[ale379]

Hello All,

I have a 2001 Sentra SE 2.0L engine with almost 200,000 miles on it and I recently I got the P0420 code, not only that but after inspecting my car I noticed that it’s been burning oil. My oil level has been low for quite sometime and I’ve seen oil residue all over the engine, top and bottom. I have also seen drops on oil on the ground.
I immediately stopped driving the car because I didn’t want to cause the any more damage than what’s already been done.

By reading the threads about the P0420 code. Seems that the code leads to a bad cat-converter, which will have to be replaced. For some reason I cannot find online a replacement part, only through the dealer, which cost and arm and leg.

On top of code P0420 I got the code for the Knock Sensor.
Questions:

1. What can I do to alleviate the problem of burning/leaking oil? Is the burning oil related and knock sensor related to the bad cat-converter?
2. Where can I find a replacement converter for my Sentra? By looking at parts it looks to be the exhaust manifold that I need and I couldn’t find it online, just at the dealer.

Thanks in advance for any help.

 

[i68k]

you should be able to find a replacement cat, or pipe section with a cat, at any parts store. try rockauto.com, or partsgeek.com, this part should also be available at local parts stores.

the knock sensor is probably detecting knocks from internal parts that are lacking oil. your se2.0 doesnt have the same problems as the ser2.5. reason being, the ser2.5 does not have an egr valve, and compensates in valve timing, which can contribute to ingesting the ceramic material from the cat.

your p0420 on the other hand, most likely means you need a new cat, but you can check your exhaust for leaks, particularly around the o2 sensors. maybe even pull the o2 sensors, if youre leaking oil internally, its possible the o2 sensors just covered with oil. otherwise you will need a new cat since it takes readings from both working o2 sensors to determine a p0420

also, if oil is ending up on the ground, it is very easy to find the source of the leak, sometimes repairs requiring liquid gaskets can be a pain tho.

 

[ale379]

you should be able to find a replacement cat, or pipe section with a cat, at any parts store. try rockauto.com, or partsgeek.com, this part should also be available at local parts stores.

the knock sensor is probably detecting knocks from internal parts that are lacking oil. your se2.0 doesnt have the same problems as the ser2.5. reason being, the ser2.5 does not have an egr valve, and compensates in valve timing, which can contribute to ingesting the ceramic material from the cat.

your p0420 on the other hand, most likely means you need a new cat, but you can check your exhaust for leaks, particularly around the o2 sensors. maybe even pull the o2 sensors, if youre leaking oil internally, its possible the o2 sensors just covered with oil. otherwise you will need a new cat since it takes readings from both working o2 sensors to determine a p0420

also, if oil is ending up on the ground, it is very easy to find the source of the leak, sometimes repairs requiring liquid gaskets can be a pain tho.

i68K - Thanks for the response.

I will check what you suggested and report back.
I was looking at rockauto and partsgeek and other websites and they don't seem to have the front cat for my Sentra 2.0. It looks like I need an entire exhaust manifold which none of the parts stores have it, only the dealer. Is this one those cases where I could go with the catless header and do the ghetto sim thingy and relocate the O2 sensors or is it just for the 2.5 engines?

I'll talk to my mechanic and see if he can find where the oil leaks are coming from and also replace the knock sensor. I'll report back my findings for those that maybe in the same boat.

thanks fof the help.

 

[SportE-B15]

is the leak on top of the engine? I had to replace the valve cover gaskets and also replaced the distributor o-ring. Look around the edges and back of valve cover for leaks. You also would want to replace the pcv.
that stopped the leak for mine.

 

[ale379]

is the leak on top of the engine? I had to replace the valve cover gaskets and also replaced the distributor o-ring. Look around the edges and back of valve cover for leaks. You also would want to replace the pcv.
that stopped the leak for mine.

To be honest, I'm not quite sure where the leak is coming from. Everytime I look around the oil residue has already hardened due to the heat. I've seen oil residue all over the engine where the valve cover is, so I'm going to check on that and report back this weekend.

