Hello,
I have a big block that runs at 230 degrees when its hot outside . When the sun goes down it runs at 210. Replaced loose cap on overflow with new. Fan spins about 1/2 turn when car is turned off. Color in radiator is green. Bought a 160 degree thermosat. Don't know if that willl help ?? What would be my next step??

 

Make sure the seals around the radiator are in place and in good shape. They're critical to make sure incoming air goes through the radiator and not around it.

Make sure the radiator fins are clear and unclogged. Also make sure the cooling system is clean and no restrictions.

Other than that, big blocks pretty much run hot regardless. You can try backing off the timing a bit and add some Water Wetter or 40 Below to the cooling system.

 

I think you want to keep as much timing in as you can to prevent running hot. The b/b in Texas do run hot, you may need to upgrade to an aluminum radiator. I have an aluminum radiator on order to help with a hot cooling system (I'm in Texas also). Tom (DeWitts radiators) promises 30 to 40 degrees cooler coolant temps...(J/K Tom... ).

 

manco10

I used to live in Vegas and had the same problems. I upgraded to an aluminum radiator, electric fans & hi flo aluminum water pump. I stay at 190 degrees no matter the outside temp or if am sitting in traffic, doesnt matter.

Stock setup will work adequately provided radiator and seals are new, shroud is complete and fan is working properly.

Cheers,

Crunch

 

Add to the list of items to check is the air dam, make sure its in the correct position and not bent up. Getting the radiator and cooling system properly flushed might help a bit. The 160* thermostat will not help, it only sets the minumum operating temp, does nothing for the top end. Electric fans are a good upgrade, especially if you drive in the traffic quite a bit. With the temps you indicate, the thermostat is wide open and the cooling system is doing all it can do in its current condition. Areas to improve are in effeciency: Air Flow and heat transfer, namely from the coolant to outside air. Crud collected inside the water jacket and radiator will interfere quite a lot with heat transfer. And any improvement in air flow is a good thing.

 

I'm sorry, but that's no way to judge your coolant. I have milk in the frig from January and it's still white....want some?

Seriously, if you don't know the exact age or makeup of the coolant then you should replace it. That probably isn't going to help you with the cooling issue but you should know exactly what is in there and what it is. The type of water is important (especially with alum. rad) because well water, softened water, and city water will all have minerals in it.

You will get many comments on the forum and maybe 50% of the advise is going to be correct. The first thing I would do is confirm your gauge reading with an (IR) infrared gun. Many of the replacement sending units read high and people that THINK they have a cooling problem really don't. Your original radiator is copper with brass end tanks and these can be rebuilt or even cleaned (rotted out) by a local radiator shop. The end tanks are removed, the core is cleaned, removing any internal crud and scale. Don't let anyone do a "flow test" as this will prove nothing. The radiator could be 70% plugged and as long as it passes any fluid the shop will tell you it's still good.
You should make sure the seals are in place and that the clutch fan is operating correctly. Cars with vacuum advance cans on the distributor can overheat when the diapham dies. Check to see if you get 12-15 degrees advance when connecting the vacuum hose, if not, replace the vacuum advance. A system that is retarded to much will overheat at idle. If in the end, everything checks out and you want/need more cooling, then an aluminum radiator will drop the temps about 30 degrees vs the copper unit.

 

What year vette? Are you sure it is overflow or reserve?

 

i have to go with the air dam also, i replaced everything related to cooling; water pump, hoses, radiator, electric fans, all helped a bit but not as much as the air dam.

 

You guys have to remember that some of these system are closed. The radiator cap is for that model, if you us the wrong cap you could be drawing in air. On the later models, the radiator fluid pulls and pushs back from the reserve. If the reserve is empty, you start pulling air.

I betting he has a load of air in the system. I live in Dallas/Fort Worth and it hasn't really got hot yet. Just around 89 for a couple of days.

 

i agree with tom-
I have a 67 big block and had simular concern-had all new system with high flow water pump-still got hot-found replacement sender not accurate-reinstalled the original and problem solved-
double check the actual temperature

 

As mentioned a 160 degree stat will not help. Are you running a fan shroud? It is absolutly critical that the rad seals to the core support so find the fatory parts or find some heat resistant foam. Not only does the rad need to seal to the core support so that the air dam is effective but you must seal every air leak between the rad and shroud because if not even a small leak will allow a lot of air to be pulled around the rad and not through it.