So i took off my manifold and cleaned the intake valves on my 5.0

[Amgil]

Couldn’t find any threads of people doing this so I figured id document it and warn anyone who’s thinking about doing this.


This is my 2015 5.0 @ 70k miles, car felt a little sluggish and like it was misfiring when cold so i decided to pop the manifold off and check how bad the carbon was, to my surprise it wasn’t as bad as I thought it’d be, but it was still pretty bad.





I always see people talk about how using seafoam or CRC will clean them, well let me save you some money and tell you that nothing you spray into your intake will take this carbon off because that stuff is baked on those valves and plus how the manifold is shaped. The only real way to get your valves clean is taking the manifold off and doing it by hand or walnut blasting them. I decided to take the doing it by hand route and it was a pain in the a$$.


Even after i took the manifold off and sprayed and let the valves soak in a puddle of crc and then brake clean, it was still difficult to scrape the carbon off. I should of bought a media blaster.

It was also a HUGE pain to get the manifold off its not just pop a few bolts off and its off, there is multiple bolts, hoses, and electrical connectors behind the manifold that are extremely difficult to get to because they are hugged right next to the firewall tucked down behind a wire harness housing that cant be removed without basically taking the whole car apart, and the bolts are behind all this facing towards the intake so its at an extremely awkward angle and there is zero room to work with it. Even using magnet sticks i dropped several bolts and nuts and had to fish them out….


I did manage to get the job done but it was a all day job and my hands and arms look like I got into a fight with a cat. I would definitely not do it again, im going to slap a catch can on and call it a day.

 

[NSXNEXT]

Any after pictures? Yeah a catch can is a no-brainer on these GDI engines. I'm amazed, given how little I drive my RSpec how much oil I catch.

Until they follow some of the other mfgrs and put an extra injector to wash the outside of the valves it's an easy way to keep blow-by from getting to the back of the valves.

 

[Amgil]

Any after pictures? Yeah a catch can is a no-brainer on these GDI engines. I'm amazed, given how little I drive my RSpec how much oil I catch.

Until they follow some of the other mfgrs and put an extra injector to wash the outside of the valves it's an easy way to keep blow-by from getting to the back of the valves.

I believe it man, when i first got the throttle body off I couldn’t believe how much oil was pooled inside the manifold! There had to be atleast half a cup!

Unfortunately i forgot to take after pictures though. when i finally finished it was dark outside and 50 degrees so i just wanted to finish and go inside and warm up. I wasn’t even thinking, sorry about that.

Here is another picture though that for some reason didn’t show up on my first post

 

[arcman]

Thanks for posting this. You tackled a tough one... that's a lot of work. Those valves looked awful. I put a catch can on around 40K and I'm surprised how much gunk it traps. I wonder if there's any way to get a borescope into the manifold to take a look?

 

[Amgil]

Thanks for posting this. You tackled a tough one... that's a lot of work. Those valves looked awful. I put a catch can on around 40K and I'm surprised how much gunk it traps. I wonder if there's any way to get a borescope into the manifold to take a look?

I think you could, just disconnect the throttle body , its easy only 4 bolts. The air chutes are at the top of the manifold

 

[glennk]

Catch can is almost a must these days. Will add one after the warranty is up. As for the buildup, I'll pay the extra for the walnut blast.

 

[Smobien]

What kind of oil and fuel are you running?

 

[Amgil]

What kind of oil and fuel are you running?

Amsoil signature series synthetic, 93 octane shell premium.

 

[coatseast]

My 3.8 GDI has 70000 miles. Low for a 2012. What symptoms indicate carbon build up and where can you get them cleaned. Does the dealer walnut blast? Only thing I notice is a rougher cold start. Once it warms up for 20 seconds it runs fine. Gas mileage is samee as new as is performance. Now those leather seats are another story!

 

[Amgil]

My 3.8 GDI has 70000 miles. Low for a 2012. What symptoms indicate carbon build up and where can you get them cleaned. Does the dealer walnut blast? Only thing I notice is a rougher cold start. Once it warms up for 20 seconds it runs fine. Gas mileage is samee as new as is performance. Now those leather seats are another story!

The dealer doesn’t offer walnut blasting but they do offer a “induction service”. All this is, hooking up a can of valve cleaner to a air compressor do-hickey and misting it into the intake manifold while the cars running. then they add a fuel treatment into your gas tank and its like $200 I believe.


Take it from me, This does NOT clean the intake valves. I’m sure it probably cleans the injectors and what not, but i can promise you, nothing you spray into the manifold will clean that crud off the valves. I do not recommend paying money for this, instead i would either DIY or pay a few hundred more for a shop to walnut blast them.


As for walnut blasting you would have to call around your local auto shops and see if any offer them, although its probably going to cost you a good chunk of change.

