Why is my 2001 cadillac running hot?

Vincent G

• 2363 Answers
• Posted on Dec 05, 2009

SOURCE: my 2001 cadillac deville is running hot still, i

When the car is completely cool,check the electric fan(s) for smooth rotation.

Clean/check/change the thermo sensor,contact and wire.

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Excavate air pocket in coolant system / check for head gasket leak

This test will kill two birds with one stone.

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MAKE SURE THE COOLANT SYSTEM and ENGINE IS COLD!

RAN THIS TEST IN A WELL VENTILATED AREA ONLY!

You will spill some coolant during this air pocket purge test.......BE KIND TO THE ENVIRONMENT and ANIMAL please clean up after the test!

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Put the front end on a pair of ramp or park your car on a VERY STEEP HILL (radiator facing top of the hill) .

Top of the coolant reserve tank

Let it ran for 10-15 minutes.

Monitor for air pockets escaping from coolant reserve tank.

Small amount of bubbles is OK at 1-5 minute mark

After the thermostat open up (after 195 F warm up) at
5-12 minute mark or after high idle you should see less bubbles.

If you do not see any in rush of bubbles then your thermostat may be partially stuck or rusted badly inside the thermostat hosing.

Give the thermostat host few gentle taps.

If you see larger bubbles surfacing after 15 minutes then should do a hydrocarbon (HC) dye test to test for potential head gasket leak.

Let engine cold down and top off coolant reserve tank.

Start monitor for coolant lost

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A coolant flush is require every 2 years or 24,000 miles.

I recommend the thermostat that has a relief pop-let to reduce the change of burst radiator and coolant hoses.

Make sure you get a new thermostat gasket,black RTV and fresh coolant for the job.

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SOURCE: i have a 1999 cadillac deville thats running hot

Have you replaced the drive belt(s) and/or checked the tightness of same?

SOURCE: 1999 cadillac deville overheating

my husband did everything that everyone else did that had this overheating problem. It was so weird that my engine cooled at a light and heated up going down the road. I have a north star 4.6 engine and this is natorious for happening. my check engine light also came on and so I had a diagnostics done which told me my #1 injector wasn't firing , car ran like **** as well. After putting in a new water pump and plugs,ect. and realized injector was good a friend told him we could have a blown head gasket. So just to see if this was the problem I went to buy a bottle of glassbeads and the auto parts guy told us to purchase a bottle of BARS STOP LEAK BLOCK SEALER NOT RADIATOR BUT BLOCK SEALER $31.99 . He followed the directions and we waited 24 hrs. before driving it. What ever the problem was has stopped my car runs like brand new and I am loving it again. no over heating no injector problem, runs great.......I hope this helps. I know its probly a temperary fix but its a fix and now we know what the problem was. SASSY

SOURCE: 2002 Cadillac Deville Running Hot

There are a few things that could cause overheating, here are some things that might help, the cooling system should be chekced with the engine cold after sitting for a while.

• First thing you might want to do is check the coolant in the reservoir tank, it should be at the proper full level.
• Sometimes when you change a thermostat there's a possibility you could get air in your coolant lines from having the coolant system opened up, this could keep your coolant from circulating through your system, if so you would need to bleed the air out of the coolant system.
• The water pump should be inspected for leaking coolant out of the weep hole's, when a water pump go'es bad it may leak coolant, which would mean the seals on the pump are bad, also listen for squeeling noise's coming from the pump when the car is started, if it squeels the bearings are bad, there is also a possibility the water pump fins are wore down from corrosion, there is no way to inspect this without removing the pump.
• check the drive belt for wear and tension, a bad tensioner or a bad drivebelt could have an effect on the operation of the water pump.
• check the pressure cap on the coolant reservoir tank for good pressure, when you remove the cap you should hear a hissing sound this means you have good pressure in your cooling system, check for corrosion or build up on the cap, clean the cap if nessary, also check the coolant in the reservoir tank it should be somewhat transparent and clean, if not you might need to have the cooling system flushed.
• check the large upper and lower radiator hose's for cracks, swelling, and proper flow. Good luck.

Mark Carrington

• 192 Answers
• Posted on May 22, 2010

SOURCE: need to locate where my 2001 cadillac deville

The thermostat in the northstar engine is located at the bottom radiator hose (unlike most conventional cooling systems), the hose connects into the housing where you will also find the water pump.

You will need to remove the air filter housing and air duct to gain easy access to the thermostat.

Remove the hose from the housing,then remove the two bolts on the flange,the thermostat can then be pulled out.

Take note of the orientation of the thermostat as you remove it.

The thermostat in the Northstar engine is a duel action device.
One end of the stem is the Thermostat(obviously) and at the other end is a spring loaded pressure valve(the thinner end).
Make sure the thermostat end is nearest the rubber hose and the pressure valve end is in towards the engine.

Don't forget the new gasket when you install your new stat, you may have to order this separately.


Overheating........

The most common overheating problem with the Northstar engine is a blocked purge line(small hose).The purge line is designed to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank (not the cap) ,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.Or trace the hose back until you find the blockage.
The hose goes in to the engine to a crossover and comes out the other side close to the thermostat housing,the blockage may be there.

Also note that the cooling fans don't come on until the coolant temperature hits around 225 degrees.
During normal highway driving the fans will very rarely come on(if at all) due to constant air flow through the radiator.They will only usually come on in heavy traffic conditions on a hot day.
But......if you have the Air Con switched on, the fans will run all of the time.