Spark Plugs

[Dagwood]

Hello Everybody Just a quick note here on spark plugs. My engine was running ok but the rpm was only600 or just under. I was about to start trobleshooting but decided to change the plugs as a first step. The rpms are now 800 after changing them. None of the plugs were unusable but had deteriorated severely after just 56000 miles so I don'tbelieve the 100000 mile interval in the book is correct. Maybe I misread it but from now on I will use a 50000 mile interval.

[DriVer]

Quote:

Originally Posted by Dagwood Maybe I misread it but from now on I will use a 50000 mile interval.

Many of us have replaced our spark plugs before their rated expiration time. It's also a great idea to replace the engine coolant before it's due time as well.

[Dagwood]

Thanks Driver . Yes I need to change the coolant and the transmiision fluid. Any idea how much liquid gold I will need?

[Akibase]

The new dual electrode, original equipment spark plugs will often last the full 100,000 BUT!!!!! One of the problems is, if you have aluminum heads, good luck in getting them out without taking the threads with them. This is a common problem on many engine makes. This can be a very expensive repair. On the Ford 5.4 it can involve the removal of the heads. In my opinion, I would change them much sooner. A set of plugs is a cheap investment compared to major engine work.
Also, if using your engine for towing, your transmission fluid and filter should also be changed more often.

[DriVer]

Quote:

Originally Posted by Dagwood Thanks Driver . Yes I need to change the coolant and the transmiision fluid. Any idea how much liquid gold I will need?

I hope this helps:

Transynd Fluid and Allison Spin-On Filter Change

[RetiredBob]

Sorry to highjack this thread, but I have another spark plug question. What's the general opinion on using anti-seize compound on SP threads? I've seen people recommend this, but have read that it can result in overtightening and stretching the threads or breaking the plug.

[bluepill]

Used anti-seize for many years as a professional mechanic and never had any problems. I always stay with the recommended torque.

[DriVer]

Quote:

Originally Posted by RetiredBob Sorry to highjack this thread, but I have another spark plug question. What's the general opinion on using anti-seize compound on SP threads? I've seen people recommend this, but have read that it can result in overtightening and stretching the threads or breaking the plug.

I have always applied Permatex anti-seize compound on the spark plug threads.

[Davel]

I think a better measure of spark plug life should be how much fuel is burned in the life of the plug rather than miles on the vehicle. A car that gets 25-30 mpg will not have a problem going 100k between plug changes. But our coaches get from 6.5-8 mpg which means there's a lot more fuel being fired in 50k miles than the car in 100k miles. Besides that, plugs that are near the end of their useful life require more spark to to fire, which works the coils harder. It's cheap insurance to change plugs sooner than later. My plugs didn't look too bad at 50k, but I changed them anyway.

Happy trails,
Dave