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1991 Sedan Deville
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19 Posts
Discussion Starter #1
I just completed a radiator change on my 91 Deville. I got the replacement radiator from a 92 Deville in the junk yard. The 92 has a wider aluminum core, and smaller fittings for the transmission cooler (I had to adapt new fittings to the 91 plumbing with some hose).

Anyway, I filled the "new" radiator to the filler neck and the overflow reservoir to the "full hot" watermark (two gallons altogether). The total fluid capacity is supposed to be 12.5 liters / 3.3 gallons. I suppose the other gallon or so is normally would reside in the motor.

So on first startup, I'm waiting for the engine to get up to normal operating temp, expecting that the cooling system will start sucking coolant in from the overflow reservoir, and I'd have to add another gallon of coolant. But before the motor can get to temp, I notice some smoke wafting up from the front of the engine, coming from somewhere below the area where the plugs are for cylinders 3 & 5.

There was some amount of trans and engine oil spillage when I pulled out the old radiator, so it could be that stuff burning off. At most, I probably lost a pint of trans fluid and maybe as much oil.

Before the radiator change (the old one developed a crack in the plastic tank), the car ran fine. I'm hesitant to let it run up to temp in case the smoke is something other than fluid spillage burning off.

Any suggestions?
 

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1992 STS / 2005 MB G500 / 2003 STS / 2006 XLR-V
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11,694 Posts
I just completed a radiator change on my 91 Deville. I got the replacement radiator from a 92 Deville in the junk yard. The 92 has a wider aluminum core, and smaller fittings for the transmission cooler (I had to adapt new fittings to the 91 plumbing with some hose).

Anyway, I filled the "new" radiator to the filler neck and the overflow reservoir to the "full hot" watermark (two gallons altogether). The total fluid capacity is supposed to be 12.5 liters / 3.3 gallons. I suppose the other gallon or so is normally would reside in the motor.

So on first startup, I'm waiting for the engine to get up to normal operating temp, expecting that the cooling system will start sucking coolant in from the overflow reservoir, and I'd have to add another gallon of coolant. But before the motor can get to temp, I notice some smoke wafting up from the front of the engine, coming from somewhere below the area where the plugs are for cylinders 3 & 5.

There was some amount of trans and engine oil spillage when I pulled out the old radiator, so it could be that stuff burning off. At most, I probably lost a pint of trans fluid and maybe as much oil.

Before the radiator change (the old one developed a crack in the plastic tank), the car ran fine. I'm hesitant to let it run up to temp in case the smoke is something other than fluid spillage burning off.

Any suggestions?
Well what else could it possibly be? The only other white smoke aside from PS/Trans/Oil/Brake fluid spillage would be coolant entering the combustion process which typically means a failed headgasket right? Obviously your cooling system was working fine before-hand and if the car isn't overheating then your analysis of fluid burnoff sounds about right to me. UNLESS your failed radiator caused serious overheating before you changed the radiator. In which case you could have block or gasket damage and in that case the white smoke (steam) would be exiting via the exhaust, not billowing from the engine.
 

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2010 DTS
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87,559 Posts
So on first startup, I'm waiting for the engine to get up to normal operating temp, expecting that the cooling system will start sucking coolant in from the overflow reservoir, and I'd have to add another gallon of coolant.
Wrong. That system is very different from the Northstar. It is an overflow reservoir, not a surge tank. Your tank is sealed off from the rest of the system by the two way valve in the radiator cap. As the system heats up and the coolant expands, the excess expanding coolant flows into the reservoir. Then as it cools and contracts, the valve opens in the other direction, NOW sucking coolant from the reservoir. That will NEVER happen during warm up.
 

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1991 Sedan Deville
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19 Posts
Discussion Starter #4
So what is the best way to refill the coolant; should I let the motor warm up with the radiator cap off and add coolant through the filler neck?
 

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2010 DTS
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Yes, but don't take too long. Once it gets to about 220 degrees it will start to overflow. Rev the engine once or twice to purge most of the air, then cap it up and top off the reservoir. Any air left in the engine will get purged when it heats up and replaced with coolant when it cools. Check the reservoir over the next few days and top off as necessary.
 

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1991 Sedan Deville
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19 Posts
Discussion Starter #6
Smoke stopped -- I guess it was just spilled fluids from the radiator change. I refilled the system per Ranger's recommendation and it runs great!
 
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