Thread: OverHeating After Reasembly. All Hoses Warm, No Thermostat Whats going on?

Finished up the GTP this morning, I was going to finish when it got warmer out side but since my DD Buick century needs head gaskets I have to get the GTP going to commute to work. Car runs amazing but after about 3-4 mins of running the temp needle just climbs like its running from something. All hoses are warm and the cooling system has pressure, system is bled, I even pulled the thermostat (even tho it was brand new) and yet im still having the same issue. The intake manifold is primed and filled to the top to the thermostat housing. I thought I knew everything about these 3.8's after a lot of servicing and an engine swap but yet im stumped on this cooling problem.
Any help is greatly appreciated.

Thanks in advance
Brandon

the fans come on?

No they dont, and according to my scanner the cars running at 130o F But the needle is right below the red i don't dare let it run any longer after that.

maybe the temp sensor is bad? 130 and over heating dont make any sense at all. unplug the temp sensor see if the fans turn on.

you can also turn the a/c on, if the a/c works the fans will come on.

or your rad is clogged.

or the water pump has no impeller left.

The temp sensor is brand new out of the box (due to me breaking the connector when pulling the LIM). But if its "faulty" how am I getting the "correct" temp on my scanner. Have you heard of any faulty dash temp needles before?

130 is not over heating temps, 230 and up is.

According to my cars dash needle the car is overheating but the scanner says otherwise, if the sensor is faulty I may get a faulty reading digitally then also. Ill try another sensor and see what I get.

could be a bad sensor new out of the box. iirc a few have complained of this in the past.

its the coolant temp sensor...there are two sides of those switches, one side for the pcm, the other for the needle on the dash...and yes they come bad out of the box, is it a duralast by chance? do yourself a favor and get an OEM one as the aftermarket ones almost never read spot on

^^ I went through 3 aftermarket coolant temp sensors and all 3 had different issues (1 of which is exactly what you're describing)

Get a GM OEM sensor and you'll be fine.

Thanks for the reply's everyone. I put in a Echilin by Napa coolant sensor in and its better but its always about 5-15 degrees off which is annoying. I'm defiantly going to go OEM but does anyone know where I can get one without going to the stealership?

Ebay also has them. Just make sure to get an ACDELCO.

Also, they needle is almost always "off" compared to the actual temp. Mine before I messed with the needles would always read 10-20* lower than what my scanner was telling me. I believe in my 2 scanners more than the needle.

Just put in an order, Thanks!