Warning: Try to avoid cutting the egr. Very difficult to repair. Try heating the egr nuts red hot with mapp gas.(essential) Also, use something other than wd40 as penetrating oil. I found it impossible to use a pipe wrench with the exhaust maniold in place. If your nut is orientated right it might work for you. It may be easier if you loosen the manifold bolts and move maniold. Obviously, dont use pipe wrench unless nut is completely rounded.

Introduction

I cut my EGR pipe to get exhaust manifold off because someone told me high temp hose with clamps could repair this. Turned out that the EGR is too hot and turns hose into charcoal. Here, I discuss using silver solder and copper coupling to repair pipe. Silver solder would be good for cracks etc in the egr pipe.

Silver solder repair of EGR pipe:

Tools

-Mapp gas $12
-stay-silv white brazing flux $8
-braze 452 handy and harmon 30 grams 45% silver $25
(you could try silfoss off ebay as it is cheaper but needs higher temperature. you dont need flux with silfoss. silfoss fills much easier
Plumbing solder cant be used as it melts at low temperature)
-self igniting nozzel. you need the newer kind that have a more controlled flame. no name brand $22. the conventional type extinguish if tilted too much.
-3/4 inside diameter copper coupling from hardware store( some type of brass might be a longer lasting material). This size is easier to pinch at top vs a closer fitting coupling .
((outside diameter of egr is .68 inches)
-Mirror with extention
-steel wool

technique

There is no copper pipe or couplings that are the right size so I used a 3/4 inch copper coupling. It is essential that the coupling have a tight fit or the solder wont migrate into the crack by capilliary action. I used locking plier to squeeze the copper tightly around the egr pipe and pinched it off at top.
Be sure to use the right flux. I concentrated heat on the egr pipe as it seemed to take longer to get to the right temperature. It will be cherry red before it is hot enough. I overheated the egr pipe several times and it did not seem to get damaged at all. I removed the exhaust heat shield and aiv to make room. It is really quite hard to solder with the egr in the car. For one thing, you cant see what you are doing. However, i had no trouble avoiding burning anything.

If you can get the egr pipe out of the car to solder it, it will be quite easy to repair. Once the exhaust manifold is out of the car, it should be easy to use a pipe wrench to get the truncated egr disconnected from manifold. The other end of egr is held on by 3 12 mm bolts. You will need 1/4 inch universal joint and an extention to get at one bolt . Some people have to get the bolt red hot(gas lines in the area so not advised) to get it out as you are not getting much leverage with the 1/4 inch extention.

Practice piece:

soldering technique

definitely an art. everybody has there own technique. the main action is capilliary whereby the solder seeks to penetrate the crack. there is also gravity which ensures the solder moves to bottom. I just heat the pipe ie the egr pipe. You dont really have to get fancy with heat distribution but you need the right level of heat. test for right temp by seeing if solder melts. The flux is also important as the solder travels on the flux. It definitely takes practice.

random pics

Tools to get at 12mm egr bolt

EGR Links

EGR plug part number

http://www.autoshop101.com/forms/h61.pdf

EGR smog

EGR plug smog

EGR operation explained

The EGR's purpose is to send small amounts of exhaust gas into the air intake to lower combustion temperatures at certain times. The EGR system is comprised of the EGR valve, BPT valve, and EGR solenoid. The EGR valve is the valve that allows the exhaust to enter the intake when the BPT valve sends a vacuum signal. The BPT valve has a small tube at the bottom that senses the exchaust gas pressure. Whe there is exhaust pressure lifting up on the valve , a vacuum signal is sent to the EGR valve. The EGR solenoid allows the ECU to shut off the vacuum signal during sit does not want exhaust in the air intake.

Cleaning the EGR

You will need carburetor cleaner and metal pipe cleaner or coat hanger or electrical wire to clean the carbon. The picture below of EGR shows how the exhaust flows through the EGR . It also shows the orifice where exhaust flows through small tube to bottom of BPT valve. These passages should be cleaned. The area where the exhaust flows into the intake should be cleaned as well. You may also want to clean the BPT filters.

EGR theory

amen @ clean the passages too
you can use a hanger, and it's only carbon, trust me there's a s*** ton more on the tops of your pistons i'm sure hahaha use carb cleaner, brake cleaner will work but is not o2 sensor safe, so use carb cleaner

egr valve dilutes your cylinder head temp by recirculating exhaust gas back into your intake. you're thinking "exhaust gas is hot, how the hell does it lower my cylinder/head temps?"..temperature wise it is "hot" but in comparison to your combustion chamber it's not. just like your anti-freeze would burn the s*** outta your skin...but it cools your motor, same thing. but anywho, the unburned fuel and other mixed gases in it helps cool your cylinders and reduce the chances of spark knock aka DETONATION. the hotter the cylinder temp, the more nitrous oxide (harmful gas aka NOX) is produced. therefore your egr valve and your catalytic converter work hand in hand to lower your NOX readings. for driveability and emissions purposes egr valve is a good thing. for performance purposes,where emmissions don't matter, delete egr and replace with intercooler and good tune =]

if you've ever looked at a nissan throttle body, it has coolant flowing through it. it does that to raise the intake air temp so your car doesn't run as lean. lean = power but lean also = heat, the extra fuel aka RICH cools the cylinder wall. running rich is safer than running too lean. anywho the car running lean heats up the cylinders and thus create NOX. on a performance motor , you want the air the engine ingests to be cool/dense, that's why there's intercoolers, and cold air intakes etc etc. anywho, hope you learned something :P

Modified by vancouverbc at 2:54 AM 4/21/2009

Modified by vancouverbc at 2:52 AM 5/25/2009