Would A Blown Head Gasket Cause This?

[bordin34]

The engine in my 73 Charger is not running well and I suspect that I have a bad head gasket. The engine idles a little rough and backfires and the vacuum readings jump a little bit. The timing is set right. I also found out my radiator cap was not holding any pressure, could it have overheated and made the gasket go bad but the temp gauge was only at the first mark. Could a bad head gasket cause similar problems?

[firefighter3931]

It's possible that overheating can blow a head gasket but you would have noticed it overheating and pouring steam from under the hood.

Run a compression and coolant pressure test if you suspect a blown head gasket. See if your coolant level has dropped and get a good rad cap on it.

The symptoms you're describing could be many things. Usually when a carb backfires it means that the air/fuel mixture is going lean.



Ron

[bordin34]

Well there was a cloud of smoke that was not oil coming out of the exhaust once it warmed up. But the coolant level is still full. I have since bought a new rad cap.

[mally69]

Well if it was cold and you saw white smoke, are you sure it wasn't steam. Mine does that alot until it warms up then the steam goes away.

[firefighter3931]

Well if it was cold and you saw white smoke, are you sure it wasn't steam. Mine does that alot until it warms up then the steam goes away.

The "steam" is actually condensation which is burning off when the engine first fires up. It's water vapor that collects in the exhaust pipes when the temp gets cold.

But the coolant level is still full. I have since bought a new rad cap.

That's good news regarding the coolant level. My guess is your problem lies in the tuneup.


Ron

[bordin34]

The car was running for about ten minutes then all of a sudden a cloud appeared and kept getting bigger and bigger. Then it slowly went away.

[mally69]

The car was running for about ten minutes then all of a sudden a cloud appeared and kept getting bigger and bigger. Then it slowly went away.

I would have to say its just steam. It does take a few minutes for the exhaust to get hot enough for the condensation to start burning off which makes steam then gets hot enough that the steam is all burned off therefore making the steam go away.  Just one more question, How cold was the temperature outside when you started it up?

[bordin34]

It was about 60 degrees. There was a rather huge cloud of smoke or steam and it lasted a good 5-10 minutes, this was after the car was already running about 10 minutes.