Seafoam works.

[renns]

Is there any downside to using seafoam? Possible damage?

There's a whole thread of bad news here:

https://www.matthewsvolvosite.com/forums ... hp?t=13217

My story is near the end of that thread. For whatever reason, my car developed a bad valve tick immediately after the SeaFoam treatment. The tick does not fade away after startup, but is present the entire time the engine is running. I've tried every remedy aside from replacing lifters, and the tick is still there. It's been a few thousand miles since, and still no change in noise for better or worse.

I sure wish I could turn back time, as I never would have removed the lid on that SeaFoam can. Others have had better luck, though, so throw the dice if you wish.

[turbotim2]

After seeing all the raving, I decided to try Seafoam. It was in one of my 96 850 NA's with 185,000 miles. I put one third in the gas tank, one third in the crankcase and one third in the intake. It reacted just as others described as far as smoking alot afterwards for a bit, stumbling on restart and throwing a P0300 code. I have noticed no performance improvements and no difference in engine "smoothness". Time will tell on the fuel mileage, I will report back once I have run a couple of tanks through it. If it doesn't improve mileage, I will chock it up to a waste of money. I am going to start another thread which prompted me to try this other then just the raving.

[1997volvo850]

And there's more - Seafoam cures cancer too!

Listening to the complaints in a few other threads I'm taking a cautious approach
with Seafoam.

I believe adding Seafoam to the gas tank does not seem like a dangerous thing. Someone said
that Seafoam attacks rubber and there is a lot of rubber in the fuel system. I guess putting
Seafoam in a full tank of gas means it is in the system for an extended period of time.
Any damage would be difficult to detect. I would be more likely to add Seafoam to a near
empty tank just so I know its out of the system.

Putting Seafoam in the oil, for a brief period of time, sounds like it will dissolve deposits
in the engine. It also sounds like Seafoam dilutes the oil and must not be left in the oil
for extended periods. Seafoams degreasing properties must reduce oil effectiveness.
Sounds like a brief application near oil change time might remove some deposits.

It seems adding Seafoam to the intake causes the most problems. This is where folks
appear to have permanently damaged their engines. It sounds like adding too much too
fast or selecting the wrong vacuum hose can lead to bad news.

I've had white smoke in my exhaust. Some people suggested a blown head gasket. I pulled all
5 spark plugs and they were caked with carbon. I could see the pistons were also caked with
carbon. (none were shiny bright to indicate blown gasket). I cleaned and re-gapped plugs and
most of white smoke disappeared)

I suspect adding Seafoam through the intake will steam clean the carbon off the plugs
and pistons. Is there another way to eliminate the carbon?

[jblackburn]

Sure. If you're still worried about it in the intake, pour some in the cylinders and let it sit for a few minutes, and then crank it with the spark plugs out into a rag. You won't risk bending anything that way.

GM Top engine cleaner is recommended by some. You can buy it pretty much anywhere you can get Seafoam.