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Infiniti Q45 Maintenance and Repair

Hello forum,

I am a nationwide expert on Infiniti's of all generations. Most of my experience deals with the 90-96 models, but I am aware of most common issues and other problems with later models as well...

I have seen there is no real guidance on this forum as far as answering of technical data, so I figured I would offer my help to assist others....

If anyone has any questions, please post in this thead and I will do my best to answer them. you may also send me an email, my email address is in my profile.


  • mlevinemlevine Posts: 381
    There are times when no power is received by the A/C unit when initially starting the car. I have to turn off the ignition and restart the car. The restart alwalys seems to work bringing power to the A/C unit. The A/C unit is part of the navigation and radio console. The car is a 2005 Q45.
    Once the A/C unit is on there is no problem. Hope you have an answer.
  • My guess is a relay is a little funky. Sometimes relays will work occasionally...
  • Hi Elwesso, I have a 95 Q45a. A few months ago the tachometer ceased functioning properly. When the engine starts the tach goes to 1000 rpm and then as I drive it will very slowly keep going until its over 8000 rpm.

    Is this a simply repair like a sending unit under the hood, or does it require changing out the dash panel gauges? Thanks!
  • So if i understand correctly, the engine RPM is being reported incorrectly.... Meaning that it doesnt rev that high and drives normally, but the tach slowly increases to 8000 RPM (in a fairly linear pattern) after a certain time period of driving....

    Does it ever start working normally??
  • Yes, you are understanding it correctly. The actual engine rpm's don't ever go to 8000 and the car drives normally. Twice the tach very briefly returned to normal operation for a few minutes. When I first start the engine the tach will go to about 1000, then it moves at about the speed of a minute hand on a clock and continues until a physical stop point past 8000.

    Obviously with an automatic the tach is not terribly useful, but it bugs me that it is not functioning properly.
  • After reviewing other messages, I'm fairly sure the engine mounts on my '90 Q45 need to be replaced (major vibration through teh steering column and floorboards at idle, around 50 mph and again around 70 mph), but let me pose this question:

    I recently had a lot of work done on the car (all the hoses and belts, holes in the A/C repaired, etc etc etc), including replacing the oil pan gasket. Would any of that have involved loosening or removing the engine mounts so that maybe the mechanic didn't tighten or replace them properly?

    Is there anything that I, a complete neophyte, would be able to spot on visual inspection?

  • Alright... ive never heard of that problem before, but I do know the instrument clusters go bad on occasion.

    The thing is you can swap each gauge out of your cluster. So if your odometer and speedo still works fine, you can just get a used cluster off ebay (94-96 ONLY) and swap in the tach assy... If that doesnt fix it you have other problems, but its not a hard swap to pull it out.

    If you need more step by step procedures and diagrams, please email me since I cant post pictures and diagrams here.... I am more than willing to help.
  • Technically, there is no oil pan gasket, but that is just semantics... It uses RTV (liquid gasket)... you CAN reseal the oilpan without dropping the Xmember, and you do have to undo the mounts in order to do so....

    However, I dont think the mounts are what is causing your vibration... If mounts were a problem, you should be able to recreate it sitting still... What im saying is if it shows up at 50 and 70MPH, rev your motor to those RPMs IN PARK OR NEUTRAL (about 1750 RPM and 2400 RPM, respectively)... if the vibration does not reappear at those RPMs under a no load condition, then its not a mount related thing. 90% of the time mount related problems (for the engine, trans and exhaust) can be replicated under no load condition, but their magnitude may be different... Not always the case when replacing trans mounts which definitely go bad... If your car has over 60k miles, replace the trans mount as preventative maintenance....

    Another test for motor mounts is to rev the motor in park... You can actuate the throttle from under the hood... Youll see where the accelerator cable hooks onto the throttle plate on the drivers side... Anyway, rev the motor pretty good (past 4000 PRM or so) a few times in park and the motor should only move an inch or 2... Basically the motor will move a little but not much... If it moves a lot then you have a mount related problem... It would not be a real bad idea to R/R the mounts anyway but i still dont think its related to your vibration... Youll know at that point if your mounts are tight enough...

    What hoses did you have replaced. You have more hoses under the hood than you think!!!!!!!!!!!!! If you had truely ALL hoses replaced (about $3000 worth of hoses at wholesale prices) I will be impressed, as its something that should be done....

    Anyway, i feel like im really babbling at this point so ill try and wrap this up... Did the car act normally before you had all this junk done?? Unless your "mechanic" is a complete moron, i dont see how you could mess up reinstalling the motor mounts... its held in by 2 nuts on the Xmember...

