| mdxforever |
| How did that oil get in there ? seems to be accumalating more on the left side than the right. |
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| mdxforever |
inside of the cover and gasket..
yeah did clean the exhaust residue (black crust) on the grooves in the cover, the gasket, in the "U" shaped inlet on the right and the holes on top of each intake tunnel. |
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| m2pc |
| Looks like it is coming from the holes with the crud. Those are intake ports? |
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| SuperTech |
| Oil accumulates in the intake from oil vapor in the PCV system. |
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| DaleB |
| What mdxforever is doing came up some time ago as a good 'mid-life' maintenance thing to do if you are handy. A couple of people who did it claimed the eingine seemed more responsive and/or smoother afterwards. |
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| mdxforever |
quote:
Originally posted by SuperTech
Oil accumulates in the intake from oil vapor in the PCV system.
There you go..I knew SuperTech will have an answer.
shouldn't the gasket be preventing this from happening though ? I guess I am just trying to find out if this much amount of oil is normal or something to do about. |
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| SuperTech |
| The oil is normal. Every engine gets a buildup of oily grime in the intake. It pools up like that in the low points over time. I wouldn't worry about it. |
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| SuperTech |
| I'd be curious as to just how much of an improvement that actually makes. That catch can will not be able to seperate all the oil from the vapors, so it'll still be getting in. |
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| ryandinan |
I apologize for resurrecting and old thread, but I do have a question...
Can you clean and reuse the same intake cover gasket? The only reason I ask, is because they're around $40 to replace.
If you can clean and reuse, what type of cleaner can be used safely, and what type of gasket sealer do would you apply, if any?
Thanks!
-Ryan |
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| ryandinan |
Well, I was inspired by mdxforever's post, and since I was tired of getting 17-18mpg averages (dropped suddenly from 21-22mpg), I decided to go ahead and clean my intake as well. Mine actually looked worse than his! Several of the grooves were completely blocked, and all of the intake holes were 50-90% blocked with carbon and sludge residue. :eek: - Reminds me of what plaque buildup in arteries must look like...
I basically sprayed some throttle body cleaner on each part, and let it soak. What was remaining, I scraped off with a screwdriver, and sucked up as much as I could with a shop vac. I used paper towels to soak up the pools of oil on top of the intake ports.
I also took the time to check the EGR valve (which seemed fine, as the plunger worked freely, and there was not much carbon buildup at all), as well as replace the PCV valve. The old had quite a bit of oily junk on the plunger, and just looked tired. I figured, for a $4 part, I might as well just change it out. The replacement had a bit different angle on the end (a 90 degree bend, vs. the 45 degree bend that the stock one had), but it didn't seem to make a difference, other than the fact that the hose had to bend a bit more to connect.
During this entire process, I disconnected the negative battery terminal to reset the ECM. Someone here mentioned that once the battery was reconnected, that you should allow the computer to set the idle speed by letting the car idle without load (no AC) until the radiator fans kick on twice. I did this, and then took it for a drive.
My MPG average for the same daily drive route climbed back up to 21mpg! Not only that, but the car runs SO much stronger now. No more surging during heavy acceleration, and it seems to have it's "oomph" back. I guess I should not be surprised, considering what the intake looked like... it was like the engine was trying to breath through pinholes... I think that the mpg may even get better, considering the ECM may need some time to learn my driving habits all over again.
The MDX currently has 96K on it, and it seems stronger than when we bought it at 45K... Not bad!
Thanks for the great thread!
-Ryan |
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| midnightMDX |
| Wow, good stuff! :D |
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| mdxforever |
| that's good to hear Ryan! |
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| oops |
| Ryan do you have astep by step instruction on how to do what you did. I hope you don't miond sharing it to us that would love to maintain our MDX. |
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| ryandinan |
I guess I should really clarify that I didn't clean the intake valves directly, but rather the intake cover, the area concealed below the cover, and the gasket (see mdxforever's pics). I believe this area is mainly for the PCV/EGR system?
When you take off the intake cover, you will see the cast valve ports (with those little holes on top of each one). I did not go any farther than this. I'm sure that if I unbolted further, and actually gained access to the intake valve ports, there would have been more to clean, but considering those ports are much larger, I didn't think the carbon buildup would have affected their function.
It was more the little holes on top of each valve port that I was concerned with, as they were VERY clogged up.
I basically just scraped and liquified the buildup with the throttle body cleaner, keeping the best of care to keep as much from falling down into the valves as possible, as I didn't want to make things any worse.
The one thing I wish I did, was replace the valve cover gasket (it's metal). I learned that it's a good idea to replace it if you unbolt the cover (I guess it compresses a bit?), although once mine was cleaned, it literally looked new. I didn't put any kind of sealer on it, as it didn't appear to have any to begin with. I also later learned, that the service manual calls for the cover bolts to be removed/replaced in a certain pattern - a procedure which I assume serves the same purpose as when you tighten the lug nuts on your wheels... Since I didn't do this either, I can only hope that it tightened adequately.
