QuestionDave, I have a '98 911 with 18K miles. I'm being told by the dealer that the plugs need to be replaced because the car is 6 years old and they could seize in the engine. What's the scoop? Is this a big job? It must be because they want $800.
Thank you
Mike
Answer
Hi Mike, There's two issues your question raises: 1. What's the big deal about changing the plugs on a 911??? ; and, 2. Should there be special considerations for your situation...where you have a very low mileage car, only averaging 3000 miles per year?
The very, very old joke when considering buying a 911 was always: great cars... "but you need two men and a small boy to do a damn tune-up". As the story goes the usefulness of the small boy is to get his little arms and little hands into places a man's hands can't go...while the two men would each shine separate flashlights into the deepest darkest recesses of the engine compartment, trying to see just what the kid was up to.
Part of the reason for the high cost of changing the spark plugs has to be to allow time for the very expen$ive Porsche technician to take parts off your car so as to access the places he or she can't see or reach...and then replace the offending parts. The $800 must be 95%+ labor because of this issue. With patience, the home mechanic can certainly perform this task.
Now, as for the idea that the original plugs will "seize". I've actually never heard this argument for changing the plugs. So if you trust your dealer then you have to trust his ideas.
On the subject of the 18,000 mile car, I would certainly discard all the normal notions that pieces and parts should be "checked for wear and replaced when they reach a certain mileage", since it will be awhile till you reach some of the significant mileage milestones.
In your case, I'd try to develop a maintenance schedule that deals with parts facing age deterioration.
For example, rubber (anything soft) seals will not last forever, so it's likely they will need to be replaced long before a certain mileage marker is reached. Does that mean to go out and replace all the rubber seals automatically??? No. Left undisturbed, even poor seals will continue to seal. So for the most part, seals should probably be replaced when you see oil stains on the floor that are new...and bother you to the point of distraction. Meaning: damn, I can't park this car in front of the Jones's house with all that oil leaking everywhere.
One more thought about rubber: THE most IMPORTANT rubber on this car is the seals on your brake calipers. They too will hold brake fluid very reliably long past their useful life, but if there was one place I'd check closely on a certain schedule, it would be this. Every so often I'd take the wheels off and not only look at the condition of the brake pads and rotors, but for sure I'd shine a light on the piston seals in the calipers for any sign of seepage. Touch them? No. Replace them? Not really...don't get too anal about this. Just keep a good eye peeled for any sign of trouble.
As for the mechanical parts which won't get very much wear but could become age corroded (which is exactly THE reason I'd check, but not necessarily replace, all the sparkplugs)... you'll likely find there are actually few of this category of parts. In the olden days the ignition points would be the first on the list...today it is probably the spark plugs. Everything else, if you drive the car every so often just to prove everything's working fine will probably not need too much attention till you notice something that's not normal. An engine miss, a brake pulling to one side, etc.
Well...now you've gotten waaay too much info on such a simple question.
If it were me I'd use the $800 for something better and I'd change (or at least examine the spark plugs myself. By the way, when you have the sparkplugs out, DO NOT put anti-seize lubicant on the threads, as that could cause them to back out...really.
I just thought of the reason you're dealer SHOULD use to justify the "SEIZED" sparkplug theory. It is conceivable that the aluminum threaded heads could mechanically bond with the iron or steel sparkplug threads as they rust (if they rust). Perhaps he's seen this before and he's trying to save you some repair dollars.
Anyway, another good reason you change them yourself. Heck, I'll do it for $749.99.
Dave
PS. Go here: http://www.pelicanparts.com/techarticles/ whenever you want another opinion on 911 tasks. I notice the tech article about changing sparkplugs is not up to Pelican's normal standards, but everything else is usually very helpful.
Oh yeah, write back to me anytime. I love questioning dealer repair estimates.
