I'm old school. Give me a carb and a real fan belt and I'm happy. About as advanced as I get is an electronic ignition. When it comes to vehicles with puters, I generally let the dealer handle it. Lets face it, if I have to have a machine to tell me what's wrong with my engine, and what the trouble codes mean, well.... it's just more complected than I'm willing to deal with.

My son called today to tell me his temperature gage dropped from normal operating temperature to full cold and shortly after his check engine light came on. It's a 2001 Monte Carlo SS 3800 V6. He went to Auto Zone and had them check the trouble code and it read "Engine under temp". Duh!

Here's the possibilities that pass my logic test. 1. Temp sender bad. 2. Low Coolant (local Chevy dealer mechanic suggested that one). 3. Thermostat failed in the full open position (it was 20* today).

Anyone have an idea what else it could be???

Centerline

I beleive you have it with the bad sensor theory

Check the wire, usually the same sensor sends info to the computer and a bad connection can cause the same situation.

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Outlawed tunes from outlawed pipes

The first thing to check is the antifreeze level. I've seen a lot of cars come into the shop with no heat, temp guage reads cold and no antifreeze in the rad. In most cases is a blown heater hose or head gasket. Its pretty rare on a newer car though. I some cases people just keep driving their cars till they quit, at which point its motor job time. If the antifreeze is good then check the other stuff. I would have to think that the Chevy dealer would have a scanner that would give out more info.

Steve

Thanks for the comments guys. My son talked to a very experienced GM mechanic this morning and he says that in the 10 years he's been working on these motors he has never seen a sending unit go bad, but if it does it almost always fails to full hot. On the other hand if the thermostat fails it almost always goes to full cold.

The kid made an appointment to have it replaced and a couple little noises checked while they're at it. I told him I'd replace the thermostat but he said he's going to let the dealer do it ... because they guarantee their work. (He knows I'm really busy right now.)

Smart kid. I don't guarantee anything, especially on this new fangled computer controlled wizz bang cosmic crap Detroit's putting out now.

Centerline

AHHH CENTERLINE: You are starting to show your age I bought my wife a new 2003 Buick LaSabre ( Showing my age) I opened the hood and didn't recognize anyboby in there that I knew...Thank God I still have the street rod to play with.................OLD DAVE

Funny that this thread appeared today because I was just thinking that on my '57 Burb body that I mounted on a '00 GMC chassis complete with Vortec engine and transmission that maybe I should sell the engine and tranny and stick an old fashion crate engine with carb and 400 tranny.
These puter stuff makes my head hurt and I certainly don't want to be stuck on the side of the road with a headache .
Anyone interested in the engine/tranny with 7K miles on it?