To gain access to the intake cover, all you need to do is remove the bolts from the plastic shroud (the one that says 3.5L VTEC ULEV on it) and take it off. You'll see the cast, dull metallic intake directly underneath. There are at least 10+ bolts to remove the intake cover. Try to remove them in a star pattern to avoid uneven pressure on the cover.
As for the PCV valve replacement, it is dead easy to do, but a bit awkward to reach. I'll have to take a picture to better describe where it's located (it's kinda centrally mounted, below the intake - has a rubber hose connected to it with a clamp) - but it simply pulls out of it's rubber boot. Slide the hose clamp down a bit to release pressure, and replace it with the new. It's just a simple plastic valve. The factory version has a 45 degree break in it - but the OEM replacement that I found had a 90 degree break. Apparently it doesn't affect the function. If you shake it, you can hear the plunger rattle around a bit (if it's not completely gummed up. It's hard to believe that such a cheap little part is responsible for such mileage/performance robbing ability...
Good luck! |
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| G. COLTON |
quote:
Originally posted by ryandinan
I apologize for resurrecting and old thread, but I do have a question...
Can you clean and reuse the same intake cover gasket? The only reason I ask, is because they're around $40 to replace.
If you can clean and reuse, what type of cleaner can be used safely, and what type of gasket sealer do would you apply, if any?
Thanks!
-Ryan
NOT A GOOD IDEA. You might get by with it, but more likely to have problems.
G |
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| Zrelaxed |
| What's the consensus on replacing the intake cover gasket? Looking across threads it looks as though many don't replace the gasket, and at least in one instance, a dealer recommended NOT replacing the gasket. |
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| mdxforever |
I did not replace the gasket and had no problems or leakage since then (2 years?).
Did not replace the valve cover gasket on the accord too when I took it off first time. no problems.
you could re-use crush washers (oil/atf) for a couple of times before replacing them. no problems there either.
so, from my experience its just a way for manufacturers and parts dealers to sell more. Now, to become the devil's advocate, when you take your car to a shop for an oil/atf change, how is the shop supposed to know how many times that crush washer has been used ? So they just change it everytime.
but then again how many times do you take the valve/intake cover off ? |
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| Zrelaxed |
With my CEL light on (multiple misfire codes) and my X stuttering under light acceleration @ 50mph and 20mph, I decided to open up the intake cover and clean out the EGR ports. They were incredibly clogged, many blocked. All it took was some carb cleaner and a small screwdriver. I did decide to reuse the old gasket (after cleaning it well). After putting her back together and resetting the codes, the CEL light has remained off and the stuttering is no longer.
Thanks everyone for your posts! |
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| midnightMDX |
| Nice, glad to hear it worked. |
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| Collie |
| Is there a specific torque spec on these bolts that hold down this access cover? |
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| highcountrymdx |
For a 2004 MDX, both the (12) 6X1.0 mm intake manifold upper cover bolts and the (4) 6X1.0 mm plastic manifold cover bolts are torqued to 8.7 lb ft, or 12 N.m, or 1.2 kgf.m.
There is no torque sequence for the plastic intake manifold cover, but the 12 upper intake manifold cover bolts are tightened in "two to three steps" in sequential order. Sorry, I don't have a scanner, but the sequence is basically a cross star pattern, starting with the bolt in the center right of the upper manifold cover. The last bolt tightened is the extreme right center bolt.
Try numbering bolts in clockwise order, starting bottom right as "Bolt #1", ending with bolt in right center of manifold as "Bolt #12":
Bolt #.....Tightening Sequence #
1...............9
2...............5
3...............3
4...............7
5...............11
6...............10
7...............6
8...............2
9...............4
10.............8
11.............12
12.............1
To keep track, get a Sharpie and mark the Sequence # next to the appropriate Bolt # hole. |
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| Collie |
| I appreciate the info. I have 10 fasteners and will apply the sequence to fit. |
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| wal92tt |
Your post inspired me to do the same. It took me less than 1/2 hour to do. I have an 04 and the cover looks much different though. Any way I can't find the pcv valve. I unplugged what looked like it but gas came out of it. Does any one know or can post a pic of it? Also, how difficult is it to change the plugs? I have about 75k on it. I changed the plugd on my wifes Fronteir and the last one on the rear was a pain. I tore off a few layers of skin off my knuckles and it took me 3xs as long as the whole job did. I do not want to go through that again. Is the MDX just as painful on the knuckles?
Thank you |
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| Markedoc |
| Thanks for the info on this thread by previous posters. Easy DIY and I cleared a lot of gunk out after 80k miles. |
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