Valve cover replacement - CEL code 0430 - 06 Infinit M35

[hsingh2088]

How's it going.

So I have been having a ton of issues with my car lately. It all started with me swapping out spark plugs at the 100K mark.

When I swapped them out, I noticed that there was a lot of oil on the threads of cylinders 5 & 6. It didn't seem right but I continued the install regardless. (This is totally my idiotic fault, I should have went with my gut and done something else, but I didn't it is my only set of wheels)

As it turns out, oil in the spark plug tube is very bad and I ended up misfiring and causing lots of smoke/burning oil.

Fast forward, I towed it to a local mechanic near by and the diagnosis came back that my valve-covers needed to be replaced, because Nissan wants to steal everyone's money by building in the spark plug tubes into the valve covers.

The mechanic had never dealt with this problem before on the 06 Infiniti M35. I told em what the issue is, and they ran a compression-leakdown test the next day, even after I told them not to start the car. They measured misfires and basically validated my initial findings. The work was done and I shelled out $1200 bucks. The car came back and it was as smooth as ever.

Fast forward to Tuesday night when I got my car back, my CEL came on. I took it to the mechanic this morning and he ran the diagnostics and it spewed out code 0430 - catalytic converter.

So here is the dilemma. When I swapped out the plugs myself and turned the engine over, it ran for about 15 seconds at the most, I turned it off and immediately called a tow truck.

The mechanic ran a compression-leakdown test to measure misfires and basically scientifically proved what I already told them. When I took it back to the mechanic this morning, they tell me that oil may have gotten down to the catalytic convert.

So hear is the dilemma:

My question to you guys are, is it possible for oil to leak down to the cat within 15 seconds of running the car? If not, then the idiot mechanics ran a compression test and probably caused the oil to spill onto the cat by running the car longer then I did and basically ignored any potential problems of oil leaking onto the cat and now I have code 0430 and possibly another $1K problem on my hands.

[Ilya]

I would run some Seafoam into the car and let it run for a few seconds, then let it sit 30 minutes, and then start it and rev the crap out of the car (see the guide in the FAQ)...see if that clears up the oil, etc.

[hsingh2088]

Thanks for the quick response. It seems that the how to for the sea foam is missing a few pictures. Is there another how to on this thread? I haven't found one yet.

Also, the shop did not turn my engine over, that was my bad.

The mechanic was pretty up front about it and I am almost certain there is oil right on top of my cat.

[pharaohEG08]

Wow man you just ran into a whole bunch of issues all of a sudden. Sorry to hear that, hopefully you can get it fixed quickly and as cheap as possible.

[hsingh2088]

Wow man you just ran into a whole bunch of issues all of a sudden. Sorry to hear that, hopefully you can get it fixed quickly and as cheap as possible.

Yea dude, pain in the a**. Check your car for oil-leaks in the spark plug tube, don't take them out, run a timing-test and then have your mechanic dig into it and repair that crap before it becomes into this nightmare.

The first-gen Ms have the most retarded design on the planet...

[Ilya]

Thanks for the quick response. It seems that the how to for the sea foam is missing a few pictures. Is there another how to on this thread? I haven't found one yet.

Also, the shop did not turn my engine over, that was my bad.

The mechanic was pretty up front about it and I am almost certain there is oil right on top of my cat.

Unfortunately I lost this pics when I closed my domain...but the line is on the left side (passenger side) of the engine and runs from the back into the side of the intake manifold...just disconnect the back portion (host clamp) and have someone in the car to rev the motor while the hose is sucking up the Seafoam (they should maintain like 4k rpm) and then once you're done, have them turn the car off. Let it sit for 30 minutes or more and then start it up and let it idle, rev it, etc. You'll probably have a ton of smoke similar to my video.

[svard75]

I suspect your cat fried (no pun intended here) because the oil contaminated the plugs which caused them to not fire and the unburnt fuel ignited within the hot cat.

I have the same issue and my plan is to replace both cats with el cheapos off ebay. There's a pair sold together for the M35 with a 5 year warranty (Provided that company will be around for the full 5 years).

[hsingh2088]

Fortunately for me, that was the first time in the day that I started the car. The cat shouldn't have been hot from driving and my engine only had 15 seconds to heat up.

So the most likely scenario is that wet fuel made it into the cat? If that's the case, will it deteriorate it over time, or can I burn it out?

[svard75]

You missed my point. Clearly you had an issue of leaking valve cover for some time. The oil contaminated the plug long before you changed the plugs out so my thoughts are that this was over a longer period of time even before you began messing around. What did the original plugs look like when you removed them? A valve cover doesn't just suddenly start to leak right?

[EniGmA1987]

A valve cover doesn't just suddenly start to leak right?

You need to be very careful revving these M35's high when the car is cold. wait at least 5 full minutes before you take the engine above 5k rpms. We have really weak valve covers and they do start to leak if you rev high when things are cold. I have had it happen 3 times, all at the beginning of winter as the temperatures are getting lower. I had it happen 3 years in a row till I finally stopped driving so hard. It was about the time my warranty ran out. lol. Never had a problem with valve covers leaking since I stopped driving hard in the first 5 minutes though.

