Hi,

My air intakes and EGR valve are caked with soot. Does anyone know why this happens and how to get rid of it.

Soot collects due to the normal diesel exhaust. Easiest way to get rid of it is to remove the EGR and block off the passages from the heads. A J code intake swap will take care off all that the cleanest way.

Soot is the main combustive byproduct of Diesel fuel - the 'richer' the injected fuel rate, the greater the soot in the exhausted gasses.

As mentioned, the Exhaust Gas Recirculation valve loads up the intake manifold on the emissions engines.

As noted above, the soot is from diesel exhaust passing through the intake manifold when the EGR valve is open.

Getting rid of the soot that is already on the manifold is tricky... You can try degreasing it, but it is hard to get the manifold completely clean.

Preventing more from accumulating is easy... Disconnect and plug the vacuum line that goes to the EGR valve at the EGR control solenoid (it is mounted on the top of the engine on the driver's side at the back - just follow the vacuum hose from the EGR valve and you will find it).

The best solution is to replace the manifold with a manifold off of a heavy duty (more than 8500# GVWR) truck. The heavy duty trucks were not equipped with EGR. A manifold off of one of those trucks will be clean and will stay clean because exhaust does not enter the intake if there is no EGR valve.

Hope this helps!

Merry Christmas! :)

I understand there must be some soot in recirculated exhaust.But this: http://www.dieselplace.com/forum/attachment.php?attachmentid=31107&d=1167021249
looks like a lot to me. I took chunks off with a spone.
I saw a pic of the air intakes in another thread and they were clean. I think that engine also had an EGR valve.

Merry Late Christmas

Yours is gray and dry, indicating the engine is running well - I'd be more concerned if it was wet, black, and nasty, like in the bottom of the intake runners.

That wet black is blowby vapors from the CDR.

Pull it, clean it with Diesel fuel, then hot soapy water - connect your water hose to the bottom spigot on the water heater in your garage for hot water rinse.

And don't forget to replace the EGR riser gasket, barely seen, there in your pic - look in Sticky 'parts point' to find the mystery egr gasket part number

Pinne65, your picture shows an EGR type manifold without the EGR valve that I can see. That would seem to allow an unrestricted flow of exhaust into the intake.

My intake manifold has the center round hole blocked with an EGR valve that restricts exhaust flow!

I understand there must be some soot in recirculated exhaust.But this: http://www.dieselplace.com/forum/***...7&d=1167021249
looks like a lot to me.

That looks pretty normal... EGR makes a mess. The intake in my truck is dirtier than that (although I disconnected the EGR the third day I had the truck - it was already dirty from 20 years of idling with the EGR on)

I can see from the pic that your truck has a little blowby (due to worn pistons and rings), but not enough to concern yourself with... Looks like a fairly average situation on an engine that is "broken in" a bit but isn't wearing out yet.

Pinne65, your picture shows an EGR type manifold without the EGR valve that I can see. That would seem to allow an unrestricted flow of exhaust into the intake.

My intake manifold has the center round hole blocked with an EGR valve that restricts exhaust flow!


I think the valve must have been removed after the air cleaner was off. The other picture had the valve installed. In addition, you can see that the surface where the valve mounts is clean. If it had been run without the valve that surface would be black and sooty like the rest of the intake.

Just remember to reinstall the EGR valve... Otherwise the truck will smoke black to a ridiculous extent all the time and will be very low on power.

Yes, I took the EGR valve off before taking this pic. And I will not worry any more.
Thanks for sharing your knowledge!