Temp Sensor Issue

[tdi]

My 03 Explorer EB w/ V8 has developed a new intermittant problem... When in traffic something (temp sending unit I suppose) tells the ECU that the engine temp is too high. The temp gauge pegs out, the dash warnings go off, the AC stops workings, yet the engine is not hot. And it will generally reset itself when the car is turned off and then restarted. Has this happened to anyone else?

 

[abarkl]

I had a very similar problem on my '03 4.0L and was convinced by members of this board that it was the t-stat that was the culprit. I was skeptical but it was true. $10 and 15 minutes and my problem was gone.

 

[tdi]

yeah, i'm skeptical too... doesn't add up. If the engine isn't hot, why would the t-stat be the culprit? Seems electrical to me

 

[tdi]

this continues to be an issue... anyone have additional ideas?

 

[tdi]

Additional information -- it's happening more regularly now, but only when in heavy traffic. And the warnings will go off once I get back to normal speeds...

 

[steventadams]

Did you replace the thermostat?

 

[tdi]

No, i can't get my brain around how the thermostat could be involved if the engine isn't actually getting hot. When the issue corrects itself, the temp swings completely back to normal range immediately. It doesn't happen gradually as if the thermostat became "unstuck".

There aren't any electrical links to the thermostat's function. I will likely replace it later this week if no other ideas surface, but I just feel like it'll be a waste of $15 and my time. I've dumped $$ at other problems with this load of crap truck, so I'm hesitant to spend anymore.

I am seriously not liking this Explorer. It has been nothing but trouble since day 1.

 

[abarkl]

Send me the $15 and don't worry about it.

 

[wood1]

When the problem occurrs, does the temp gauge climb instantly. Or does it climb slower?

If the T-stat is failing, it might be sticking closed, then snapping open, the temp would fall pretty quick...

I'd risk the $10 and 5 minutes to see if it's an easy fix...

 

[tdi]

It climbs instantly. I will try it and let y'all know... if it works, you guys can commence mocking me.

 

[abarkl]

I'd rather have your money but I'll start with the mocking since I was such a skeptic myself.

 

[Merc02]

Temp Sensor Issue, My solution

I had this problem last spring on a 325mile trip. The temp sensor would peg, alarms go off etc. The engine itself was fine and not overheating. So I would hit the "reset" every 10 or 15 minutes to shut off the alarms and get the display back.

I crawled underneath when we got back home a few days later. I found the wire that connects to the temperature sensor was broken in such a way that it would sometimes be connected and sometimes not. It was worn from rubbing next to something that I can't remember right now. I trimmed the wire, srtipped both pieces and twisted them together with an electrical wire nut. I then wrapped some electrical tape over all that mess and tried to place the wire away from the rubbing area.

That fixed my problem.

 

[tdi]

well, i replaced the t-stat, and added coolant in the process... it hasn't happened since. I'll do a separate post about its current error codes.

 

[wood1]

Preparing to commence mockation sir!

 

[tdi]

Ok, hold the mockery for the time being... it happened again. Its been a while since I changed the TStat (a month or so), and today was the first time it happened since. I am beginning to wonder if it is in fact getting hot. Perhaps the engine is slowly losing coolant? I did add coolant when I changed the TStat previously. I dunno...

I think I've mentioned before that the engine does have a slight miss and I get error code 402 pretty regularly. Could this all be related? Perhaps there is a head issue? Bad head gasket?

 

[wood1]

Is your coolant getting low? What is code 402 anyway?