Have a 2001 Grand Caravan that was at the shop today (3.8L engine w/82K miles.) The Service Manager indicated they could not do a tune-up due to the fact that one of the plugs on the front bank was seized in the head and he was afraid to strip the head out.
Any idea how prevalent a seized plug is in this engine and what the success is of trying to get them out without tearing the threads out of the head?
It isn't uncommon if you fail to use anti-sieze on the threads when you install them. Tearing out the threads isn't all that big of a deal as you can put in a helicoil.
Matt
Those platinum plugs stay in for so long, this is probably your first replacement/????.. you can soak them with a penetrating oil, I recommend rust penetrate from Chrysler, it works great, soak them over night and try to remove them cold.
Glenn Beasley Chrysler Tech
I believe the plugs were replaced by the same dealer at ~ 30K miles. So what can you offer on how often this might happen and how offen the penetrating oil is successful (what are the odds that the Dodge dealer gets it out without charging me to replace a head?)?
See the previous remark on heli-coils. And a heli-coil might not even be necessary.
You take the plug out, using whatever violence is necessary. This will tear up the threads. Now you put a thread-cleaner through the hole. In my experience, this will normally end up with threads that work well enough to get compression, which is all you really need.
If this isn't good enough, you re-thread the hole with a bigger tap, and put in an insert called a heli-coil. In Nomen Nescio's ideal world of $150,000 Neons, all aluminum heads would have heli-coils installed at the factory.
It's really hard to imagine taking out a seized plug causing so much damage that a heli-coil can't fix it. If the service writer seems to be uncomfortable with this idea, something is really wrong.
Yes, it may be time to switch to another shop.
Matt
Really? I've heard just the opposite. AL expands at a rate higher than steel. Steel plug inside of aluminum will get looser as the temp goes up.
Matt
I replaced the original platinum plugs in our '96 T&C at some mileage over
100K. They came out with completely reasonable effort. The plug boots were more difficult to remove than the plugs. Another interesting fact: even though some of the gaps were about 2X the factory setting, the car still ran great. There was no change that I could detect in performance or gas mileage before and after.Ken
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