95 Roadmaster over heating

V8, both rad fans work. Only one comes on when vehicle is running. Put 12 volts to the other fan while vehicle was running (for max cooling) but car still overheated. New termistate. Vehicle has been flushed out 3 times in the last 6 months. Primary and Secondary fuses and relays are good. Still over heats. HELP....

Thanks

GT

What do you mean by over heating? Is it boiling over or does it show hot on the gauge? I ask because if you are going by the gauge it could be a bad sending unit. The second fan only comes on when the a/c is turned on. Go to Impala SS Forum.com and do a search. There you will find answers to any question you will ever have regarding your RM

What do you mean by over heating? Is it boiling over or does it show hot on the gauge? I ask because if you are going by the gauge it could be a bad sending unit. The second fan only comes on when the a/c is turned on. Go to Impala SS Forum.com and do a search. There you will find answers to any question you will ever have regarding your RM


I let it run for about 1/2 hour. With the cap off the rad fill tank, it just keeps getting hotter and hotter until it just starts boiling out the fill tank. I even tried to vent any air at the vent screw on the tstat housing. Temp gauge rises with water temp and will get about one mark from the red. At that point I shut her down. The second larger fan motor on the drivers side will never comes on. With the A/C or Heat on max it does not matter. To see if the larger fan worked, I put 12 volts to it directly from the battery and it did run. As the vehicle was running I jumped the larger fan with 12 volts. Now with both fans running the vehicle still overheated in about the same amount of time.
So as before I still have two problems with this vehicle. One, overheating and two, the larger rad fan does not come on.

Thanks guys


GT

Have you replaced the fan relay? That might correct the problem of the fan not coming on. Have you replaced the water pump? On your LT-1 the pump is driven by the cam and has no belts to drive it. Even if the pump is not leaking it could be bad.

Have you replaced the fan relay? That might correct the problem of the fan not coming on. Have you replaced the water pump? On your LT-1 the pump is driven by the cam and has no belts to drive it. Even if the pump is not leaking it could be bad.


I swithed out the secondary fan relay with the primary fan relay and the small fan on the passenger side works, as before. The secondary fan (driver side) does not come on. Same as before. The water pump has no visable sighns of leaking. At one time I did flush the block out at the tstate housing. I ran water thru the block until it was clear and hot. Indicating circulation thru the block and a working water pump.

I'm going too try and get a manual. I must be overlooking something that is not of a usual problem. Please keep the comments coming.


Thanks all


GT

That's it for my ideas. I missed the LT-1 boat, I have a '93 RMW, so try the Impala SS Forum. There is a lot of activity and you will get all the answers you need.