    If you need any other help with this, post up or email me!! :)
  • patpat Posts: 10,421
    You can post pictures and diagrams on your CarSpace page. That way they'll be available if people need them in the future. ;)

    We really would rather have the exchanges occur in the discussions instead of off-line. That way all interested parties will benefit.
  • honestly, I was so pissed off by the time I paid the guy, I didn't even pay attenetion. This guy's labor runs on the cheap side and I had about $1400 worth of parts and labor.

    So if it's not the mounts, (I'll go test the no load conditions in a little bit) any ideas?

    Oh - and to answer your other question, the car sat unuswed for about 2 years. When I got it back, it as running liek a dream, that was on August 15th, .
  • Update - this morning the vibration was at a minimum, almost gone.
  • let me know if it returns and how, that will tell me a lot.
  • dondredondre Posts: 2
    my 93 q45 shakes badly sometimes when i do about 40 mph. it feels like it will shake me out of the car but i will hit the brakes and slow down, then acclerate again and it will stop. what could that be?
  • elwessoelwesso Posts: 42
    it could be a driveshaft related issue, that was my initial though but the fact that it does not do it under all conditions sort of makes that theory go bad.

    does the vibration go away if you manually downshift to 3rd gear at 40MPH. You should drive in 3rd gear until you get past 50MPH or so anyway! I do!
  • dondredondre Posts: 2
    i had it looked at today. they told me that my bushings from my rack and pinion needs to be replaced. but i am thinking that if that is the case why doesn't it do it all the time. i was thinking that it could be the driveshaft also.
  • elwessoelwesso Posts: 42
    The rack bushings probably are not causing the vibration problem. Most of the time if rack bushigns are shot the car will have goofy steering. For instance, if you take a right turn, and return it to center, the car will drive straight but the steering wheel will be off-center....

    Driveshaft problems are fairly common, especially on older Qs.
  • The vibration has returned and gone away again, but last night we have something new!

    The message area started indicating "low battery change" every now and then on the way home. Then it would be "OK" and then back to "low battery," where it stayed after getting off the highway.

    When I got out of the car, there was a hissing sound, like a tire rapidly deflating. It seemed to be coming from the back of the engine when I opened the hood, but then when I bent down to the gound to see if it WAS a tire, it seemed to be coming more from the front. Radiator is full this morning, nothing suspicious puddled on the driveway, either.
  • My power seat control is not working to make the seat move forward. It works in all other directions. But when it gets moved back the seat will not move up. there is nothing caught in the seat or anything. bottom line is How can I move the seat up manually? Is there anything I can do to the control to make it move?
  • mild1mild1 Posts: 2
    I'm looking to buy a '99 Q45t. The only one available where I am is a higher mileage car (111K). The price seems decent (12800 cdn) and so I went to test drive the car. Here's what I noticed.

    1. The brakes looked a little corroded from the outside, peering through the 5 spoke wheels. Is this a major problem?

    2. When braking, the car doesn't slow down smoothly and there is a slight vibration. Is this consistent with warped rotors, or could it be something else?

    3. When cruising at about 40mph, on top gear overdrive, i encountered a small hill. I purposely tried to let the car climb without it dropping down a gear. While the car did it, it seemed to continually hesitate just a little every second or so as it was lurching up from around 1500rpm. Is this a problem? what could it be?

    3. For a worst case scenario, what and how much money am i looking at to make a car with 111K mint condition?

    Everything else with the car was decent. The tilt wheel does not go up or down, but the dealer guy said he'd fix it if I bought the car.

    I have a copy of the Carfax report, and the car is clean with no accidents or problems. I'd like to know what you think about this car, as the dealership seems like your typical used car lot.


  • elwessoelwesso Posts: 42
    First off, 111k is NOT high mileage at al.. The car is just getting broken in...

    1. If the rotors are just rusted a little on the surface thats not really a problem. The rotors will rust just from sitting for a while. If the car isnt driven every day youll see some rust accumulate, especially if it rains or is moist. My car ususally sits for about 2-3 weeks at a time and the rust accumulates, but goes away right after i drive it..

    2. Pretty common. Youll think this sounds crazy, but it really works... Yes its warped rotors, but one way you can sometimes make them feel better is to go on an open road and SLAM on the brakes at about 70MPH. Press the pedal down to the floor... A lot of times rotors arent actually warped, but rather material from the pads sticks on the rotors... By really clamping down on the brakes you can sort of smooth the rotors out a little yourself. may not make a huge difference but its worth a try, and youll at least know that your braking system works good.. Otherwise you cna just resurface the rotors at probably $20 a corner... I do this to my car, and Ive done it to other people's cars. They think im crazy, but when they come back and see their vibrations arent as bad and it didnt cost them anything, all is well!!

