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Discussion Starter #1 (Edited)
i would like to get a consensus about cleaning the intake manifold.
i have read several posts about the use of seafoam and other chemicals and others that do a whole disassembly of the intake manifold.
i can see the chemical approach as being more benificial as it gets all through the system more or less.
i also have a few questions about the use of these chemicals. do they have any affect on the catalytic converter as they go through?
i ask because i removed the top cover plate off my manifold this am as i was curious to see its condition( 04 and 60K miles)i expected a certain degree of dirt but did not expect to see small pools of dark almost oily fluid. i could not determine if it was engine oil but definitly not fuel. would like to know what and where that came from.
anyone?

thanks
pete
 

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I believe the oily gunk is actually motor oil that gets past the PCV. I soaked it up with small wads of paper towel. The amount was small enough (1/4 cup total?) that I doubt it would have hurt anything had I left it. Changed the PCV.

The top plate of my manifold was nearly clogged with crusted sooty stuff. I had to manually scrape out the channels with a dental tool. Carb cleaner didn't touch it. As bad as it was, I doubt Seafoam® would have had much effect. If you just have a small amount of oil and some varnish build-up, Seafoam might be worth a try. It won't damage the catalyst.
 

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We have an 01 and I just cleaned the intake manifold for what I think is the first time ever. We just bought the van a few weeks ago, it's got 110k miles.

Anyways, so I pulled the intake manifold off to do the EGR cleaning and cleaned the intake manifold out at the same time. It's pretty normal for there to be a lot of gunk in the intake manifold, especially after some miles. Ours was caked with oily nasty gunk. It was somewhat wet so it must have been a combination of oil vapors and other junk that's gotten in there over the years. I had to take two cans of carb cleaner to it in order to clean it completely. I sprayed it down, hosed it off, sprayed it down, hosed it off etc. I had to do that like 6 times before I got it all the way clean. That junk doesn't come off easily and I don't think you'd be able to get it clean without removing it and taking your time cleaning the every passage out.
 

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Discussion Starter #4
thanks,,appreciate the quick replies.
i guess a general clean up is in order then ( but perhaps not necessary) i figured that the fluid accumulation was a result of the egr system, so thanks for reassurance of that. i wonder, did you notice any problems prior to cleaning the manifold that prompted you to clean it, or was it a gee whiz thing?
 

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I cleaned ours because the van was hesitating a bit while trying to maintain speed with light throttle, classic symptoms of the EGR passage clogging issues.

So I took it apart to clean the ERG passage and cleaned the whole intake manifold at the same time.
 

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labattsipa said:
t. i wonder, did you notice any problems prior to cleaning the manifold that prompted you to clean it, or was it a gee whiz thing?
In my case it was a holy crap! thing. I was buttoning things up after a valve clearance check and noticed the deposit. The van ran fine prior, but I bet we weren't far from something like LincolnW experienced.
 

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Discussion Starter #7
just so we know what im looking at. here is the manifold with the top cover off. please note all the build up on the metal gasket
 

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Discussion Starter #9
and this is the bottom side of the cover plate. note the carbon buildup.
 

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Your top plate actually looks much better than mine did. The channels had build-up on all 4 walls like a narrowed artery. My gaskets had some pitting and corrosion, so I replaced them. This was at about 102,000 miles.

The fluid in your manifold seems similar to what I had.
 

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Thanks guys for the photos. I've been dreading doing the EGR ports on my 2002 with 149K miles. Changed the EGR valve after P0401 since it was the easiest to do. Most posts refer to the earlier manifold with little on the later ones. Looks like I might just get by by pulling the top plate and doing a little scraping.....
 

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Just removed the top plate last night. The EGR passages look just like the photos, completely clogged with black crust gunk. The ports themselves were almost 100 closed off and the EG port (hole in the bottom of the well towards the throttle body) was full of crud as well. Used a vacuum cleaner and x-acto knive to clean out the crud. Wire brushed the gasket since I didn't have a new one. This was certainly the P0401 problem although I haven't driven it enough to know for sure just yet. Does anyone know how the computer knows that EGR flow is low? I couldn't find anything about the logic in my manual. This EGR passage cleaning should be regular 50,000 mile maintenance item. Hats off to the Honda engineers for making this such an easy job compared to the earlier manifold design.
 

