Cooling Fan Sensor Help

[LDO]

I have an early model 283 that does not appear to have any sensor ports in the heads. I only have one on my intake manifold which goes to the temp sensor. The 2nd sensor that turns on my cooling fan is currently mounted into the normally plugged top hole on the water pump. This port doesn't seem to have the flow needed across the sensor to turn on my fan. Yesterday, my temp sensor read 207 and my fan never came on.
- I know the temp switch closes at the 180 mark as I tested it this weekend.
- I know the fan works because I have a manual override wired in and it comes on when I hit the switch.

I am considering this part as an option. "This 1" aluminum spacer mounts below the thermostat housing & gives you an additional pair of 3/8" N.P.T. female ports. These can be used for quick and easy connections for a temperature gauge, fan switch, or various sending units."

Looking to hear from anyone who has used it or anyone that can give additional advice or recommendations.

Thanks!
LDO

[dwcsr]

That will work fine for what your doing.

[solidaxel]

Take a look at a water outlet thermostat housing for a 78 Chevy pick up with a 350.

My "new" 78 has a temp sender for thermo control for the distributor, this housing could be used for a sender for fan or guage.

The one you show will work also.

If you ground your sensor wire at the sensor, while the engine is hot or cold will it turn on the fan?

[LDO]

Thanks Solidaxle,
I've also found another option after some serious google searching.

My fan sensor has two wires. One has 12v to it from the key, the other is the power (turn on) wire to the fan relay. When the switch closes, it energizes the fan relay sending 12 to the fan. This setup is made by Derale Cooling. When I touch the wires together, yes, the fan comes on. And when I bypass the sensor using a rocker switch in the cab, the fan also comes on. I dipped the sensor in hot water this weekend with a meter attached and checked for the water temp when i got continuity; right around 180 and my spare sensor performed the same way.

[dsl30263]

I installed a derale brand fan thermostat w/relay this weekend also. Mine is adjustable. Is yours?

[LDO]

Originally Posted by dsl30263

I installed a derale brand fan thermostat w/relay this weekend also. Mine is adjustable. Is yours?

no, mine is not adjustable.

[solidaxel]

From your description I would think that the temp switch would switch the relay and not the fan,

My temp switch provides the ground to the relay and the high voltage or bat. current is on the high side of the relay, it is only a 1 wire temp switch

[LDO]

Originally Posted by solidaxel

From your description I would think that the temp switch would switch the relay and not the fan,

My temp switch provides the ground to the relay and the high voltage or bat. current is on the high side of the relay, it is only a 1 wire temp switch

Yes, you are correct. It does.

[solidaxel]

So is it working with the temp switch?

I re read your post and we are on the same page!!

[LDO]

I'm sorry, I don't mean to be vague. The fan isn't turning on with the temp switch in the ckt.

However, when I connect the two wires (going to the sensor) together, the fan comes on so I know the relay, fan and associated wiring works.

My belief is that the sensor, being mounted on the water pump, is either not receiving enough flow across it to heat up, or the water flowing by it is cooler than the water flowing by my temp gage sensor.

During my check, my temp gage was reading 205. The fan never came on.

Hope I explained it correctly.

[solidaxel]

Yes it could be in a steam area (not touching liquid) not deep enough........... or does it have teflon tape on the threads, but it has two wires and does not use the body as a circuit, ground.

Keep working on it you will find the problem!!

[MrDude_1]

does your 283 block have a port in the water jacket, on passenger side? it might be hard to see, but if it does, you can just use a OEM switch to ground it.. I personally used this setup for years on older cars that were converted to electric fans.. just ask for the thermal fan switch for a 1991 305 TBI Camaro RS.
the switch will connect to the block (ground) so have it trigger your relay.

[solidaxel]

Originally Posted by MrDude_1

does your 283 block have a port in the water jacket, on passenger side? it might be hard to see, but if it does, you can just use a OEM switch to ground it.. I personally used this setup for years on older cars that were converted to electric fans.. just ask for the thermal fan switch for a 1991 305 TBI Camaro RS.
the switch will connect to the block (ground) so have it trigger your relay.

What is the ON OFF temp of the switch?

[dwcsr]

Originally Posted by solidaxel

What is the ON OFF temp of the switch?

1991 305 TBI Camaro RS. D1855B +/-4 degrees this switch is 220 on / 200 off on a Ac delco switch and +/- 8 on cheapo switches

[MrDude_1]

Originally Posted by solidaxel

What is the ON OFF temp of the switch?

Whenever I get one from the parts store, I'm offered multiple temps... I usually pick 185.

Unless its for a factory EFI car. Then I pick higher.
Posted via Mobile Device