Fuel system cleaner before Oil change?fact or myth

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I have read on this forum that you are suppose to use a fuel system cleaner (shock/full dosage)right before your oil change. As in, pour in the system cleaner and use up that whole tank of gas Then change the oil. Is this really true? Is the system cleaner affecting the oil? Thank you
 
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I would, because depending on which additive you choose it can cause oil dilution or harm the ad-pack in the oil... Also if it washes anything away in the combustion chamber it could be trapped in the oil. ;\)
 

JHZR2

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There have been claims that some adds show elevated soft metal wear when certain fuel adds are used. If this stuff is going into the oil, it can cause more wear, I suppose. THe question really becomes if the fuel add burns off or remains. The wear will be wear, regardless... if it remains in the oil, accelerated wear will continue to increase.
 
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 Originally Posted By: oilboy123
Better to be on the safe side and do it towards the end of the oil change IMO.
I agree.
 
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Data is inconclusive either way. Unless you have a seriously poor running engine with leaky injectors, bad A/F ratio, no thermostat, and tons of blowby, I wouldn't worry about when you add the FI cleaner. The well maintained engine in good running condition with a normal OCI shouldn't be affected at all. We also have many products that are user dosed with every tank throughout the maintenance interval. There isn't any massive failure of engines caused by FI cleaner, is there? Time to grab a rental car, toss in a bottle of Regane into the 'oil', drive it a month and then pull a UOA!
 
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If fuel ends up in the oil (it does) then your fuel treatment will as well. That being said is it enough of an issue to worry about? Do people worry that much about fuel being in their oil from the beginning of the interval to you drain it?
 
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If you drive your vehicle for over an hour that will burn off most if not all the fuel/moisture in your oil.
 
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I'd say it takes less than that. Simply getting the car up to temp in a reasonable fashion goes a long way towards making the oil happy.
 

Peted

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Thanks guys. I'm asking because I just changed my oil and I don't feel like waiting 8K or so miles to put in some Sl-1 or Regane ect..
 
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I'm sorta with undummy here. I think that we're so below the "damage" threshold that any effects, at worst, would be like a dental cleaning is in regard to your gums. Not an event that you would do daily, but necessary. I could also be dead wrong, but even if I am, I don't think it reaches the point of being significant. The liabilities, if any, are outweighed by the benefits. I'd also say that I don't do it until after I've drawn a sample just to prevent any effects on a UOA. I don't need false indicators entering into the view when they've only been there for 5 minutes (one tank).
 

Peted

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 Originally Posted By: Gary Allan
I'm sorta with undummy here. I think that we're so below the "damage" threshold that any effects, at worst, would be like a dental cleaning is in regard to your gums. Not an event that you would do daily, but necessary. I could also be dead wrong, but even if I am, I don't think it reaches the point of being significant. The liabilities, if any, are outweighed by the benefits. I'd also say that I don't do it until after I've drawn a sample just to prevent any effects on a UOA. I don't need false indicators entering into the view when they've only been there for 5 minutes (one tank).
Good idea.
 
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I think the only harm that could come from it is if you were going to get a UOA done. These cleaners have, and will, affect a UOA and make trending very difficult if you don't have someone like Terry behind the numbers.
 
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