Temperature problems...

[XonDubs]

Ok well, here goes nothing. This is on my 96 Limited 5.0 AWD with 120k miles.

The radiator sprung a leak, so I put in a new radiator, thermostat, lower radiator hose, and flushed the entire system, and installed a new temperature gauge sending unit(the one wire one).
The gauge goes all the way up to that line before the red and the "check gauge" light comes on.

My questions are, how often do these gauges go bad?

The instrument cluster, for some reason was swapped out to a 5-speed cluster. Would that change the reading of the gauge? Like do the 2 different clusters have different values? I don't know if the cluster came out of a V6 5-speed or a V8 5-speed(if there is one)

Also, what sensor/sending unit does the DIC display in the center counsel use for when it does the "system checks"?
Because when the gauge is that high, and the "check gauge" light is on, the DIC tells me that the engine temp is "OK".
So does this get it's readings directly from the computer or no?

Thanks in advance for any help.

 

[Ford_Nova]

While in class not long ago we were talking about something like this and thought that it might help. Depending on where you put the sending unit it might not be in water, but rather steam. If thats the case you will eventually fry the sending unit.

As for the consel, im dont really know how the computer works, but im guessing theres a separate sending unit for the computer or you would throw a code saying faulty temp reading or something like that. (p1288-p1299 is cylinder head sending unit)

 

[XonDubs]

I put the sending unit in when it was all full of coolant.

So the counsel most likely is running off the same sensor as the ECU sees?

 

[Ford_Nova]

If you meant exactly what you said, "when it was all full of coolant", unless you had a pool of coolant gush out it still might be in an air pocket (top of engine typically).

Your new sending unit might have a different coefficient value (resistance) than the one that originally came with it.

 

[XonDubs]

If you meant exactly what you said, "when it was all full of coolant", unless you had a pool of coolant gush out it still might be in an air pocket (top of engine typically).

Your new sending unit might have a different coefficient value (resistance) than the one that originally came with it.

Yeah, I kinda meant that. When I pushed it into the hole to start threading it in, coolant was pushing out around it.

Also the gauge is reading the same as it did before the thermostat and sending unit change...

 

[Ford_Nova]

Ok, sending unit is in liquid which means that there is a difference either between the gauge and the sending unit. If the gauge worked before you did all this then its the sending unit. Being one wire it could be messing with the gauge in some way or another, or you could have wired it in wrong.

You said that the computer still read that it was ok, which means that there is a different sending unit for the computer. If you had bothered that in any way the check engine light would be on.

 

[Cobraguy]

what year cluster did you install? They do indeed make a difference

 

[XonDubs]

I didn't install the cluster. It came like that when I bought it, so I'm not sure.

 

[CmdrPopNFresh]

Also the gauge is reading the same as it did before the thermostat and sending unit change...

....maybe its actually overheating. did you check codes? cause there are two sensors one for the pcm to read and one for the gauge to use.

 

[marragtop]

Consider getting a laser temperature gun to find out what the engine temp really is. They are only about $30... http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96451

 

[Four0Sport]

id say the problem lies in the temp sending unit. im pretty sure the message center gets its temp from the comp which gets its reading from the ECT sensor located on the opposite side of the water neck form the temp sending unit. there is a way to test the temp sending units on here.. i think its by grounding if off on the motor and the guage should shoot all the way to hot? im not sure, might wanna search that. or try a different temp sending unit. I think all of the ford ones are the same through a few years.

 

[XonDubs]

....maybe its actually overheating. did you check codes? cause there are two sensors one for the pcm to read and one for the gauge to use.

If it was actually overheating, wouldn't it be boiling? And wouldn't the "check engine" light be lit? And the DIC in the counsel wouldn't be reading coolant temp "OK" right?
The upper hose isn't getting super hot. It actually feels about how it should be.

id say the problem lies in the temp sending unit. im pretty sure the message center gets its temp from the comp which gets its reading from the ECT sensor located on the opposite side of the water neck form the temp sending unit. there is a way to test the temp sending units on here.. i think its by grounding if off on the motor and the guage should shoot all the way to hot? im not sure, might wanna search that. or try a different temp sending unit. I think all of the ford ones are the same through a few years.

Yeah, that's what I was thinking too. Either sending unit, or the gauge. I know when I bought it, they had the gauge disconnected.

Consider getting a laser temperature gun to find out what the engine temp really is. They are only about $30... http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96451

Yeah, I think I have one of those laying around somewhere. I'll have to look for it.

 

[XonDubs]

Ok I noticed also, the lower radiator hose never really gets warm/hot. And today I noticed both hoses are rock hard. I'm thinking this may not be so good...

 

[XonDubs]

Anyone? what are the possibilities it could be a bad water pump?

 

[Cobraguy]

It's not unheard of...but it is extremely rare. But if you can't seem to see water moving anywhere, it might not hurt to pull it off and look.

 

[XonDubs]

What else would cause the lower hose to not get hot/warm then? blockage in the motor?

 

[my98nnj]

The lower hose is the return line so technically it should be cooler then the upper hose.
The fact that your hoses are getting hard could be an issue.
Did the engine overheat when the rad. sprung a leak?
Excessive pressure in the cooling system could be caused by a blown head gasket.

 

[XonDubs]

Ok, so I dropped it off at a shop today to figure out what's going on with it.
I guess it's really only getting up to 183-ish degrees and that's it. Everything else tested fine. So they are thinking replace the thermostat again and throw in a different cluster, and it should fix all my problems.
Not bad for only spending $37 with tax on diagnosis.

Yup, they narrowed it down to just the cluster being wrong.

 

[Cobraguy]

Is it a white faced cluster?

 

[XonDubs]

No it is black.