Ask a mechanic thread... Q & A with an ACTUAL mechanic!

[Brewmaster]

I recently changed the rear brake pads on my Infiniti but did not change the rotors (car has about 100,000km or so). Since doing the change, I get some loud squeaking coming from the brakes but only for the first 30 seconds or minute of driving after being parked for awhile. Any idea what might be causing this and what I should do to fix it?

[Locke]

Originally Posted by Brewmaster

I recently changed the rear brake pads on my Infiniti but did not change the rotors (car has about 100,000km or so). Since doing the change, I get some loud squeaking coming from the brakes but only for the first 30 seconds or minute of driving after being parked for awhile. Any idea what might be causing this and what I should do to fix it?

I'm no mechanic, but I've made this mistake.

Always do pads and rotors together. They're parts that touch each other.

Yes, 'thats what she said.' Beat you to it.

[Nufy]

Originally Posted by bigtmac19

I'm sure I will get slammed for this (who goes to the dealer for a bulb) but when I get a bulb warning, I usually just go to the dealer, because they will do it for me, and it doesn't cost more than a few dollars - so that's where my bulbs are from.

First time I had a tail light warning in my truck I called the dealer...

Yep bring it in...we can change it for you.

12 for the bulb plus a half hours labor...

Total estimate close to $100.00.

Luckily the owners manual listed the bulb required.

$4.59 at CT and 20 minutes of my time to swap it.

Dealers are great for some stuff...

[GGG]

Originally Posted by Brewmaster

I recently changed the rear brake pads on my Infiniti but did not change the rotors (car has about 100,000km or so). Since doing the change, I get some loud squeaking coming from the brakes but only for the first 30 seconds or minute of driving after being parked for awhile. Any idea what might be causing this and what I should do to fix it?

That sounds like rust build up on the pads that gets worn off after driving.

As for Rotors if you replace the pads before they are worn out you don't need to do the rotors.

[automaton 3]

Originally Posted by Locke

I'm no mechanic, but I've made this mistake.

Always do pads and rotors together. They're parts that touch each other.

Yes, 'thats what she said.' Beat you to it.

I'm also not a mechanic but I believe the conventional wisdom is you only need to replace the rotors if out of spec or very warped/damaged.

If in spec for thickness you could also consider have them turned, depending on the cost vs. replacement.

[Locke]

Originally Posted by automaton 3

I'm also not a mechanic but I believe the conventional wisdom is you only need to replace the rotors if out of spec or very warped/damaged.

If in spec for thickness you could also consider have them turned, depending on the cost vs. replacement.

Good point, but unless they're something special (drilled/vented/carbon fibre/etc.) rotors are cheap like borscht.

[btimbit]

Dropped a small tool into the engine bay, and no matter what angle I try and look or reach, or how much light I use, i can't find it. Just looked for a whole hour. I'm sure you've ran into this TOTO, any advice?

[TOTO Flames]

Originally Posted by btimbit

Dropped a small tool into the engine bay, and no matter what angle I try and look or reach, or how much light I use, i can't find it. Just looked for a whole hour. I'm sure you've ran into this TOTO, any advice?

MANY TIMES!!!!

It is the most frustrating thing in the world, I usually get lucky and after hours of searching, I find it. Other times well..... I'm out a $30 socket.

[TOTO Flames]

Originally Posted by automaton 3

I'm also not a mechanic but I believe the conventional wisdom is you only need to replace the rotors if out of spec or very warped/damaged.

If in spec for thickness you could also consider have them turned, depending on the cost vs. replacement.

Correct Sir! With VW if you don't replace both you will have a loud squeal, also there is no min spec for machining so you really have no choice. Having said that, the pad composition is better nowadays then before. Pads last longer but the downside is they are very noisy in the morning or cold days.
If you ask me though I would rather have the minor convenience of noisy brakes for the first few minutes of my drive, rather than having to replace them every 30 or 40K.

[btimbit]

Originally Posted by TOTO Flames

MANY TIMES!!!!

It is the most frustrating thing in the world, I usually get lucky and after hours of searching, I find it. Other times well..... I'm out a $30 socket.

Normally I'd buy another one, knowing that the second I do the original will pop up again. Unfortunately in this case it's a specialty tool that costs $300

Now that I've taken a break and let the anger subside I'll go look again. Fingers crossed!

[Fuzz]

It's always in the last place you look.

[speede5]

Originally Posted by btimbit

Normally I'd buy another one, knowing that the second I do the original will pop up again. Unfortunately in this case it's a specialty tool that costs $300

Now that I've taken a break and let the anger subside I'll go look again. Fingers crossed!

I work on airplanes and have spent hours looking for a lost washer or nut. You can't leave anything floating around that could jam a flight control.

I have used borescopes to look around in areas I can't see, and I have a cheap inspection camera from Canadian Tire that I use at home. It helps a lot.

If you know the general area it fell in, put some sticky plug valve grease on the end of an extension or a flexible grabby tool (the name excapes me, looks like a antenna) and prod around. Sometimes you'll get it to stick or at least move it.

[schteve_d]

I've had an ongoing issue with my 2008 Jeep Grand Cherokee (with a V6) that I've been messing with and haven't been able to figure out. Would love to hear if he might have an idea.

