Stewart Warner "Wings" water temp inaccurate

Seems I read a post on the HAMB about the inaccuracy of the SW "Wings" electric water temp gauges. Have searched but can not find the thread.
My SW pretty much reads 230-240 all the time after about 20 minutes of driving, regardless of traffic or open highway. It never boils over, hisses, gurgles, or makes any of the normal sounds of "hot". I have used a Fluke infared heat gun to check the temp of the aluminum thermostat housing and it never reads higher than 180-185. The engine is an FE and they tend to run a bit warmer than most. I would very much like to get an accurate water temp gauge but don't know if SW makes a thermocouple type gauge in the "wings" model. Has anyone else had "high" inaccurate readings from SW water temp gauges, and if so, how inaccurate were they reading? My gauge appears to be reading up to 50 degress higher than actual engine temp. I have a 160 degree thermostat and the car will sit and idle all day at around 160, but as soon as I start driving it goes up to the 230-240 range. Running straight water with some water wetter. And, one more question.....I have read about adding some anti-corrosive additive if you run straight water. What is available to use as an additive for corrosion protection in a straight water cooling system?
Thanks in advance...

BOutlaw

 

Is this one of the new Wings gauges or an old original 6V job? If you're worried about the temp reading until you get the problem sorted out or even need a "second opinion" gauge, I found that those little direct screw into the manifold Moon temp gauges are very accurate.

 

Yep, we have one and it reads 20 degrees hotter than the motor is. But I have never had one electric water temp gauge in my life that reads dead on, they always seem to read warmer that what the engine is. Even the Teleflex marine gauge in my 27 reads 10-20 degrees off.

We've used the temp gun like you and shoot the entire engine and it always verifys that the gauges are wrong, so we just take that into account now and don't worry about what it is saying. I am running a Mr Gasket radiator cap with the thermometer in the top and it is always dead on and cooler than my gauge in the dash.

Also, don't run straight water, run a 50-50 mix with green antifreeze. We also use Barr's Leaks Antirust/water pump lubricant additive and since using it the insides of the cooling system stay spotless.

Don

Ah, Brad, I didn't realize it was you posting the question, I'm not awake yet. Congrats on your win at BP.

 

I just ordered one the other day got the sender was extra.
Hope i got a good one.

 

I don't have a quick answer but I had a similar problem in my daily driver 49 PU (282/t350)
Start it up idle right around 160-175 OK (160 thermostat) Take out for errands/shopping whatever and it went up over 200 -210. I replaced all the usual suspects but the problem persisted. I used one of the cheap HF infrared thermometers on it and all appeared OK, about 185 where it exited the thermo housing to the radiator.
Put in a second sender, and new gauge, same as original and it read very close to original, also high.
Checked 12v to gauges, hmmmm, over 14volts. Checked one wire internal reg alternator and yup putting out more than 14volts, closer to 15v, once rpm up to set it to charging. I installed a mini regulator circuit just for the temp gauge by using a 12v Zener diode/resistor to clamp the voltage to the gauge to 12v. Now it reads just about exactly what I see on a analog glass thermometer in the radiator or the infrared from HF.

 

I had a new water temp guage do the same thing. Same symptoms as yours. I let it go for a couple of years, changed it out with a new one and its fine. I think like anything else, some work and some dont.

 

Fleetside, thanks for the tip on the Moon temp gauge, was unaware they were available. And, the SW temp gauge IS a newer (Chinese/Mexico) 12V model, not the older gauges that actually worked.
Hey Don, thanks for the response and the tip on the Barrs. I'll check that out. My "system" is starting to look crappy and its all new, i.e., radiator, hoses, etc. I'll also switch over to a 50/50 mix as you suggested. I was not sure if I was really running hot and wanted to take advantage of every opportunity regarding cooling so kept it at straight water. Still sorry I did not get to meet you at BP> Hope to see you there next year.
BobF, I NEVER even considered that exceeding 12V's would affect the gauge indication. I know I'm putting out a tad over 14Vs because the Voltmeter installed just stays on 14V's if its running. I'm sending you a PM requesting the details of the diode/resister apparatus you built. Sounds like it cured your problem. I am SURE a LOT of folks would like to see what you built as well. But, we hot rodders are generally pretty ignorant when things go electronic, or at least I know I do. I know what a diode is, but designing and building such a device if certainly not something I would be able to do without some pretty basic instruction and diagrams. Thanks for bringing that up and i would encourage you to post the details. Regardless, I'm sending you a PM. I'm sure interested in trying your "fix".

