Why should you never drive with an engine flush in?

[RDY4WAR]

The particles of sludge it loosens will get caught by the filter, down to a certain micron in size, depending on the filter, but the product itself will remain in the oil, and therefore, in the engine, until you drain it. I'm no chemist, but anything that isn't engine oil isn't a lubricant, which is why I won't use flush products or 'cleaners'. I prefer to let high-detergent synthetic oils do the work. IMO, solvents are the opposite of oils, and will break down the components of the oil that are supposed to be protecting the bearings from metal-to-metal contact. I can't recommend flush products at all, and I certainly can't recommend leaving them in longer than prescribed.

That's not how all of that works. Synthetic oils don't contain any more or less detergents than conventional oils. Even if they did, detergents don't clean up sludge and varnish. The role of detergents is to isolate and neutralize acidic contaminants in suspension to prevent them from causing oxidation and corrosion. They exist in engine oils more so to keep the oil clean, not to clean the engine.

Secondly, solvents are what's needed to breakup sludge. They exist in all engine oils in the form of esters or naphthalenes but in usually very low concentrations just as seal conditioners.

Just because an oil has a lot of ester doesn't make it a bad lubricant. Red Line HP series oils are up to 40% ester and have excellent HTHS ratings. High Performance Lubricants HP SAE 30 EF is an ester oil with an HDEO add pack for blending with other oils as a flush with no sacrificing lubrication. Valvoline Premium Blue Restore is ~60% ester serving the same purpose.

I agree with what you say though when referring to the gimmick aftermarket "fix in a bottle" type flushes (Seafoam, MMO, Motor Medic, etc...) that are usually just pale oil with some alcohol tossed in (and maybe a little chlorine). They don't do anything except make your wallet lighter.

 

[JT20]

I think the brand new Mobil 1 oil has begun meaning away a certain "blocker sludge" within the first 100 miles. That could be a part of why overfilling it made the noise (scary, sub 1-second noise onna cold startup) stop.. because of more oil pressure on a partially blocked oil pump??

These are just guesses.

 

[Dasteufelhunden]

Exactly. Why do you want to flush? Modern oils are getting better each year, and flushes are normally due to a lack of maintenance. A bottle of something won't save a piece of machinery that has not been maintained. That a westernized way of thinking. And if anyone is buying a vehicle that needs a flush, why buy it? It hasn't been maintained.

The categorical claim of modern oil getting better falls short as the engine designs vary and have a different impact with different design. Are modern engines all getting better? Then why are we still having modern cars having gunking problem at less than 30,000 vs. 100,000? Flushes are not only beneficial as a compensating intervention to inconsistent maintenance, just because you maintained it like a baby does not mean your engine will yield that outcome that you think you covered all the grounds for.

 

[kschachn]

The categorical claim of modern oil getting better falls short as the engine designs vary and have a different impact with different design. Are modern engines all getting better? Then why are we still having modern cars having gunking problem at less than 30,000 vs. 100,000? Flushes are not only beneficial as a compensating intervention to inconsistent maintenance, just because you maintained it like a baby does not mean your engine will yield that outcome that you think you covered all the grounds for.

Ahh the pro flush guy is here. What cars are having “gunking” problems at less than 30k?

Glad I didn’t know this before I put over 440k on my sludge monster 1MZ-FE. Somehow I think it’s directly related to better oils, but thanks anyway.

 

[rob1715]

Ahh the pro flush guy is here. What cars are having “gunking” problems at less than 30k?

Glad I didn’t know this before I put over 440k on my sludge monster 1MZ-FE. Somehow I think it’s directly related to better oils, but thanks anyway.

Not worth arguing with him. He's using whataboutism, or tu quoque logical fallacy, that attempts to discredit an opponent's position by charging them with hypocrisy without directly refuting or disproving their argument. Keep your 1MZ-FE and I'll keep my slight oil burning 1ZZ-FE 1.8L and be done with it.

 

[TiGeo]

One side says "I used XYZ magic flush and my car ran XXX miles with no oil issues therefore, XYZ magic flush is great, you should use it". The other says "I haven't used any XYZ magic flush and just changed my oil and my car ran XXX miles with no oil issues therefor, XYZ magic flush isn't necessary and does nothing." Based on this, does XYZ magic flush hurt your engine? Is XYZ magic flush necessary for long vehicle engine life? You can't answer either b/c there are too many other variables besides XYZ magic flush to comment. So change your oil frequently and use XYZ magic flush if that gives you the warm fuzzies...hahaha

 

[Krieg]

Well, I am over-thinking this engine noise. (This only on every other start up noise that is not present when the engine is running, specifically.) What if whatever oil passage that directs oil to my filter is plugged up. It may or may not be the case but, I am asking myself if more oil should be coming out when I take the filter off (which is very easy to get to.)
II did intend this as a more general thread but I could use why I'm even thinking about it on mine for the context, sure.

If?

 

[DallasTexas]

I have used 1/2 Quart of Kreen in my Diesel Benz OM606 engine with 8 quart capacity for 500 miles as recommended (Kreen evaporates) with extremely good results on an engine with 250k + miles. With another 1/2 in fuel tank. Morning engine knock gone forever.

 

[JT20]

I have used 1/2 Quart of Kreen in my Diesel Benz OM606 engine with 8 quart capacity for 500 miles as recommended (Kreen evaporates) with extremely good results on an engine with 250k + miles. With another 1/2 in fuel tank. Morning engine knock gone forever.

Doesn't Seafoam evaporate too? (I know it's not Kreen)

 

[spasm3]

Doesn't Seafoam evaporate too? (I know it's not Kreen)

The alcohol and naptha evaporates leaving behind the light oil.

 

[DallasTexas]

Doesn't Seafoam evaporate too? (I know it's not Kreen)

Probably

 

[Kamele0N]

Kind of surprised nobody asked me what I did.

Well I am eating dinner. Then I go outside and finish it up.

Did you just put a new oil filter and change the oil with 0w20?

0w20 is excellent grade for flushing

 

[wolfox03SS]

I have read before that solvent based flushes not just thin the crankcase oil, but they too can quickly strip metallic surfaces of any anti-friction materials that "plate" an engine's surfaces from a fully formulated oil. So running an engine with a flush in it is simply "Stripping" it like paint thinner, taking away any benefit of your oil's barrier protection. On it's heels, the solvent prevents that barrier from re-establishing itself as the solvent flush is active. Further, you're running on purely hydrodynamic lubrication of the liquid oil still squeezing where it goes - but it's much thinner with the solvent flush circulating. Almost no protection.

That's why I *think* you do not run her in gear, nor let her run above an idle when flushing.

Since you're into Mobil-1 products? Try a "flush" with one of their high mileage formulations and spin on a fresh filter after a few, quick back-to-back oil changes with the high mileage formulation. That should safely, slowly clear you right out unless you have mountains of goop hiding inside. Best check to settle all arguments, IMO? Just pull one valve cover. Preferably on the side without the PCV plumbing routed to it so you can assess a worse case scenario. (Have a replacement cover gasket handy) Then judge for yourself how dirty your machine is.

I've had a little experience with some start up clatter on new to me engines and a few friends', family members. As soon as I get them on a diet of fresh, in spec oil - they clean up. Sometimes a bit of grit or dislodged gunk can catch in an ADV in the filter and let them drain down. On restart, yeah, clicky-click-clack for all of 4 seconds until the oil pumps up the the heads again. Spinning on a fresh filter and topping up the oil would quiet them down quick.

Good luck with your new to you Scooby!