Bought a used BMW and have already changed the oil but forgot to run some fuel cleaner. I was curious are BG44, Techron and Redline the main cleaners to look for, any opinions as to which are the best? And is it a must to change the oil or how long can wait before changing it after running the cleaner.

Thanks

Why do you think it needs a fuel cleaner?

Out of the ones you listed I've been happy with Redline SI-1 and I have run it after an oil change. No issues. I generally like to put it in the last tank of gas before an oil change, run it right down, re-fuel and then change the oil but there is nothing saying you have to do it this way.



Some manuals call for it. My Toyota Highlander did.

I called Techron's support line a few months ago, and the guy told me that it didn't matter (when during the OCI to run the cleaner). I have read as much in threads on here, on the same question.

Thanks for the feedback, I had bought a used bmw and was unsure what fuel the prior owner was running in it and since I was changing out all the fluids thought id run a cleaner as well.. I know BMW uses Techron and sold under the BMW name but not going to pay dealer price.

It was a long time ago, but way back when Chevron had a recommendation that the best time to us Techron Concentrate would be right before an oil change. The rationale was that the high detergent content could get into the oil and deplete some of the oil additives. I suppose the idea was to have a fairly short time where the additives were artificially depleted. They didn't really explain it though. A lot could have changed, including what went into the bottle as well as the additives used in motor oil.

This part is what scares me...

Techron makes the BMW cleaner, but Redline is a great brand as well.

When I got my last used car, I used 4 different ones in 4 different tanks of gas. Probably stupid but I was confident I had all the bases covered.

Just for the sake of conversation, over a million miles driven and not one ounce of "fuel system cleaner" has ever entered my tank. Shrug?

Used Techtron and BG44K. Just once every few years. Probably not too critical if you use Top Tier gas. Never heard of an issue of the oil change before but could make sense I suppose.

Besides the extra detergents possibly depleting the oil additives, another argument for using the fuel cleaner just before an oil change is this: the cleaning action may add carbon to the oil, making it dirty quicker, and you don't want that extra carbon running around your motor for thousands of miles. Can't say what cleaner is better than the others, but all 3 that you mention are known to be effective. I've heard many times that the BG44 is "the best" but those 3 all work. Good luck with the "new" BMW.

In my opinion it would not matter in a good condition engine. If you have done UOA's and your engine shows no fuel present in the used oil sample, than fuel additives won't be present either.

BMW sells relabeled Techron through their dealer network for twice the price. Do with that info what you will.

Red Line used to sell a product called SI-2. It was supposed to be a less concentrated version of SI-1. I saw it once (20 years ago or longer) and it carried a BMW equivalent part number. That was supposed to be a one bottle per tank fuel treatment. It's no longer listed, but the MSDS is still available.

https://www.redlineoil.com/content/files/tech/SI-2%20MSDS.pdf