    3. Im sure your definition of mint and my definition of mint are 2 different things... To make the car as new your gonna have to throw a lot of parts at it, as the car is 7 years old!!!!

    Carfax reports really dont tell me anything, because you should be able to tell if a car has been wrecked...

    If you can get the dealer service records thatd be great.
  • mild1mild1 Posts: 2
    Thanks for the tips! It definately eases my mind somewhat. When you said 111K was not high mileage, you were refering to MILES, right? Cuz 111K kilometres would definately be on the low side. I'll see if I can find any service records for the car, I plan to talk with the dealership guy tomorrow; I seriously doubt there will be any.

    I'm just mainly concerned with a car that may need a buncha new suspension bits (struts, cvs, bushings) with this kind of mileage, but I'm surely going to send the car to my mechanic to check it out before I buy.

    Thanks again! Much appreciated. I'll let you know how it goes.

  • waliswalis Posts: 35
    Firstly, thanks for taking time to help Q45 owners with their are a true gem.
    Question #1: My antilock light will not go off on my 1992 Q45. Also, the brake pads worn message on the message board won't go away. I changed all pads (front & rear). The sensor is connected on the rear passenger brake and still no solution. How can I solve this problem?

    Question #2: My car rides well except for a vibrating sound that seems like maybe one of my tires is bad. I've changed all four tires about three different times trying to solve the problem but to no success. I just changed the passenger side wheelbearing and still didn't solve the problem. Could it be another bearing or something else? Please help!
  • elwessoelwesso Posts: 42
    Who cares miles vs KMs.... WHen cars last 300,000 miles 111k is just a scratch on the surface. not saying yours will last that long but 250k should be no problem.... I know probably 10-15 people with Q45s of any year over 250,000 miles, and 2-3 over 320k miles...

    Main thing thats gonna be worn out is the shocks... as well as tension rod bushings.... Just factor in $2000 in new parts and labor and you wont be disappointed... I can assure you, youll be amazed by how the car will be after a suspension rehab, especially if its all original stuff.

    People really like to cheap out on brakes, and 10 feet can make or break you in terms of a panic stop....

    Just so you know, its AGE that kills stuff not so much mileage (especially with suspension components)...

    The drivetrain is going to be solid assuming the oil has been changed regularly... Just let me know as many details as you can.
  • elwessoelwesso Posts: 42
    For the ABS light, theres a few things it could be... Best thing to do is put it in diagnostic mode and see what it thinks is wrong.... COuld be as simple as the relay or something else...

    For the brake pads worn, i always take the sensor wires and short them together. I put an aftermarket brake kit on my Q (no sensors) and I did this to make the things go away. Just short it, you should know when its time to replace the brakes anyway without the idiot light.

    Could you describe where the sound is coming from(front/rear left/right)... Is it a high frequency or low frequency vibration.... theres a few things it could possibly be... but id rather have mroe details before going for that.
  • waliswalis Posts: 35
    It's definitely from the front. It's more from the passenger front. It's a low frequency vibration very similar to a bad tire. It's not my tire becuase i 've tried three different brands and it still didn't fix the problem.
  • elwessoelwesso Posts: 42
    lift up that corner (its best if the other corners are on the ground for stability) and pull and push on the wheel and see if theres any play.... im almost thinking about a bad tie rod end... or something.... Generally tire related vibrations come and go at different speeds...
  • waliswalis Posts: 35
    please help by telling me what to look for if I can lift and take the wheel off the car. Is a bad tie rod easily detectable? How do I check for it? What steps do I need to take in inspecting it? Thanks!
  • elwessoelwesso Posts: 42
    you dont necessarily need to take the wheel off the car, just get it up in the air (off the ground) and shake it... you should feel NO play at all... Make sure the steering wheel is locked as well...

    Most auto shops would be abel to tell you if you have bad tie rods.
  • waliswalis Posts: 35
    Okay...I did exactly as instructed and found no play whatsoever on both front wheels. They were as stern as they could be. Is there any other thing you can think of? The vibration is resembles a sound from a bad, unbalanced tire. It's from the front. I also noticed that the front passenger wheel doesn't spin as freely as the driver side. PLEASE HELP! I did have the rack & pinion changed at some point. I'm not sure if the vibration started right after that or much later. Please advise!
  • elwessoelwesso Posts: 42
    Hmm... This could be something maybe like a stuck caliper and your rotor is really warped.... Sounds pretty goofy... It could also be a REALLY bad wheel bearing, but normally bad bearings make a lot of noise... They could cause a vibration but ive never really heard of that, but i reckon most wouldnt let them get that bad.
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