Home page

Cool! NEW FEATURE! Add "Your Corvette Story" today

C3 Engines

Back to top of thread

Re: Engine overheating (8/18)
 6/13/17 7:11pm
manchestersharkLifetime Member
Lifetime Member
Send Private Message

Equinunk, PA - USA

Vette(s):
1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.


Joined: 10/31/2007
Posts: 1981

You could also by pass the temperature switch and wire it hot to a manual switch. That way you could turn it on and off at your leisure. It also assures you it's on and running.
Re: Engine overheating (9/18)
 6/13/17 11:05pm
73shark
Standard Member
Send Private Message

Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 549

Is the area between the A/C condenser and radiator clean? 

Are all of the seals around the radiator intact and in place? 

Is the air dam under the front end there? 

Might check the t-stat in boiling water to see if it opens all the way.  Saw a statistic once where about 20% of new ones are bad.

Is the spring in the lower radiator hose that keeps it from collapsing?

Assumptions I made are that the electric fan and engine-driven fan are operational.

______________

1973 L-82 4 spd

Re: Engine overheating (10/18)
 6/14/17 5:05pm
Toplander
Former Member

Send Private Message

Athens, IL - USA

Vette(s):
1975 coup 4speed leather interior. Silver with oxblood interior


Joined: 7/13/2016
Posts: 3

I have the same problem with my 75. I have a new Champion 3 core radiator with dual electric fans and fan shroud. I have removed the factory fan and clutch, changed thermostats from 195 to 180 and now back to 195 with a single 1/8" hole drilled in it. The fans come on at 180 degrees and are blowing the correct direction (pulling air through the radiator and blowing out towards the engine). When replacing the radiator i also replaced the core support, all the radiator seals and the air dam  underneath. My temp gauge reads 230 degrees which I have verified with a heat gun. So far I have tried everything i can come up with on forums except replacing the lower radiator hose, mine does not have a spring in it, but by watching it it does not collapse and both hoses are hard from internal pressure. Any Ideas?   

______________
Re: Engine overheating (11/18)
 6/14/17 5:14pm
gtr1999
Limited Member
Send Private Message

CHESHIRE, CT - USA

Vette(s):
1969 350 4 spd drop top 1972 350 auto coupe


Joined: 5/2/2016
Posts: 61

check timing and carb for being too lean.

______________
Re: Engine overheating (12/18)
 6/14/17 5:44pm
Toplander
Former Member

Send Private Message

Athens, IL - USA

Vette(s):
1975 coup 4speed leather interior. Silver with oxblood interior


Joined: 7/13/2016
Posts: 3

I did notice today that my glass fuel filter at the carb is never full and fuel flow only seams to be a small squirt every so often. I have already ordered a new fuel pump as mine does look to possibly be original. I will also borrow a timing light to see what the timing is set at. The engine has always run very good. thanks for the help, I will let you know what i find.  

______________
Re: Engine overheating (13/18)
 6/14/17 9:12pm
Tomtall
Former Member

Send Private Message


Vette(s):
1973 Coupe -- 454 / 4 speed - Black on Black, Greenwood aftermarket turbo hood, Greenwood GTO style front bumper.American Racing Vector rims.


Joined: 3/5/2016
Posts: 43

Fan shroud in place ? Ignition Timing correct ? Collapsed radiator hose ? Slipping water pump belt ?

|UPDATED|6/14/2017 6:12:32 PM (AZT)|/UPDATED|
Re: Engine overheating (14/18)
 6/15/17 3:17am
stingrayjim jrLifetime Member
Lifetime Member
Send Private Message

SHELBYVILLE, TN - USA

Vette(s):
1976 L48 auto

1978 L82 4speed

1994 LT1 6speed


Joined: 7/5/2002
Posts: 3942

Toplander.  You might have an air bubble in the system....try running it with the cap on loose and see if there is a difference.... and besides the lower radiator hose, you might have a water pump issue.??  Hopefully it isn't a  head gasket....

And the fuel filter, mine does that too, i have one of the glass type filters with the replaceable filter. Using an electric holley blue pump it doesn't fill up either, but it gets fuel, so, all that really matters :)
 


|UPDATED|6/15/2017 12:17:30 AM (AZT)|/UPDATED|
Re: Engine overheating (15/18)
 6/15/17 8:42pm
gtr1999
Limited Member
Send Private Message

CHESHIRE, CT - USA

Vette(s):
1969 350 4 spd drop top 1972 350 auto coupe


Joined: 5/2/2016
Posts: 61

Hi Guys
Just one thing, please get rid of those glass inline filters those are very risky, if they break you have a fire.


______________
Re: Engine overheating (16/18)
 6/15/17 8:50pm
Dblancha79Gold Member
Gold Member
Send Private Message

Weatogue, CT - USA

Vette(s):
1979 C3 L82 350 cu in


Joined: 6/29/2015
Posts: 38

Thanks all for ideas. I think I found the issue. The air dam was flopping so I wired it open awhile ago to get max air in the engine compartment that gets so hot. When the car idles I think the engine fan pulls air from the open air dam vs through the radiator.  Also when I installed the aluminum radiator the fan shroud doesn't fit tight to the radiator. I'm in the process of buying rubber seals to add to the shroud.  I also don't think the new temperature switch I bought some time ago works right. I put it in boiling water but can't get an ohm reading through it.  I may just wire the electric fan to a switch as suggested as I know the electric fan works if you get 12 volts to it.

Thanks everyone.


______________




"Made to be run hard"
Simsbury, Ct.
Re: Engine overheating (17/18)
 6/18/17 9:48pm
Toplander
Former Member

Send Private Message

Athens, IL - USA

Vette(s):
1975 coup 4speed leather interior. Silver with oxblood interior


Joined: 7/13/2016
Posts: 3

My car was definitely running lean because of a weak fuel pump. after replacing the fuel pump the filter remains full and performance is much better, as far as temp goes todays test drive it ran 205 degrees, although the air temp was only 80 compared to 95 when it was running 230 plus. I will still check timing and try with rad cap loose to see what happens. thanks again for all the help.    

______________
Re: Engine overheating (18/18)
 5/19/19 5:51pm
Dblancha79Gold Member
Gold Member
Send Private Message

Weatogue, CT - USA

Vette(s):
1979 C3 L82 350 cu in


Joined: 6/29/2015
Posts: 38

So a continuation of my problems from 1/17 post. I thought I solved the overheating issue with the 160 degree thermostat but only on normal street driving.  At time trials yesterday after 3-1/2 laps it overheated again and I believe I burned up some connecting rod bearings based on the noise coming from the bottom of the motor. 

I've checked and or fixed all the suggestions from the 2017 post so I am at a loss as to what it could be.

The two thoughts I have is not enough air is getting through the radiator because of the transmission cooler in front or the duel fan set up I have has to go and side by side fans installed.  Any Help would be appreciated.

FYI: I was running the car between 3500 and 4500 RPM in second gear on the three speed automatic transmission for maximum torque through the turns. It should take it in my mind without overheating but does someone know differently?



______________




"Made to be run hard"
Simsbury, Ct.