first time on a engine that's done over 70k tend to put half can can in then run car for 30 miles then add the rest and run for 20 miles,, reason is it dont over load the oil with carbon as on especially diesels some people have done it after 100k full can driven car for 50 miles blocked up oil filter totally stupid and then blame the product,, on very dirty engines i would stick full can in and just do a run car on the spot for 40 minutes at 3000 revs at least you have a chance of listening to it do its job, ie cleans out the lifters and tappet noises that are there due to dirt disappear anything thats worn out might make more noise,, but at least you know its worn out rather than a surprise one day that ends the engine in my view,, what seafoam does is to break all the crud and carbon soot off the metal parts and load it in the oil,, i have used it for past 20 years on all kings trucks and cars and diggers even odd boat never had any issues with it,, but i do read some stories online about it how they blame the cleaner for killing a engine,, then i read on and see they have poured a can in the inlet on a diesel and wonder why its broken a rod as fluid dont compress,, or its been used on a cooked totally nailed engine before hand and removing the dirt has highlighted its end of days, not the seafoam fault,, just a stupid person touching something without reading about it first and some common sense it would seem,,,
mate of mine used it for first time on a 4x4 with 70k on it in fuel system as it had injection knock or tick, he phoned me up and said cannot believe how that worked he said he sat there at idle for a hour and could hear it change note back to the correct diesel noise,, i know all this as i have so many times on diesels used it in fuel filter dirt and ran cars with diagnostics hooked up and watch the injectors mg/s readings all level out in front of my eyes
