[1997ThunderbirdLXV6]

Even though my 3.8 (naturally aspirated) only has about 40.000 miles on it, it is 25 years old. So I figured it can't hurt to try some cleaners.

After watching several "Chrisfix" videos, I decided to use Seafoam Spray. For those unfamiliar with it, it's the one that uses a tiny hose which is routed directly towards the throttle plate.

I followed the instructions to the letter, and here's what surprised me: all of the videos on this subject show dense, white smoke from the exhaust. In my case, the smoke was white, but it was very light during the injection of the product, definitely not thick clouds of smoke. During the subsequent drive, there was hardly any smoke.

...again, I followed the instructions exactly. So why hardly any smoke?

As to the results, I actually do feel an immediate improvement in smoothness. My car always (i.e., in two months of ownership) had a somewhat rumbly idle; that seems totally smoothed out now. Unless I'm imagining things.

 

[Trunk Monkey]

Why hardly any smoke?

A: Because your engine wasn't that dirty.

I suggest dropping another can regular of Seafoam in the gas tank with a fresh tank of gas and then leave it alone. No need to do more.

 

[supergordo]

Well I've used the seafoam with the straw many times. It doesn't smoke that much in my experience. If you want to see the smoke, then get the bottle of regular seafoam and let it suck into the intake with a vacuum hose on the engine. You'll get more smoke for sure.

 

[1997ThunderbirdLXV6]

If you want to see the smoke, ...

I mean I'm good without any smoke. I was just surprised based on testimonials.

 

[Grog6]

A proper seafoam treatment fogs the whole neighborhood, on a 100k mile 4.6, anyway.

 

[supergordo]

I mean I'm good without any smoke. I was just surprised based on testimonials.

Seafoam recently added the can with the spray nozzle and straw to make it easier for people to use. But I still think the old fashioned Sea Foam method works best. Besides, who doesn't love a smoke show??

 

[Grog6]

The first time I did Lazarus, my neighbor came running with a fire extinguisher, I told him "seafoam", and he knew instantly what I meant. I love thus place. He's a Chevy guy, and built some nice trucks.

 

[T6Rocket]

But the old way of having it suck into a vacuum hose is a little dangerous. Go too aggressive and you could hydrolock the motor. I've had the motor make a pinging/knocking sound as it stalled. Have not done it since.

Just go WOT for 5-6 seconds at least a couple times every 200 miles. These engines loaf along at 1500-2000 RPM normally, they need to be worked a little harder to clear the carbon out.

Al

 

[Darin10]

Yeah, I was just about to say that if you drive it hard or if the previous owner did you probably won't see much smoke. I never sea foamed my Thunderbird but I did it with my 2001 Camry and it didn't smoke even a little bit with 250,000 miles.

 

[Kenz]

Not really sold on Seafoam doing much of anything besides a smoke show. It's this decades Marvel Mystery Oil. Most of the fuel additives and cleaners are mostly Kerosene anyway.

 

[Rocketdog]

I love Seafoam. I have used it on every used car I have owned.
I have used it in the spray form and the liquid form to clean parts and as an engine treatment. It can be added to the fuel or oil, but I have never put it in the oil.

The key I found after a couple unsatisfactory treatments (little smoke) was heat sinking the intake manifold.
Use it as directed, but make sure the engine if heat soaked...like up to full operating temp for 30 minutes.
Then, have somebody run the throttle to keep it running, and put the entire can into the throttle body. This will take several minutes. When the can is empty, immediately shut it down and let it cool completely...like for an hour at least.

Remember, it took 20+ years to get that dirty, it will not come out immediately or all at once.
However, if you do as stated above you will have a smoke show like no other, I promise.

I ended up removing the intake and cleaned it manually, then ported it for kicks. Upon removal, I found a lot of carbon on both the intake and exhaust sides of the heads.

Before installing the Mark engine, I pulled the intake and exhaust manifolds and cleaned everything manually. Even that engine, with only 60k miles on it had a lot of carbon in the intake and exhaust portions of the heads. There was not much inside the intake manifold itself, and using Seafoam, I was able to get everything clean like new. The Seafoam really softens the carbon deposits.

I even made a Seafoam drip system to run in the PCV tract to constantly clean the top end if needed. A simple lubricator or Filter, Lubricator for an air compressor tool works pretty well. I used to fill it up and let it drip about every 2 seconds, and it kept my 2v NPI engine really clean, and that one had almost no valve stem seals left and smoked hard.

Good luck

 

[Grog6]

By 20 years old, these cars get heavily gunked up, mostly from the recirculated oil from the pcv valve, and the sludge from the egr. I drive my cars very hard; high rpms just increase the flow from the pcvcircuit, and that doesn't clean anything.

 

[Darin10]

I guess I just used the seafoam wrong then. Does the car you are taking about have a metal intake @Rocketdog? Is heat soak significant for a plastic intake?

 

[1997ThunderbirdLXV6]

I love Seafoam. I have used it on every used car I have owned.
I have used it in the spray form and the liquid form to clean parts and as an engine treatment. It can be added to the fuel or oil, but I have never put it in the oil.

The key I found after a couple unsatisfactory treatments (little smoke) was heat sinking the intake manifold.
Use it as directed, but make sure the engine if heat soaked...like up to full operating temp for 30 minutes.
Then, have somebody run the throttle to keep it running, and put the entire can into the throttle body. This will take several minutes. When the can is empty, immediately shut it down and let it cool completely...like for an hour at least.

Remember, it took 20+ years to get that dirty, it will not come out immediately or all at once.
However, if you do as stated above you will have a smoke show like no other, I promise.

I did everything except, after application and shutting off, I only let it sit for 10 minutes. Then I drove it again. That was per the instructions on the can.

 

[Rocketdog]

At 12.99 a can I would try the wait for an hour. Far more satisfying results.

 

[T6Rocket]

Prolong the hydrolock for an hour? As that seafoam is sitting for an hour, it is likely leaking past the rings into the oil, so keep that in mind.

Al

 

[Grog6]

Seafoam is the commercial equivalent for the old trick of transmission fluid and water, shook up in a coke bottle we used in the 60's.
The water cracks the carbon loose, and the trans fluid dissolves it.
The smoke is equal parts oil fumes and steam.
It basically steam cleans the cylinders.
If you hydrolock it, you're doing it wrong.

 

[Rocketdog]

I don't think you can hydrolock a V8 with a spray can of Seafoam.
The long heat soak has worked for me for many moons, that's why I recommended it. I don't recommend sucking Seafoam in through a vacuum line without a way to meter it.
Good luck!

 

[Rocketdog]

I guess I just used the seafoam wrong then. Does the car you are taking about have a metal intake @Rocketdog? Is heat soak significant for a plastic intake?

Like I said, I use it on all my cars. To answer your question about metal vs plastic intake manifolds...it does not matter because the engine temps remain the same. The plastic obviously has different properties than aluminum but the specific gravity or mass is irrelevant as the temperature envelope is constant.
Get it hot, spray the whole can in there and shut it down for an hour.
Your next start up will be dramatic, I promise you.
My Corolla has a plastic manifold and 275k on it. I did that one in February and got the locals all stirred up with the show.
That thing smoked as much or more and for longer than the 170k NPI 2 valve did. It was spectacular on a crisp -7f NH morning.

 

[Darin10]

The way I did it was put it in the gas tank. I will spray it down the throttle body post the results. I also didn't think that the block would keep the intake hot anyway.