1959 Buick sending unit for temperature gauge location question.

[h=2]1959 Buick 364 ci temperature sending unit location[/h]

In general, not specific to your Buick V-8, if the temp switch (for indicator lights) or sensor (supplies a variable current for a gauge) is placed near the thermostat, then you can pretty much tell how hot the water is RIGHT THERE and also notice when the thermostat opens. In the case of some vehicles, this can result in the gauge "over-shooting" the normal operating needle position just prior to the thermostat opening, then the needle dropping below that when the thermostat opens, then returning to the "normal" position after things get stabilized. This has been an issue, even on the later model Buick V-6 engines, resulting in various modifications to the thermostat's flange (i.e., a drilled hole to allow "bleed though" to help dampen the "wild" gauge movements at thermostat opening, a drilled hole with a restrictor floating in the hole) to help lessen gauge movement to "a too high level", then returning to normal.

Still, though, having the temp sensor/switch mounted near the thermostat was how they used to do it, back then, by observation. Even for the manual gauges with the capillary tube connection. By the middle-later 1960s, it became more common to find the temp switch/sensor on the side of the cylinder head (ala Chevy V-8) to check the actual water temp "in the engine", in conjunction with a "metal temp" sensor in the back of the cylinder head to get a better reading at higher engine temps.

By comparison, Chrysler used temp switches/sensors near the thermostat, but did not seem to have the same "needle over-shoot" issues which some GM brands did. The Chevy V-8s had them up there, too, in their earlier years.

There might be a few more details more specific to your Buick V-8 which others might add.

Enjoy!

NTX5467

Yellow circle is sending unit on a 61 engine...yours could be at blue circle

Thanks all for the information. "Old Tank" thanks for the photo. I took a look and I think I found it, but I have attached some photos just to make sure. It is a bolt head with a coiled wire going into it, and the other end goes through the rear fire wall. Could this be it? Seems to match the general location shown in your photo towards the rear of the engine. Thanks everyone!

Yellow circle is sending unit on a 61 engine...yours could be at blue circle

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Correct on your pic, Dan.

Ok, great thanks again. Now I remove and try to find a new one.

Wait up! that nut is what holds a bulb in the head and the whole assembly is continuous with the gauge in the dash by way of a capillary tube. There are no new ones...only rebuilding services.

Oh, I see, good to know. Haven't put a wrench on it yet. Well, I guess in order to have it rebuilt it has to be removed, so I assume the correct method would to take the gauge cluster off and disconnect it from there first and then turn the nut loose? Correct? Does anyone know who rebuilds these. Actually, I am not totally sure it is the sending unit, as it might be the gauge itself. All my gauges work except the temp gauge, but I just assumed that it is likely the sensor as opposed to the gauge based on my limited mechanical work on other cars, where it always seems to be the sensor and not the gauge.

The sensor in the engine has to go through it's hole in the firewall to be removed from the car, so it makes no difference to remove the gauge from the cluster first. IT will have to be removed eventually but it won't help you to get that bulb out of the motor.

Chances are that nut is holding onto the tube and will cause the tube to split and break upon removal. That nut is nestled into a larger nut which is nested into the head. The smaller nut is usually loosened first, so the larger nut can be turned. This is a somewhat dicey operation. If it were me, I would be doing the following.

#1 I would make sure that the water level is up to the top in the radiator. Since a mechanical gauge either works or it doesn't, the one thing that would stop it from working (it its intact) is low water level.

#2 Since the engine runs, every day for at least one week I would start the car and bring the trans to operating temperature. I would then pull the trans dipstick and dribble some hot trans fluid onto both nuts. If the car cannot be driven I would devise some method to heat a small amount of trans fluid and drop that on the bolts. You can always use the hot trans fluid from another car too.

#3 I would carefully use a small wire brush ( hardware store or tool bin at NAPA) after the third day to brush around both nuts each day, so that the hot trans fluid can have a chance to seep into the threads of both nuts.

Since the main objective is to try and get that thing out without totally separating the bulb from the small tube, this is not a job to be rushed. Also get a line wrench for the initial loosening of the smaller nut. This will help prevent rounding the outside edges of that nut.

And I would work this scenario for as long as it took to get that nut out of there, unless you source a new gauge. In that case I'd have the old one out by cutting the tube and using six point sockets with breaker bars.

John, like my 55 it appears that there is only one nut on his car. Anyhow, where are all of the '59 Buick folks? If the car has had regular use, the nut and bulb will usually release with little problem....the biggest problem is getting the gauge out of the dash. To drive the car, install an aftermarket mechanical gauge.

Thanks John and Old-Tank for the guidance. Yes it appears to have only one nut and the car is driven regularly on most weekends on short trips, etc. Just to clarify, is the tube connected to the back of the temp gauge permanently? Or can it be detached where I can replace just the gauge to see if it is the gauge itself, or are they consider all one in the same or one unit? I am used to replacing electric sending units on 1970s cars, where if the gauge does not work it can be field tested by grounding, etc,., but this "tube" set up on the 1959 Buick is new to me, so PLEASE forgive my ignorance, and all my questions. Old-Tank suggested going to a standard mechanical unit which I had not considered before. Is that the same as the electrical type common of the 1970s cars? Where the spade connector fits over the top of the sending unit and a wire runs back to the dash, or are you talking about something else. Would I have to tap into neck by the thermostat for installing an aftermarket unit or ? How to you find the correct calibrated sensor for a car that never came with a mechanical unit. Switching over to an aftermarket unit might solve this entire issue, as an option. Thank you gentleman.

