After cleaning the engine of my recently purchased 1997 Tacoma (through the throttle body and fuel system), my oil has turned very black. I now want to use Amsoil Engine Flush to clean it. The instructions say to run the truck for 10-15 minutes and then immediately drain the oil/flush. Due to the fact this truck hadn't been maintained, and the looks of the oil, I'd like to run the flush for 20 minutes, let it sit over night, run it for 20 minutes again and then drain the oil. Are you aware of any problems this might cause?

 

In your case do it two or 3 times.

You really don`t want to let the stuff sit any longer then you need to.

I wish I knew the whole chemical formula it could turn into something once hot and mixed with hydro carbons that turns solid as it cools

Then it is your engine so Do what you will.

 

There are a few ways to look at this. If your engine is really gummed or sludged, loosening the crud and detritus will do more damage than good. The loose particles will clog small engine oil passages and....well, you decide if that's a good thing.

These products offer the fanciful notion of pouring a pint or so of miracle stuff in your engine and 20 minutes later all the sludge, gunk and evil spirits pour out your drain plug.

If you really want to do this correctly you should pull the heads and have them cleaned in a tank. That's not cheap, but it's better than clogging oil passages.

Ultimately your are better off committing to a regime of 5,000 mile oil changes wi a quality detergent oil.

 

Thanks for the heads up. I’ll stick with the manufacturer’s instructions. I sense you are suggesting using the flush with each of the next two oil changes, if the oil continues to be dark. The truck actually runs very smoothly and gets good gas mileage (I just drove 190 miles on ½ tank of gas). I didn’t see any sludge or build-up of any kind when I replaced the valve shims, though I did see fine carbon that wiped off easily. The rest was fairly clean. I sense the carbon is from using Amsoil Power Foam through the throttle body and Red Line SI-1 in the fuel. I plan to change the oil and filter every 4,000 miles, once the oil remains semi-clear. Till then, I’ll be changing the oil and filter every 3,000 miles. If the oil remains opaque at 4,000 miles, I may eventually extend the changes to every 5,000 miles. This is the challenge of buying a vehicle that hasn’t been well-maintained, but I hope to get it back on track, eventually. I wish I could give you the ingredients for Amsoil’s engine flush, but I doubt they’d release that proprietary information.
I appreciate the feedback.

 

Oil does turn black .

I have never changed any that was not black after a few hours of driving.

 

What I do is every 20,000 km, I flush with a cheap engine oil by:
1. Drain the old oil.
2. Place a rug over the oil filler opening and apply compressed air.
3. Fill the engine with a cheap engine oil and run it for 15 minutes, then drain it again, then remove the oil filter, and then apply compressed air to the oil filler opening.
4. Install new oil filter and fill with new oil, Red Line Diesel 15W40.

I drain and refill every 5000 km as per Toyota recommendations on the hood underside sticker. I replace the oil filter every 10,000 km.

HTH

 

I know oil gets dark, but not as dark as what is in my engine right now. There's an awful lot of carbon in that oil. I think what I'll do is to drain and replace my son's oil first, as his Accord's oil is ready for a change by mileage but still looks golden. I'll then run the flush through my Tacoma and replace my oil with my son's used oil, running for 15 minutes and flushing it out with that and then replacing that oil and the used oil filter. Hopefully, that will get rid of more of the carbon. I'm not sure what the compressed air would accomplish, other than potentially force dirty oil into the cylinders that have open valves... if it hasn't drained by gravity, I don't see how compressed air could force significantly more oil out.