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Simple question (maybe), can I spray carb cleaner into the port that the EGR valve mounts to? There is visible carbon build up that can't be good. Where would it drain to? Thanks. Rob

 
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03 civic.....

What problem are you trying to fix?
People don't just wake up one day thinking "I'ma gunna take dat derr thing offn hear an has me a lookiesee!"

Everything in the intake side of the EGR ports will end up going into the intake, and therefore into the engine.

 
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gearbox had posted a tuneup mod a while ago with a number of things that a novice such as myself could accomplish, the EGR valve cleaning being one of them. it was filthy, below the valve looks even worse, hence my question. I can't imagine it is good for the car to have that amount of soot. Not trying to solve any problem necessarily, just learning my car. Any thoughts on the question?

 
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The EGR valve passes hot exhaust into the intake manifold. There WILL BE carbon, no matter what.

Whatever carbon you can see at the valve itself is minimal. The major amount of problem carbon buildup occurs where the EGR passage(s) dump into the open intake chamber. When you have a problem, the problem will be there, not at the valve (unless the valve is stuck).

Your question: You can spray cleaner in where the valve mounts, but it will end up going into the intake. So will any carbon that comes loose, right along with it. If you go nuts with liquid, you can cause bigger problems for yourself, so be careful. The engine will run bad until the liquid is cleared out too, so expect that when you fire it up.

Also, no spray products I have ever tried can clean the carbon. I always have to scrape it by hand, use a roto-rooter tool, or BURN IT OUT. I also never have time to wait around for results.

The main priority when cleaning the EGR system is for there to be FLOW, and that it is evenly distributed to all cylinders (if the manifold is that type). It can still flow fine with some carbon buildup. But when carbon chokes off sufficient flow--that is when problems and codes start.

If you don't have a P0401 code, or a misfire at steady road speed that is CAUSED by the EGR, I wouldn't be messing with it. But then again, I don't have time or get paid to mess around.

Edit: I didn't see the video

 
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So there are two ports under the egr.... a goes-in-ya and a goes-out-ya. The one closests to the front of the car comes from the exhaust, the other goes into the egr passages then to the intake.

See #7 in the image. That contains the egr passages that distributes the gas evenly to all 4 cylinders.



Now look at this....


See the black circle in the bottom right.... that is where it goes. That is the port coming out of the head from the egr valve that goes into #7 from the first image. See all that black stuff on the intake for the #4 cylinder.... it's all black goo. Sticky carbon from me spraying carb cleaner down the egr port. The carbon was there and isn't the result of me spraying carb cleaner down the port, but it turning into a goo likely is.

That's a fairly sized hole(the ports under the egr). Atleast relative to the size of the egr passages. As ezone said, the passages are likely to clog first. Just clean the valve and be done with it. Remember, it is exhaust gas going thru there.