coolant boiling? help me

[modulexplode]

So literally an hour ago my car started smoking from the coolant reservoir and it was just a huge mess. it started when I locked myself out of my car, while it was running, stupid, I know. I was just wanting some input as to if anyone knows what that might be. I know some about my 240 but not that much.

it's a 91 Coupe. pretty much stock engine.

[Steady_One_S13]

Have you tried bleeding the cooling system? Changed out thermostat??

[OutToWinPAHC]

There is air in the system.

Cause is from a bad bleed job, a coolant leak (which could be head gasket related). Has it overheated before now? Did you recently flush it out?

I would check for intermix (coolant in oil, oil in coolant). If that was good I would drain and refill the cooling system (1 bottle redline water wetter, 1.5 gallons of green anti freeze, 2 gallons of distilled water). I might also change the Tstat and hoses too.

[LingeringSuicide]

IF you bleed the system and it keeps bubbleing out and smells like exhaust fumes your headgasket is done...

[OutToWinPAHC]

If it smelt like burning coolant it would not smell like exhaust fumes (fuel). It would smell really sweet kinda, and steamy or white in color.

Head-gaskets dont just fail normally, yeah they can just break down overtime, but usually you run low on coolant, fans stop working, Tstat doesn't open, you get a leak which causes the overheating. The overheating then warps the head or decking and causes the head gasket no longer to seal.

Constant bubbles is new air entering the system, either from a leak or compression.

[modulexplode]

The only thing I had noticed really was the coolant res was a little dark colored to me. So most likely it seems like all fingers and thoughts are pointed at blown hg maybe?? I didn't get to check anything out it was getting dark and I have work in the morning so I left it at my moms across town.

[Wc240]

dont condem the headgasket without proper diag. have you checked your clutch fan? while sitting parked and running, with it overheating, sounds like a cooling problem(clutch fan, bleading, covered radiator) also, if a headgasket sitting long enough to boil, would be losing/burning coolant. since your resevoir is full, probably not. just saying check all the easy crap first instead of just goin right at the headgasket

[OutToWinPAHC]

Yeah check the other things first.

Fans works, is there leaks, is there intermix? Bleed it properly.

If there is intermix, check compression.

[Steady_One_S13]

^Indeed. Check those small things first. Then, bleed the system thoroughly.

[allenms240]

To bleed it, we just park up on an incline and take the cap off and idle the car, correct?For how long though