[Pollock]

I spoke with a local mechanic at a dealership who is also a friend. He uses this cleaning method on his direct injection engine every 10,000 miles. But uses a different brand that I dont remeber. Says it cleans the build up off the valves.

[Alain]

I’m fairly certain that the people who don’t care about this GDI oil issue are those that don’t plan on keeping these cars for a long time. I plan on keeping this car forever since they are becoming a dying breed with the introduction of electrification.

By the time this carbon becomes an issue your warranty will have probably expired. So saying GM will take care of it is a misguided assumption. I’m not a conspiracy theorist but I’m sure GM or any manufacturer is not worried about people having warranty claims due to the carbon since by the time your check engine light goes on due to misfires, or you start noticing shitty performance the car will be out of warranty.

Anyways, like everything else, we all have a choice to make. For $350 bucks for a catch can I get piece of mind that my engine won’t have this carbon issue.

This specific method of spraying this stuff is fairly new I believe. I wouldn’t use it on my $74K car yet. I’m gonna wait a while and see what type of side effects these sprays may bring. But on a beater (like my girlfriend’s car) it’s a good alternative.

[SJFGTO]

Originally Posted by Alain

I’m fairly certain that the people who don’t care about this GDI oil issue are those that don’t plan on keeping these cars for a long time. I plan on keeping this car forever since they are becoming a dying breed with the introduction of electrification.

By the time this carbon becomes an issue your warranty will have probably expired. So saying GM will take care of it is a misguided assumption. I’m not a conspiracy theorist but I’m sure GM or any manufacturer is not worried about people having warranty claims due to the carbon since by the time your check engine light goes on due to misfires, or you start noticing shitty performance the car will be out of warranty.

Anyways, like everything else, we all have a choice to make. For $350 bucks for a catch can I get piece of mind that my engine won’t have this carbon issue.

This specific method of spraying this stuff is fairly new I believe. I wouldn’t use it on my $74K car yet. I’m gonna wait a while and see what type of side effects these sprays may bring. But on a beater (like my girlfriend’s car) it’s a good alternative.

Well said...or well typed. I totally agree. I plan on keeping mine too. $350 is cheap insurance against an issue that will manifest itself over time. Since my warranty is long gone for other reasons anyway, no worries that I will become the next internet legend everyone has heard of but nobody knows who had a warranty claim denied because of a catch can.

[Alain]

Originally Posted by SJFGTO

Well said...or well typed. I totally agree. I plan on keeping mine too. $350 is cheap insurance against an issue that will manifest itself over time. Since my warranty is long gone for other reasons anyway, no worries that I will become the next internet legend everyone has heard of but nobody knows who had a warranty claim denied because of a catch can.

Thanks.

As far as catch cans and warrantees. I don’t see why someone wouldn’t uninstall a catch can prior to bringing their car to a dealership for warranty work. Yes, it’s an extra step to take, and yes you may have to pay for two tow trucks (one to your house if you brake down on the street so you can uninstall the catch can and a second one to the dealership for repairs). But that’s the extent of the hassle, it’s totally worth the extra hassle if it’s going to save your warranty.

The only issue might be if you don’t perform your own regular maintenance (oil changes). If you bring it to your local dealer for oil changes while having the catch can installed then they’re obviously going to see it and you’ll be exposed.

If you’re one of those people that lets the dealer change your oil and they see you have a catch can DONT TAKE YOUR CAR TO THAT DEALERSHIP IF YOU HAVE A WARRANTY CLAIM. Uninstall the catch can and bring the car to the next closest dealership.

Maybe I’m missing something that makes my logic invalid. But I don’t think I am.

[hawk02]

Originally Posted by Alain

Thanks.

As far as catch cans and warrantees. I don’t see why someone wouldn’t uninstall a catch can prior to bringing their car to a dealership for warranty work. Yes, it’s an extra step to take, and yes you may have to pay for two tow trucks (one to your house if you brake down on the street so you can uninstall the catch can and a second one to the dealership for repairs). But that’s the extent of the hassle, it’s totally worth the extra hassle if it’s going to save your warranty.

The only issue might be if you don’t perform your own regular maintenance (oil changes). If you bring it to your local dealer for oil changes while having the catch can installed then they’re obviously going to see it and you’ll be exposed.

If you’re one of those people that lets the dealer change your oil and they see you have a catch can DONT TAKE YOUR CAR TO THAT DEALERSHIP IF YOU HAVE A WARRANTY CLAIM. Uninstall the catch can and bring the car to the next closest dealership.

Maybe I’m missing something that makes my logic invalid. But I don’t think I am.

This may be sound advice for folks with an LT1 or one of the LS engines, but on the LT4 installing and removing a catch can is a bit more of an ordeal. It's crazy to think one has to uninstall a catch can every time you take your car in for warranty work. Not counting oil changes, I would have had to uninstall a catch can no less than four times in the 2+ years of ownership. I had catch cans on my other three Camaros, but this one is going to stay catch can free. I just don't see that it's worth it.

