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confused overheating


jmos6969

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You need to go to Autozone, rent the block tester kit, buy the test fluid. Do not add coolant, etc. as adding new coolant will give a flse negative test result. Follow the directions with the tester - if the blue fluid turns green or yellow, you have a leaking headgasket(s).

Have you verified the water pump belt tensioner is not frozen/corroded and the belt has the proper tension and is actually operating the water pump?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Yeah, less than 50-50 will cause overheating.

If the car still overheats with 50-50 coolant, then you need to run the car for a couple of days and then test the coolant for combustion products. If you've just changed the coolant, the test won't see anything.

The smell test works when you have a lot of head leakage. A spurt of steam into the heads when climbing a hill will cause a steam bubble at the thermostat which will cause flash overheating, but there may not be enough exhaust in the coolant to smell. But, passing the smell test is a good sign.

Northstars don't have a credible path for oil in the water from head leakage. I have heard of oil in the water in old iron engines that did not have the head(s) properly torqued. If you have oil in the water in a Northstar, it's probably from the oil cooler tank in the radiator.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I have a 2000 Cadillac SLS with a overheating problem. Changed water pump, radiator cap, thermostat, checked purge line fluid flowing. When it starts to overheat if I rive the engine the gauge goes back to normal, then starts to rise again. Secondly, the battery light comes on when I'm at idle for a period of time. Third, the blower for the heater sometimes does not turn on unless I kick the lower panel on the passenger side on the car. Any suggestions on my problem ?

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I have a 2000 Cadillac SLS with a overheating problem. Changed water pump, radiator cap, thermostat, checked purge line fluid flowing. When it starts to overheat if I rive the engine the gauge goes back to normal, then starts to rise again. Secondly, the battery light comes on when I'm at idle for a period of time. Third, the blower for the heater sometimes does not turn on unless I kick the lower panel on the passenger side on the car. Any suggestions on my problem ?

You should start a new thread for this vs. hijacking an existing thread.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I would check one more thing that has not been mentioned. Check the tensioner pulley on the water pump belt. Sometimes the spring can get weak and belt does not have enough tension and slips causing poor circulation. Also check to see if the pulley bearing is bad. My tensioner pulley just fell apart because the bearing froze causing poor circulation and overheating. I replaced tensioner pulley and all was good.

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How much fluid should be coming out of the overflow hose ?

Nothing should come out of the overflow hose under normal operation.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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The bolt with a hole in it from the waterpump housing to the surge tank should have a steady stream like a dog pissing on a fire hydrant. If the surge tank is filled up 1/2 way when cold, then a cold start, there should not be coolant or air coming out of the rubber overflow tube on the pressurized cap. if you stick the rubber overflow tube in a jar of water, you should not see massive air bubbles blowing out. A few bubbles here and there are fine. But if the bubbles are steady, then that is an indication of head gasket failure. Be careful handling that rubber tube if a suspect car is hot - when the car overheats, hot coolant will come spraying out of that hose.

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  • 2 months later...

Thanks again for all the help on my 96 cad getting rid of it. Ok plz need help on new cad 2001deville dhs now the problems is check engine light came on the codes read Po420 yes 420 lol and Po 741. Plz need help I put in some lucus slip tranny fix it in today now it was low on tranny fluid so I put both lucus and some tran fluid. I hope that helps because the rpms go high sometimes and mileage is bad. What can I do? Thanks

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P0420 Catalyst System Low Efficiency
P0741 TCC System Stuck Off

The cat is cracked or otherwise bad or going bad.

I wouldn't put anything in the transmission except Dexron VI.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I hate to break it to you but the P0741 specifically means the torque convertor is bad, Unless (and only unless) it is followed by a solenoid code.

There is no fix other than removal to fix that, Usually the fluid leaks out of the convertor and runs dry causing it to overheat and fail.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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You need a new cat.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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