Another Round of Spark Plug Diagnosis

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4,397
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Parts Unknown
A few look as though they were getting a dose of oil and perhaps some poor filtering of the intake air or poor sealing of the intake ductwork... The wet one #3 doesn't look like it is firing. If you were burning coolant, the plug's insulators would be white and extremely clean looking.
 
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Messages
16,712
Location
NH
Originally Posted by spavel6
What do these plugs tell you?
That I'd rather be vehicle shopping. They look a bit old, no sharp edges on the center electrode? If this isn't driven a lot, or has other issues, I'd replace and monitor.
 
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15,226
Location
N.H, U.S.A.
They look bad. Some oil fouled others ??? fouled and mixture off. One doesnt look like it was firing at all - that will screw up everything. Engine rebuild time. Or at least valve seals and check for coolant loss. Does a the oil test for coolant? Pressure test?
 
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24,137
Location
MA, Mittelfranken.de
Any kind of additive use in oil or fuel? You can get a quick and dirty head gasket test for short money that will at least tell you if combustion gasses are getting into the cooling system past the gasket or a small crack in the head casting, check the oil for coolant contamination and look for external leaks at the head, if nothing comes up its probably not a head gasket. https://www.amazon.com/gp/product/B01N1NA22J/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
 
Messages
59
Location
GA
Originally Posted by ARCOgraphite
They look bad. Some oil fouled others ??? fouled and mixture off. One doesnt look like it was firing at all - that will screw up everything. Engine rebuild time. Or at least valve seals and check for coolant loss. Does a the oil test for coolant? Pressure test?
And that's probably from his head gasket problem....the spark plug tip is getting steam cleaned with every firing.....
 
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391
Location
VA
"What do these plugs tell you?" That that engine isn't feeling healthy right now. Have you done a compression and leak down test on the cylinders? Wouldn't be at all surprised to find out this truck has plugged up cats
 
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4,363
Location
Southeast
How time has passed. I've driven worse. These wouldn't be far out for a carbeurated car at 80,000 miles back in the day. Center top pic catches my eye, if it were a fuel additive, that look would be more consistent among plugs. I'm curious if there's a coolant involvement, though it's a little dark in color for that. Plugs along won't give the full story. You have other things going on that affect diagnosis. -m
 
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15,226
Location
N.H, U.S.A.
Originally Posted by Gebo
What is the make and model of these plugs? grin
I was looking at autolite Ir for my wife's subaru could be them. Stainless Steel body and that inverted funnel shaped Ir tip. here is a new one: [Linked Image]
 
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4,848
Location
VA
Originally Posted by ARCOgraphite
Originally Posted by Gebo
What is the make and model of these plugs? grin
I was looking at autolite Ir for my wife's subaru could be them. Stainless Steel body and that inverted funnel shaped Ir tip. here is a new one: [Linked Image]
Thanks, ARCOgraphite. I was more interested if they were the correct plugs for his Ranger.
 
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1,876
Location
South Carolina
First picture: Left plug is firing normally. Center plug is carbon fouled (old?). Right plug is not firing. Second picture: Left plug is firing normally. Center and right plug are oil fouled.
 
Messages
15,226
Location
N.H, U.S.A.
Originally Posted by Gebo
Originally Posted by ARCOgraphite
Originally Posted by Gebo
What is the make and model of these plugs? grin
I was looking at autolite Ir for my wife's subaru could be them. Stainless Steel body and that inverted funnel shaped Ir tip. here is a new one: [Linked Image]
Thanks, ARCOgraphite. I was more interested if they were the correct plugs for his Ranger.
I assume he has a waste spark 3 coil system. NO - these are the wrong plug - but he has other issues for sure. Waste spark need a reverse fire plug on that coil end. If a dist, these will do fine. - if the engine is healthy.
 

spavel6

Thread starter
Messages
421
Location
Seattle, WA
Hi Guys, Thank you for all the responses! Very interesting insights. Turns out this is the [/u]4.0 L[u] engine and not the 3.0L The head / headgasket is leaking. The coolant is milky, and there is bubbles in the radiator. The PO filled it with the "miracle in a bottle" stuff, so there is sand and flakes in the coolant. Also, the radiator drain does not release coolant when opened, so who knows what condition the radiator itself is in. Currently taking off the heads, and am hoping there is no visible cracking. Debating whether I should resurface the heads (cast iron) or just clean them up and replace the gasket. My understanding is if they aren't cracked, cast iron tends to warp less than aluminum. BTW, the spark plugs are Motorcraft Platinum SP486[/u]
 
Messages
134
Location
YYC
The 4.0 SOHC Cologne engine has a known timing chain issue, so check the condition of the plastic timing chain guides if you do end taking the heads off. Your drain plug on the rad is probably just plugged up from the the junk in the cooling system, I'd take the plug out and clear the drain with a pocket screwdriver. If you do end up repairing the engine be sure to thoroughly flush the radiator and engine block before refilling with coolant.
 

spavel6

Thread starter
Messages
421
Location
Seattle, WA
Thanks Jake_J for the pointer on the chain guides. I'll check them out. Is the remedy to replace the guides only or the chain itself as well? What is the likelihood that the cast iron head is not warped when a head gasket blows?
 
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