Intake clean. WOW!

Dropsix · March 26, 2015

I just did a few squirts tonight. Engine is at 7000miles or 11000kms approx. didn't do as much as most of you. Just a few cycles of 10 seconds each. I figure I'll do it again every 10000kms.

Didn't chance anything for me and didn't expect it to but I believe in the concept and will do it as maintenance.

darkfox1 · March 26, 2015

I just did a few squirts tonight. Engine is at 7000miles or 11000kms approx. didn't do as much as most of you. Just a few cycles of 10 seconds each. I figure I'll do it again every 10000kms.

Didn't chance anything for me and didn't expect it to but I believe in the concept and will do it as maintenance.

Right.. you don't really WANT it to make a difference cos that means your engine was getting dirty inside. If it never makes a difference.. you're probably running much cleaner.

I figure you could PROBABLY make this part of your oil change procedure if you wanted to. CRC recommends it every 10k miles, maybe every 3rd oil change if you do 3k changes.

ToesonTheNose · March 26, 2015

Just a heads up to anyone going to do this after as many miles as I have on my truck (over 70,000km/45,000 miles). I was just doing some errands and I noticed my mileage decreasing big time, went from my average of around 20l/100km to almost 27l/100km and then I noticed my idle started to get pretty rough while in drive and stopped at a stop light. When I went to accelerate my check engine light came on.

I used torque to find the code, having a feeling a head of time what it would be and I was right. P0420 catalyst bank below threshold. Now I am not 100% certain the seafoam caused it, but I don't think I'm being unreasonable by assuming the free'd up carbon is now stuck in my catalytic converters.

I reset the check engine light and my mileage has dropped back down to 23l/100km just in the short trip home. I checked torque again when I got home and the truck hasn't finished runnning its test on that catalyst bank yet so I can't update on this. Luckily if it does come back it should be covered under warranty.

The other possibility is that I have an exhaust leak, hopefully they do not give me any grief about my welded on muffler if I have to take it in for warranty.

would like to hear more on this

nadrojcote · March 26, 2015

I'll update if it comes back.

Spurshot · March 26, 2015

I'm not a believer that at 30k miles the backside of the intake valves on these engines (one in good mechanical condition) will have buildup of carbon such that airflow is restricted. I think something in the flow sensing loops got cleaned and is working correctly.

nahulu77 · March 26, 2015

Just a heads up to anyone going to do this after as many miles as I have on my truck (over 70,000km/45,000 miles). I was just doing some errands and I noticed my mileage decreasing big time, went from my average of around 20l/100km to almost 27l/100km and then I noticed my idle started to get pretty rough while in drive and stopped at a stop light. When I went to accelerate my check engine light came on.

I used torque to find the code, having a feeling a head of time what it would be and I was right. P0420 catalyst bank below threshold. Now I am not 100% certain the seafoam caused it, but I don't think I'm being unreasonable by assuming the free'd up carbon is now stuck in my catalytic converters.

I reset the check engine light and my mileage has dropped back down to 23l/100km just in the short trip home. I checked torque again when I got home and the truck hasn't finished runnning its test on that catalyst bank yet so I can't update on this. Luckily if it does come back it should be covered under warranty.

The other possibility is that I have an exhaust leak, hopefully they do not give me any grief about my welded on muffler if I have to take it in for warranty.

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nahulu77 · March 26, 2015

Keep us updated with your situation, hope everything works out.

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Spurshot · March 26, 2015

There'd have to be a huge amount of carbon to plug the converters to the point of an error code. More likely, the Seafoam coated the catalytic surfaces of the converters or a sensor and caused the code. Some extended high speed driving may burn off whatever is in there.

Edited March 26, 2015 by spurshot

gone_fishing · March 26, 2015

I'm not a believer that at 30k miles the backside of the intake valves on these engines (one in good mechanical condition) will have buildup of carbon such that airflow is restricted. I think something in the flow sensing loops got cleaned and is working correctly.

I'm not sure if you saw my post of the intake valves on my engine Hard to say if there is enough buildup on the valves to affect performance but I would like to see less: http://www.gm-trucks.com/forums/topic/168709-intake-manifold-off-with-pics-of-intake-valves-with-deposits/

nadrojcote · March 26, 2015

It could very well just be some residue built up on the cats too, I'm taking a 250km trip tomorrow night. I'll be watching for it to come back.

Gmcant33 · March 26, 2015

I'm not sure if you saw my post of the intake valves on my engine Hard to say if there is enough buildup on the valves to affect performance but I would like to see less: http://www.gm-trucks.com/forums/topic/168709-intake-manifold-off-with-pics-of-intake-valves-with-deposits/

Did u take pics after the cleaning ??

Spurshot · March 26, 2015

I'm not sure if you saw my post of the intake valves on my engine Hard to say if there is enough buildup on the valves to affect performance but I would like to see less: http://www.gm-trucks.com/forums/topic/168709-intake-manifold-off-with-pics-of-intake-valves-with-deposits/

Hard to say for sure from just those pix. Did you see oil from the PCV tap, downstream, inside the manifold? I'm wondering if this could be a valve guide oiling issue with a little reversion spreading it upstream?

darkfox1 · March 26, 2015

I've torn down a few LSx motors and I've never sen valves look anything like that.

Pistons yes, but valves no. (they weren't direct injection of course..)

I know that if you have that much gunk on your throttle body it will stick, cause rough idle and other misc. problems though.

I would agree with spurlock it doesn't make sense to me that it improved as much as it did. A tangible difference in performance and fuel economy should not come from such a thing at only 30k miles. How much of it is in my head? How much of it is a switch back to summer fuel? How much of it is a change in my driving habits? Probably more of it than anyone gives it credit, but it's hard to measure those things.

I think the main takeaway, at least for me is even if it doesn't make a significant difference, if my valves look like gone_fishing's valves, or even half of that.. a $10 can of cleaner and ~20 minutes of my time (well ok more if you include the driving and all) is good piece of mind.

I'd also be more likened to believe the error code would be chemical and not a chunk of stuff clogging the cats. You'd have to have pretty big intake valves and pretty big chunks (thick ones too) to not be destroyed by the pistons. I mean think about what that chunk would have to do.. flake off the intake valve into the piston, survive the explosion, get pushed into the exhaust valve, survive the heat and pressure of all the other cylinders and make it all the way to the cat as a chunk large enough to get caught in the cat's "filter." Not impossible I'm sure, but probably less likely than a chemical soak on the o2 sensor.

That being said.. if the CEL comes back.. please let us know what, if anything.. the dealer does.I can't imagine they'd buck a warranty claim, even if they knew you ran a valve system cleaner.

Spurshot · March 26, 2015

All this got me thinking about getting a cheap borescope to check out my intake tract and valves. A little looking and I found a $30-40 usb scope that works with a laptop. I ma y order something soon.

BIG THUNDER II · March 26, 2015

All this got me thinking about getting a cheap borescope to check out my intake tract and valves. A little looking and I found a $30-40 usb scope that works with a laptop. I ma y order something soon.

Great idea! Keep us posted.