Plug Color?
Thread Starter
Le Mans Master
Joined: Jun 2011
Posts: 8,049
Likes: 329
From: Charlotte NC
St. Jude Donor '14-'15
Plug Color?
So I removed the NGK TR55 plugs and installed new AC Delco 41-104 Iridium Plugs. I have never had plugs come out this color before. It looks like a rusted color. Anybody seen this before? 
Melting Slicks
Joined: Oct 2010
Posts: 3,024
Likes: 793
From: Tollesboro Kentucky
I have seen some plugs that had a reddish tint to them after using different gas in my bikes.S&S stated this was usually caused by additives in the fuel.After trying different gas for a few weeks plugs came out looking normal.Just a thought.
Advanced
Joined: Nov 2006
Posts: 56
Likes: 9
From: NH
Did a quick search.
It could be rust in the fuel system...What makes spark plugs turn red? (askinglot.com)
or additives...
It could be rust in the fuel system...What makes spark plugs turn red? (askinglot.com)
or additives...
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,629
Normally would say additive in the fuel, but with the amount of build up on the entire plug, looks like our burning Dexcool in the cylinders from leak isntead.
How the level in the radiator fluid tank been holding steady, or has it been dropping?
With all the plugs/cylinders the same, would almost day to say leak into the intake manifold itself.
How the level in the radiator fluid tank been holding steady, or has it been dropping?
With all the plugs/cylinders the same, would almost day to say leak into the intake manifold itself.
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Melting Slicks
Joined: Oct 2010
Posts: 3,024
Likes: 793
From: Tollesboro Kentucky
I didn't know there was any way coolant could get into the intake on these engines.My plugs looked exactly like these until I started using a different gas station.This was on an air colled engine.
Race Director
Joined: Oct 2004
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You are correct. No coolant in any LS intake I am aware of. However, it could be entering the cylinder via a bad head gasket. But I doubt that's happening, because I've never seen all 8 cylinders leaking at the same time. Probably in the fuel, or a rich condition...
Thread Starter
Le Mans Master
Joined: Jun 2011
Posts: 8,049
Likes: 329
From: Charlotte NC
St. Jude Donor '14-'15
Normally would say additive in the fuel, but with the amount of build up on the entire plug, looks like our burning Dexcool in the cylinders from leak isntead.
How the level in the radiator fluid tank been holding steady, or has it been dropping?
With all the plugs/cylinders the same, would almost day to say leak into the intake manifold itself.
How the level in the radiator fluid tank been holding steady, or has it been dropping?
With all the plugs/cylinders the same, would almost day to say leak into the intake manifold itself.
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,629
Was thinking on the lines/fitting of coolant cross over/steam pipe leaking under the intake, and one or more of the intake runner seals not sealing off correctly to the heads, which would allow the leaking fluid to get into the intake running of the manifold itself, to draw coolant into all the cylinders that way.
If you had a blown head gasket, it would just be just one of the spark plugs that would look like crap do to it burning a lot more dexcool instead.
Or what every fuel additive your using, it leaving a lot of trace behind by the turn running on the richer side instead. Hence running too rich will leave the plugs sooted in a grey/blackish color, and then additives would cause the pink tint to that.
If you had a blown head gasket, it would just be just one of the spark plugs that would look like crap do to it burning a lot more dexcool instead.
Or what every fuel additive your using, it leaving a lot of trace behind by the turn running on the richer side instead. Hence running too rich will leave the plugs sooted in a grey/blackish color, and then additives would cause the pink tint to that.