 

Brad, when we first got my Sons Olds motor running we just put in a 50-50 mix . When we tore it down a few months later to build the new motor we were shocked to see that the block had a rust coating inside and the spring inside the lower radiator hose was rusted already. For the second motor we still used the 50-50 mix but this time we dumped in a bottle of the Barrs Leak antirust stuff. After a while we checked the cooling system and it was as clean as new and the spring that we replaced in the lower hose was bright and shiny.

I have since drained the cooling system on my 23 and added the same Barrs Leak product because I liked what it did for his so well. A guy we ran into at a show told us he has been using it for years and said he has the same results with it. And I think it is only like $ 3 a bottle.

Don't get it confused with the regular Barrs Leak that stops leaks, this one says antirust, water pump lubricant on it.

 

Wow, ain't the HAMB great....
Don, thanks for the clarification....I'm off this afternoon to get me some Antifreeze and Barrs antirust......I hate rusty stuff!

 

Before you give up on the electric, make up a jumper cable and run it from the body of the sender right to the battery ground cable...see if reading changes.
Best not to trust any SW gauges that aren't a lot older than you are, but that is an unfortunately expensive path. Gauge freaks get poor fast.
If the ground test doesn't show a route to fixing this, go get a tube type gauge. At least you can test it right on the stove...just stick the bulb into a pot of water and see what it reads as it approaches and reaches boiling. It's worth some trouble and money to have a temp gauge that reads close to reality

 

if you search on Ebay for a dc to dc convertor they have a ton of them listed and they are only about 10 to 15 dollars. they will take up to 25volts and output a rock steady 12 volts. it's nice because they are in a sealed enclosure about the size of a matchbox. Hope this helps.

http://www.ebay.com/itm/DC-DC-Conve...225?pt=LH_DefaultDomain_0&hash=item3cba54c459

 

But why would gauges be calibrated for 12 volts?...they would only see 12 with engine not running, around 14 is the normal running voltage on a 12 V car with generator or alternator turning. Regulating back to 12 would seem pretty odd for something meant to be used on a running car. If it is wrong at 14, it is wrongly calibrated.

 

Bruce, I'll try the sender ground trick this afternoon and see if it changes anything, and you do raise a good point on the 12 volt calibration, because we all know a proper charging system will put out 13.8 volts or so. I certainly don't have an educated answer for that question, but it seems that BobF got some satisfaction from his diode/resister device that held the voltage to a steady 12 volts. I certainly am willing to try as purchase of an older SW gauge for the prices they bring is out of the question. "Old Guy" provided even more info where such a device was already available. I have sent BobF a PM regarding the device he fabbed up. He seems to be happy with the results. SW just ain't what it used too be...........

 

Ground is a real concern...you have sealant on the threads, paint, gaskets, and rubber all along the path back to the battery. Engines often need several extra grounding points to fully overcome all the isolations...I think the addition of voltage regulation into the circuit corrected badly calibrated gauges rather than correcting the needed voltage.

 

Makes sense to me, I have no doubt that SW's quality suffers or is non existant as compared to "back in the day". Keeping prices down by moving offshore dosen't really mean anything if the product does not work.

 

Some Cars, I know a British Lotus had a voltage stabilizer installed in the gauge circuit to keep the voltage at 12V. Thats all I know about it.


Ago

 

How could that be a gauge problem? Not trying to be a dick, but the gauge doesn't know whether or not the car's moving.

Bob

 

SW has been very good about replacing the defective wings gauges we got, so far we had an oil pressure and tach where the needles fell off, and an electronic speedometer that you couldn't calibrate. (as soon as we put a new one on it did exactly what it was supposed to do.)

When you call them the call goes to somewhere in Texas, on the Mexican border, because they build them in Mexico. Between SW and Summit they stood behind everything, but it was still a hassle , and a set of these ain't cheap.

Don

 

You're right Bob, the gauge does not know, but the engine is obviously getting hotter when driven, but not 230-240 degrees. When I checked the thermostat before installing it, it was actually opening closer to 180 rather than 160. The gauge is reading hot throughout its range as far as I can tell.