The sensor in the engine has to go through it's hole in the firewall to be removed from the car, so it makes no difference to remove the gauge from the cluster first. IT will have to be removed eventually but it won't help you to get that bulb out of the motor.

Chances are that nut is holding onto the tube and will cause the tube to split and break upon removal. That nut is nestled into a larger nut which is nested into the head. The smaller nut is usually loosened first, so the larger nut can be turned. This is a somewhat dicey operation. If it were me, I would be doing the following.

#1 I would make sure that the water level is up to the top in the radiator. Since a mechanical gauge either works or it doesn't, the one thing that would stop it from working (it its intact) is low water level.

#2 Since the engine runs, every day for at least one week I would start the car and bring the trans to operating temperature. I would then pull the trans dipstick and dribble some hot trans fluid onto both nuts. If the car cannot be driven I would devise some method to heat a small amount of trans fluid and drop that on the bolts. You can always use the hot trans fluid from another car too.

#3 I would carefully use a small wire brush ( hardware store or tool bin at NAPA) after the third day to brush around both nuts each day, so that the hot trans fluid can have a chance to seep into the threads of both nuts.

Since the main objective is to try and get that thing out without totally separating the bulb from the small tube, this is not a job to be rushed. Also get a line wrench for the initial loosening of the smaller nut. This will help prevent rounding the outside edges of that nut.

And I would work this scenario for as long as it took to get that nut out of there, unless you source a new gauge. In that case I'd have the old one out by cutting the tube and using six point sockets with breaker bars.

A mechanical gauge is composed of the gauge, tube ( bulb inside the head) and pipe. It is a one piece unit as there is a gas inside the system that causes the gauge to move in relation to the water temperature. That is why you have to remove the Tube from the engine and pass it back through the hole in the firewall to get it out.

As for a replacement you can still get a mechanical gauge today which will still be a one piece unit. The calibration is not to the motor. The calibration is internal to the gauge package. It should give you an accurate reading regardless which engine it is installed in. You can also get an electrical unit which will have a separate Tube and gauge, and which you have to wire in accordance with the manufacturers directions. Again no special calibration is needed as long as you use the right sensor with the gauge.

You can always use a hang under the dash external gauge while researching having your original unit fixed, or searching for a replacement unit.

I don't seem to recall what the issue was, but if you want to check the accuracy of the instrument panel gauge, you can use an infrared non-contact thermometer to check the metal temperature where the capillary tube/nut combination is. Of course, drive the car about 10 miles on the highway (for good measure!) before you check it.

To clarify, there is NO electricity in the gauge mechanism, only the illumination in the instrument panel. It is a "manual" gauge situation, rather than otherwise.

Thanks for the pictures and information.

NTX5467

OK thank you, so I do have a "mechanical gauge" already in the car as a factory setup it sounds like from your description. I thought that was something different that what I had, when it was suggested to try an aftermarket "mechanical gauge". It sounds like it is the same thing. Would the hang under the dash unit require drilling and tapping into the engine to install the sensor? I assume this the more modern type type electric gauge. Installing one would make it safe to drive while I figure out how to remove and disconnect the defective unit, and have the original rebuilt in the meantime.

A mechanical gauge is composed of the gauge, tube ( bulb inside the head) and pipe. It is a one piece unit as there is a gas inside the system that causes the gauge to move in relation to the water temperature. That is why you have to remove the Tube from the engine and pass it back through the hole in the firewall to get it out.

As for a replacement you can still get a mechanical gauge today which will still be a one piece unit. The calibration is not to the motor. The calibration is internal to the gauge package. It should give you an accurate reading regardless which engine it is installed in. You can also get an electrical unit which will have a separate Tube and gauge, and which you have to wire in accordance with the manufacturers directions. Again no special calibration is needed as long as you use the right sensor with the gauge.

You can always use a hang under the dash external gauge while researching having your original unit fixed, or searching for a replacement unit.

Drilling into the engine is not a good idea. The factory location in the engine for your existing tube is ideal in my opinion. Those rear corners are likely to be the hottest parts of the engine, located so far away from the radiator and the action of the water pump. I would recommend removing the factory tube and gauge unit, then installing the temporary unit in the existing port in the engine. Note, you should see a coil of capillary tube bent in a two or three turn circle in the system. If you put in a mechanical gauge try to recreate this, because that is the area that flexes as the engine vibrates during use and that coil will reduce metal fatigue in the capillary tube.

I think you have the understanding of your car now. Aftermarket mechanical gauges will usually come with bushings to adapt to various engines. My 55 nailhead needed no bushings, however I had to make a spacer to go between the nut and the bulb (nut bottomed out before getting tight enough). An electric setup would work also as a temporary fix.

Willie

Yes indeed! Finally got it! And learned a few things as well. Thanks!. I already have started researching some of the hanging temp gauges on line, and see some brands even come with additional size fittings to adopt to various existing holes, etc. I think that will work great until I can get the stock one rebuilt.

I think you have the understanding of your car now. Aftermarket mechanical gauges will usually come with bushings to adapt to various engines. My 55 nailhead needed no bushings, however I had to make a spacer to go between the nut and the bulb (nut bottomed out before getting tight enough). An electric setup would work also as a temporary fix.

Willie