Overheating Problems!

[Vipersix]

I have a brand new four-core aluminum radiator, twin electric fans, and an electric water pump. I just replaced my thermostat with a new 180 degree piece and drained, flushed, and refilled 70% coolant. Even with all of this, my temp increases about 75 degrees within 20 seconds with no inclination of stopping.

The only thing I can think of is maybe my water pump is going bad. Any ideas?

 

[Darrin]

Just for craps sake...Put the stock fan back on and run it without the electric ones. If it works then the fans don't pull enough....also check the fan rotation...a buddy hooked his up and the wires were backwards and it was blowing not pulling.

 

[HISSIN50]

Water rejects heat ~2.6 times more efficiently than E/G coolant. You want to bias the stoichiometry towards water. You need enough coolant for corrosion resistance, freeze protection and lubrication.


That said, that's not the issue. Are you sure the system is burped? Rapid fluctuations in temps are often due to air in the system.

I would pressure test the cooling system.

Though you're hardly stock, here's a little tech note on cooling systems (biased towards 94-95's).

If you post more info about how it operates at speed vs stopped, what kind of gauge you're using, where the sender is, etc, we can try to help more.
E.g., if your sender is in the t-stat housing, you can see a rapid increase in the reading.

Good luck.

 

[68keyblr]

I just had a very similar problem. All new parts, including a high volume water pump. Car ran nice and cool until one day the temp kept going up. No leaks, no weird noises. I noticed the fluid was stagnant in the radiator, so I figured I had a stuck thermostat - replaced it and still the same thing. I tore off the water pump, and the impeller had busted off of the shaft!

Replaced the high volume water pump with my stock slightly used water pump and it works fine, runs at the same temp.

Start the car (engine cool) with the radiator cap off and let it idle. Put your left hand on the upper hose so you can feel it heat up when the thermostat opens. When that happens, you should see the coolant in the radiator start moving as the coolant starts to circulate.

If the coolant stays stangnant after the thermostat opens, then your water pump is bad.

 

[HISSIN50]

68, did you have any weird noises due to the separated impellar?
Just curious.

 

[68keyblr]

surprisingly, I didn't. The weep holes were clean and I'd never seen a water pump physically fail like that, usually just get seepage out of the weep hole when the bearings go bad.

That high volume water pump had caused a ton of problems though -

1. Blew a heater hose off and drained the coolant.
2. After I fixed #1, it split the heater hose.
3. Replaced the heater hose, then it blew out the backing plate gasket.
4. Impeller broke off of shaft.

Conclusion - don't run a high volume water pump unless you *have* to. The stock pump keeps my 331 10:1 motor nice and cool.

 

[Vipersix]

1) Yes, both fans are sucking, not blowing. They are dual speed fans so maybe I'll try bumping them up to their max.

2) The engine runs fine (i.e. cool) when I have my blower disconnected; the only time heat is an issue is when I install the blower belt.

3) I also thought maybe it might be air in my system but I can't figure out any easy process to ensure the air is out other than starting and stopping the pump. I can only run the engine about a minute or two before I have to shut it off to avoid heat damage. I suppose I could run it a while with the blower belt off though... there's an idea.

4) Water is definitely moving through the radiator though it seems to me to be a bit sluggish. I may try taking the thermostat back out and try circulating the water around the entire time.

5) This puppy doesn't operate at speed unless I'm pushing it down a hill! I just finished building this engine and am still attempting to tune it. Can't tune it if I can't keep it from overheating though!

6) Just so you don't get confused with my setup, this is not your average 94 Mustang. The only thing '94 on it is the body. No computer, no engine, nothing. I flip a switch to turn on my water pump and I flip a switch to turn on my fans. It's all or nothing.

 

[91foxbod50]

Holy ****.. that things friggen nutts ^