From: Blown49 (Original Message) Sent: 9/23/2002 10:49 AM
I need to replace my stock temperature sending units on my 8BA. Any ideas for a source?

Appreciate your help in advance.

Blown 49

From: Lars B Sent: 9/23/2002 10:52 AM

Try http://www.macsautoparts.com/
Has worked for me :-)

From: Blown49 Sent: 9/23/2002 1:11 PM
Lars,
Thanks for the info. I looked on the web at the parts available and also called them. Don't whether or not mine is as stock but I think it is. Mine has a 2 wire switch in the left head and a one wire sending unit in the right head. Looks as though Mac's may have the right head style but the girl I talked to couldn't fine a picture of one for the left head with 2 terminals. I left my name & number with their technical assistance and will have to wait untill they get back to me.

Again thanks for the quick response to my post.
Blown 49

From: Blown49 Sent: 9/23/2002 3:04 PM
Lars,
Temp sending units found!!! You were right, Mac's carries both but is out of stock on the 2 post unit. Should be in in a week or 2. Part numbers:

Single wire unit for right head #V10884 @ $47.50
Dual wire unit for left head #V10990 @ $47.50

I went to big car show this weekend, about 250 miles each way. Temp indicated erratic from below 1/4 to above HOT and back and forth. sometimes staying above the hot. I don't believe the motor was hot at all. Pulled over when it started, popped hood, upper radiator chrome return pipes were hot but overly so, no hot smell and the radiator was not excessively hot either. I have a thermostat in the radiator that starts the electric fan at around 170 degrees radiator temp. It never started the fan and again the radiator was not too hot to touch or the radiator inlets either. I honestly believe it's an instrument problem and not overheating. I've ordered the sending units and will change them as well as the t'stats (which are only 3 months old) when senders arrive.

Thanks again for the lead on the parts from a distance. The internet can be a beautiful thing! The help on this site is even better.

Keep your wheels down and your antenna up!

Blown49

From: Russ/40 Sent: 9/23/2002 4:10 PM
I just received a mailer from JOBLOT. They have them advertised. At work now so not sure about the cost, but think they were about that much and were NOS.

From: Overkill Sent: 9/23/2002 5:18 PM
Blown49,
Have you proven that the senders are at fault? Have you tested the wiring and gauge to be good. (While you're waiting for the back order) Maybe you don't need both senders and two new themostats....Overkill

From: fearless Sent: 9/23/2002 7:48 PM
My luck with cheap aftermarket sending units/gauges hasn't been real good. Do the higher end sending unit/gauges come with the NOS style cable/wire from sending unit to gauge? I'm leaning towards Stewart Warner.

From: DanL Sent: 9/23/2002 9:33 PM

If I understand it correctly, an open circuit in your temp circuit would cause the gauge to go HOT. I'd check for open/intermittent connections between the motor and gauge before I spent $100 on temp sensors. Disconnect both ends, connect an ohm meter/continuity tester to each end. Wiggle the wires as much as you can while checking continuity.

From: Lars B Sent: 9/24/2002 7:40 AM
As I understand it the two wire unit don't do anything under normal conditions. It's the one wire unit that performce the actuall measuring. The two wire unit only goes into action when an overheating situation occurs, (by breaking the connection?!)

From: 52merc Sent: 9/25/2002 12:04 AM
To check out the senders, first of all the two terminal unit is only an on/off unit. At normal operating temperatures, it has continuity between the terminals and serves only to complete the circuit to the single terminal unit which is the actual temp sender.
In a situation where overheating occurs on the left side of the engine, the two terminal unit will ground the long terminal and cause the temp gauge to go all the way HOT.
To test, check for continuity across the terminals at normal temp. There should be continuity. Then check for continuity between each terminal and ground (the threaded base). There should not be continuity. If you have continuity to ground the unit is faulty.
If you have a candy thermometer , you can heat some water to about 210 deg F. At that temp the sender should have continuity between the long terminal and ground. If it meets these tests, it doesn't need to be replaced.
To check your gauge unit, ground the wire to the engine. The gauge should go to full HOT.
The gauge should sweep between COLD and HOT if you ground and then disconnect the wire. Give it a minute or two to react.
If the guage does not sweep fully or goes much beyond the scale, it may need to be calabrated or replaced.
The single terminal unit can be tested by heating the unit in water. Again a candy thermometer will help to monitor the temp. Connect an Ohmmeter between the terminal and the base and observe the meter reading as the temp rises. Resistance should decrease as temp increases.
Sorry, I don't have the correct values for the resistance at certain temps here with me. Perhaps someone else has them near at hand.
A few simple tests may help narrow down your problem before you spend your money.
Be sure to check all wiring and terminals for condition and cleanliness. A lot of the old wiring was made of steel strands and would break several strands at the terminals causing high resistance in the system. Also make sure your grounds between engine and body are good.


Hope this is of some help.
Daryl

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