Hey Everyone. Just did a coolant flush, new thermostat and radiator cap. With the coolant back under pressure my top radiator hose burst and coolant went everywhere.

Didn't think much of it. Replaced the hose and no more leaks. But after this, the car developed a significant hesitation under load (accelerating at traffic lights). 

Pulled the plugs and one of the plugs was covered in coolant (where the radiator hose burst). I had resigned myself to thinking it was a blown head gasket, but I installed a new spark plug and the problem has gone away (for now).

I have done a chemical test on the coolant for exhaust gases which was negative. Car is not overheating. No coolant in oil. 

Is there any way coolant could have got into that cylinder because of the leak from the burst hose or am I kidding myself and it's probably a head gasket?

'91 Legacy EJ22

Cheers!

Most likely just went down the spark plug wire and into the plug hole.

I agree with Imdew. 

This coolant may have caused a short in that spark plug circuit, this dropping that cylinder or producting a weak spark at best. 

Cheers 

Bennie

Thanks guys. So you think it managed to pass the spark plug thread and into the cylinder? Do you think that seems unlikely given the spark plug was done up quite tight?

I think they are saying in was around the plug in its 'well' .

does the exhaust smell sweet-ish? that would be coolant leaking into a cylinder. Are you losing coolant volume?, alsways check in the radiator when coolant issues may be present. The overflow bottle does need to be about half full - but its level is not a good reflection of actual coolant volume when 'issues' are on-going.

Thanks for the prompt responses everyone. You were on the money. The coolant pooled around the top (white part) of the spark plug and was shorting out. Problem fixed. Thanks again guys!