Hi,
First off, I know this post looks long - my apologies! - but as you can see upon closer inspection I've broken the text into a lot of bullet points to make it an easy read.
General Question
With respect to the following two mechanical mysteries, am I too far along to file for Hyundai arbitration? Or might there be solutions?
Car Stats:
2001 Elantra GLS Automatic Stock everything Only OEM parts (including oil filters) ABS/TCS 4-wheel disc brakesFirst Longstanding Problem:
=B7 An acceleration rattle started around 150-300 miles and is growing worse with time
=B7 This frog-in-the-throat sound takes place under acceleration and low RPMS (up to about 40mph - then it either goes away or engine noise drowns it out).
=B7 I hear no abnormal engine noise when completely stopped at a light.
=B7 This acceleration rattle lasts 10-20 minutes in duration, whereas it used to last less than 5 minutes.
=B7 The noise is worse when engine is cold or car was previously driven roughly 2-4 hours beforehand.
=B7 The sound seems louder in cool/damp weather [winter fuel blend????]
=B7 It is not so obvious in hot, dry summer weather [summe fuel blend????]
=B7 Gas brand and octane rating makes no difference [that I can tell]
=B7 I have a 2mpg drop in fuel efficiency (the car only makes about
20-21mpgs in city driving for past two years or so).=B7 Just this past week: Dealer replaced OEM Spark Plugs with NKGs (same spec). Original plugs were carbon-fouled though there is less than 30K on odometer and these are supposed to last 100,000 miles (but car is 5yrs old so could this still be "normal"?). Dealer blames carbon deposits on bad gas, not on whatever causes the engine rattle or ping in the first place.
=B7 I've never seen a CEL entire time I've owned the car. Beginning to think one or more sensors don't "talk" to the computer since there is a problem everyone can hear yet it never trips a check engine light. Dealer seems to be of the general philosophy that if a check engine light isn't on, there is no problem. On the other hand, everyone who has heard the problem doesn't deny it (including the corporate rep).
=B7 Dealer efforts to fix or explain problem include: Heat sheild "tightened". "Cold selenoids are noisy" (tech tells me in 2001). Dealer finally agrees to measure valve clearance (first one in 2002 normal, second one in 2004 "out of spec", final one conducted the very next day by Hyundai corporate rep finds "no problem"). Next told that I am hearing lifters and this is a normal sound until oil gets from pan to lifters (true, I hear lifter noise but that lasts about a minute at startup whereas the other noise seems to be related to acceleration). Little over a year ago this same Hyundai rep checked my car's thrust washer/bearing (no sign of metal debris, no problem found (NPF). Hyundai Customer Service Hotline alerts me to Exhaust Manifold recall: Dealer checked but finds no sign of cracks so they did NOT replace exhaust manifold. Motor mount replaced over a year ago - no change or improvement on noise.
=B7 What I've done: Tried oil additive. Tried higher octane (a few years back - didn't notice an improvement). Tried gas additive - injector cleaner?-about two years ago (only resulted in rough idle and misfiring engine).Been using 10/40 oil instead of 10/30, which is what the dealer uses at oil changes.
My Impression
Based upon what I've been told about the condition of my spark plugs
- despite only 30K on the odometer - it sounds like a case of "spark knock". I suspect either a bad knock sensor that the car's computer doesn't receive valid data from or a sticky valve lifter or bad valve guide. I've also heard, though, that a rattle or pinging type sound in the engine can come from the timing belt tensioner. It IS true that when I lift the hood I hear some tapping from under the plastic cover. So can anyone vouch for that theory?
Second Longstanding Problem
=B7 I have ABS and four-wheel disc brakes. Almost since Day One I hear the rear brake/wheel thumping at stops, which oddly enough sounds almost like someone stuck in the trunk and pounding lower right side of the car body with a fist!
There are two things that bring on the thumping sound:
=B7 Sitting at a stop with my foot resting too lightly on the pedal - in which case if I let up or stomp down harder the thumping noises disappear.
=B7 Second, I sometimes hear the same noise after I first pull into my driveway, put the car into park and pull up the emergency brake. It goes on about 30 seconds and anyone standing on the driveway or sidewalk when it occurs can hear the sound too.
=B7 The dealer has been unable to reproduce the noise and so they have done little or no diagnostic work.
=B7 Last week I had my car in for an oil change and now the dealer says my rear brakes are in need of replacement but not the front. A year ago I had 50 percent remaining on the front and 30 percent remaining on the back brake pads. Now I have 20 percent left on the rear of the car (but they didn't tell me the figure on the front.) The dealer wants me to pay for rear brakes even though they admit that the front brake pads should wear out somewhat faster than the rears.
My Impression
Normally, I would agree that brakes are wear-and-tear items and I should foot the bill. But based on a conversation with an independent mechanic, I feel some or all of this should fall under my warranty. Reason: The independent mechanic told me that if there is more than 10 percent discrepancy between the wear on the front and rear brake pads
- which is true in my case - than there is a possibility that something is grabbing or the ABS is kicking in when it should not be and wearing down the rear brakes prematurely. As stated, I've been hearing this brake thumping on an intermittent basis for years and it is on record at my dealer that I've complained of it. So who should pay? For that matter, what could cause disc brakes to do this? Could the rotor be warped? What else might cause this noise?
CONCLUSION - I need all the help I can get!!!!!!!!!!
My dealer can't seem to put two and two together. Meanwhile, I've been visiting Hyundai forums for years to try to get a leg up or a helpful word of advice (which diagnostics to perform and in what order, for example). The only Hyundai discussion I've come across that seems to have REAL Hyundai techs is HERE, so I'm hoping I that if you are one of them you can reply to this post (thank you!).
Can anyone else reading this post relate? If so, was there a solution to a similar problem on your car?