My car's been running really hot the past few days (just under the max line), today it overheated at a stop light, got an 0334 code, and overflow reservoir was boiling. Top and bottom hoses were both hot (very hot), and there is no leaking. Should I try a thermostat/flush first, or is it probably a blown head gasket?

Thanks...I know zip about the coolant system, so not sure where to begin.

 

Change out the thermostat. Same thing happened to me last week. Bought an oem thermostat and replaced it. Refilled coolant and bled properly. No more overheating.

 

So you kept driving it despite the overheating? Nice.

Head gasket blows as a result of overheating, won't be the root cause.

Are your fans working? That can cause an overheat in traffic even if everything else is working good.

 

Yeah...not the best decision I've made. I was going to work on it this weekend, was hoping it would be ok.

The fan is blowing, but it's a lot noisier than I remember it being.

I'll try the thermostat this weekend and see if it helps.

 

Yeah last summer my Z started overheating. There was no leak, fans worked so I guessed it was the thermostat being stuck. After my friend came by to drop off some tools I was able to remove the thermostat and cut out the springs. It worked, i was able to drive with the needle at 40% from overheating.

Needless to say the first stop i made was to a dealership to pick up a brand new thermostat. They're about $30, I dunno why you'd risk it. Now if I were you I'd be worried about the engine since the car did overheat.

Next time just drive without a thermostat if you really needed to drive the car!

 

this +1

 

My thermostat got somewhat stuck during my last time attack event.

I drove home and I revved the engine up a couple of times to help thermostat open a bit when it's time to switch coolants (when water temp needle moves up). The trick works because the temp needle goes down once you do that.

 

Update: Thermostat install fixed the issue, what an easy fix. I feel like an idiot for not doing it the first day it ran hot, it was ridiculously simple.

$30 for thermo and gasket, put a drain pan under the car and swapped the thermostat (I didn't drain the coolant, I lost maybe a 1/4 gallon by swapping it out as quick as possible), top off, bleed, and done. The longest part was waiting for the car to cool off to bleed the system.

 

Ugh cooling system is always a pain. Glad to see you got it fixed.