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Discussion Starter #13
of note;
im trying an experement on this right now by running 2 cycle oil with my gas.
there have been some threads on this using synthetic TCW3 2 cycle oil as an additive in ratios of 1 oz to 5 gallon of gas.
based upon the research/hearsay this additive have benificial results when added to your gas, including restored power, lubrication of the top end, fuel system and cleaning of the ring packs and reversing the effects of carbon build up in the engine.
it does not damage the cat or the ox sensors.
when i pulled the top place off my intake manifold i only cleaned the bottom of the cover plate and the metal gasket (by the way, those that remove the gasket, make sure you put it back on in the correct orientation).
i have run 5-6 tanks of gas thru my car since i started with the TCW3. i plan to remove the cover plate again here in the near future and see if the egr is is cleaning up on its own.
 

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I wouldn't expect the two-stroke oil to do any good. Condensation of vapors in the exhaust gasses is inevitable once they contact the relatively cools surfaces of the manifold and cover plate. Thankfully Honda made this easy to clean out. By the way, I've gone two trips now without a P451 code! The two stroke oil might provide a little upper cylinder lube so the bores will now last 550K miles vs. 500K miles without. The TCW oils are really made for bearing lube in two strokes that do not have pressurized oil systems for the bottom end. They work really well at that while resulting in minimal (but not zero) build up of carbon around the rings. Now to start running down my P453 code..........
 

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Discussion Starter #15
tell ya what, go over to ls1.com and read up on a thread called "been testing" it has about 35 pages to it on the TCW3 issue.
look into it and see what you think.
pete
 

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Does Labatts make an IPA? Never heard of it down here. Anyway, I still stand by what I've said. Observations of cleanliness in two strokes would be due to the fuel/oil mix being inducted into the crankcase. The gas keeps it clean under there (remember when we used to wash our parts in gas?). The two stroke oil is designed to lube and then burn with little residue (ash they call it) which can stick the rings (death to a two stroke). Two strokes still get deposits that must be removed over time but they are much better than they used to be. Check out an ultralight aircraft forum to see how much they worry about burnt oil residuals and ring sticking. I used to fly a Rotax powered one. No reason to expect cleaner EGR runners. It was interesting to see that the oil might have some beneficial effect on fuel plumbing for old cars by cancelling out the the alcohol effects. I would expect Honda engineers to select alcohol compatible hardware for anything built recently. Still, who knows, many people perceive good things with the oil, including a close friend of mine. I still think it is about as beneficial as taking one a day vitamins.
 

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Discussion Starter #17
yes, labatts used to make an IPA, but not in a long time. clear bottle and it was good.
the TCW3 is ashless so no residue by what im reading.
the claimed benifits are cleaning of the ring packs so better or renewed compression, lubrication of the top end, fuel system ( injectors). the mix ratio is so low, 500:1 that the oil is virtually completly burned, ashless, and no reports of oxygen sensor fouling or cat.
this is not claimed to be a miracle in a can by any means but more of a preformance renewer and another way to perhaps cheaper or for those that prefere to monitor for them selves and have more control over what is in their tank.
one person described the gas sold to day as being very "dry" as in there was none or little pressance of effective additives that would have a real benifit.
like i said, plently of good reading available on this subject.
pete
 

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labattsipa said:
i plan to remove the cover plate again here in the near future and see if the egr is is cleaning up on its own.
Hey labattsipa - just curious if you had any further information on this front?
 

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Discussion Starter #19
i did pull the cover plate off and there was still crap in there, so far everytime ive pulled the cover off, i clean it and the gasket.
the carbon build up as far as im concerned is not drastic, but what looks to be normal. does this action of adding the TCW3 help to reduce it?
i can't see any evidence of it, but the TCW3 does help in other areas that are benificial. the clean up on the intake manifold would have been a bonus
 

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EGR Port Cleaning on '02 Ody

Pulled the plenum cover off today for the first time and cleaned the EGR passages on our '02 Ody with 140K miles. The ports and passages were still open, but not by much. We were getting a slight surging at idle, and this seems to have eliminated it. Expect to use at least one can of throttle body cleaner along with a small screwdriver and a brass brush. I cleaned the metal gasket and reused it without a problem.

There was a little oil on the inside of the plenum chamber, but I just soaked it up with an old rag and cleaned off the residue with the throttle body cleaner. Overall a very easy but necessary job.
 
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