 

OK, how about this: Isn't the temperate gauge really a volt meter in disguise? Doesn't it read voltage to ground through a sensor (thermistor) whose resistance is directly proportional to temperature? If the gauge reads too high over the entire range, then the resistance value of the sensor is wrong. Why couldn't you "calibrate" the gauge by adding or subtracting resistance between the gauge and sensor until you get the reading correct?

Bob

 

On that...first test with direct ground of sender body to be sure problem is in the gauge parts and not external voltage problem. After that, re-calibrating with voltage controls would work, but this is a brand-new major brand gauge, not anything vintage or irreplaceable, so why add complexity to a once simple circuit when SW needs to find you a replacement that works?? That's their job. Bringing a good old part back online is one thing, fixing a brand new paid for part is something else, especially when adding working parts that should not be required is involved!

 

I agree 100%, Bruce. However, experience has taught me that the same people who create problems are rarely capable of solving them. I'm putting Stewart Warner's people in that category. Sometimes it's easier just to come up with one's own solutions to problems than to butt heads with companies that aren't capable of making a decent product.

Bob

 

Which part is bad, the sender or the gauge. I would try to find out what the specs are for the sensor and check it with a good thermometer and an ohm meter.

 

I don't know if the problem is one or the other, but suspect that the problem is a combination of the two. There have been so many complaints about the new SW stuff, that I have to agree with Bob and Bruce....it was created by SW and they probably don;t have a fix for it other than another replacement. I will check the sender ground today to see if the indication changes AFTER this weather moves through the area. I have already contacted BobF and he was kind enough to provide some data for a stable voltage device, which seems simple enough to build. He indicated it fixed his erroneous gauge problem so I'm going to give that a try first. It seems that SW is not very accommidating with respect to technical issues. I will post the results of this attempted fix. Hopefully it will solve the problem. I can always replace the gauge and sender, but I am just not convinced that option will solve the problem. I'm retired, so I've got the time to run by Radio Shack and pick up a couple of cheap electronic components and give it a try. I appreciate all the assistance. Back soon.

BOutlaw

 

I'm keeping an eye on this. My "mechanical" SW wings temp gauge wire (conduit, conductor??) broke right at the bulb, so I ordered an electric gauge / sender to replace it. I was tempted to try to solder the thing, but I'm not sure if it would work as the copper conductor looks to be hollow. Any one have any luck repairing one of these?

 

I think the crux of the problem with any of these gauges is that they are simply not 100% accurate regardless of who makes them. When I was in the marine business a customer bought two water temp gauges for his twin engine boat. He came back later complaining that they read different from each other, and even when he swapped them side to side they still read the same, so it was not an engine temp difference it was the gauges simply reading differently.

We gave him a new set of gauges and he came back again complaining these still read different. To make him happy I called the manufacturer and got a tech guy on the phone. He said to me "Buddy, these are $ 30 gauges, how accurate do you expect them to be? They aren't precision instruments, they just give you a general idea of what the temp is."

I guess there is some logic to that. How much accuracy do we expect from one of these at what they cost?

Don

 

Just watch for water droplets suddenly appearing on your windshield! That's the bottom line...

 

I'd use an ohm meter to read the sensor's resistance at the highest gauge reading. Using that as a baseline, you should be able to add resistance in series to bring the gauge reading down. From what I've read, the sensor is basically a linear device, so you could use Ohm's Law to determine the resistance value. For example, if the gauge is reading 10% high, add 10% more resistance between between the gauge and sender. Maybe I'm over simplifying this, but Ohm's Law is free and resistors are cheap. Of, course, I'll defer to any electrical engineers on board cuz' I don't know much about electricity, but it's worth a try.

Bob

 

That's what I was thinking. Maybe an adjustable rheostat to dial in the gauge to match the the engine temp measured with a laser temp gun. I don't need dead nuts accuracy but 20 degrees off is crazy. I only use mechanical temp gauges.

 

I am having the same exact issue with an Autometer gauge. Compared to a temp gun it is very accurate until it hits 160. I took someone with me yesterday and they hung out the window with a temp gun. Meter showed 250 and temp gun showed 190. As the water temp increases so does the Differencial Temperature between the two.