Forgot to put rad cap back then almost overheated (1 Viewer)

[OTEP]

I was doing some work on the motor when I forgot to put the rad cap back on. I went to run an errand and drove the vehicle with the rad cap left at home.

It started to overheat (needle went to almost red). And when I popped the hood, there was some coolant loss (i needed a large water bottle to fill it up again).

Is it normal to lose coolant when the vehicle is driven without the rad cap?

 

[lp2k]

I would suspect yes, with the heat and everything going it will spew out

Sent from my iPhone using IH8MUD

 

[dontblink]

Yes, it's definitely normal.

That cap is meant to release the pressure when the coolant expands.

You need to burp your system now to get all the air bubbles out.

Crack a beer, open the coolant reservoir tank and run the engine with the heat on high for 10 minutes or so. You'll see the air bubbles working their way out.

Top off as needed.

 

[OTEP]

Thanks! Got me a bit worried there. Felt like a total idiot for forgetting to put the cap back on.

 

[NLXTACY]

Is it normal to lose coolant when the vehicle is driven without the rad cap?

Only if you drive it long enough to let the truck warm up to operating temperature. That's when the thermostat opens up and the water starts flowing. Then its going to start puking.

Bigger issues is that the system is supposed to be under pressure. For every pound of pressure you put on a closed system, at sea level, you increase the boiling point ~3º. So a 12# cap will increase your boiling temp an additional 36º to 248º. When there is no pressure on the system you reduce the boiling point.

As mentioned, you need to spend the effort to properly burp the system/purge of air.

 

[OTEP]

Considering the high ambient temps here (around 37 degrees C), I drove about 20kms in mixed urban before the needle went up. I actually noticed it while stopped at a pal's house to drop off Christmas presents. Had time to shut it off and cool down.

Learning the art of burping now.