Hi

I have a 1994 Accord LX with a cooling problem.

I just bought it so I have no history on it.
I had it inspected ( insurance required) and the Honda shop said it
had a hole in the rad. It was not overheating or anything but
I could see that it was leaking and the whole rad had that green corroded
look.
So I bought a new rad and installed it along with a new
thermostat and filled it up with coolant .
Now I start it up and within 5 minutes the temp gauge goes up to
the redline.
Meanwhile my upper rad hose is Hot and my lower hose is Cold.
Also both fans on the rad do NOT turn on at all.
I have no idea if they came on or not before I replaced the rad
But the car was not overheating on a long ride home so
I am thinking they must have been working .
I have reattached all connections ( fan switches etc)
Don't know what it could be.

Any helpful advice would be greatly appreciated

 

If the lower radiator hose is still cold, the thermostat has not open. There also may be air pockets trapped in the cooling system if the thermostat did not open during the air bleeding process.

 

I did not initial bleed it because I did not know about the bleeder valve until you mentioned bleeding the system .
So I just went out and opened the bleeder valve about halfway and started the car , same result, car was at redline
within 5 minutes and bleeder valve was showing no purge

 

You need to drain the coolant out, then add the coolant, with the bleeder valve open. Check that the thermostat is installed correctly, and that it opens.

 

I can try that but I don't see the difference between what you are suggesting and the coolant being already in the rad right now

 

These are some general steps to purge the air out. It may be a problem with the thermostat or installation if it continues to overheat without the thermostat opening though.

1. Turn the heater control to max heat.
2. Remove the radiator cap.
3. Some Accords have an air bleed bolt near the thermostat housing, where you would loosen the air bleed bolt, then fill the radiator with a 50/50 coolant mix to the radiator neck. Tighten the bleed bolt as soon as coolant comes out in a steady stream without bubbles. But, this is not always necessary and sometimes ineffective. (This step can be skipped or may not be applicable to your car.)
4. If you want, you can jack up the front of the car which will help to get the air out easier. But, not necessary. (This step can be skipped.)
5. With the radiator cap off, start the engine and run it till it is at operating temperature. Add coolant as necessary. This may take a while, I usually run it until I see no more bubbles or air coming from the radiator for a while.

I usually rev the car up a little while the car is warming up to help get the air out and to open the thermostat faster, and refill as necessary along the way. Later, I will also feel the lower radiator hose to make sure the coolant is warm which tells me the thermostat has opened. (But, be careful of the fans, belts, etc.).

 

thank you for that info but I did all that and have the same problem ( gauge was redline before the bleeder valve even had a chance to purge anything

 

the fans do not come on so it heats up fast !

 

The bleeder is only opened when filling the coolant with the engine off.

The main purging is done at the radiator filler opening.

The fans won't come on until the coolant temperature is above 199 degrees F.

Either the thermostat was not installed properly or not functioning properly or some other coolant flow problem.

 

If you can't even purge the cooling system without it overheating, then either check the thermostat installation or just take it out and see whether it still overheats right away.