fuel injector cleaner - when (arguments)

[crinkles]

I just had a thought the other day.

The status quo seems to be to add the cleaner on the last tank prior to an OC, to drain the oil after using the cleaner.
THe injector bottle usually says AFTER the OC.

In a sound engine, the fuel system would be generally isolated from the lubricant to some degree (otherwise you have a fuel dilution problem?) so wouldn't it make sense that it DOESN'T matter when you add the cleaner?

That is, if you are concerned about the FI cleaner contaminating the oil you have a much more serious fuel dilution problem...

Any crud burnt off in the fuel system or cylinder would be combusted and exhausted and not end up in the oil?

Any thoughts. I may be totally wrong.

 

[Shannow]

Porsche (at least used to) recommend Techron, and only a certain number of doses per OCI, but it was certainly more than one.

 

[tdi-rick]

Crinkles, the problem is blow by and what the detergents do to the oil. Caltex used to only recommend two or so doses with Techron per OCI.
According to a man I trust on oil matters, ethanol blends, and ULSD is creating problems with lubricating oils too, which he is seeing in UOA's. The aromatics are playing merry h#ll with oils, and a lot of the additives used by oil blenders aren't coping.
It's a combination of fuel dilution and just plain ol blow by.

 

[crinkles]

Ok good. SHows you how much I know!
The valvoline injector cleaner says 5 x400mL bottles per OCI is OK... that's a lot!

 

[steve20]

FWIW I use Techron or V Power twice a year about 1K before an oil change


02 Corvette
95 Corvette
04 Tahoe
05 Accord

 

[Gary Allan]

Well, in our average run of the mill oils and engines, I'd say that it doesn't matter when you do it. It may alter your UOA indications a bit. If I'm using a shock dose cleaner (as opposed to the labor intensive perpetual treat rate method), I sample via pump first, then treat the tank, then when it's exhausted, change the oil.