Al B

Got the urge too get my C4 back too road worthy condition
Only has 36 thousand miles for a 84 ,
Purchased 20 plus years ago , Now were in our seventies , too fat, in/out tuff , wife complains car too hot , mufflers too loud .,
Considered Selling no market for C 4s , selling for a few grand ? NO WAY , So the vette sits , Might give it too one of my grandkids , THEY WONT MAINTAIN

Car has had over heating issues for long time , , Some times its fine , other times it over heats ??
. Since I seldom use it not an issue , but decided too correct

Always felt radiator was culprit , ( original )

Purchased installed new radiator today . Lot of leaves between a/c condenser & radiator but not enough too block air travel .
This model 1984 only has one cooling fan .
Always felt car ran too hot , ( if memory is correct ) factory set , fan too turned on around 225 closing around 205

While back , too help with vehicles temp , Purchased a low temp sensor . turns fans on 187 ,
Thermostat removed , ( can re-install ) sitting on table ( I am in FL )

Today after new radiator install , fan turns on 187 , After 15 minutes idling , ( Running with water , coolant when corrected ) ) water starting coming out thru radiator cap
Over heating ??? DAMN
Process of elimination , what else is left , water pump ???? replaced years ago , Water pump when NG leaks is it possible not turning fast enough too cool car
belt seems tight ,
Not enough tension on belt causing water pump not too turn fast enough, belt is new and tight ??
What else would cause over heating ?????????

THANK YOU

Hot Rod Roy

Are you sure the cooling system was completely filled before you started the engine? It sounds like you had a big bubble in the engine that caused the water to gush out of the radiator as the engine warmed up. Is the water that came out of the radiator rusty?

Al B

That's what I was thinking , at first , air pocket but I did not just fill it and start ,
I opened valve flushing entire system , while idling , Remember brand new radiator
Old rusted water came out but eventually entire system was flushed clear , Fresh water from a garden hose on top, coming out thru bottom flushing entire system , Eventually closed radiator cap , closed valve on bottom , Topped off from over fill contained this way entire system was filled , Ran and then over heated like my thread indicated ?
Water was coming from under radiator cap when radiator was totally filled ??? Should this happen ? Had no place too go , shouldn't it come thru overfill not cap
Cap should not let any liquid out ? , causing what I am thinking is over heating

Cruisinfanatic

leave cap off and run. Can you see circulating fluid?

Randy M

Just because water is coming out the radiator cap doesn't mean the car is overheating. What temperature is the water at when this happens? Have you replaced the radiator cap? Caps can go bad.

Al B

Hey guys thanks
I am going too get my buddies heat gun , and see what temps engine is running since my dash cluster has sun burn
This morning purchased new radiator cap , tight fit , no water coming from underneath lip , Also a new thermostat with gasket ,
. I removed other thermostat while back hoping it would help ,
As I said in my earlier post new radiator just installed yesterday
While back installed a Lower temp sensor turning fan on 187
This morning before I bolted down thermostat ran a garden hose water traveling thru
Topped radiator off with water , closed radiator cap and topped off water ;thru over fill hose ,,
Turned on car , after a short while fan kicked on , idled 15 minutes , started hearing hissing , Damn over heating , No water coming thru radiator cap so other cap was NG but still overheating ,
I am going too remove new thermostat and see what happens with water flow .?
What else could be blocking , water pump ?? failure
Water is circulating in radiator

thank you

383vett

There is a hose that goes from under the radiator cap to the coolant reservoir. Does this exist?

bac22

Possible the engine coolant temp sensor is bad providing false reading which might explain why sometimes it's been find and other times a problem. Otherwise If it's overheating idling then either there's a blockage in the system or the water pump isn't working correctly.

xrav22

Time for a water pump, it probably has a little rust ball for an impeller. The water pump should be done with all the things you are doing.
Also make sure thermo is installed correctly(just sayin).

Izzy Dizzy

Just curious, did you get a new radiator cap?

Al B

Upon closer inspection water not circulating very fast if at all .
Replaced water pump years ago , Life time warranty (, hoping box store has me still in system ) ,
New radiator cap did stop any water coming from under cap ,

thanks

65Z01

If you do change the WP be sure to fill with "coolant" not just water as the WP will need the lubrication.

Tom400CFI

No, no, NO. The water pump most definitely does NOT need coolant for "lubrication". IDK why this lore goes on, and on, and on...

The water pump's bearings are very well lubricated by grease, and sealed...so they don't know or care about what fluid is used for cooling. No, you do not need to "lubricate your water pump" with coolant. Nope.



.

BLUE1972

If I remember right the fan is turned on by the computer. This is actually in the dash. If the dash is bad then this may be an issue.

My 85 had issues. I ran a relay and temp sensor to the fan. No more overheating issues..

VikingTrad3r

is your cat plugged? that was the case with my 86.

https://www.corvetteforum.com/forums...the-cause.html