[CPJ LB]

not sure how long you had the leaky valve covers and the oil in the spark plug tubes, but you may want to also check the coil paks related to the oiled spark plug tube(s). that will also contribute to misfire and poor mpg's.

as far as cats...you can always pick up a set from the G35 forum classifieds....you can save a lot of money going that route for replacement cats....typically $100-$200 a pair... I've gone that route when I ran hi flow cats and needed a set when getting smogged

[svard75]

A valve cover doesn't just suddenly start to leak right?

You need to be very careful revving these M35's high when the car is cold. wait at least 5 full minutes before you take the engine above 5k rpms. We have really weak valve covers and they do start to leak if you rev high when things are cold. I have had it happen 3 times, all at the beginning of winter as the temperatures are getting lower. I had it happen 3 years in a row till I finally stopped driving so hard. It was about the time my warranty ran out. lol. Never had a problem with valve covers leaking since I stopped driving hard in the first 5 minutes though.

Sound advice.

[hsingh2088]

You missed my point. Clearly you had an issue of leaking valve cover for some time. The oil contaminated the plug long before you changed the plugs out so my thoughts are that this was over a longer period of time even before you began messing around. What did the original plugs look like when you removed them? A valve cover doesn't just suddenly start to leak right?

That is probably an accurate statement, but what I've been wondering is, why hasn't my CEL gone off prior to me changing the plugs? If it had been leaking for a long time, shouldn't any burned fuel/oil have already leaked into the cats; thus, setting of the code P0430 and P0420? (btw, only P0430 was set off, there was no P0420)

The plugs looked pretty bad, there was corrosion on the anode and tip (I live in Houston, very humid weather and salty air because of the Gulf), and traces of burned oil around the threads, but cyls 5 & 6 had the most wet oil on them when I pulled them out, probably half a tea-spoon each.

In any case, hopefully all of this will blow over soon, if not, looks like I'm going to have to fork over a few hundred for replacement cats, might as well change both.

[hsingh2088]

not sure how long you had the leaky valve covers and the oil in the spark plug tubes, but you may want to also check the coil paks related to the oiled spark plug tube(s). that will also contribute to misfire and poor mpg's.

as far as cats...you can always pick up a set from the G35 forum classifieds....you can save a lot of money going that route for replacement cats....typically $100-$200 a pair... I've gone that route when I ran hi flow cats and needed a set when getting smogged

Thanks for the advice dude. The coil paks were fine, the only thing that went bad was one of the plugs I replaced. The other 5 plugs were fine when the mechanic tore everything apart. These engines are ridiculously hard to work on...

[hsingh2088]

A valve cover doesn't just suddenly start to leak right?

You need to be very careful revving these M35's high when the car is cold. wait at least 5 full minutes before you take the engine above 5k rpms. We have really weak valve covers and they do start to leak if you rev high when things are cold. I have had it happen 3 times, all at the beginning of winter as the temperatures are getting lower. I had it happen 3 years in a row till I finally stopped driving so hard. It was about the time my warranty ran out. lol. Never had a problem with valve covers leaking since I stopped driving hard in the first 5 minutes though.

Thanks for the advice sir! Warming up the engine is very important in any condition. I live in Houston so the cold air lasts for about 3 months and the coldest temps we see are 40 degrees on a good day. On really good days, the city decides that it's too "dangerous" to drive on the roads, so they shut the freeways down - pretty wicked ...

[svard75]

You missed my point. Clearly you had an issue of leaking valve cover for some time. The oil contaminated the plug long before you changed the plugs out so my thoughts are that this was over a longer period of time even before you began messing around. What did the original plugs look like when you removed them? A valve cover doesn't just suddenly start to leak right?

That is probably an accurate statement, but what I've been wondering is, why hasn't my CEL gone off prior to me changing the plugs? If it had been leaking for a long time, shouldn't any burned fuel/oil have already leaked into the cats; thus, setting of the code P0430 and P0420? (btw, only P0430 was set off, there was no P0420)

The plugs looked pretty bad, there was corrosion on the anode and tip (I live in Houston, very humid weather and salty air because of the Gulf), and traces of burned oil around the threads, but cyls 5 & 6 had the most wet oil on them when I pulled them out, probably half a tea-spoon each.

In any case, hopefully all of this will blow over soon, if not, looks like I'm going to have to fork over a few hundred for replacement cats, might as well change both.

Orange burned plugs are a good indicator you're running too lean, brownish gummed up means its an oil leak. Catalyst codes can be pending for a while before they trigger the final code or SES light. I think it was simply coincidental.

[hsingh2088]

If it's running to lean, what do I need to do to combat that problem?

[svard75]

Heres a good guide.

http://www.verrill.com/moto/sellingguid ... rchart.htm