BMW M5 Forum and M6 Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
1,548 Posts
Discussion Starter #1 (Edited)
So just changed my spark plugs and Pre-Cat O2 sensors and DAMN were they dirty..

Quick question before I begin.. When I took the cap off of one of the new O2 sensors a small amount of anti seize got on the sensor but I wiped it off as best I could.. Is this ok or is my sensor going to be shot from this?

Anyways.. What do you guys think of my plugs and sensors? The plugs are pretty fouled and the O2 sensors look like they were running rich and lean at the same time?
Confusing...
Can't really test how well or how much better my car is performing because its pouring outside.. went for a test drive and my wheels would just spin..
go figure..
Thanks guys
 

Attachments

·
Registered
Joined
·
131 Posts
Don't worry about a little antisieze , most o/2 sensors come with it on the threads or supply a small tube to put on the threads when installing. If it was a concern there would be warnings in the packaging.
I also like to dab a little on the threads of the spark plugs which prevents nature welding of threads to head.

Don't be to concerned about the colors as if the ses light was not on before the work the car was probably working properly.
 

·
Registered
Joined
·
450 Posts
+1 on What was the mileage on them?

My pre-cat O2s looked pretty much like that at 55k miles and my car had been running rich due to bad thermostat. My plugs were a whole lot cleaner/less build up on them. What's up with the far right plug in the first picture? That looks pretty corroded.
 

·
Registered
Joined
·
1,067 Posts
Those look fine...some of the threads might be a bit oily on the plugs which could suggest the valve cover gasket is weeping around the spark plug holes (common in almost every car with plugs that go through the center of the valve covers).
 

·
Registered
Joined
·
131 Posts
My pre-cat O2s looked pretty much like that at 55k miles and my car had been running rich due to bad thermostat. My plugs were a whole lot cleaner/less build up on them. What's up with the far right plug in the first picture? That looks pretty corroded

That's from a little water getting in on top of spark plug. Possibly from pressure washing engine.
 

·
Registered
Joined
·
1,548 Posts
Discussion Starter #9
The car has 61,500 miles on it..

And yea ard that one was just rotated.. lol
Thanks guys..
I'm thinking I should change my thermostat soon..
 

·
Premium Member
Joined
·
13,589 Posts
Don't worry about a little antisieze , most o/2 sensors come with it on the threads or supply a small tube to put on the threads when installing. If it was a concern there would be warnings in the packaging.
I also like to dab a little on the threads of the spark plugs which prevents nature welding of threads to head.

Don't be to concerned about the colors as if the ses light was not on before the work the car was probably working properly.
It also multplies the torque value on the threads, making it easier to strip these expensive and rather delicate aluminum heads. It's best to pass on the anti-seize in this case.
 

·
Registered
Joined
·
1,548 Posts
Discussion Starter #11
My car still doesnt feel very zoom zoom yet..
It will take about 150 miles for the car to reset right guys?
I had the battery unplugged for about 3 to 4 hours while I was working on stuff last night..
 

·
Registered
Joined
·
1,548 Posts
Discussion Starter #12
For some reason I'm actually feeling slower today...
I hope this is normal! 20 miles driven so far
 

·
Registered
Joined
·
1,548 Posts
Discussion Starter #13
For some reason I'm actually feeling slower today...
I hope this is normal! 20 miles driven so far
 

·
Registered
Joined
·
1,159 Posts
Regarding the corroded plugs; I experienced this recently and for some time I've been wondering how water had gotten in to the plug space, it's well covered and almost completely sealed and, there's no coolant pipe or channel near to either bank that could cause this. I'm certain its water damage, oil would be different.

As has already been suggested, washing the engine would probably cause it but I'm sure mines never been washed. My only other thought was a windscreen washer pipe had detached itself from the nozzle and was pumping screenwash over the engine. My bonnet (hood) lining drops where it should cover the washer nozzles (another little thing to sort) so any fluid would drop directly onto the engine.

Check your screenwash hoses!
Hth
 

·
Registered
Joined
·
1,548 Posts
Discussion Starter #16
Performance issues solved for the most part I believe..
she's real fast again.. I THINK
There might be some lost horsepower somewhere but not too sure..
 
1 - 17 of 17 Posts
Top