Temp Gauge Not Reading - how hard is sensor to replace?

[Beachdrifter]

Hi All,

So Sunday I took 5945 out and noticed the temp gauge was not working after about a 20 min drive. Just read like the car was turned off.

1. Tapped on the gauge to see if it was "stuck", and nothing.
2. Searched the forums on here, and read about how to take the green wire on top of the sensor and ground it to check if it's the gauge that's bad or the sensor itself. I guess it's supposed to spike if you ground the green wire momentarily to tell you the gauge is working. (haven't had the chance to do this yet)

3. Assuming my sensor is bad, I take it my fans will still kick on and off because that runs off an entirely different switch (off the driver side coolant pipe).

4. Lastly, if I have to replace my sensor, how hard is it? I am away from my car at the moment and was wondering what needs to be done to change it. I heard it's on the passenger side manifold near the firewall. Hope it's not too hard; if it entails leaving the valley of death bare, maybe I will leave that to when I have to change something else in there as well.

5. Any other ideas to check before rulling out a bad sensor?


Thanks all for any thoughts,

--Randy

[vwdmc16]

My car which sat for a number of years did that as well, I checked and replaced the ring terminal connector at the sender first and that didnt fix it, turned out the nut that connects the printed circuit board to the gauge was loose, i was able to tighten it up by hand by reaching up behind the cluster

[Ron]

Do the test you mentioned and if the gauge then moves you are on the right track. You really don't have to take the green wire off, just run a wire to it from a good ground. You do have to be sure the green wire is getting a good connection...

It's not that bad to get to and waiting to fix that or an oil gauge it is really asking for it...

The gauge's circuit shouldn't affect the fans.

[Bitsyncmaster]

Unplug and plug back in the connectors on the bulkhead (box near the ignition coil). That is the most common failure for the temp gauge.

[Jonathan]

Just to clarify, if we have the "otterstat" sensing switch in the driver's side coolant pipe which tells the fans to either turn on or not to turn on based on how hot the coolant is, where is the temperature sensor which is relaying the analog value of the coolant temperature back up to the instrument cluster temperature gauge? That's likely something I may have overlooked ensuring it was plugged in correctly in helping out a friend with his car.

Looks like it is #45 on this page:

http://store.delorean.com/c-330-1-1-5-cylinder-headvalvetrain.aspx

Although it just shows it in space. Anyone have a photo of their engine showing this plugged in?... and better yet, what the connector looks like and perhaps showing what colour the wires are for it?

[jawn101]

Just to clarify, if we have the "otterstat" sensing switch in the driver's side coolant pipe which tells the fans to either turn on or not to turn on based on how hot the coolant is, where is the temperature sensor which is relaying the analog value of the coolant temperature back up to the instrument cluster temperature gauge? That's likely something I may have overlooked ensuring it was plugged in correctly in helping out a friend with his car.

Looks like it is #45 on this page:

http://store.delorean.com/c-330-1-1-5-cylinder-headvalvetrain.aspx

Although it just shows it in space. Anyone have a photo of their engine showing this plugged in?... and better yet, what the connector looks like and perhaps showing what colour the wires are for it?

Here you go man. The wire is green with an O-type terminal that goes under a nut. You will have to really blow the picture up to see it though.

http://dmctalk.org/attachment.php?attachmentid=11998&d=1342550581

[dmc6960]

Also, the nut and stud on the sensor have a high tendency to rust. If your replacing the sensor you may have to cut off the wire and attach a new lug to it.

[Jonathan]

Is it even remotely possible to check to ensure the connection is good without taking the top portion of the engine apart? Like somehow reaching/looking around the back of the engine, and feeling around with your fingers? I am guessing if the sensor we have was completely unplugged/corroded off at the wires, I might be able to feel that with my finger tips?

[jawn101]

Is it even remotely possible to check to ensure the connection is good without taking the top portion of the engine apart? Like somehow reaching/looking around the back of the engine, and feeling around with your fingers? I am guessing if the sensor we have was completely unplugged/corroded off at the wires, I might be able to feel that with my finger tips?

You would need to be a bit of a contortionist but I bet you could detect a major issue like the wire being completely disconnected, sure. But good luck replacing the sensor if it turns out to be bad... :)

[dmc6960]

Step up on a step-stool and lean far over the engine. You'll see it without needing to be a contortionist. Getting to it on the other hand...

[Jonathan]

Okay, sounds good. I'll give it a shot. I'm hoping to just confirm whether the wire is attached or not. I believe there have been many items replaced in and around the engine on this car, and I'm optimistic that it might be as simple as the connection isn't snug. Hopefully it doesn't involve replacing the sensor itself. Won't know until I try!

[dmc6960]

Hopefully it doesn't involve replacing the sensor itself.

And if you do have to replace the sensor, your going to have a lot of coolant pouring out of it after removal. Optionally you could drain the passenger side coolant from the engine through the [easier to access] drain plug. Just remember to refill and re-bleed.

[82DMC12]

I can verify the sensor can be replaced without removing intake or fuel injection. But I do have small hands.

[Dangermouse]

I don't know if anyone rents (or can you borrow) one of these

http://www.homedepot.com/catalog/productImages/300/45/454a5688-7b51-4522-95b5-842040e39dd8_300.jpg

[Beachdrifter]

Thanks all for your input, great thoughts. I'll check it out when I have time and will let u all know. Any other experiences to share, please do!

