Fluctuating engine temps

[bourbon driver]

I just installed a 6.2 into my gas suburban along with a Banks Sidewinder package. In the process, I installed a brand new radiator, water pump, thermostat and heater coil and all new hoses. A few weeks ago, the temperatures fell to around 8 degrees one morning. Ever since, my temperature gauge has been fluctuating wildly -- over in the red, down to about 150, red, 150 -- it's driving me a little nuts.

The heater is acting weird, too -- it blows ice cold, then hot.

Any ideas?

 

[Russell]

Two things I'd check:

1. Make sure the cooling system is bled properly. It it has a bunch of air bubbles, it could be vapour locking till it nearly overheats, then have the thermostat open and allow a ton of cold water from the rad to gush into the engine.

2. Make sure the thermostat is working properly. If it is sticking shut till way over it's temperature, then sticking open till way under it's temperature it'll do the same thing, hold water in the engine till it overheats, then allow freezing cold outside water to flood the engine.

Either way, I'd fix it before I drove it anymore, those kind of wild temperature fluctuations are never good for an engine...

 

[BKinzey]

What Russell said It could be something as simple as the thermostat is in upside down.

 

[bourbon driver]

Thanks!

While I was home a few minutes ago I checked the radiator fluid level -- it was about a gallon low. I'm sure that wasn't helping, but I'll check the thermostat as well.

Thanks!

 

[kennyw]

If your low a gallon of antifreeze that would definitly answer the questions. Heater goes cold because no coolant is getting there.