Need Help: Water Pump Removed - Heating Issue?

[camaro1969]

Background: 1969 Camaro, running a 350 sbc, aluminum radiator with electric fan (sucking air from grill inwards), 180 degree thermostat. While driving, I tend to start overheating quite quickly. Within 5 minutes of my drive, i reach 180 degrees, within 20 minutes i am about 200, and if I am idling in traffic at 200, I will reach about 220-225 within 4-5 minutes.

To find the bottom of my over heating problem, I pulled my water pump to see whether it could be a counterclockwise rotation on a v-belt system.

Are you able to tell by the picture whether the water pump i have is the correct water pump for my application? I run the belt on the grove side of the pulley and the pump pulley rotates clockwise (looking from in front of the car).

That being said, the water pump is a generic china brand, Dynapak np1063, I couldn't find more details, other than there is a "B" casted in the inside of the water pump housing. *see image* Can you recommend a good water pump replacement, american made?

Thanks

https://www.dropbox.com/s/lihd2fztdt...531_094530.jpg
https://www.dropbox.com/s/8aickcoph2...531_094538.jpg

[Vince@Meanstreets]

Has it ever boiled over?

[Che70velle]

Vic, those numbers aren't insanely uncommon. My z06 corvette was the same way. Does the car eventually boil over?
What do you know about the engine as far as over bore, compression ratio, and ignition timing? Does your radiator have a shroud on it, or just a fan mounted on the core?
I can't help you at all concerning the water pump.

[camaro1969]

it has never boiled over. the hottest its got to was about 235, and i got it home just in time to let is cool down.

overbore is .30, originally a 327 block. I do not know the compression ratio and i haven't checked the timing, i can check.

fan has a shroud build on it.

[Vegas69]

At the rate your temp rises, I bet your cooling fan is undersized. If the rest of your cooling system checks out, better electric fans or a gm clutch fan and shroud are in your future. Two twenty five in traffic is just to hot for an old school small block with a carb.

[GregWeld]

Here's what I always ask guys when they come to my place with an "overheating" issue.


What are you going by for your temperature?


The gauge?

An infrared gun that has taken temps on the inlet and outlet of the radiator to see if there's a temp drop?

Does your "gauge" match the readings of an recent assessment of the motors temp?


WHERE in the motor is the temperature gauge? Head? Block? Near Thermostat?


If the gauge creeps up in stop and go traffic - or at a stop - does the gauge show immediate cooling off if you begin to move? Or does it stay high?



What does the gauge read - say - cruising along at 45 or 50 MPH?

[camaro1969]

thanks todd.

@greg, as most users have mentioned, 225 is just too hot, i am aiming for under 200 at any given time (whether in traffic or whether driving).

I am using my autometer gauge to monitor my temperature.

I havent used an infrared gun to test inlet and outlet temps, I can and will after I put the water pump back on. At that time i will compare the gauge to gun.

The gauge is near the thermostat, in the front of the engine on the manifold.

Stay im at 220-225 while sitting for a few minutes, when i start driving it will start going down eventually to around 210-220, will not go below 200 what so ever.

At cruising speed, gauge reads around 200-215. I am at 180 for only about 5 minutes or so, even when cruising, and then will go up to 200+ where it will stay for remainder of the drive.

Temp outside when is 15 degree's celsius or more.

thanks for the help.

[GregWeld]

My guess is your gauge is off by 20* -- and your cruising at 180 -- and traffic has it up to 190 - which would be normal - although like Todd said - your electric fan should hold the temp + or - 10 degrees... and should be able to kick on at a stop and then cycle.

Keep us posted.

[Che70velle]

The temp never coming down below 200 while cruising rules out the fan, but as stated above, you can't always trust the gauge.
If your radiator is the correct size, and relatively clean on the inside, and assuming the gauge is accurate, then either the water pump isn't doing its job, or the thermostat is malfunctioning.
You run a lot of rpm while cruising?

[Vegas69]

I agree that it should run cooler than 200 down the freeway unless you are turning some rpms or you have a 195 tstat. It's to early to rule out the fan for low speed operation in my opinion.