I've a '98 2.2 Liberty 220km. Drove 50 or so km Sunday and was standing in front of the car and heard bubbling. Popped bonnet and lid off the overflow and watched it bubbling from the radiator overflow hose in the overflow bottle. Coolant in the bottle a bit frothy. No oil. No coolant in oil. Oil cap clean. Not overheating*.
I'm pondering if a head gasket is leaking. I can do a compression check and peek at the plugs. It was recently pressure tested as fine as it *did overheat once parked idling on my steep drive for 15 minutes with the air con on flat out while I loaded the trailer. When Boxer service checked it (I thought it had done a water pump) they idled it for ages, pressure tested, tested coolant with the dye kit, all inconclusive. Never done it before nor since.
Not sure how long it's bubbled like this, once it's hot again I'll check if it does it running, it was just an incidental find. I know when an engine is turned off it can get hotter as coolant isn't circulating but I'm pondering the head gasket(s). Hope not buuut if I got to do them I got to do them...
On further investigation
Well I pulled the plugs and the two rear plug leads pulled the centres out... grrrr.
Plugs all look the same. Were stiff to unscrew as whatever anti seize was well dry. No obvious coolant burn on the plugs. Compression test 195psi on 3 200psi on the last one, gotta be happy with that. Supercheap sell bosch plug sets for 2.0, 2.5 but not 2.2 sigh. Two generic bosch leads for the moment, coolant topped up and a new radiator cap.
![Image](http://i.imgur.com/4lyQyryl.jpg)
Started and flogged around the local hills to heat up. Now it bubbled a bit as it filled the overflow bottle but then stopped. I let it idle for 15 more minutes and no bubbles, stopped the car and no bubbles. I'll heat cycle it a few times and then look closer at it again. I'm optimistic that the plug cap may have been leaking but realise it may be a failing head gasket.
I'm keen to find the current choice of head gasket kit, timing belt and water pump supplier via either the US or local and time removing the engine and giving it the once over. I want to get another few years out of this car, it's worth nothing and the paint has gone off but it's a great reliable hack for mountainbiking, building supplies and work with nice cold air con!