EGR Gasket (Page 1/2)
Notorio NOV 10, 11:51 PM
Hi All,

Working on my high NOx issue (88GT, 5spd). I took the EGR tube OFF to confirm that the gasket with the #11 orifice was installed correctly, that is, on the intake side, not the EGR side. Sadly, it WAS correctly installed. I have two replacement gaskets at present and the hole size is different: one is 6 mm and the other is 7 mm. Does anyone know what the #11 size is??

John
Notorio NOV 11, 02:22 PM
One other thing: I was surprised that some oily liquid was collecting on the gasket on the intake manifold side. My first thought was perhaps my pretty-new PCV valve was at fault. Thoughts?
Notorio NOV 15, 10:23 AM

quote
Originally posted by Notorio:

Hi All,

Working on my high NOx issue (88GT, 5spd). I took the EGR tube OFF to confirm that the gasket with the #11 orifice was installed correctly, that is, on the intake side, not the EGR side. Sadly, it WAS correctly installed. I have two replacement gaskets at present and the hole size is different: one is 6 mm and the other is 7 mm. Does anyone know what the #11 size is??

John



Good old Rodney. He confirmed for me that the size is 6 mm.

I'd still like to hear people's thoughts on the oily fluid ...
fierofool NOV 15, 07:38 PM
It could be that you have some blowby and it's being pulled in through the metal tube that runs to the intake snorkel at the throttle body. Check the rubber intake snorkel to see if you have oil there. Most intakes I've ever removed had a good heavy coating of black oily substance inside.
Kitskaboodle NOV 15, 11:01 PM
Pic provided for reference only. ( if this helps) (see attached pic below)
As an additional fyi, I had the small orifice egr tube gasket on the “wrong” end. (egr valve side)
Even after correcting this, my Nox numbers were still about the same. (I took it to get smogged again because I thought this was the culprit but it failed again with pretty much the same Nox numbers.
Kit
ArthurPeale NOV 16, 02:28 PM
Man, now I'm confused. I was going to order gaskets for my EGR system, and it looked simple enough, but if I'm understanding correctly, each end of the EGR tube has a different gasket.

And the valve assembly has a couple of different gaskets available? There's one with tiny holes, and one without, the body shapes are different...
PhatMax NOV 16, 03:22 PM
I believe the EGR Gasket has two different gasket is because there is a “spacer” block between the ear and the exhaust pipe.
I’m not sure why it makes a difference which end the smaller one with the restriction goes
ArthurPeale NOV 16, 03:41 PM

quote
Originally posted by PhatMax:

I believe the EGR Gasket has two different gasket is because there is a “spacer” block between the ear and the exhaust pipe.
I’m not sure why it makes a difference which end the smaller one with the restriction goes



Seems that Rock Auto only offers the one with the larger hole for the tube.

Where is everyone finding their gaskets?

edit - better yet, are there alternatives? We cobble stuff together all of the time, like using VW exhaust gaskets on the manifolds. Are there any gaskets that are "close enough" in terms of size of tube, and spacing of the holes?

[This message has been edited by ArthurPeale (edited 11-16-2022).]

Notorio NOV 16, 04:11 PM

quote
Originally posted by Kitskaboodle:
As an additional fyi, I had the small orifice egr tube gasket on the “wrong” end. (egr valve side)
Even after correcting this, my Nox numbers were still about the same. (I took it to get smogged again because I thought this was the culprit but it failed again with pretty much the same Nox numbers.
Kit



Kit, doesn't this suggest that your EGR system as a whole isn't working correctly? In your tests of components, the Solenoid works and the vacuum is sufficient to open the Valve. But given the same NOx results with the orifice in the two different locations, NOx is hardly effected. [I guess an alternative explanation is that the restrictive gasket gives the same exhaust flow regardless of which end it is sitting in.] This would mean the dire warnings about the intake side being the correct location are wrong.
Kitskaboodle NOV 16, 10:05 PM
If you check Rodneys site (egr section) and also the FieroStore, both will tell you that A) the small orifice gasket goes on the intake plenum side and the “normal” bigger hole egr tube gasket goes on the egr valve side. B) The reasoning for this is that IF you get a vacuum leak at the egr tube, the restriction will minimize the vacuum leak.
If you have the FieroStore egr tube, you can use the big hole gasket on both ends as the tube has a built in restriction already.
For the factory egr tubes (which have both ends the same hole size, this is when you need the restrictive gasket.
Kit