I am sitting here in front of a nice new Cadillac Deville I purchased and I was told that the EGR Valve is failing. So I thought to myself how to replace the EGR Valve in a 2004 Cadillac Deville? So here is what I researched and found.
- Disconnect the vehicle’s battery
- Disconnect the wire harness plug on top of the EGR valve.
- Then use a 10 mm deep well socket to take off the two nuts holding the heat shield in place
- Take the two bolts out that are below the two nuts.
- Once you do this you will be able to lift off the EGR valve.
Are you needing this part? Check out my store I put the part that I found and used on my project from Amazon. Do you need to know How to replace the EGR Valve in your 2003 Cadillac Deville? Follow the step by step guide to the end, and you will be done before you know it!
Tools needed for this repair
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- Ratchet (½” or ⅜” will do the job)
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- 6-inch extension
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- 10 mm deep well socket
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- Putty knife
Are you needing one of these tools added to your collection? I went ahead and added them to the Tool Catalog for you. I found the tool on Amazon and have checked the reviews and quality of the set.
What does an EGR Valve do?
With vehicle exhaust regulations increasing daily, the creation of an EGR valve or an Exhaust Gas Recirculation valve came to be. The EGR valve on your vehicle recirculates the exhaust gases that create the formation of smog in our atmosphere. So to prevent the creation of these gases, the valve recirculates those gases back into the combustion chamber. This process decreases the combustion temperature in the cylinders.
By lowering the combustion temperature, this decreases the amount of 
smog-producing nitrogen oxides that your vehicle exhausts. When an EGR valve is failing this process cannot take place, which then prevents the EGR Valve from recirculating the gases, and it will not decrease the combustion temperature.
This process will let the vehicle release the average amount of nitrogen oxide into the atmosphere, creating smog.
In the states that perform a smog test on your vehicle before it can pass inspection to register your car, a failing EGR valve will make you fail this inspection.
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Where is the EGR Valve located on the 2004 Cadillac Deville?
With the 2004 Cadillac Deville having the Northstar V8 engine in it. You are going to find your EGR Valve located left of your brake reservoir. You will need to take the Cadillac cover off to access the EGR Valve. Here is the manual I used for all of the torque specs I needed for this repair.
You will need to pull up on the cover; it does not have any bolts holding it in; it is just pressed on to its mounting bolts. The picture to the right shows the area your EGR Valve is located in circled in red.
When can I tell my EGR Valve is failing in my Cadillac Deville?
EGR Valves are just like any part of your vehicle and have the possibility of failing over time. With the job of the EGR Valve being recirculating exhaust gases this increases the chance of carbon build up in the part, and making it difficult for the EGR Valve to do its job. So how can you tell if your EGR Valve is failing?
First of all, you will receive a check engine light, and a code will come up on your vehicle, that code is the dreaded P0404 Exhaust Gas Recirculation (Your EGR Valve is stuck open). The engine codes that are a part of the P400
series all deal with your EGR Valve. If the check engine light comes on and you do not have a code reader take your vehicle to the nearest auto parts store like an O’Reilly’s or AutoZone etc., and they will be able to read what code is making your engine service light come on. Your vehicle can also have a rough idle, reduced power, and a reduced fuel economy due to the EGR valve failing.
You will also be getting a clanking and pinging from your EGR Valve. Remember any time that you hear something that doesn’t sound right on your vehicle you need to track that problem down ASAP! If the clanking or pinging is coming from your EGR Valve, then you found your culprit.
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Why is a bad EGR Valve bad for my car?
Your vehicle will receive a decreased amount of power if you have a bad EGR valve. The engine can stall and hesitate on acceleration, so overall your car will not be running at its peak performance due to the failing EGR Valve. This repair can also run around $260 to $350 if you take it to an auto repair shop to diagnose and repair.
So if you feel comfortable completing this repair yourself, I highly suggest you complete the repair yourself to save some money. If you are already reading this, then you are more than comfortable with working on your vehicle. So save yourself some money and complete the repair yourself.
Are you needing this part? Check out my store I put the part that I found on Amazon and used right there on my project.
Should I replace or clean my EGR Valve?
In the process of cleaning your EGR valve, you can use some carb cleaner from your local auto parts store. A can of this carb cleaner can run you in between $4 to $6 depending on the brand you pick.
A new EGR valve online will run you in between 35 and $40, but if you go to a junkyard or a Pick-n-Pull, you can get this part for 10 to $15. Also cleaning your EGR valve can buy you a little bit more time but does not guarantee it will work to 100% of its capabilities.
So since you are already saving a considerable amount of money by doing this repair yourself. I suggest you buy the new EGR valve online to prevent any malfunction of the part in the near foreseeable future.
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Is there anything I need to remember when reinstalling the EGR valve?
When reinstalling the EGR valve back onto your car, remember to replace the gasket that was below the EGR valve. This gasket is in the shape of a large diamond and can only be installed one way. This helps all of us out, especially if you are doing this repair after a long day of work or it is nice and hot outside.
Remember before putting the gasket on taking a putty knife and scrape the old gasket off. This will make sure that the new gasket has a solid seal on its aluminum base. When you have the new EGR valve installed, make sure you reconnect the battery and clear the service engine light code so you can take a test drive to make sure that the problem has been solved.
As long as everything is tightened and the vehicle handles great on the test drive, that completes the replacement of your EGR Valve, great job!!
Thanks for checking out my article everyone and I hope it helped you out with your Cadillac! I hope to see you in my next article!
