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what is a normal engine temp?

1K views 12 replies 5 participants last post by  Ranger 
#1 ·
My GF bought a '97 Deville Hearse. Going over it for her, I noticed the coolant reservoir seemed low (couldn't see coolant level in filler hole) So I bought some pre-mixed Prestone and filled it till you could see the surface of the coolant. Fired it up with an outside temp of 63F and the dash readout showed me 205F after it warmed up.
Engine is the 4.6 liter Northstar. Don't these things run at 180 degrees like any normal GM?
 
#5 · (Edited)
Your thermostat is set to begin opening at 188 and fully open at 206. Cooling fans go to SLOW at 224 and fast at 236 - with no A/C function set the engine cools to 213, fans turn off, cycle repeats. With any A/C compressor function set fans run in SLOW all the time.

Several threads on all this in Engines; Northstar sticky threads.

Proper coolant level, cold, is halfway up in the surge tank. There's a FULL COLD legend and flat arrow molded into the tank top - follow the arrow across and down the side to the midseam. (EDIT: based on his posted pictures, it appears that the surge tank - indented for A/C filter/dryer placement - does not have a FULL COLD legend. In any event - proper level, cold - is about at the tank seam.)
 
#6 ·
Thanks for the replies guys. I've never owned a Caddy before, let alone a newer one. I grew up with Chevy small blocks that ran at 180
degrees. When I saw 200 and climbing, I got super concerned. The car doesn't even have a licence plate yet, and I was thinking I was in trouble.

I guess before asking about the fans, I should let the car get up to temp (with the A/C off) to see if they come on.

I'll take a closer look at the coolant tank for that arrow and get the proper level.

Update to follow.

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Ok, well it never warmed up past 206F...the fans never came on either.

Heres a picture of the top of the coolant reservoir...no arrow that I could see.
The level off the coolant is between 3 and 4 inches to the bottom of the filler neck.


And, what is this? Its under the hood right over the headlight.
 
#10 ·
The Northstar runs at about 190 - 205. Normal. If no A/C function is set, in heavy or slow traffic, fans go to SLOW at 224 degrees, the engine cools to 213, fans turn OFF, the cycle repeats. IF conditions are really horrible or there's something wrong with the cooling system fans will go to FAST at 236, but that's rare or never.

Fans should run in SLOW any time some A/C compressor function is set - DEFROST, for one condition that is always overlooked.

Fans almost never run above 25 mph - they aren't needed.

The surge tank pressure cap (16 or 18 psi) raises system pressure in order to raise the coolant boil point to about 265 - 270 degrees.
 
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