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My Dewitt Rad and Dual Spal fans came with the sensor in the top inlet of the rad. I have one fan on that, the other I have to come on whenever the motor is on. I found out that if I don't have at least one fan on when the
a/c is on it will quickly cause the condenser to overheat and stall the compressor. Sensor is just under the hose
Last edited by redwingvette; 05-12-2019 at 10:58 AM.
I'm trying to diagnose a cooling problem. I have the dual Spal fan set up on my DewItt's radiator. I'm using a fan controller. I'm wondering if I placed the sensor for the fans in the correct location? It is in the radiator hose attached from the radiator to the thermostat housing.Craig
The spal fan switch must be grounded to work. If you mounted it in the middle of the hose the ground is the coolant. DeWitts adds a weld bung just below the inlet tube for mounting the switch. This location sees the hot fluid coming from the engine and provides a positive ground for the switch.
The spal fan switch must be grounded to work. If you mounted it in the middle of the hose the ground is the coolant. DeWitts adds a weld bung just below the inlet tube for mounting the switch. This location sees the hot fluid coming from the engine and provides a positive ground for the switch.
Here's a pic of above. On at 195 off at 180, works great.
Street Rat, if your fans are coming on and staying on, and the car is still running 210* in traffic, the temp switch location is not your problem....As long as the fans are on, they are on... That temp may be all the fans are capable of cooling your motor down to. I would verify you are getting full voltage to the fans to make sure they are running their full speed. Sometimes those variable/PWM controllers do funny things.
To answer your question, I run my temp switch in the driver side of the radiator tank (Dewitts)...they put the bung there for a reason. I did have to run a ground wire from the radiator to the frame of the car for the switch to work. That location will make the fans come on a little later then having the switch in the head but its fine. Mine comes on about 188* and turns off about 178*. It'll cycle like this all day long.
FWIW, I don't use any kind of PWM controller.... Just an on/off temp switch, AC compressor trinary switch and a manual toggle switch for emergency.
Mine is PWM also, and the sensor is installed at the bottom near the outlet per the manufactures install instructions. Never had a problem, but mine is adjustable so I set it where I wanted the fan to start running.
I wonder if for a test you bypass the control and just run the fans constantly if there is any problem keeping the temps down. If it can't,.....fixing the sensor location will gain you nothing.
These cars are a royal PIA to get all the air out of the system, and if you have air,....you're not using 100% of the cooling capacity. I jacked mine up so the front was four feet off the ground, and ran the car until the Tstat opened while the radiator cap was off. Top the coolent, put on the cap and be sure the reservoir is full. Did that three times to get all the air out.
I had a bad sensor at one time.
The fans were not coming on at all.
I flipped the override switch to put the fans at full blast until I got it figured out.
I got a new sensor and now I've been chasing this new issue with the higher temps at low speed.
After your responses I have decided to put the sensor in the lower radiator hose using one of the AutoCoolGuy brass adapters.
The turn on temps are adjustable with my controller.
I'll post pics and results after the changeover.
Ordered parts yesterday from the AutoCoolGuy. Yes Daryl is even available on Sunday. Excellent customer service is the norm.
Craig
Last edited by Street Rat; 05-14-2019 at 01:47 PM.
The spal fan switch must be grounded to work. If you mounted it in the middle of the hose the ground is the coolant. DeWitts adds a weld bung just below the inlet tube for mounting the switch. This location sees the hot fluid coming from the engine and provides a positive ground for the switch.
Hello Tom,
Thanks for your response.
I'm going to put this brass connector in the lower hose.
I am assuming that I will need a ground wire from the adapter to the radiator.
Can you confirm this Sir?
Craig
yes ground the brass, you could create electrolysis if you rely on the water to conduct the electricity. ( even though it's very minimal)
You problem could be the temperature sensor is going too deep into the engine and almost touching the metal surface, not just measuring the water temp.
I found one of the pumps I had - Gates flowed very badly at low RPM. (+ it leaked after 20 minutes). The Auto-zone replacement pump had better flow and the temp gauge showed lower readings at idle. (sometimes more expensive is not worth it)
On my 85 I run an AL tube which I got from Speedway with a 195 sensor for Fan #2. The 185 sensor is in the manifold and the car runs well within the desired temp I want. I did drill a 5/64 hole in the stat to make it easy to air bleed and keep water moving.
I am assuming that I will need a ground wire from the adapter to the radiator.
No, you do not. The sensor you are using has 2 wires which completes the circuit. I expect the wires and sensor element are isolated from the brass sensor body so the body of the sensor isn't part of the circuit at all.
The switch Tom was talking about is a typical 1-wire temperature switch that typically screws into the engine. These use the brass body of the sensor to complete the circuit, which in turn means the engine that it's screwed into is part of the circuit.
Hello Tom,
Thanks for your response.
I'm going to put this brass connector in the lower hose.
I am assuming that I will need a ground wire from the adapter to the radiator.
Can you confirm this Sir?
Craig
This seems like a bad idea to me, isnt this some of the coolest temps in the entire system?
I put my sensors in the heads so the ecm knows the temp of the heads and the gauge shows me.
No, you do not. The sensor you are using has 2 wires which completes the circuit. I expect the wires and sensor element are isolated from the brass sensor body so the body of the sensor isn't part of the circuit at all.
The switch Tom was talking about is a typical 1-wire temperature switch that typically screws into the engine. These use the brass body of the sensor to complete the circuit, which in turn means the engine that it's screwed into is part of the circuit.
Although we're all so used to grounding the living crap out of everything on these cars... not in this case
The two wire sensor don't need a separate ground, my derale one is actually held on with tape and there is no electrical contact to the rad at all
M
Six years and zero problems, with a single BMW dual temp sender, mounted in a Metric to NPT adapter. Three wires coming out, one for the low temp (180) and one for the high (200), then a single ground wire. Easy location to wire, because it's a straight line back. along the inside of the valve cover and to the firewall harness.
I received my brass adapter and sensor today. I installed them in the lower radiator hose. Started it and filled the radiator. I drove it around the block but not far enough to really test things out.
It's raining today so I don't know if I'll get to test out the new setup today. Still got to top off the coolant.
I received my brass adapter and sensor today. I installed them in the lower radiator hose. Started it and filled the radiator. I drove it around the block but not far enough to really test things out.
It's raining today so I don't know if I'll get to test out the new setup today. Still got to top off the coolant.
More results as available.
Craig
why would you want to put the temp sensor in the lower hose where the temp as cooled off?
why would you want to put the temp sensor in the lower hose where the temp as cooled off?
I had the sensor in the top radiator hose (still installed). I wasn't getting the cooling results that I expected.
I placed a different sensor in the lower hose basically to see what the change (if any) would be to my cooling temperatures.
The sensor sends a signal to the fan adjustable controller which supposedly varies fan speeds as the engine heats up.
The possibility exists that the controller may be bad.
I have a hard time believing that my little 9.5 compression engine runs this hot. The sensor for my Autometer temperature gauge is in the left cylinder head between cylinders 1 and 3.
I have yet to get it test driven with the sensor in the lower hose. No rain today.
Update later today.
05-12-2019, 08:20 AM
