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1994 seville sls
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35 Posts
Discussion Starter #1
Yesterday i had to pull her over..she overheated very badly ... all of a sudden. I put her in the shop asap...it was soo hot i couldnt even drive her. No smoke, no leaks, no steam...just a (engine coolant very hot) message on the display. I dony know if i lost coolant or blew a head gasket but she overheated horribly. I just purchased this car and i do not know if coolant or thermostat has ever been changed (128,000) miles.
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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If there was no coolant loss, and it hasn't run hot before, then there was probably a water pump drive failure (belt, tensioner/pulley, seized water pump).
 

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1994 seville sls
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Discussion Starter #3
Re: overheating 94 sts

Yea its never run hot before and it didnt say "low coolant" on the display. I just replaced the serpentine belt a few weeks ago but i have never changed the water pump.
 

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White Diamond '03 DHS (with DTS floor shift)
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Re: overheating 94 sts

If low coolant was accurate and not just a bad sensor, that would do it, BUT then you have to figure out where the coolant is going and having "just bought it" and having "no leaks" is not a good sign. Might want to do a block test.
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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He said it didn't say low coolant.

Dannybo, the water pump is at the rear (drivers side) of the engine. The main accessory drive belt has nothing to do with it.
 

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1994 seville sls
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Discussion Starter #6
Re: overheating 94 sts

Okay, so basically what ur saying is that the waterpump isnt belt drivin...understood. ill probably ave him still test the block just to make sure its in good standing. I will also have my mechanic look at the water pump
 

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Re: overheating 94 sts

no, the water pump IS belt driven ... just not by the serp belt on the passenger side of the engine

it's belt driven by a pulley off the camshaft on the driver's side of the engine
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Re: overheating 94 sts

The water pump IS belt driven - by its own dedicated drive pulley and tensioner - at the rear (driver's end) of the engine. The pump drive pulley is a TIGHT press fit on the left bank intake cam snout extension.

Look under that metal shroud - (sorry, Chris.............)
 

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2002 STS/ 1994 STS
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229 Posts
Re: overheating 94 sts

Danneybo, you don't have a metal shroud. Yours is black plastic, and the spark plug wires are also channeled into it.
look at the bottom of this picture. Carefully remove it..
 

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1994 seville sls
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Discussion Starter #12
Re: overheating 94 sts

So i talked to the mechanic and hes still working on finding out what the problem is, he checked the tstat and the coolant tenp sensor and they are both working coreectly. He said it starts up bone cold and jumps to 250 and right to 300 out of nowhere

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Hes testing to see if there are any wiring issues. Any guesses?
 

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Re: overheating 94 sts

if it jumps to high temps like that i really do think its time you get the block test done and if it goes yellow you sir have exhaust gases in the chamber which means HG is ready to be fixed!
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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danneybo said:
So i talked to the mechanic and hes still working on finding out what the problem is, he checked the tstat and the coolant tenp sensor and they are both working coreectly. He said it starts up bone cold and jumps to 250 and right to 300 out of nowhere

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Hes testing to see if there are any wiring issues. Any guesses?
So it's not actually overheating? Just an incorrect temp reading?
 

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1994 seville sls
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Discussion Starter #16
Re: overheating 94 sts

The car isnt getting hot at all its just saying it is on the gauge and shutting off.
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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Wait. The engine is turning off? Or the DIC is telling you to turn it off?
 

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1994 seville sls
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Discussion Starter #18
Re: overheating 94 sts

The dic says "coolant too hot" and shuts the motor off... i think theres a safety feature that makes that happen. Could b wrong tho.
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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No. You'll get a message telling you to idle the engine (maybe, not sure on your year), but it won't shut itself off.
 

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Re: overheating 94 sts

just a point of clarification ... you do have a northstar engine, right?

the thread title says 94 sts but your profile says 94 sls

i can't remember if the 94 sls had the northstar or the 4.9

but the discrepancy warranted a double-check
 
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