Thanks for the response.

 

[i68k]

best way is to power wash the motor, the right way! , so after you can see the new oil leakage. otherwise, find that fresh leak

im not positive about the 2.0, you would have to do some research on the catless headers, it can be done. you just need to figure out where the o2 sensors are going, i hear some headers only come with 2 bungs, and theres 4 o2 sensors. the safest way is to use the antifoulers on the secondary o2 sensors. the ghetto sim, antifoulers, etc are for a lot of different cars, not just a 2.5

you should have your mechanic test the knock sensor, from what it sounds, the knock sensor is working as it should. it may have just detected parts knocking because they didnt have oil.

 

[ale379]

best way is to power wash the motor, the right way! , so after you can see the new oil leakage. otherwise, find that fresh leak

im not positive about the 2.0, you would have to do some research on the catless headers, it can be done. you just need to figure out where the o2 sensors are going, i hear some headers only come with 2 bungs, and theres 4 o2 sensors. the safest way is to use the antifoulers on the secondary o2 sensors. the ghetto sim, antifoulers, etc are for a lot of different cars, not just a 2.5

you should have your mechanic test the knock sensor, from what it sounds, the knock sensor is working as it should. it may have just detected parts knocking because they didnt have oil.

i68K and SportE - thanks for the responses and suggestions.

I was able to figure out where the leak is coming from. According to my mechanic it comes from the valve covers and another seal at the bottom of the engine (don't know which one he was talking about).

As far a the catless headers - I've been doing my research and I haven't found anyone that has done it on 2.0 SE Sentra, only on the Spec V types. I searched this forum and other nissan forum and I couldn't find anything........ Have you come across on any catless header installation for a SE. 2.0?

Thanks.

 

[i68k]

make sure you keep your oil up to level.

the valve cover gasket is straight foreward, but your lower gaskets are probably liquid gaskets, and are kind of a pain to redo. if you do these yourself, take your time and do it right, so you dont have to do it again.

maybe you missed this thread?
http://www.b15sentra.net/forums/showthread.php?t=167963

if you get a catless header, and it has only 2 bungs, you can always bring it to a welding shop and have them install the othe 2 bungs in the correct location, or even weld the antifoulers on for you. otherwise, you may need to check a sr20 forum, they should have a few alternate methods for you to use.

 

[ale379]

make sure you keep your oil up to level.

the valve cover gasket is straight foreward, but your lower gaskets are probably liquid gaskets, and are kind of a pain to redo. if you do these yourself, take your time and do it right, so you dont have to do it again.

maybe you missed this thread?
http://www.b15sentra.net/forums/showthread.php?t=167963

if you get a catless header, and it has only 2 bungs, you can always bring it to a welding shop and have them install the othe 2 bungs in the correct location, or even weld the antifoulers on for you. otherwise, you may need to check a sr20 forum, they should have a few alternate methods for you to use.

Thanks for the info.

My mechanic is going to do this work for me so I'll tell him to his time in fixing the lower gaskets.

As far as the header, I guess I missed that thread. By reading in this forum and sr20 forum, it seems like everyone is satisfied the SSA Header. Is this the website that sells those headers?..... xx.ssautochrome.com?

Thanks.

 

[i68k]

im not positive where you can get the ssa header, i know markspecv sells headers for nissans, not sure about that particular brand tho. i know hes here, and on facebook.

 

[ale379]

im not positive where you can get the ssa header, i know markspecv sells headers for nissans, not sure about that particular brand tho. i know hes here, and on facebook.

thanks for the info. Before I buy the header and I went ahead a send a sample of my oil to Blackstone Labs. I'll wait and see what I get from them.

I already contacted Markspecv, hopefully he'll have some available.

Thanks for the help.

 

[i68k]

hopefully blackstone will have good results for you. the sr20 is a very strong motor, unlike the qg and qr, and i dont hear many people having motor problems with the sr after blowing a cat, this is very much a common problem with the qr. let us know how your results turned out.