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[coatseast]

Do you have a recommendation for a catch can? I suppose that might be a thing to ask my mechanic to install but not sure how hard it is or if it’s worth it this late in the game… Car has 70,000 miles I guess it can’t hurt at this point

 

[TinsleyC]

Does a catch can make much of a difference? Like, can it cut the buildup in half?

 

[pulsar]

Does a catch can make much of a difference? Like, can it cut the buildup in half?

Well, I guess it depends on exactly how much oil the CC actually catches and holds vs what may seep by? I get maybe a couple of ounces in my cans at oil changes which I normally do at 4000-4500 miles. I installed my CCs when my G70 was still fairly new with very low miles. I’ll measure what I collect at next oil change. I’m also assuming as the engine ages some the amount of oil mist traveling thru the PCV system slowly increases so more oil would get collected, or lacking a CC more oil gets burned back thru the engine The proof will be in a few years I borescope the induction system to see what the valves look like? CCs are a preventative item, certainly not a make or break item for most people change their cars every few years. My Infiniti was 9 years old when it got hit and totaled and my Mazda convertible I still drive is 15 years old if that gives you an idea how long I keep my cars. I’m the anal retentive type who takes very good care of my cars so keeping excess oil out of the intact system was worth it to me.

 

[Amgil]

Do you have a recommendation for a catch can? I suppose that might be a thing to ask my mechanic to install but not sure how hard it is or if it’s worth it this late in the game… Car has 70,000 miles I guess it can’t hurt at this point

As of now I can’t recommend a particular catch can because I don’t know much about the different brand and which ones are good or not, I’m going to do some research before i put one on.


I do not believe a catch can would be hard to install at all, as both the crank case hoses can be easily reached without removing anything.

Generally speaking the sooner you put a catch can on the better though, and with 70,000 miles, your valves are probably looking similar to mine.

 

[Amgil]

Does a catch can make much of a difference? Like, can it cut the buildup in half?

Can’t answer from personal experience because i have yet to install one, but from my research on various forums and YouTube, id say they do help a significant amount. The sooner you put one on the better, especially if you plan on keeping the car more then 100k miles.

The second best thing you could is run a good quality oil in your engine and change it regularly. I would absolutely not run anything but full synthetic. The higher the quality of the oil, the less carbon buildup you will get on the valves and intake.

A good quality full synthetic oil will have less evaporative loss then cheaper synthetic blends or dino oil. Cheap oil = much more oil vapor in the blowby, which in turn gets sucked straight from your crankcase back into the intake to be burned in the combustion chamber. All that oil vapor cakes up on your intake valves over time.


I would do some research on the internet, there is a couple videos on YouTube that test evaporative loss of various engine oil brands by heating the oil in containers and measuring the weight afterwards.

 

[greekgeek]

I had the dealer do the GDI induction service last week on my 5.0, first time at 63k miles. Totally worth it. They claimed to remove the AIM and hook it up to some machine all the way to the tailpipe.

Immediately noticed a much smoother idle, and way less vibration when at a stop while applying the brake. Throttle response is much improved, very smooth- drives like new again. I didn't expect anything as dramatic as all that.

will also check to see if gas mileage rebounds.

 

[Slip_Angle]

@Amgil - Sorry if I missed it but what were the results? Did the car run better or the same?

 

[princelybug]

Great job @Amgil

 

[G90Matt]

As of now I can’t recommend a particular catch can because I don’t know much about the different brand and which ones are good or not, I’m going to do some research before i put one on.


I do not believe a catch can would be hard to install at all, as both the crank case hoses can be easily reached without removing anything.

Generally speaking the sooner you put a catch can on the better though, and with 70,000 miles, your valves are probably looking similar to mine.

Did you install a catch can? If so, can you post a pic of where you fit it in? I'm using your posted picture to help the walnut blasting guy this weekend with those three tough bolts on the back of the manifold.

I bought a can and didn't install it. Couldn't find a place I felt it would fit. But if I see it done, I can give it a try.

I have 58k miles on my 90 5.0. I've done the Berrymans GDI treatment three times, just before each oil change at 5k. The last time didn't seem to have very good results. So I'm pulling the trigger on the walnut. A local company said $875 plus tax. I asked for pictures of before and after. If they're good I'll post.

 

[5.0KDM]

Did you install a catch can? If so, can you post a pic of where you fit it in? I'm using your posted picture to help the walnut blasting guy this weekend with those three tough bolts on the back of the manifold.

I bought a can and didn't install it. Couldn't find a place I felt it would fit. But if I see it done, I can give it a try.

I have 58k miles on my 90 5.0. I've done the Berrymans GDI treatment three times, just before each oil change at 5k. The last time didn't seem to have very good results. So I'm pulling the trigger on the walnut. A local company said $875 plus tax. I asked for pictures of before and after. If they're good I'll post.

Here's the write up. Oil Catch Can DIY. I didn't use the hard lines. I reused the old pcv line and bought a small 1/2" line from autozone. it works really well. I empty mine every 1500mi and boy does it collect a lot. I am also running the mishimoto OCC.