So I searched for threads on this and couldn't fine one. This Thread is based on experience and may be different from yours.
Seafoam in your crankcase is bad because when you pour it in with your oil it not only thins out your oil so it no longer has the same protecting properties it had before you poor the seafoam in it also loosens a large amount of gunk at one time and can clog your oil pick up causing the engine to be starved of oil it lets all those chunks be pressed through your bearings and score or clog them. Please if you insist on using the stuff only put it through a vacuum hose straight into the intake or your gas. But just doing regular oil Changes cleans the engine fine! Good luck and if you have questions or anything to add feel free!

i only use it for valve cleaning, once a while i use it in my fuel tank but never in the oil.

Hopefully the owner of my old engine took it apart. I put that stuff in all 3 places in my old 22RE. Nothing was wrong with it before I replaced it.

* pour *

Poor is exactly what you will be if you use that stuff wrong...hello new short block

Exactly why I don't use the product at all.

Chevron Techron is a much better fuel system cleaner IMO.

Go to new engine knock after seafoam?

for my story regarding the product.

My first post is on page 1. My second post is on page 2.

Also go to: Seafoam for another thread about Seafoam and read what U.G.N. says about his 4Runner after using Seafoam.

Thank 541joseph for starting this thread. I hope you don’t mind I add my view.

Yes your posts and that thread is what made me decide it would be a good idea to try and help people. Thanks for your input!

I've only ever used it in my old trucks fuel tank. Think of it like this, fuel dilution causes crankcase explosions on our engines on the ship. When you're putting somthing like seafoam into your oil it's almost like putting fuel into it. That just needs a high enough temp or a small spark to ignite and you're out of an engine. I've seen it before on ships...not fun.

Im not promoting SeaFoam-But it is a Petroleum based product and will mix with your oil and not cause any damage in that sense. Unless your draining 2 quarts of oil and adding 2 quarts of Seafoam I dont see an issue... its not thinning your oil that much. About every 3rd oil change ill pour a half a can in my crankcase and drive it about 100 miles then change the oil. Ive never seen a chunk of carbon or sludge come out on that oil change after but my engine is clean and maintained.
Unless you have an engine that's full of sludge or extensive amounts of carbon I wouldn't expect anything to "clog" your pickup tube.
Ive never had a problem. But every owner is different and every engine is worn and abused in a different way. There are directions on the can-
All it takes is one moron to try to fix a sludge filled engine with 2 cans of seafoam, blow the thing up and blame seafoam.
EDIT:Forgot this-
Your oil is filtered before it gets to the bearings anyway. You would clog your oil filter before it sent tons of "carbon" particles thru there. The same guy that uses too much seafoam for too long probobly also uses a Fram oil filter--haha

What oil filter would you suggest? Honest question.

From all the research I have done over the years the Factory Toyota are the best. Second choice or in a pinch would be a Wix Filter
For my Mustangs and old Fords- Factory Ford or the Ford racing versions Only-
Frams are for the thousands of sweatpants wearing zombies who shop at walmart and dont know any better as far as im concerned. I wouldnt put one on my enemy's lawnmower

Searching which oil filter is best will open a giant can of worms but most will prove how fram are cheapos. I bought a case of Toyota OEM filters on Ebay for like 40 bucks- basically a buck or two cheaper than at the dealership. Hope this helps

Most all additives are Snake Oil and good Marketing.
The only fluids in your engine should be oil & coolant.
Gas might count too, but that usually blows up...

Seafoam has a higher flash point than your oil. So comparing it to putting fuel in your oils is absurd. your oil will combust before your seafoam will.


When used as directed Seafoam and other like products will not change the viscosity of your oil enough to make a difference. besides as your oil ages it looses its ability to do its job, adding seafoam is no different than used oil.

Also, seafoam is not magic in a bottle, it does not break everything loose and drop it into your oil pan like a load of dirt. It takes time, and your filter should (if you are using a good filter) catch and debris that is dislodged over time.

Even so, I do not put it in my crank case simply because I change oil regularly, use OEM filters and I do not use cheap no-name fuel. I don't care if people use seafoam or not, but random unsubstantiated claims of it being dangerous are silly.

I recommend not using oil additives and following a good maintenance schedule and use good quality consumables.