inline 6 water temp problem

[Alex]

I bought a new water temp gauge for my 78 CJ5 AMC 232 i6 motor. I unscrewed the forward plug under the exhaust manifold coolent flowed out before i screwed in the temp gauge bolt, wiring it all in and it wont read a temp, i drive around the field 10-20 min and doesnt move. any idea's? and what is the normal running temp for that motor?

 

[73CJ]

Did you wrap the threads with teFlon tape? It needs to ground trough the threaded connection.

 

[Cheepjeep85]

id say 73cj is correct you have a ground issue.

 

[bondo258]

When you remove the sender, you have to squeeze the upper rad hose until coolant comes out the sensor hole. Then start threading it in as you're squeezing some coolant out. Very easy to get an air pocket, otherwise.

Or a bad ground, as others have said. Try using pipe dope instead.

I unscrewed the forward plug under the exhaust manifold coolent flowed out

Did you put an aftermarket gauge in the block, or just replace your stock one? Were you trying to bleed air out from below the sender? That won't work, Bubbles rise.

If aftermarket what sort of gauge? If a mechanical aftermarket was installed, I hope you didn't bend the tube too much. If so it's trashed.

If electrical what did the directions say?

I bought a new water temp gauge

A new gauge, or Sender?

You can't use any sender with any gauge, they need to match up.

 

[IOPort51]

I have only seen the temp sending unit in the back end of the head, not the block.

 

[bondo258]

I have only seen the temp sending unit in the back end of the head, not the block.

That's why I asked about aftermarket stuff. Not much clear info in the OP.

My stock wire could reach that coolant passage. It's that long. but it's to shallow, unless you use an adapter. those square threaded plugs are hard to get out after twenty something years, that's for sure. Before I picked up a Haynes book, I was thinking the manifold heater temp switch was the temp gauge, among other things. Previous owners manual choke and jury-rigged hand throttle covered the head mount sender completely.

How was your inspection/ shake down cruise, BTW?

 

[IOPort51]

How was your inspection/ shake down cruise, BTW?

It was good. everybody made it home and I learned a few things. Strangely enough I am having over heating problems too but I think that is just a engineering mistake I made on the fan.
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[BusaDave9]

Is it an electrical or mechanical gauge? You don't have to worry about grounding a sending unit for a mechanical gauge.
You are using the sending unit intended for that gauge? They have to match resistance.

 

[Cheepjeep85]

Is it an electrical or mechanical gauge? You don't have to worry about grounding a sending unit for a mechanical gauge.
You are using the sending unit intended for that gauge? They have to match resistance.

I had something typed up about mech gauges but edited it after I reread his post where it said something about wiring up a temp gauge

Droooiiddd 2

 

[Alex]

Hey, so i did put teflon tape on the threads so that is probably the problem :/ and what temp would be normal?

 

[BusaDave9]

Hey, so i did put teflon tape on the threads so that is probably the problem :/ and what temp would be normal?

Do you have a mechanical or electrical gauge?
Ground doesn't matter if mechanical gauge.

 

[BusaDave9]

a AMC 258 i6 / 4.2l should run at about 200°
The thermostat is 195°

 

[Alex]

It is an electrical gauge

 

[BusaDave9]

then, yes, a bad ground very well could be your problem.

 

[Cheepjeep85]

Hey, so i did put teflon tape on the threads so that is probably the problem :/ and what temp would be normal?

Yep I'd say that's your problem the sensor grounds through the intake/head where ever you have it


Droooiiddd 2

 

[73CJ]

I have only seen the temp sending unit in the back end of the head, not the block.

Back of the head on a 4.0.

On the thermostat housing - 1 or 2. I run 2, one for the gauge and one for the fuel injection.

The FI sender would not fit by the valve cover. It's body is much larger in diameter. The head ltakes a small diameter sender.