The question is, is it uncommon to have signs of a blown head gasket without the sweet smelling exhaust or smoke out the tail pipe. In another car I owned the HG failure was a big production, overheating, smoke screen, coolant lost.


At the moment I'm loosing coolant (an overflow tank every two weeks), an occasional cylinder 4 misfire (p0304), and extra pressure in the expansion tank plus hydrocarbons. What I don't have is smoke, over heating (running 186 highway, 188 in town, 195-201 idle), I can pass a cooling system pressure test, and there is no coolant in the oil or oil in the coolant. It seems to run just fine day to day hot or cold. It just seems odd that it runs fine and I'm getting misfire at a cylinder that is not near a coolant passage. Any wisdom?
Oh oh and I have replaced all visible hoses, along with heater throttle gasket. I am mostly sure I'm not loosing coolant externally.

 

valley pan gasket been replaced? i had almost the same symptoms except for the hydrocarbons in coolant, rear driver lower intake was hand tight, as in i removed the bolt with my hand.

 

Would that cause misfire? If its the valley gasket I should probably do the HG too?

 

mine leaked out the back of the motor. I would deff look at doing the HG but also make sure when you take it in to ask the over all depth of the head vs factory specs. mine was machined before and threw me for a loop.

 

Howdy driftology, I had the exact same symptoms as you, losing coolant but without smoky exhaust, overheating, coolant in exhaust, and a misfire on cylinder 5. However I decided to do a head gasket replacement just to be sure. When I removed the heads, sure enough, I had a pressure wash cleaned cylinder number 5. Which obviously meant that coolant was getting into that cylinder, getting compressed, and pressure washing it clean.

I would suggest changing the head gasket, replacing the thermostat with a 180* one, and getting an ultragauge to watch your temps. What kind of milage do you have?

 

Thanks for the info. Got an ultra gauge a week after owning the disco as well as the 180 t-Stat (had to drive it from California to NY pulling a trailer). I guess I will get ready to replace it as soon as the weather is nice. The engine is semi fresh, only about 70000 miles on it. I pretty sure it hasn't been apart yet. Fingers crossed it's only a gasket and not the block.

 

Coolant can only go two place, leaking or burning

 

X2. Same exact symptoms down to the pressure in the coolant system. I was told it was a dropped sleeve, but replaced the HG's anyway and all is well.

 

Got a little coolant smoke out the tailpipe today. Hg parts on order. Now I need a warm couple of days since I don't have a garage to work in.