coolant air pocket?
coolant air pocket?
04-15-2008, 06:24 PM
04-17-2008, 08:29 PM
Welcome to AF.
The first thing is to state the model, year and mileage of your Deville. This greatly affects the advice we can give you.
IMO you do not have an air pocket. It's something else, either a bad thermostat (if you are lucky) or a blown head gasket.
Any air pockets in the cooling system will work themselves out as you run the car, especially over a few days. Therefore, if they exist, they would be at their worst the first time you run the car after adding coolant. The last few sentences of your post indicates the problem gets worse over time, not better.
A thermostat that's stuck closed creates a straightforward overheating problem and is easy to fix. A blown head gasket makes an engine overheat because compression gases leak out of the cylinder and into the coolant jacket on the engine. This introduces air or gases into the cooling system and pushes out the coolant into the overflow tank. Eventually enough coolant is displaced to allow the engine to overheat.
Sometimes, if you have a blown intake manifold gasket or cracked cylinder head, intake manifold vacuum will suck coolant into the combustion chambers. However, an engine doing this usually produces visible sweet smelling smoke out the exhaust.
Have a mechanic do a cylinder leak down test and a cooling system pressure test to isolate the cause.
A word of warning, the 4.1 / 4.5 / 4.9 liter V8 engines are pretty straightforward to fix. However, you have big trouble if you have a Northstar 4.6 liter engine with a blown head gasket. These engines have a defect in the way the head bolts thread into the block. A fix for a blown Norhtstar head gasket is typically several thousand dollars, so an accurate diagnosis is vital.
04-18-2008, 06:51 AM
Check the radiator hoses to see if one is really squishy. It may be collapsing under load. Could also be a clogged radiator.
05-01-2008, 07:17 PM
Just as coolant flow restriction can reduce radiator efficiency, so can airflow restriction. Bugs, dirt, leaves, and bent fins are always bad news. Careful cleaning and patience can cure these ills. :wink:
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