EGR Replacement
Thread Starter
Racer
Joined: Jan 2007
Posts: 322
Likes: 0
From: Chapin South Carolina
EGR Replacement
I have a new EGR but I have never taken the plenum off the car. I noticed the Torx screws and looks like several gaskets to watch out for. Any advice would be greatly appreciated....
Corvette Enthusiast
Joined: Oct 2007
Posts: 6,793
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From: So. Cal.
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plenum.
Should not be too difficult. If I remember correctly, (at my age this is an issue), one of the torqes bolt is a different lenght than the rest. Thats the only issue I had when I had mine off. 
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Any advice would be greatly appreciated....
-be very careful with the solid plastic vac lines as they can get very brittle over time
-remove the TB from the plenum; this is a good time to do the TB coolant bypass mod so you won't ever again have to drain coolant just to remove the TB
-remove the plenum bolts and smack the plenum with a rubber mallet to loosen it
-label from where each plenum bolt came
-use some PB Blaster on the EGR vavle bolts before trying to remove them
During assembly:
-you may likely be able to reuse the old gaskets but a Fel Pro Top End set from AutoZone is not a bad idea
-hand start ALL plenum bolts before applying a wrench to avoid cross threading
Melting Slicks
Joined: Apr 2002
Posts: 2,118
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From: St. Charles, MO Route 66 Corvette Club
Here are some additional details on pulling the plenum on early C4s. Follow steps 1 thru 12.
http://webpages.charter.net/buddiel/...al)%201-04.doc
I hope this is helpful to you.
http://webpages.charter.net/buddiel/...al)%201-04.doc
I hope this is helpful to you.
Thread Starter
Racer
Joined: Jan 2007
Posts: 322
Likes: 0
From: Chapin South Carolina
Should I unbolt the pipes from the top plenum piece or unbolt the pipes from the throttle body? I realize I may not calling things the correct name. I am working on learning the correct names, so please feel free to correct me.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
OK:
-intake base: sits atop the engine and bolts to either head
-runners: sit atop and bolt to the intake base and bolt to the Plenum
-Plenum: sits atop and bolts to either runner
-TB: bolts to the front of the Plenum
There are (4) bolts holding the TB to the front of the Plenum and (I believe) (4) Torx bolts holding each runner flange to either side of the Plenum.
There is a hard plastic vac line under the bottom of the TB and one to the RH side.
There are two vac lines to the RH rear side of the Plenum, the metal break vac line to the LH rear of the Plenum and an electrical connection to the MAT connector under the rear of the Plenum.
I'm not sure what you mean by the "pipes"??
-intake base: sits atop the engine and bolts to either head
-runners: sit atop and bolt to the intake base and bolt to the Plenum
-Plenum: sits atop and bolts to either runner
-TB: bolts to the front of the Plenum
There are (4) bolts holding the TB to the front of the Plenum and (I believe) (4) Torx bolts holding each runner flange to either side of the Plenum.
There is a hard plastic vac line under the bottom of the TB and one to the RH side.
There are two vac lines to the RH rear side of the Plenum, the metal break vac line to the LH rear of the Plenum and an electrical connection to the MAT connector under the rear of the Plenum.
I'm not sure what you mean by the "pipes"??
Thread Starter
Racer
Joined: Jan 2007
Posts: 322
Likes: 0
From: Chapin South Carolina
Thanks that helps a lot. Do I unscrew the intake base from the plenum or the intake base from the engine? It looks easier just to unscrew the intake base from the plenum but I don't want to hurt anything.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
65Z01 has given good info.
You will want to remove the 8 torx bolts (4 on each side and T40, IIRC) from the plenum (the aluminum piece that the throttle body is mounted to). Just use a rubber hammer to jar it loose from the runners. You will have to remove the brake booster line, all the throttle body lines, throttle cable bracket (three 10mm bolts), and the MAT sensor connector. Once the plenum is off, you will have access to the EGR and inspect the runner to plenum gaskets to assure they are not torn (there are tabs that stick out of the gaskets and can easily be bent or torn). If so, you will need to replace them because they can cause vacuum leaks. You may need a special Crowfoot wrech to take the two EGR bolts out.
You will want to remove the 8 torx bolts (4 on each side and T40, IIRC) from the plenum (the aluminum piece that the throttle body is mounted to). Just use a rubber hammer to jar it loose from the runners. You will have to remove the brake booster line, all the throttle body lines, throttle cable bracket (three 10mm bolts), and the MAT sensor connector. Once the plenum is off, you will have access to the EGR and inspect the runner to plenum gaskets to assure they are not torn (there are tabs that stick out of the gaskets and can easily be bent or torn). If so, you will need to replace them because they can cause vacuum leaks. You may need a special Crowfoot wrech to take the two EGR bolts out.
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Racer
Joined: Apr 2006
Posts: 419
Likes: 1
From: Kelso WA
No need to remove the runners from the intake, just undo the 4 bolts on each side that hold the runners to the plenum (3 across the top and one on the bottom). The hardest part for me was removing the bolt on the EGR valve towards the back of the engine. I ended up having to bend a box end wrench as the bolt was too rounded off to use an open end. I also couldn't use a 12 point box end, had to be a 6 point. I went to Sears and bought the wrench individually, then put it in a vise and bent it in a couple of places until it worked.
I also used a vacuum to suck all the carbon out from the intake below the EGR valve. I did not remove the throttle body, either. Just undid everything connected to it and removed it with the plenum. The FSM says to replace the plenum to runner gaskets, but I don't think that's necessary as long as yours are still in good shape.
I also used a vacuum to suck all the carbon out from the intake below the EGR valve. I did not remove the throttle body, either. Just undid everything connected to it and removed it with the plenum. The FSM says to replace the plenum to runner gaskets, but I don't think that's necessary as long as yours are still in good shape.
