spark plug red in colour

stevemc · Post by **stevemc** » 01 Jan 2011, 09:44

my c3 1.4 8v ,it has a very small misfire at low revs ,so i have just changed the plugs ,they where ngk ,only done 2000miles ,but the white ceramic around the electrode was red and the whole end of the plugs were redish in colour to ,my driving is mostly on m/way at around 65mph ,but i only get 37 mpg ? .it seems very low ,Citroen say 44mpg extra urban , any ideas ????

citronut · Post by **citronut** » 01 Jan 2011, 11:35

is it 1 or all plug tips that are redish colour, i would sudgest coolant ingress into the combustion chamber/s (head gasket ???)

regards malcolm

andmcit · Post by **andmcit** » 01 Jan 2011, 11:39

Yep, a copper reddish powdering of the plugs does certainly suggest there's
coolant burning in that cylinder. May even get spewed out of the exhaust too
in reddy brown traces.

Andrew

stevemc · Post by **stevemc** » 01 Jan 2011, 11:50

all the plugs are red ,but the exhaust is totally clean ,its so clean it looks new

HDI · Post by **HDI** » 01 Jan 2011, 12:19

Apart from being red do the plugs look very clean, the bottem of the threaded body that is exposed to the combustion chamber and the earth electrode too ?

andmcit · Post by **andmcit** » 01 Jan 2011, 13:03

Sounds like octane enhanced fuel can have this effect which doesn't have any
serious effect on running with the plugs being OK to use...

Interesting pics here:

http://www.gtr.co.uk/forum/139824-red-b ... plugs.html
http://www.camaros.net/forums/showthread.php?p=1245147

VertVega · Post by **VertVega** » 01 Jan 2011, 20:04

andmcit wrote:... Interesting pics here:

http://www.gtr.co.uk/forum/139824-red-b ... plugs.html
http://www.camaros.net/forums/showthread.php?p=1245147

Thanks for the links. I checked those pics, very interesting

.

I made a Google search also and found several other cases (mostly car forums from US).
Good to know this because "classical" Spark Plug Symptoms with pictures don't include the red-brown case yet

stevemc · Post by **stevemc** » 02 Jan 2011, 09:38

mine are the same as the gtr link ,i dont run any additives in the fuel ,the car has done 76000 miles ,i drive 24 miles to work and 22 of them are done on a main road at around 65mph , would you believe it i am a psv fitter ,and no one in our workshop has seen plugs this colour ,but we only do diesels

citronut · Post by **citronut** » 02 Jan 2011, 10:46

Steve wrote
"but we only do diesels"

regards malcolm

Stempy · Post by **Stempy** » 02 Jan 2011, 14:44

FWIW I run both my vehicles on super unleaded and the plugs always come out red like the pics. Whether they would be the same on regular fuel I couldn't say.