Hi what would be the best temp settings to switch thermos on and off on a mildly worked 351 clevo with EL thermos on alloy radiator. 4 speed 3.5 ratio 9" in XE Falcon. will be using a Tridon thermo switch intend to weld a socket into radiator tank to fit switch. Live in Tassie so country roads lots of hills and some strip racing. I am thinking maybe on at 95 celsius off at 90 But I don't really have a clue.

Hello,

This is a bit of a how long is a bit of string question. Do you have Air-con ? If so you will need a fan running at low Car speed. EL Fans run at 2 speeds, they run together in series ( low ) and parallel ( high ). I would set them up as separate fans. Run one with the Air compressor, and the other from a Temp switch. Now you will need to set it just above the thermostat, or it will never turn off. Are you going to fit the sensor in the top or bottom tank ? I have dealt with thermo's for nearly 40 years, and there is crap stuff and wrong opinion's out there. Air is a significant factor in what you choose with your set-up.

Hi thanks for replying. It has no aircon, and it is a crossflow alloy tank (tanks either side) . I am aware that the fans spin at different speeds , I actually have the same set up in an XF Falcon running a 351 Windsor that me and my sons club race at symmons plains. It has the same set up except I use a toggle switch and just leave fans running when on the track. It works great even with one slow fan. I have thought about getting another fast fan from another set and replace the slow one. The advice about sensor placement is good , I didn't know that it would keep running if in radiator and I hadn't got to fitting a bung to radiator yet. I will fit sensor to thermostat housing like you said. I have gone ahead and brought a trico sensor that turns on at 85 c and off at 80 I was going to try a 90c on 85c off but decided to go lower for a start and see how it works out. I am using a highflow thermostat as well. what do you think about the stop start temps any ideas

Hello,

Tassie gets cold, if you over-cool the heater and demister will be bad. Plus you are wasting fuel. What I would try is 2 temp switch's, top and bottom tank. Top turns Fans on and bottom off. Run each Fan off a separate relay and fuse. You would need to experiment with Temp settings. I found at highway speed the Fan slowed the Air flow, I used to drive to Sydney and mostly the Fan never came on, but if it did it didnt turn off. That was DC rubbish though. I would experiment a bit, but have an over-ride switch.

OK,
thanks for the input. some good ideas.

Hello,

I said above the thermostat meaning at a higher temperature. The capillary tube devices are quite accurate, I often put a thermostat in a saucepan of water and add a thermometer. I can see what temp it opens, and then closes. It all happens over a few degrees, they dont snap open or shut like some people seem to think. Thinking out loud a bit here, in your position I would get an adjustable switch and calibrate it using the saucepan and thermometer. Write the temp in Texta on it when it switches. I would mark it from 60 to 100 in 10 degree intervals. You will need a Multi Meter to do this. Then road test it and see what you get. With no Air, you only need the Fans at low speeds and stopped in traffic when the temp goes up.
Edit, try this on the bottom tank. Most of the Thermo switch's come with a rubber saddle, so you can try it top or bottom without any Radiator mods. See what works well and maybe Post the results for others. ( that use search ! )

Once again, run 2 fuses and relays. Think about an over-ride switch also. I have fond memories of 351 Clevo's when I was a teen. The old man had a ZG. I had a blonde GF.

Thanks again I will keep you posted.

hello, its summer, my Cleveland was running an 82 degree with a viscous fan and no shroud, highway it sits on 190 loaded(car on the back) or unloaded... in traffic for 15 minutes, it is 200 then 220 then no numbers....so I put a 71 degree in with a 16 inch thermo and no engine fan, the fan pulls air from the front. highway it now sits 182 or 5..... thermo on in traffic, same as before..... new green coolant... wanted the Toyota red but the price is a lot more.... now my next search is for a restrictor plate to sit under the thermostat... I googled those words and got an American site wcc cougars for the product... have you got the restrictor plate? regards jon

Hello,

Thanks for joining in Jon, 1st hand knowledge. A common mistake with Cooling systems is to take out the thermostat. The gauge sits lower, but the engine runs hotter. It is still making the same amount of heat, only the coolant is not taking it away. It seems a " black art " to some, and typically many dont find the cause, they just change the symptoms. Most Cars when new had no Cooling problems. Some have always been close though.

Hey guys I will let you know how I go soon , this engine has only done 30 minutes running sitting in the shed to run the cam in. It was getting hot so we removed thermostat for some of this time. I have re fitted the highflow thermostat and the plate in the block under that is still there. I have Just fitted alloy radiator and EL Falcon thermos. I am waiting for a thermo switch I ordered to turn up. I have fitted a mechanical temp guage and oil pressure guage for now until I am sure the standard XE Falcon ones are correct. there are two position on top of the standard thermostat housing for accessories so this is where temp sensor and thermo switch will go for now and see how it works out. Thermo switch is on at 85c and off at 80c I will watch and see if I need to swap this for higher or lower switch. I think the thermostat opens about the same so I may need to go with a higher temp switch maybe 90 85. Its just a starting point for now. Car is nearly ready for a run down the road. cheers for the interest and ideas. I will post some pics of the thermo set up for you to look at.