maxnix
NICO Supporter
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18557 posts
1995 Q45, 1995 Q45t, 2000 Q45
Austin TX
7-22-2002
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| « Re: Cooling system diagnosint - Water pump? (dusred) | 6:47 PM 8/8/2008 |
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OEM or mystery 3rd party sourced parts?Critical for thermostat, tank tops and water pump.
Brian
1995 Q45 & Q45t & 2000 Q45
Discover the power of the button!
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jimbyjimb
Offline
302 posts
1992 Q45
Seattle wa
4-3-2008
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| « Re: Cooling system diagnosint - Water pump? (dusred) | 5:46 AM 8/9/2008 |
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When the car is cold loosen the radiator cap, do not remove, loosen. Start the car and wait for it to reach peak temp and then remove cap. If the pump is functioning you should be able to see circulation in the radiator. It's a simplistic test but works 9/10 times in my experience in pump functionality determination. If you need more clarity feel free to Email.
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Q45tech
Q45 Guru
Online
12401 posts
1990 Q45 319,000 miles
Marietta , Georgia
4-30-2002
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| « Re: Cooling system diagnosint - Water pump? (jimbyjimb) | 8:39 AM 8/9/2008 |
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Pumps never fail: they leak from weep hole, make noise from bad seals and bearings, or reduce flow from acid eaten impellers.Since head gasket failure is extremely rare unless the engine has been overheated. You always check coolant for hydrocarbon gases [use the typical device] and measure pressure build up time and ramp up rate. To confirm. Using aftermarket parts which are only 95-90% as efficient to new oem may reduce the safety spread. Really difficult to diagnose without accurate temperature number and a time to rise chart, idle rpm, ambient temperature, ac on/off. Many times overheats are somethings you forget like the rubber air surround around radiater allowing an air feedback fom engine compartment to the input side of rad. A restricted airflow condenser, dead auxillary electric fan in front of condenser. high idle rpm, more than 50% AF in coolant.
http://www.t3auto.com/
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dusred
Wheel Nerd
Offline
1259 posts
Previous Q45 owner, 09 Corolla, Ford F250 Diesel truck
St. George UT
5-26-2008
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| « Re: Cooling system diagnosint - Water pump? (Q45tech) | 1:01 PM 8/9/2008 |
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Is there a way to test the AUX fan?
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maxnix
NICO Supporter
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18557 posts
1995 Q45, 1995 Q45t, 2000 Q45
Austin TX
7-22-2002
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| « Re: Cooling system diagnosint - Water pump? (dusred) | 6:24 PM 8/9/2008 |
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| Quote, originally posted by dusred » | | Is there a way to test the AUX fan? |
Just observe it.It would also help us to help you if you would answer the questions asked.
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dusred
Wheel Nerd
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1259 posts
Previous Q45 owner, 09 Corolla, Ford F250 Diesel truck
St. George UT
5-26-2008
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Okay, I haven't driven the Q for a few months since I made this thread but the problem still exists so I want to figure it out.To answer your questions, Tech, the water pump doesn't leak from the weep hole or make strange noises. The car has been heated up but I have never let it get past the safe zone on the engine temp gauge. What's the typical device you use to check for hydrocarbon gases? I have only used OEM parts on my car. What is this "rubber air surround" you speak of? I just cleaned the air condenser so that shouldn't be a problem. I was suspecting the AUX fan because it didn't seem to be blowing as hard as it should be. I really appreciate the help, Tech, and others on here.
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Paul Wall
Online
1650 posts
1993 Infiniti Q45 123,000 Miles
Ipswich MA
12-22-2007
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| « Re: (dusred) | 3:39 PM 9/28/2008 |
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I think he mean a coolant pressure tester (Available at Auto zone for rent for $75).
Formerly ppastosBlack 1991 Q45 with TCS Part Out TONS OF Q45 STUFF FOR SALE!!! Paul
Current Car: 1993 Q45 Green 11/92 Hybrid of 1994 Q45 and 1990 Q45
 Mods done: 1994 auto dimming mirror, rare CD changer controller, 1991 vent lights, tranny cooler. Things done to restore to factory specs: New master cylinder, set TPS to .44 volts " Pedestrians stare  and cops bow down  , whenever the Q45 glides through town " - totaljett
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maxnix
NICO Supporter
Offline
18557 posts
1995 Q45, 1995 Q45t, 2000 Q45
Austin TX
7-22-2002
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| « Re: (dusred) | 5:57 PM 9/28/2008 |
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| Quote, originally posted by dusred » | The car has been heated up but I have never let it get past the safe zone on the engine temp gauge.
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The lag in the temperature guage is so great there is no guarantee the engine's temperature did not transgress into the fatal zone. Further more, once the senor has no liquid surrounding it, the actual coolant termperature is unknown to it, so the engine will be overheating in at least that location, but the guage won't indicate it.Aluminum has little tolerance for over heating.
Modified by maxnix at 7:38 PM 10/10/2008
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dusred
Wheel Nerd
Offline
1259 posts
Previous Q45 owner, 09 Corolla, Ford F250 Diesel truck
St. George UT
5-26-2008
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Okay,Lets say it did "overheat" how can I tell what damage was done? And if it did do damage to the engine/head gasket how can that effect the cooling system?
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Q45tech
Q45 Guru
Online
12401 posts
1990 Q45 319,000 miles
Marietta , Georgia
4-30-2002
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| « Re: (dusred) | 6:08 AM 9/29/2008 |
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Assumming an overheat, a blown warped head and gasket will alow combustion gases into coolant, raising the pressure, which can be read on a coolant system pressure gauge. The Combustion gases [hydrocarbons] bubbles can be analysed with the hydrocarbon/gas test tool.The point is tools are necessary along with technical education to use them. At least the ability to follow written instructions precisely.
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fixer
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54 posts
08 Sentra
Las Vegas NV
6-5-2008
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| « Re: Cooling system diagnosint - Water pump? (dusred) | 3:06 PM 10/10/2008 |
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I have had aftermarket radiator cause your kind of problem on a Q45 from utah. I live in Las Vegas and the summertime temps get pretty high. I got a Q fronm utah that complained of overheating and raditaor and thermostat was replaced, there was no coolant leaks, I tested with a pressure tester. and the head gasket was fine, I tested with a block tester. what I found was an aftermarket radiator installed. I recognized the afterrmarket radiator because the markings were different and the shape of the top tank was a little different. maybe to the untrained eye the radiator would look like a factory radiator. If you installed a used factory replacement, you may have a partially clogged radiator. It will need to be flushed by a radiator shop.
about the block tester, it is a tube that fits on the opening of the radfiator for the cap, and has a bladder on top to suck gasses from the radiator. you fill with block tester fluid that changes color if exhaust gasses are present. the cost of the tool is minimal and the fluid isnt much either. you can purcahse from any tool distributor. you may have trouble finding it at pep boys or auto zone
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Unnatural1
Offline
146 posts
1994 Infiniti Q45
Denton Texas
3-7-2007
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| « Re: Cooling system diagnosint - Water pump? (fixer) | 3:32 PM 10/10/2008 |
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NAPA sells block tester kits.When does it get hot? Will it sit at idle and overheat or only overheat while driving/cruising? If you have access to a laser thermometer use it to take some temp readings of the radiator at a couple of points; top, bottom, and each side. There will be some temperature variation but not like a 100*F difference.
~Brendan <--Advice worth what you pay for it.
ASE Certified Technician
Mazda Senior Certified Technician1994 Infiniti Q45 - Modified factory air box, Amsoil synthetic fluids
1991 Nissan 240SX SE Coupe --SOLD--
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