[Alain]

I respect your preference hawk.

Personally, if removing the catch can is going to save me hundreds or thousands of dollars in warranty work...... I’ll gladly spend the 3 or 4 hours it might take me to remove it.

If keeping this car is a possibility for anyone, it would be wise to spend the $350 and the 3 or 4 hours on the weekend to install a catch can. Unless you know you’re going to be doing motor work down the road, then install the can at that point.

The motor will eventually suffer one way or another if the oil on the valves is not addressed.

[k20attack]

Has anyone posted any video/pictures of an LT4 valves being coked up with minimal miles on it?

[Gunkk]

Originally Posted by k20attack

Has anyone posted any video/pictures of an LT4 valves being coked up with minimal miles on it?

Nope. None that I've found. I found only one anecdotal report @ 70k miles, mentions soft "gooey gel" on the stem but no buildup on the valve, no pictures in the post, but you can read up for yourselves:

reference: https://www.corvetteforum.com/forums...post1597562696

copy/paste:

85K had the supercharger manifold off earlier this year.
Didn't see any coking on the valve head itself. Didn't see any build up on the valve head itself.

I did see a slight build up of a gel type residue on the valve stem.
This was right at the point on the stem where the valve is fully open and the stem has retracted into the head as far as it goes.
In other words this gooey gel gathers where the travel ends and where the seal ceases wiping the stem.

My observation was this gel could possibly coke if one were not using synthetic oil, but its on the stem not the seat or back of the valve head (so who knows if this would cause a problem).
However as it was in my case the gel was easy to remove.
Since the build up was not very large I assume once the glob gets to a certain mass or weight it falls off and gets sucked into the engine and burned.
The other thing I noted is my oil consumption is only about 1/4th qt or so between oil changes using the oil life monitor for oil change intervals.

Sorry I didn't take photos.
But knowing what coking valves look like, I wasn't concerned when I saw my valves at 70Kish miles with the oil consumption I have.

JMHO .....YMMV.

[EDFHOBBIES]

Mine will be off Monday interested to see..

[Pollock]

Make sure you are using Top tier rated fuel. The mechanic I was talking to said that helps too.

Edit: I also cant remember what the technical term is but you get carbon build up when both the intake and exhaust valves are open at the same time. That is something a catch can wont help.

[Gunkk]

Originally Posted by Pollock

Make sure you are using Top tier rated fuel. The mechanic I was talking to said that helps too.

Edit: I also cant remember what the technical term is but you get carbon build up when both the intake and exhaust valves are open at the same time. That is something a catch can wont help.

You're probably referring to Atkinson cycle engines, which keep the intake valve option for a portion of the compression stroke, which reduces the effective compression ratio and results in a slightly more efficient cycle due to less losses from compression work (at the expense of total power output).

Combining Atkinson cycle & GDI is not only a waste of effort because fuel can be controlled directly, but it's disastrous for valve buildup.

Atkinson is useful in non-GDI hybrids where efficiency matters more than power, and the electric motor can cover the gap.

[k20attack]

Originally Posted by Gunkk

Nope. None that I've found. I found only one anecdotal report @ 70k miles, mentions soft "gooey gel" on the stem but no buildup on the valve, no pictures in the post, but you can read up for yourselves:

reference: https://www.corvetteforum.com/forums...post1597562696

copy/paste:

Thanks. For all of the talk about valve cleaning sprays and catch cans you'd think we'd have a treasure trove of evidence showing how the LT4 cokes up to high hell. Hopefully someone will get some proof in pictures on this forum soon. I've been debating doing a catch can, but without some unbiased proof (not from a catch can MFG), I'm not sure I can pull the trigger.

[Subcool]

I asked this question in another catch can thread with no response, my tuner showed me a piston that was damaged pretty badly from a catch can check valve failure and the ball check sucked into the engine, has anyone else heard of this happening?

[Alain]

Originally Posted by k20attack

Thanks. For all of the talk about valve cleaning sprays and catch cans you'd think we'd have a treasure trove of evidence showing how the LT4 cokes up to high hell. Hopefully someone will get some proof in pictures on this forum soon. I've been debating doing a catch can, but without some unbiased proof (not from a catch can MFG), I'm not sure I can pull the trigger.

Give it time. Two reasons why I think we haven’t seen many pictures of build up.
1- the LT4 hasn’t been in the Camaro for very long. I’d be curious to see if on the corvette world There has been more documentation since they have had the LT4 for longer.
2- you have to do some seriious dissasembly to be able to get to the valves and take some pics. That’s not something most people are going to do often. So hard to take pictures.

Originally Posted by Subcool

I asked this question in another catch can thread with no response, my tuner showed me a piston that was damaged pretty badly from a catch can check valve failure and the ball check sucked into the engine, has anyone else heard of this happening?

I’ve never heard of this. Which catch can company was it?