If one changes the oil on a regular basis there should be no need to put it in the crank case, when one drains the oil all of it never comes out therefore some of that stuff is still in the motor, I have never put any foreign chemicals in any of my motors and never would, I think it would thin the oil and possibly cause problems....

 

+1, I've never used it in the oil and don't see the need if the oil is changed at the proper intervals, although I have used it as an induction service many times and swear by it. I've done before and after comparo's with a boroscope and seen how clean it makes the valves and combustion chambers. I like to recommend it as a yearly/12k preventive maintenance.

 

I just let the truck run in the driveway for a few minutes. i just drain and refill with new oil. i dont do the oil every time, just once a year. i do the other two at every oil change. I run synthetic and change it every 5000 miles

 

I use seafoam all the time i put in one of the vaccumm lines while its running smoked white first time i did it just cleaning things up but never put it in the oil says u can but i wouldnt trust it. We put seafoam in all our firetrucks everytime we put fuel in them and they start everytime and these trucks are old c10s and miltary 5 tons

 

It is the equivalent, somewhat close to, GM top engine cleaner that is used at the dealerships for major tune ups. I've used seafoam for all of my vehicles. The wife's car smoked quite a bit, not surprising.

Here's some info from another thread:

FIRST and FORMOST, I'd like to thank Jim Davis @ Seafoam for personally taking my phonecall and answering all my questions before I put SEAFOAM in my truck.

What you will need

1) Funnel or Screwdriver (to put it in the gas)
2) I used a 20oz disposable Cup and eyed into fours as measuring points
3) SEAFOAM

First and formost my truck is tapped for boost : ) So it ill be a lilttle different.

What you need to know.

YOU DO NOT NEED TO CHANGE YOUR OIL WHEN DOING SEAFOAM! Jim Davis himself personally puts it in his oil and drives it that way until thnext oil change. Removes sludge and build up as well as keep it to a minmial! IT IS SYNTHETIC OIL FRIENDLY!

You MUST.

have atleast 5-8 gallons of gas in your truck.
The correct Vacum Source to suck it through is next to the BRAKE BOOSTER. Runs Parallel.

1) Gas: I had a quater of a tank left and I put in 5 more gallons worth of gas.

RULE IS: 1 oz per gallon.

2) We have 5 quarts of oil in our engine. 1 and half onces per quart AKA 7 n 1/2 Onces of seafoam into where we put out oil.

3) I did this byself so I ran a long Vac line into a position where I I can tilt the cup witht he hose on the deep and gas it.

4) Start your engine in a well ventilated area THERE WILL BE SMOKE! I reved my truck at 3000rpms till the smoke was gone. Looked in my cup there was still some seafoam in it. Got that sucked in and gassed it more!

5) Re installed Vac line and be done!

 

I have heard that you need to change your spark plugs after running seafoam. I have 75K on my truck and plan to try it out pretty soon. I have used it on my Honda and works wonders but did hear you should change your spark plugs.

 

You don't need to change your plugs, but I always like to change the oil after a Seafoam treatment...

 

ran some thru the intake of my welder today to see if it would clean it out and that thing had a good bit of smoke come out of it but did not do much for my truck when I used it in it. Welder runs smoother now but truck runs the same

 

posted this a minute ago dont be afraid to run it thru the crankcase i run it thru every car i work on

as to the guy who doesnt trust seafoam i have ran it thru sbc bbc ls1/5.3/4.8/6.0 and some other ls series engines without any problems and most of the cars are $100k show cars making big horsepower.

on top of the electrical work i do i offer preventitive maintance and i do the following in this order.
8oz seafoam in tank
fill with 93 octane
4oz thru a vaccum line
seafoam deep creep in the intake and tb or carb
4oz in the oil
run hard for 50 miles
change oil royal purple/k&n oil filter
change fuel filter
change air filter or clean and re-oil it
change plugs usually ngk (high end iridium or lasers sometimes i use autolite racing plugs)
plug wires....rotor cap and button if it has one
drain differential fluid
replace with royal purple
drain tranny fluid
replace filter and use royal purple tranny fluid
grease u-joints tie rod ends etc with royal purple
drain coolant and flush radiator, block, hoses and heater core
replace thermostat and gasket
fill with antifreeze and add purple ice
then drain power steering and add royal purple
and if im not having to travel to do the job i have nitrogen put in the tires
then crank her up and run the **** out of her
synthetics kick ***