doing anything manually and just driving on some High Mileage and/or HDEO oils might do the trick over time as far as keeping the engine running. On the other hand, if you have a not quite sludge situation, you may be able to attack it with shorter intervals using quality oils. Start off with Pennzoil Yellow Bottle(PYB) + 1 quart of Marvel Mystery Oil(MMO) or whatever 20% of the refill volume is. Run that for 2,000 miles and drop that two or three times. So, recap 3 oil changes by 6,000 miles. Consider opening the first oil filter you remove and then the subsequent filters. Use basic filters like a Purolator Classic, there is a chance an uber fine filtration media could clog more quickly, some may even suggest changing the oil filter midway during the oil change interval. You could then follow with more conventional short intervals or start getting more aggressive with a full synthetic. The favorites for cleansing are generally Ultra/M1/Red Line/Amsoil...for your situation I'd imagine Ultra is the best bang for your buck considering it's current formulation with loads of calcium. That's also why most like PYB. Another option is to switch to something like Rotella T5 or T6, a HDEO. Just a thought. Depending, you may be a candidate for Kreen. It all depends on the actual condition of your engine right now, some methods may be too weak/too aggressive.
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Go with PU or PP, both will clean the engine. I would avoid a HM oil. Kreen or Auto-Rx are other things to try. I would forget the MMO although there are a bunch on this forum that swear by it. You probably should start by pulling a valve cover and having a look see. If its gooey then try Amsoil flush. You can wipe off as much as you can with a rag, but would not get into wire brushing. If its hard and crusty sludge then Auto-Rx or Kreen.
"Another option is to switch to something like Rotella T5 or T6, a HDEO." +1 You may dope it with a quarter of Redline if you whant more esters for cleaning and/or lowering the viscosity of the HDEO (ie using fex 0w-20 to thin out a 15w-40 HDEO) Do some short oci´s like 1000-3000 miles in the beginning. You may start with a "flush" run the cheapest oil you can find for half an hour and dump it.
Originally Posted By: ac_tc
You may start with a "flush" run the cheapest oil you can find for half an hour and dump it.
Half an hour won't do anything, to be honest with you. I've ran dedicated engine cleaners for 20 mins with directions of idling for 10-15 mins and pulled the valve cover again after having new oil in the engine for a few days and the results between pulling the valve cover before the idle flush were literally ZERO. Caked, burnt on varnish and other grime needs a lot of time to come off. A powerful cleaner needs to be flowing through the system for a week or two (300-500 miles) with normal driving and a decent amount of WOT (Wide Open Throttle) runs to redline or close to really build up some heat and oil pressure and have the oil spray everywhere. I'd do that as a first flush with a cheap dino oil and filter.
Seafoam works. And you don't need to change it out after a certain mileage. Run in the whole interval. It has done wonders for my old lady's Chrysler mini-van with a 3.0 motor. The oil fill hole was black. Couldn't even see the cam turning. I put a can of seafoam in for the last 1500 kms of the interval and I can already see it's cleaning. I used cheap co-op 5w-30 oil. I again used same oil. Will seafoam again for 2000 kms and take pics
Im prob not gonna do anythign special at this point, prob just pick and oil and run some short intervals to flush out anything we may have loosened when we did the intake change. Otherwise I plan on driving this thing for a little while then sell it anyway. It was more of a fixer upper to start with. ltslimjm, I registered long ago, followed and read many threads, just never posted. Its not really slimy or anything, just black discolored and kind of grainy between your fingers. Under the intake was a little worse, looked like some sediment in the lifter valley, but still black and all discolored. I shop vacced much of it out though as I tried to clean up any spilled coolant.
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Is there before / after pics of MMO actually working? I can't seem to find anything when i search. I find it hard to believe that one OCI at full strength will do anything.
I will take a few of my old lady's van now,then after seafoaming the crankcase. Likely be next month before I have to change the oil but once the seafoam goes in I will take weekly pics. See if it even does anything.
I will second the cleaning ability of Seafoam. Get a can of regular and a can of the spray, "Deep Creep". First, use the Deep Creep (DC) to clean the throttle body, manually agitating with a stiff bristle toothbrush, reaching as far into the TB throat as you can. Then spray some more into the throat, let set for at least 20-30min, then go for a drive. Next, use 1/3 of the can of DC through the brake booster line with the car running, and turn it off the second you stop spraying. Let set for at least 30min (longer = better), then turn it on and prepare for a smoke show. Do the same through the PCV system. This should get both ends of the manifold. Put 1/2 to 1 can into your gas tank immediately before filling up (like a regular FI cleaned, do it at the gas station). This will clean injectors, fuel level sender, fuel lines, valves, and combustion chambers. You can also put it into your oil, at a 1.5-3oz seafoam per quart of oil ratio. Start at the low end. Do this 100-200mi prior to oil change, preferably you would pour it in and go drive 100 miles on the highway, as it will thin the oil. Immediately drain and put in fresh oil and oil filter. This WILL clean, but it is a strong cleaner, so before using it in the oil I would suggest using a less severe solvent to loosen things up, such as MMO. I have had excellent results with the above. Alternately, you can use a strong oil with excellent cleaning properties, running it for 3-5k miles while doing frequent filter changes. I would recommend Redline and Royal Purple "with Synerlac", as they cleaned out three sludged BMW engines of mine to a literal like-new shine, and have kept them that way. I would suggest: Do a full oil change and fill with RL/RP and a good filter. Change the oil filter every 500-1k miles, adding oil to compensate for what is lost via filter change (this will also help keep the ad pak fresh). Do this until you hit 5k miles, at which point it is time for a full change. Refill with either oil, new filter, and follow the same steps except to extend filter changes a little bit, perhaps every 1k-1.5k miles. Change oil after 5-6k miles. At this point, when you do the oil change, the last filter should be coming out significantly cleaner than when you started. Since it will now have been over 10k miles with 8-16 filter changes, your engine should be significantly cleaner. Run Redline SI-1 FI cleaner through the gas at "+0mi, +500mi, +1500mi, +3kmi, +5kmi, +6kmi, +8kmi, and +10kmi". That is the schedule I followed, and while doing the oil change at either the 5k or 10k point, replace the fuel filter. The three techniques described above will clean very thoroughly but should be plenty gentle so as not to knock loose any chunks of sludge. The Seafoam
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