Hello all,
My 56 is over heating. I have replaced he radiator, thermostat and flushed out the system. The hot light is still coming on. When I run the car with out the radiator cap on it does not over heat. With it on it does. It is a 327. I have tried two different types and they nether work. I am thinking it needs the OEM with not safety valve to it.

Thank you in advance for any and all help.

Joe

 

A 327 is a Chevy sized Engine, unless you meant 324 cubic inch

 

From memorie you need a 7psi radiator cap if its a 324ci , thats what my 55 has and was recomended, check the ones you are using and go from there.
cheers chris.

 

What temp is it reaching???

 

Not sure how hot. But the hot light came on on the dash.

 

borrow or buy a hand held infrared temp sensor to measure the temp at the radiator to determine it in fact it is really overheating. When looking down the at the liquid does it appear to bubble and boil or does it flow steady?

 

if memeory serves me, the hot light comes on at 211 degrees.......john

 

I got a infrared thermometer. It reads 211ish at the thermal sensor. At the thermostat cover it reads 220. At the radiator cap it reads 215. These are the temps when the hot light comes on. A couple questions for this.
Would a bad head gasket cause this?
Would old fuel be a cause of this?
Any other thoughts?

Thank you

Joe

 

well, water pumps are cheap and i didnt see that you replaced it already. give that a shot. i had a similar problem a year or two ago with my olds, it turned out the rad shop didnt repair my rad like they should have. half of it was clogged. check to see if you have any cold spots in the rad......john

 

John,
The entire bottom of the rad is cold. Even where the coolant hose connects to the e gone at the bottom side is cold. The top portion is hot. About 220 degrees. I know the pump is working.

 

Sounds like a highly restricted radiator, if the lower hose is not kinked or blocked and water pump is pumping.

Pull the radiator and put the cap on. Hold a garden hose int he top hose and crank it up full blast. There should be no restriction as it comes out the bottom.

How old is the water pump? There have been uncommon times when the impeller freewheels on the shaft or where it has been rusted to next to nothing...

 

I agree with the above, joey lights i did see in your starting thread that you flushed the radiator but if you have done this with a hose it probably isn't enough , after 50 plus years (if its the original radiator)lots of crud can build up, i would suggest pulling the rad out and giving it to the experts to flush and service.
cheers chris.

 

I was thinking about installing one of these radiators out of a 55-59 chevy truck. If you look at the over all dimensions they are about the same size as our radiators. I only see two problems; one the mounting brakets would push it foward a bit which I think I could get around, and two the lower outlet would be a problem for you guys with stock engines (324s)

http://cgi.ebay.com/ebaymotors/?cmd=...K%3AMEWAX%3AIT

 

???? Why would you even think for a moment about putting a truck rad when you could get an original rad with "NO" alterations.....!!

 

I would look into the water pump.

 

From who, do you have a link or a place that sells these also do they sell aluminum ones?

 

I don't have links for you. but any Radiator and gas Tank repair facility can order a new Rad Core and install it with your old top and bottom Tanks.
I do think like what has been said earlier in this Thread that your Water Pump is quite suspect with your problem. when you have your Rad removed it's really easy to remove your Water Pump and check out the empellers to see if they have deteriorated and causing your problem.

 

Is this the second radiator in this is car?Your thread states that you replaced the radiator, did the original also heat up? Is the last radiator new or just a second hand extra? If new I would look for some other problem other than radiator.You might have a bad radiator cap or as mentioned before need a recore.....Tedd

 

Well I think it is solved. It is a recored radiator, new cap, new thermostat. What I ended upndoing is drilling a 1/16" hole in the thermostat. I read that people have done that before. I guess there was a air pocket around the thermostat that was not letting it open. I feel heat at the top of the rad and then feel it cool down as it goes to the bottom.
Thank you all for your help. Hopefully this will be it for the heating issue.

Joe