Using Fuel Cleaner - Redline Si-1 before or after oil change?

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I remember with things like Techron, the recommendation seems to be do it right before an oil change.

Wondering about the logic behind this, I don’t think fuel injector cleaner is going to really contaminate the oil or remove some large amount of carbon from the engine into the oil. That is, for a well maintained mid mileage car. Fuel injector cleaner might just clean the nozzles of the fuel injectors optimizing spray patterns.
 
Injector cleaner has nothing to do with the oil. It's about adding it before fill-up rather than after.

You add the SI-1 when the tank is low, drive it around a bit, then fill up.
 
Chevron did a study a few years ago that showed that some PEA fuel cleaners could drastically increase engine varnish if used a few times at the recommended dose within a 10k mile OCI. Some of the PEA or its byproducts does get into the crankcase and it can cause issues.

Ideally you'd want to use it, then maybe run an extra tank of fuel through the engine before changing the oil. If it's just one application within a conservative OCI, it probably doesn't matter.
 
Chevron did a study a few years ago that showed that some PEA fuel cleaners could drastically increase engine varnish if used a few times at the recommended dose within a 10k mile OCI. Some of the PEA or its byproducts does get into the crankcase and it can cause issues.

Ideally you'd want to use it, then maybe run an extra tank of fuel through the engine before changing the oil. If it's just one application within a conservative OCI, it probably doesn't matter.
https://bobistheoilguy.com/forums/t...ci-and-looked-at-it-with-an-endoscope.381420/
 
Now at Advance Auto

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Chevron did a study a few years ago that showed that some PEA fuel cleaners could drastically increase engine varnish if used a few times at the recommended dose within a 10k mile OCI. Some of the PEA or its byproducts does get into the crankcase and it can cause issues.

Ideally you'd want to use it, then maybe run an extra tank of fuel through the engine before changing the oil. If it's just one application within a conservative OCI, it probably doesn't matter.

Didn't know about the varnish, I'll look into that. But PEA essentially survives combustion so it's likely to make it into the crankcase (and onto valves, through the exhaust orthrough flow reversal on the intake). It breaks down carbon bonds, so it likely has an effect on ringland deposits aswell.

Also, combustion chamber deposits tend to increase for some reason.

It's a case of "some is good, more isn't better and too much definitely isn't right".
 
I remember with things like Techron, the recommendation seems to be do it right before an oil change.

Wondering about the logic behind this, I don’t think fuel injector cleaner is going to really contaminate the oil or remove some large amount of carbon from the engine into the oil. That is, for a well maintained mid mileage car. Fuel injector cleaner might just clean the nozzles of the fuel injectors optimizing spray patterns.

Injector cleaner has nothing to do with the oil. It's about adding it before fill-up rather than after.

You add the SI-1 when the tank is low, drive it around a bit, then fill up.

Chevron did a study a few years ago that showed that some PEA fuel cleaners could drastically increase engine varnish if used a few times at the recommended dose within a 10k mile OCI. Some of the PEA or its byproducts does get into the crankcase and it can cause issues.

Ideally you'd want to use it, then maybe run an extra tank of fuel through the engine before changing the oil. If it's just one application within a conservative OCI, it probably doesn't matter.
I talked with David Ward about this. It’s not quite so much the PEA, but more the PIB/PIBAs that, if there is a large enough amount in the oil, will rapidly oxidize and cause a (possibly) significant viscosity increase. I don’t pretend to understand the chemistry behind that but I consider the source to be legit enough to trust that advice.

This is why most of the injector cleaners say that the timing of use during the OCI isn’t as critical; just the fact that you only use one treatment per OCI to prevent too much PIB/PIBA to build up in the oil and have detrimental effects. This is why the last tank of gas before an OCI presents the least risk; ~300-500 miles and maybe a week or two with some of these compounds in the oil and then you’re changing it.
 
When Techron was a relatively new product, the instructions on the bottle carried warnings about dosage limits within the span of an individual OCI, and suggested usage closer to the end of OCIs.

Those admonishments have disappeared, but I still tend to heed their advice.
 
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