Redline si1 on half or full tank?

Aug 8, 2005
stamford, CT
I'm about to do my oil change!!! Yay!! I always use crc gdi intake cleaner.gunn a have about ,3,700 miled,5 months on oil,giltet.Turning dark black 3,200 miles in.I've read about redline,instructions say full tank, up to 20 gallons. My tank seems to be a 14_15 gallon..98 Buick lesabre.let needle go near empty,and it's 14.5 gallons nowhere near 18 it's supposed to be.
Others have run cleaners,with half a tank. Instead of full tank,so cleaner is more concentrated. Ok to do that,with red line gas additive?
Full tank. Half tank is like putting extra detergent in the washer and then running a quick cycle, not nearly as effective.

Why the CRC IVD cleaner on a port injected Buick? Probably wouldn't hurt but definitely not necessary since a fuel additive hits the valves.
Put the whole bottle in the full tank, even if it's only a 15 gal tank. The run as much of that tank as possible before filling up again.
I wait until near empty and pour in whole bottle then fill tank.
Used whole bottle on 11 gallon tanks through 18 gallon... no difference.
In the past, I have noticed that overdosing with FSC's has caused the CEL to come on. Once I ran through that particular tank of fuel, the CEL went away. So, if anyone does in fact overdose the tank with too much of a FSC(I can't say what is too much for your engine mgt. sys.), just don't use too much over the recommended dosage.
More than the recommended dosage probably gives you diminishing returns as far as the benefit.
So, just a waste of money.

Redline has a maintenance dosage that is half a bottle up to 20gal.
If you used the GDI intake cleaner or generally use top tier fuel the half bottle is probably more than sufficient.

I'd rather run longer at the recommended dosage versus higher concentration for shorter interval.
So, run 1 bottle in full tank at least, but even consider half bottle for 2 consecutive fill ups.
For 14 gallons tank, I will just dump and fill up the tank till full. If smaller tank, I will split the bottle into 2 applications consecutively.