Oil leak with SBC 400 and oil cooler update

[Joel Wilson]

Okay, I bit the bullet and ordered premade AN oil lines for my remote filter and oil cooler. Got all that installed and we are good to go. Got the oil temp sender wired in. I just put in a 3 pole switch and have my trans temp and oil temp switched to the same gauge. Works good and wasn't that hard really. My next little project is do I put in a relay with an automatic thermostatic switch or do I just put in a manual switch? The thermostatic switch has 2 prongs and the relay only has 4 wires so I'm not exactly sure how that is going to work. The relay has one heavy short red, one long red, one black and one brown. Short red goes to the fan, long red goes to battery, brown goes to ign or fan switch, and black goes to thermostat. So would the thermostat then get the brown and black wires from the relay? I like the idea of the whole thing being automatic but I also like having the backup idea of just being able to turn the fan on with a switch. Right now I have the secondary trans cooler and the oil cooler sandwiched on top of another with the fan on top but I don't get a whole long of air flow through the bottom cooler. So I might need to do something different there. Maybe.

Oh yeah, I fixed my trans leak by relocating my trans temp sender to the oil pan itself. Not ideal, I know, but it solved my leak. Right now, with no fan on the secondary cooler, my trans oil temp saw no more than 165 and that was with a lot of stop and go and idling in town when it was 114 outside. AC was not on since that is on the list of things to get working again. That was trans oil pan temp. Engine coolant temp was no more than 160 and that was on the bottom coolant hose. Also keep in mind, I am running a +3 qt transmission oil pan and a 7 qt engine oil pan.

Joel
norcal

 

[Keitha]

Why do you say the trans temp sender in the oil pan is not ideal? I have mine in the oil pan.

 

[Joel Wilson]

Why do you say the trans temp sender in the oil pan is not ideal? I have mine in the oil pan.

I was hoping to get a temp of the transmission fluid coming out of the converter prior to going into the coolers. Unfortunately, in my small podunk town, the only way i could plumb that temp sender into those cooler lines was with a bunch of brass fittings and reducers which led to a decent size leak. I am much happier with my sender on the side of my pan.

Joel
norcal

 

[6872xtc]

I was hoping to get a temp of the transmission fluid coming out of the converter prior to going into the coolers. Unfortunately, in my small podunk town, the only way i could plumb that temp sender into those cooler lines was with a bunch of brass fittings and reducers which led to a decent size leak. I am much happier with my sender on the side of my pan.

Joel
norcal

I am fine with the sender being in the pan. Semi trucks have them in the case on manual transmissions. So my idea is that you get an idea of the temperature of the majority of the component.
Not sure if I am correct though.

 

[Wes Harden]

so I have been wrestling with sensor location, mine is in the pan. With sensor in the out going cooler line you get torque converter temp, but what is that temp info good for ? My understanding is the
high temp oil will damage the seals the friction materials. Sensor reading from the pan will give you an average running oil temp. I have also read of people putting the sensor in the oil pressure test port, idk if that is even a good location as the it is a dead head location. If you were to have a sensor in the out going and the pan you would have a complete picture. Converter slippage and cooler efficiencies.

 

[Joel Wilson]

so I have been wrestling with sensor location, mine is in the pan. With sensor in the out going cooler line you get torque converter temp, but what is that temp info good for ? My understanding is the
high temp oil will damage the seals the friction materials. Sensor reading from the pan will give you an average running oil temp. I have also read of people putting the sensor in the oil pressure test port, idk if that is even a good location as the it is a dead head location. If you were to have a sensor in the out going and the pan you would have a complete picture. Converter slippage and cooler efficiencies.

I think outgoing and pan locations would be best. Then you could the torque converter temp, temp that the transmission actually sees (pan temp) and the efficiency of your trans cooler(s). A simple toggle switch between the two sensors and you are good to go. I just couldn't get all those brass fittings to seal, I'm good with the pan temp. Maybe someday, I'll put a second trans sensor in there, but for now, I have no leaks and I still have a decent transmission fluid temp.

Joel
norcal

 

[dyeager535]

...My next little project is do I put in a relay with an automatic thermostatic switch or do I just put in a manual switch? The thermostatic switch has 2 prongs and the relay only has 4 wires so I'm not exactly sure how that is going to work. The relay has one heavy short red, one long red, one black and one brown. Short red goes to the fan, long red goes to battery, brown goes to ign or fan switch, and black goes to thermostat. So would the thermostat then get the brown and black wires from the relay? I like the idea of the whole thing being automatic but I also like having the backup idea of just being able to turn the fan on with a switch...

I would guess the switch just completes the circuit (two pins have continuity) when the temp is correct for it to switch. In that case only one wire would go from the relay to the switch, the other pin could then be run to ground.

You could easily run a switch and relay. I'd just make sure it was all ignition switched so you'd never forget it being on. I'd forego a switch unless you ford deep water often. Even if you needed to turn the fan off infrequently, just unplug the relay or switch. If the relay failed or for some reason you wanted to force the fan to run, jump the fan lead to battery 12v. Or leave a pigtail hanging so you easily can if needed and using a molded connector at the relay. Properly done, I can see no reason to want to override electronic control of the fan, save for fording or relay/switch failure.

All sorts of ways to do it. One of the reasons I enjoy tinkering with circuits.

 

[Wes Harden]

the switch just closes the control side of relay(coil). I wired my trans cooler fan relay ignition hot on the load side 12 ga, and ignition hot on control side 16 ga, using the tamp switch to close to ground on the control.

 

[Joel Wilson]

I would guess the switch just completes the circuit (two pins have continuity) when the temp is correct for it to switch. In that case only one wire would go from the relay to the switch, the other pin could then be run to ground.

You could easily run a switch and relay. I'd just make sure it was all ignition switched so you'd never forget it being on. I'd forego a switch unless you ford deep water often. Even if you needed to turn the fan off infrequently, just unplug the relay or switch. If the relay failed or for some reason you wanted to force the fan to run, jump the fan lead to battery 12v. Or leave a pigtail hanging so you easily can if needed and using a molded connector at the relay. Properly done, I can see no reason to want to override electronic control of the fan, save for fording or relay/switch failure.

All sorts of ways to do it. One of the reasons I enjoy tinkering with circuits.

About the only reason I would want to add a switch would be for relay failure. I don't plan on doing any fording plus the fan is about the same level as the intake so if I were to ever get water that high, bad bad things are going to happen. Right now, I've got the relay wired in but with the temps we will be having for the next week or so, I don't think anything will get warm enough to have it kick in. It will be interesting to see what makes the oil temp rise or lower.

Joel
norcal