Question about Cadillac Cars & Trucks
Its possible you've installed the thermostat upside down. If this is not the case, then I think you've got an air bubble in your cooling system. It could work itself out or while the engine is cooled down, you can open the radiator cap and see if its at all low on coolant.
Posted on Feb 20, 2015
SOURCE: 1999 Caddy Deville A/C problem
A/C systems are hard to diagnose without having access to the vehicle. One of the most common problems is undercharge (Not enough freon in the system) indicating a leak somewhere in the system. Other causes could be a burnt A/C compressor clutch fuse, defective compressor clutch, defective compressor/belt, defective High/Low pressure switches in the system, defective evaporator icing switch, defective wiring... Basically, you're better off getting the system diagnosed by a good A/C knowledgeable mechanic...
Posted on Aug 13, 2008
SOURCE: 96 cadillac deville overheating
Check for coolant flow at the Purge line,this is a common problem on the Northstar.
There is a small diameter hose coming from near the top of the coolant tank,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.If the hose is clear, check for blockage at the nipple on the tank.
Posted on Aug 14, 2009
Yes it can be the head gasket,one way to tell,is make sure the engine is cold,like in the morning.Take the rad.cap off,add water until full.Turn over the engine and let run,while looking at the opening(where the cap goes).Is the water coming out like really fast,maybe as much as a fountain?If so,then it is a head,or head gasket.If you would like to bleed system of air I can tell you how.If there is air in the cooling system,it will run hot.With it cold,or cool,not hot or real warm,fill the reservoir with water up to 3/4 full,over the fill mark.Fill the radiator full,and replace radiator cap,and reservoir cap.Make sure the hose from the reservoir to the radiator is in good shape,no holes or crimped anywhere.start the engine with the ac off.At this point the cooling fans should not be on.There not supposed to be on unless you straight wired them.Before the fans come on by themselves,or the vehicle runs hot,and right before not to soon,cut the car off.Go in the house and get on computer for about 30 to 40 minutes,and go back out side and check the water level in the reservoir.Is it down?if so add more water and repeat process until engine runs at normal temp.The fans should come on,and go off on there own,with the ac off.Let me know the out come.
Posted on Aug 29, 2009
OK, check that the 2 fans are turning on when it gets to operating temperature. If not, replace the 3 or so relays that control the two speed fans on your car.If that doesn't solve the problem, then you may have to buy new fan motors and also have the harness replaced if necessary to make it cool reliably.
I had this problem on a 1997 Cadillac Deville Limousine that overheated over 157 deg. F and went into its limp mode for cooling the engine off by allowing 1/2 of the cylinders to circulate fresh air into the engine in case all antifreeze would leak out or the car would overheat.
Don't run the Northstar engine too long, more than 45 min. at a time in this limp mode.
Good luck on this repair of your Northstar Engine.
Posted on Jan 02, 2011
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