82Powerhouse

1982 Corvette
350 CID

I replaced the original fan and electric fan with 2 Hayden fans. 3710 16 inch at the back of the radiator, and 3690 14 inch in front of the radiator. The radiator is double the size of the original one. The problem is that it is overheating now. I looked at the Hayden website and 2 3690 14 cinch fans are recommended, totaling 2500 CFM. What I put on totals to 2750 CFM. This looks like it should be enough to keep it cool. I believe that the water pump is working, if not, then that is the cause. Any ideas?

TIA,
CDM

chris75stingray

are the fans spinning in the right direction?

is it running cooler on the highway?

what temp are you running?

82Powerhouse

The fans are running in the correct direction.

it still gets hot on the highway.

She just continually climbs to the red zone of the temp gauge - 260 I think.

pauvil

how's the t-stat?? is it opening?? try taking it out and see what happens...

isosceles

did the over heating problem happen gradually or temps just started climbing one day? Did it start once you removed the mechanical fan?


While the motor is COOL, remove the radiator cap and start it up. Once it gets up to 160-180, the T-stat should open and water will start moving to the radiator. You should be able to see water squirting out the ends of the tubes in the radiator if you look in the tank with the cap off. If not, rev it a little then look. Be careful of a backsplash or burp of air. Don't want to get burned. If you rev it and still no coolant moving, the radiator could be clogged or the water pump is bad.

Check for vacuum leaks. Plug every vac port on the carb except for vacuum advance.

Check timing. Not enough advance will make it run hot (Thanks Matt G.)

Pull the plugs too. If the mixture is too lean it wil be really tough to cool down. The lean mixture could be caused by a vacuum leak.

those little Haydens might not have enough flow to work. I had to get a monster Bosch fan with a shroud out of a Volvo to keep my L48 cool with the A/C on down here in SW FL.

Boofers

How are you turning the fans on and off? Maybe the fans are not on enough. If you have a temp sensor perhaps it is rated too high or not mounted in a location that heats up enough to turn it on. With the fans on does it feel like a whole lot of air is being moved through the rad?

bs82vette

OK,the engine side of the radiator fan 3710 has reversible blades per Hayden and you have it pulling towards the engine?
The fan mounted on the front of the radiator also has reversible blades also and they are pushing towards the radiator?

pws69

First thing I would suggest is to remove the front (pusher) fan and see what happens both at curb and on the road. Pusher fans CAN be helpful but they have been proven to be OBSTRUCTIONS in many cases - particularly on the highway.

The other thing I seem to remember [but cannot substantiate at this point] is that when running pusher AND puller fans, they should be the same size/CFM or they will "fight" each other.

holley505

Check your factory Gauge.... It could be a bad gauge... at 260 degrees I think it would smoke and stall out. Has it boiled over yet?

THE ROOSTER

you haven't changed the temp. probe in the motor have you???

In our motor swap, we changed/purchased a new one & our gauge did the same thing, pulled the old one out & installed in new motor & no problems since!!!

82Powerhouse

Yes it has boiled over, and it starts to sound bad once the gauge says it is that hot.

BerniesVette

Once you have checked all the things listed above. And if it is still overheating remove the thermostat and, either, throw it away or replace it with a high flow mode. I recommend running without it personally.
Bernie

THE ROOSTER

it could have an air pockect in the cooling system... Try jacking the rt. side of the car up & with the rad. cap off, run it for a while adding fluid as needed... Might want to have a someone in car to turn it off quick, if needed!!!

82Powerhouse

I examined the Theromostat, and I think it was too small. This is a new one that I put in at the same time that I did the fans. I took it out and will see what it will do now - once the silicon is dry of course