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funky looking spark plug - any ideas?

N

NeXJ

NAXJA Forum User
Location
Los Angeles
SO after an overheat on the freeway (see other post if you care to) I just swapped out my t-stat and after firing up the engine to see if the seal was good i noticed the 4.0 was running rough and so I started pulling plugs to look at them. I pulled number one and got the following. Deep reddish and WET looking... could this possible be from coolant in the cylinder? Anyone have any ideas? thanks much in advance.


spark1.JPG

spark2.JPG



PS - while trying to upload a pic I found I could not - there's no way to upload anymore?? just posting from a URL?
 
here ya go...
http://www.mudinmyblood.net/forum/view.php?pg=sprkplgchrt
Glazing appears as a yellowish, varnish-like color. This condition indicates that spark plug temperatures have risen suddenly during a hard, fast acceleration period. As a result, normal combustion deposits do not have an opportunity to "fluff-off" as they normally do. Instead, they melt to form a conductive coating and misfire will occur.
http://www.mudinmyblood.net/forum/images/plugcolorchart_files/plug_insulationfault.jpg
 
Last edited:
That almost looks like rust. Like from a head gasket leaking coolant and water into the cylinder and its rusting, possibly from your overheating issue. May be another explanation if you are still having issues
 
i just put it back in and fired it up to see if it was just me being paranoid. but now there's coolant coming out from the header... not good! am i screwed?
 
no mine is a 92 with a 97 engine (and therefore 97 head) - though I had it worked on once before. Yes - i just had a bad overheat a few days ago... well head work is better than needing a whole new engine (i was sort of worried that the internal walls were corroded through - since when i bought the engine it was full of coolant and sitting for quite some time - but hopefully not!)
 
thanks- it's in the shop now so we'll see - hopefully a gasket... if not then a warped head. my nightmare scenario is that the coolant passages corroded through to one of the cylinders or the crankshaft or something.
 
I didn't really drive it that long when it was overheating though - not like last time i had that happen ten years ago when i had a much worse overheat and the engine was all locked up.
 
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