spark plug change experience

[m5james]

Originally Posted by FSETH

There is plenty of evidence that BMW's running 15,000 mile oil intervals is just fine, first trans fluid changes at higher mileage can contribute to failures and leaving OE plugs in for 100,000 works. Have you ever heard of anyone who's BMW engine failed do to wear becaue of following 15,000 mile oil intervals?

As long as a quality oil is used, I've got no issues with extended intervals, and people have tested their oil to confirm that there was still life left. LONG gone are then days of 3k oil changes, I even go 5k between changes on my 270k truck.

[c4racer]

Originally Posted by patholiar

what is the torque spec for the plugs? I am interested in doing this but scared of over torquing it

typically in an AL head, you tq the plugs to maybe 20lbs. It isn't much. What I do is hold the 1/4" ratchet near the head and get it snug but don't put a lot of muscle into it using the full leverage of the ratchet handle if that makes sense.

[m5james]

Originally Posted by patholiar

what is the torque spec for the plugs? I am interested in doing this but scared of over torquing it

Tighten till they seat and then a little bump...they don't need to be super tight. I just do it by feel.

[c4racer]

Originally Posted by m5james

Tighten till they seat and then a little bump...they don't need to be super tight. I just do it by feel.

same here - that was a better way to describe it than my attempt!!

[admranger]

Doing it by feel is dangerous for armchair mechanics.

Buy a torque wrench and do it right if you don't have a lot of experience wrenching. A torque wrench costs way less than fixing a stripped spark plug hole.

[FSETH]

I am looking into the torque specs as well as I will be doing this in the next week or so. I ran across a thread where a member here said the Bentley manual suggested 23 +-3Nm 18+-2ft-lbs.

I also saw this e46 TIS

30 ± 3Nm, thus 22 Lbf*ft, with a tolerance between 19.9 Lbf*ft and 24 Lbf*ft.

It may be the same as our cars, but I am still looking for the X5 stats.

I do agree that using a torque wrench and getting these as close to spec as possible is important. There are too many issues that can happen if you over or under tighten them.

[JCL]

Originally Posted by admranger

Doing it by feel is dangerous for armchair mechanics.

Buy a torque wrench and do it right if you don't have a lot of experience wrenching. A torque wrench costs way less than fixing a stripped spark plug hole.

[JCL]

Originally Posted by m5james

As long as a quality oil is used, I've got no issues with extended intervals, and people have tested their oil to confirm that there was still life left. LONG gone are then days of 3k oil changes, I even go 5k between changes on my 270k truck.

I agree. I went 8,000 km/5000 miles on my daughter's Toyota. It had a small sump, high rpm, and short trips.

I think it is interesting that people all seem to refer to the manufacturer's recommendations as 'extended'. 15,000 miles isn't extended, it is standard. Extended is more than 15,000 miles. Less than 15,000 miles (or whatever the lights call for) is reduced intervals, which is fine for those that want to do that.

I notice on the Mobil 1 site that they refer to Mobil 1 5W-30 as being recommended for intervals up to 15,000 miles, as recommended by the manufacturer (refer to individual manufacturers). They have moved on significantly from the 'more frequent is good' recommendations that oil companies made for years in order to sell more oil. I am not sure how long they have been promoting 15,000 mile intervals, but I found it interesting that they came out and said their oil would stand up to that interval fine, and the lawyers let them put that in the advertisement.

I wonder what the safety margin is on the 15,000 (from BMW and from Mobil) since BMW are fine with owners running far over that and not impacting extended warranty costs with CPO qualification.

[switchman]

Here's a good reference spark plug chart with the recommended torque values;

[FSETH]

Thanks! 23 +/- 1.5lb/ft.

Where did you find this info?