[OverlandMan]

Thanks all for your input, great thoughts. I'll check it out when I have time and will let u all know. Any other experiences to share, please do!

Any update on this? I have the same problem and am going to perform the basic checks aforementioned in the next day or so. I'd like to know if/how you resolved.

[DMC5180]

An appropriate sized GearWrench might make quick work of that task from above. You don't have much room to swing a normal Ratchet without removing some items.

[Beachdrifter]

Any update on this? I have the same problem and am going to perform the basic checks aforementioned in the next day or so. I'd like to know if/how you resolved.

Hi all, was able to finally look at this last night. LoL. So started with the basic check and leaned over the engine to check the sensor, when i noticed the little green wire had come loose from the top of the sensor. Looked like the nut had come loose all these years and fell off. So i found another one and reconnected to the terminal. Voila , this morning the temp gauge came back to life!

I love easy fixes !!! Thanks for the info, this was a good thread. Good luck Overland, hope it's an easy one.

[OverlandMan]

Hi all, was able to finally look at this last night. LoL. So started with the basic check and leaned over the engine to check the sensor, when i noticed the little green wire had come loose from the top of the sensor. Looked like the nut had come loose all these years and fell off. So i found another one and reconnected to the terminal. Voila , this morning the temp gauge came back to life!

I love easy fixes !!! Thanks for the info, this was a good thread. Good luck Overland, hope it's an easy one.

I fixed mine too and similar to yours it was easy. I used a paper clip to snake behind the glass/plastic on the cluster and "bumped" the gauge. I cycled the key and the gauge went from the 6 o'clock position to the normal 100 degree position. I then tested the sender and verified it worked. Finally, I cranked the car up and ran it for a few minutes. The temp gauge appears to be working fine now. I'll keep an eye on it and if it messes up again, I'll replace the gauge.

[mej7000]

My Temperature gauge is completely dead... I've been following the advice in this thread and I have a question...


I worked a small wire with alligator clips onto the post of the temperature sensor. Turned the ignition to Aux, grounded the other end of the wire with alligator clips and still got no movement from the temperature gauge.
I've plugged and unplugged the all the connections at the bulkhead.
I checked under the dashboard and the nut on the PCB seems tight.

Can I check the operation/connection to the Temperature Sensor with an Ohm meter? Given the previous troubleshooting attempts I would think that the resistance between Ground and the Temperature Sensor terminal would decrease as the engine warms up??? -- Therefore, if that is true, if the resistance does not decrease then I either don't have a good connection to the Temperature Sensor terminal or my Temperature Sensor is bad???

[MrChocky]

My Temperature gauge is completely dead... I've been following the advice in this thread and I have a question...


I worked a small wire with alligator clips onto the post of the temperature sensor. Turned the ignition to Aux, grounded the other end of the wire with alligator clips and still got no movement from the temperature gauge.
I've plugged and unplugged the all the connections at the bulkhead.
I checked under the dashboard and the nut on the PCB seems tight.

Can I check the operation/connection to the Temperature Sensor with an Ohm meter? Given the previous troubleshooting attempts I would think that the resistance between Ground and the Temperature Sensor terminal would decrease as the engine warms up??? -- Therefore, if that is true, if the resistance does not decrease then I either don't have a good connection to the Temperature Sensor terminal or my Temperature Sensor is bad???

If the problem is in fact, the gauge, it's not too hard to replace - it's just a bucket load of disassembly. It comes out as a section from the instruments. I think I have a replacement if you need.

The sensor itself doesn't seem too hard to replace - unscrews from the rear of the engine block I guess. I've not done this myself.

[David T]

If you grounded the wire and got no movement it sounds like the gauge or the wire going to the gauge is the problem. Check the continuity of the sensor wire to the gauge and if it is good, check that the gauge is getting voltage.

[Helirich]

I’ll give you a tip if you need to replace the sensor. Do it from under the car. I replaced mine from the top and it was a bear to get at. Later, I was changing the starter and I saw the sensor and would be much easier to do it from there. I do have the DPI exhaust, so it’s possible this tip won’t be as good if you have a crossover in the way.

Edit, One other thing. When I grounded my sensor wire, it pegged the gauge so hard the needle stuck there. I thought it might have hurt it, but later it came unstuck. Makes me nervous about grounding that wire.

[Josh]

I’ll give you a tip if you need to replace the sensor. Do it from under the car. I replaced mine from the top and it was a bear to get at. Later, I was changing the starter and I saw the sensor and would be much easier to do it from there. I do have the DPI exhaust, so it’s possible this tip won’t be as good if you have a crossover in the way.

Edit, One other thing. When I grounded my sensor wire, it pegged the gauge so hard the needle stuck there. I thought it might have hurt it, but later it came unstuck. Makes me nervous about grounding that wire.

That's the needle getting stuck against the clear plastic of the cluster. a well placed smack on the side of the binnacle will free it.

[Helirich]

That's the needle getting stuck against the clear plastic of the cluster. a well placed smack on the side of the binnacle will free it.

That makes sense. I probably knocked it loose on a pot hole.