Engine: Where is the temp sending unit on 60's 289?

[pbrown]

I have been slowly addressing the little problems with my 59 Silver Hawk that the PO told me he had "upgraded" to a 64 Cruiser 289 V8

One of the issues is a non-functioning temp gauge. When the car is started it slowly creeps up, but within a minute or 2 has gone fully to the right.

There have been threads on temperature gauges that suggest that most failures are because of the sender. So I am about to pick up an ECH TS6460 from NAPA.

Here's my problem - I can't find the existing sending unit!

My research indicates that it might be on the front driver's end of the cylinder head. But I see nothing! I'll post a picture in a few minutes to show you what I see.

And on another note, I have both the oil breather caps on the valve covers as well as the central oil riser. My readings tell me that it should be one or the other, correct? So who knows what engine parts I really have - it may be a combo....

Thanks in advance


Phillip

[pbrown]

And the promised pics:

[StudeRich]

Hi Phil, follow the Orange wire from the harness, it breaks out near the Steering gear. If it is disconnected or grounded that is part of your problem.

If you look closely at the end cap on the back of the left head it should be there but if not, try the Right Head, it can go there also even though it does not belong there.

If you have the Full Flow Oil Filter at the Right Lower rear of the Engine then you have no need of the Oil Filler Pipe, you can remove it, and Cover Plates are around in Members Garages, and the Gasket is available at Stude. Vendors, also the Correct Temp. Sender.

UPDATE: I see the Pics were added while I was posting this, they do not have enough Light or Flash, but it appears there is a jury rigged A/C System on there as well.
Unfortunately we can't see the Rear area where the Sender and Wire would be.

[StudeRich]

After double enlarging the Right Side Pic. I was able to spot the heater Hose going to the Right Head rear Cap location, which is an aftermarket A/C auxiliary location for the hot water heater inlet hose, so that eliminates a Temp. sender on the Right Head, so it has to be on the Left Head.

Where is that Red looking wire going that goes straight down the firewall behind the Throttle Bellcrank? If it is truly RED and not Orange it should be the Hot with Ign. on, wire for Overdrive Cars not used on others.
If they connected that to the Temp. Sender that would be a problem!

[pbrown]

Already learning something!

The pic of the 259 I looked at led me to believe incorrectly that the connector would be on the front of the engine.

Now that StudeRich has informed me that it is on the back of the engine, I have found it! Many thanks StudeRich !

The wire is orangey red, but does indeed appear to be orange.

The current sender is connected via a connector that is held in place with a nut (see pic)



The picture in the SI catalog has a different connector. The interchange from Rock Auto and NAPA show the same "knobbed" connector - and I am not familiar with the mating piece.

What do I need?



Phillip

[gordr]

Yes, that's the sending unit, and it would appear to be an aftermarket one. The orange wire is probably the correct wire, too. The original sensing units have a stud with a little disc on the end of it, and the matching wire terminal is a 1/4" female spade connector. At least, a spade connector will work for it. First thing I'd do is disconnect the existing sender, and turn on the ignition for a while, and see if the gauge reads anything. If it still pegs out, you might have a short to ground, or possibly the gauge unit in the dash is wired backwards. If the gauge now stays at zero, it would suggest that the sending unit is bad, or an incorrect one. A six volt sending unit would do that, but the six volt ones used in older Studes have a much larger threaded body, and won't fit the threaded hole for a twelve volt sender.

[RadioRoy]

Has the insulation rubbed off the wire where it is rubbing on the firewall?

[pbrown]

First thing I'd do is disconnect the existing sender... If the gauge now stays at zero, it would suggest that the sending unit is bad.

Now that I've disconnected the sender, the gauge now stays at zero when the car is running - so I'd agree that it is the sender.

NAPA says their ECH TS6460 is the correct part, and it looks just like the one from SI.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Temp-Sender-Switch-Gauge/_/R-ECHTS6460_0166851028

I can get the NAPA one tomorrow - am I headed down the right path?

[pbrown]

The sender unit that's in it looks like this one. So it may indeed be the wrong one.

[gordr]

A '56- '57 sending unit should be for a 12 volt gauge, but almost certainly there are sending units for Brand X applications with a low resistance, meant for 6 volt use. Or the sender could just be faulty.

[StudeRich]

The '56-'57 Senders in that LARGE size you saw the Pic of, are NLA at most sources and probably NAPA, also $60.00 may be deal killer.

You can either search one out or change the mounting plate to the '58 to '64 small sender type.

[gordr]

If the sender plate has a half-inch pipe thread to suit the older big sender, a simple fix is to use a pipe bushing to bush it down to 3/8" pipe thread to suit the more modern sender. Sure, the sensor of the new sender may not stick as far into the coolant, and be a little slower to respond, but I doubt you will notice that. Ultimately, the entire sender will be at engine operating temperature.

[jclary]

If the sender plate has a half-inch pipe thread to suit the older big sender, a simple fix is to use a pipe bushing to bush it down to 3/8" pipe thread to suit the more modern sender. Sure, the sensor of the new sender may not stick as far into the coolant, and be a little slower to respond, but I doubt you will notice that. Ultimately, the entire sender will be at engine operating temperature.

I was thinking the same, 'cept you might encounter clearance problems with the firewall. Depending on the circumstances of the initial install, the previous owner might have just grabbed the nearest part that would "fill" the hole. I confess to committing that oversight myself.

[pbrown]

It appears that the PO used an incorrect sending unit. The one that came out of it (even though it had the threaded connector like the big one) was that "smaller" size and the NAPA piece was an exact replacement.

The system now climbs to 180 and stays there. Woo-Hoo!

Thanks to everyone that helped!

[pbrown]