For a year and a half or so, I've had a heating issue. If I let it warm up to operating temp before driving, and keep my speeds under about 105 or so, all is good. If I don't let it get to operating temperature, even in warm weather, it will never get there if I jump right on the highway, which I do where I live. If I let it warm up to operating temperature, then drive on the highway at anything above about 105 km/h, it slowly loses temperature, from the half where the gauge normally sits, to about the quarter mark where it will hold steady while at the same time losing heater temperature in cold weather. If I slow to below 105 or so, the temperature will climb back to it's normal half on the gauge.

If I don't heat it up and drive on the highway right away, the CEL comes on ten minutes of driving or so. The code is something to do with not warming up to correct engine temperature. After a few normal drive cycles of warming it up properly the CEL goes away until the next time.

Also when say driving through the mountains, running at normal operating temp, the temp will drop slowly on a hard pull but never goes below the quarter mark. When doing this in the winter it also loses heat until you crest the hill and get your foot out of it at which time, if you are under 105 km/h, it will slowly build temp (and heat) again.

I've run a winter front in the winter which did not help. I replaced the water pump and have replaced the thermostat three times (twice with a napa part and once with a dealer part) with no change. I installed a new rad cap and changed/flushed the fluid. I'm aware of the bleed screw that has to be used to burp the air out of the system after opening it.

It's not a real big deal but now and then I'd sure like to drive over 105 in the winter! It's more irritating than anything. Hope that all made sense!

[Fuzz]

Is there an electric fan on the rad? If so, is it spinning all the time, or only when hot? In your situation, sounds like it should never come on.

I'd suggest a Saskatchewan thermostat, but it sounds like you tried that...

[GreatWhiteEbola]

I broke the timing belt in my Lancer and potentially did damage to the head/valves. In your experience, would pulling the spark plugs and witnessing significant oil accumulation be an indication of valve/ seal damage? I have a cheap USB video bore-scope that will take it's maiden voyage into the head of this car, I don't know what I might see...I am looking for valve impressions on the pistons. Any additional advice in this situation? TIA and it's great to have someone with real training weighing in, THANK YOU!

[Bill Bumface]

I have one! I have an annoying rattle (sounds like a suspension related component, but can't confirm) and a vibration (entirely possible it's unrelated). How do you diagnose this stuff?

I've already done one driveshaft (it was for sure bad, helped a bit with the vibration), an alignment, tire balance, both upper engine mounts.

I'm curious if it could be control arms, but when I check for play and compare to youtube videos it really doesn't seem all that loose. Is there a good test that you can pull off that doesn't require years of experience of knowing what "play" feels like in a control arm?

I also know one set of tires seems kind of messed. But I get the vibration with both sets.

[TOTO Flames]

Originally Posted by GreatWhiteEbola

I broke the timing belt in my Lancer and potentially did damage to the head/valves. In your experience, would pulling the spark plugs and witnessing significant oil accumulation be an indication of valve/ seal damage? I have a cheap USB video bore-scope that will take it's maiden voyage into the head of this car, I don't know what I might see...I am looking for valve impressions on the pistons. Any additional advice in this situation? TIA and it's great to have someone with real training weighing in, THANK YOU!

Valve impression on the pistons is a good indication. In my experience oil on spark plugs is a leaking valve cover. The best test is a compression test. If you have low or 0 compression, chances are you bent valves. Obviously to do this you have to replace the timing belt. Also the sound of the vehicle when you turn it over is a good indication of bent valves. If it sounds like a spinning wheel and not an engine that turns over, chances are you damaged the valves.

Having said that, most interference engines once the belt snaps the cylinder head needs to be removed for further evaluation and from experience its never good.

[TOTO Flames]

Originally Posted by Bill Bumface

I have one! I have an annoying rattle (sounds like a suspension related component, but can't confirm) and a vibration (entirely possible it's unrelated). How do you diagnose this stuff?

I've already done one driveshaft (it was for sure bad, helped a bit with the vibration), an alignment, tire balance, both upper engine mounts.

I'm curious if it could be control arms, but when I check for play and compare to youtube videos it really doesn't seem all that loose. Is there a good test that you can pull off that doesn't require years of experience of knowing what "play" feels like in a control arm?

I also know one set of tires seems kind of messed. But I get the vibration with both sets.

Sorry but without the vehicle in front of me, I cant even tell you where to start, vibration and noises can be caused by many things. A test drive with you is where i would start then i would put it up on a hoist and start to look for obvious signs.
Sorry for the terrible response but noises are always the most annoying things to diag as they can literally be anything.

[WCan_Kid]

I've put this out to a number of people and it remains a pure mystery.
1998 Porsche Boxster, runs like a dream most of the time, but when outside temps get into the 30's it will randomly stall.
No warning, no codes thrown, just all of a sudden the engine stalls. Never happens on cooler days and it doesn't matter if it's idling in a parking, driving city speeds (50-60km/h) or highway speeds (100km/h +).
I do get a whiff of gas, like it's flooded, just after it happens and if I'm stopped it acts like an old carburated engine would when flooded. On the highway I can just push the clutch in and then release to jump start it again, will run fine after that for a random amount of time (1/2km to 1 or 2 km's before stalling out again).
Have had it checked out and the tank lines re-routed at an independant Porsche shop to no avail, along with other shops/mechanics including my usual guy who typically figures out anything I throw at him.

[Bill Bumface]

^I'll let the real mechanic chime in, but have you ruled out a bad MAF?