Coolant residue in spark plug tube

JoeyG85Z · Post by **JoeyG85Z** » 21 Jun 2019, 12:08

A few days ago by 94 850 Turbo tossed the CEL. The codes indicated it was running rich and that cylinder three was misfiring, in addition to the P1310 random misfire. It was about 15k miles since I swapped out the plugs so I figured what the hell. Everything looked ok except cylinder four. The contacts were fine, but the upper electrode, wire boot and the inside of the tube has a white powdery residue. It really looks like dried coolant but I can't figure out how it could have gotten there. I wouldn't think a failed head gasket would result in coolant getting there, especially without fouling the plug.

In addition, for the past few months I've been noticing a coolant smell after I come off of wide open throttle and the turbo lets off if my windows are open.

I did the test to detect combustion gasses in the coolant and it didn't show any.

So, am I going to be replacing the head gasket soon?

Post by **abscate** » 21 Jun 2019, 13:09

I would guess no on the head gasket. White residue could be many things other than coolant. Are you losing coolant at any noticeable rate?

Klausc · Post by **Klausc** » 21 Jun 2019, 14:04

JoeyG85Z wrote: 21 Jun 2019, 12:08
In addition, for the past few months I've been noticing a coolant smell after I come off of wide open throttle and the turbo lets off if my windows are open.

I did the test to detect combustion gasses in the coolant and it didn't show any.

So, am I going to be replacing the head gasket soon?

Head sounds OK. That white stuff could be a plug wire shorting.

Check the coolant tube that goes to the turbo, it can leak down to the exhaust and cause a stink.