[Kiri68]

Right before winter I bought a 1968 Chevy Impala with a 327 in it. Small blocks are supposed to run between 190 - 210, and it was running at 190 until I drove it on a 60 degrees F day (first actually warm day) and it got up to 220. It ran 220 on the way to a friends house, but ran at 210 on the way back after it was dark and had dropped by 10 degrees outside. I really don’t want it running that warm and it’ll only get worse the warmer it is outside so it’s been parked for a few days. Where should I start in figuring out why it’s running hot? I’m new to owning a classic car so I’m just looking for some advice.

 

[Ed Jones]

Not familiar with older models really but how’s the overflow tank look? Assuming it has one.
if not, flush with water and see if it’s coming out gunky or clean. I had an issue similar with an 04 i bought. Smoking, overheating quick and causing to lose power uphill. It did need some new hoses but 90% of the issue was Oklahoma red dirt inside the cooling system

 

[Ed Jones]

Posted comment twice my bad

 

[62BillT]

Also, replace your Thermostat. It could be sticking.

If it still runs hot, just let us know.

 

[Kiri68]

Also, replace your Thermostat. It could be sticking.

If it still runs hot, just let us know.

I actually purchased a 180 thermostat with the intention of replacing it. I think they came stock as a 190? Not sure. That was the first thing I wanted to do but I wasn’t sure if there was anywhere else I should look first before flushing and replacing the thermostat.

 

[Brhatweed]

They ran far lower in those days, check the factory books but I believe they were in the 160F range for the 327. Regardless of the opening temp 220F is not "overheating" but only cause for concern, steam pockets in the heads or restrictions in the radiator would be my first suspects. Is this a non factory AC car with only a 2-row radiator or something aftermarket?

 

[62BillT]

I actually purchased a 180 thermostat with the intention of replacing it. I think they came stock as a 190? Not sure. That was the first thing I wanted to do but I wasn’t sure if there was anywhere else I should look first before flushing and replacing the thermostat.

Flushing the Radiator would be a good idea as well. You may want to do both at the same time.

Also, make sure you don't have any leaks anywhere. If it gets hot again, shut the car off and inspect it closely. A leak can raise the temperature pretty quick.

 

[Rick Mann]

Here's what to do. 1) You've already got a 180 thermostat 2) Check the flow through the radiator. If it's original or don't know how old it is... replace it. 3) Get a Prestone radiator flush kit and backflush the cooling system OR take it to a shop. Check the condition of the water pump. 4) Check the timing.