Bostonian1976 Posted December 12, 2009 Share Posted December 12, 2009 I've got 155K on this car that serves as the winter mobile. I've solved most issues, but have two left: 1) The check engine light has made a habit of coming on lately once the engine reaches normal operating temp after about 15 minutes of running. Code is P0325, knock sensor. What to do? Haven't changed out plugs yet - could bad plugs cause this? 2) I have a clunk/knock coming from the front right when I hit a bump. Is there something that's known to cause this issue in this car? Thanks for the help! Link to comment Share on other sites More sharing options...
ece_tim Posted December 12, 2009 Share Posted December 12, 2009 1) Um, test and replace your knock sensor? 2) I don't think there are any particular issues, but the usual suspects: blown strut, bad strut mount, sway bar, sway bar endlinks. Get under there and look for any scuff marks where something might be rubbing. Have your alignment checked - if something is wrong and the car won't hold an alignment, they will notice. Not sure how to test the strut mount. Link to comment Share on other sites More sharing options...
Bostonian1976 Posted December 12, 2009 Author Share Posted December 12, 2009 Thanks very much. Car tracks perfectly straight and tires wear evenly. Is there anything in the steering system that could cause this? It's probably struts - I recently replaced the rear brakes and noted the struts still had factory inspection orange marks. Yeah - it's 11 years old with 155K Link to comment Share on other sites More sharing options...
ece_tim Posted December 12, 2009 Share Posted December 12, 2009 Well now don't go running to the first thing you want it to be. A blown strut would not necessarily make a clunking noise. Research the symptoms of each of these to help your diagnosis. The car certainly could use new struts due to its age, and while you're at it you ought to replace the strut mounts as those are relatively cheap. While you're doing that (or having it done), have all the other bushings, end links and ball joints inspected. It is unlikely the clunk is due to anything in the steering. If it were, you would also hear the noise when steering. Link to comment Share on other sites More sharing options...
fatboy1214 Posted December 12, 2009 Share Posted December 12, 2009 if you put your car on a jack or lift or what not wiggle that tire up and down and side to side if theres play up and down is ball joint side to side is tie rod which both will make pretty good noises that you wont ever want to hear Link to comment Share on other sites More sharing options...
xiaomanbluce Posted December 15, 2009 Share Posted December 15, 2009 I have the similar sound, but comes from the driver side, and when apply brake, the sound disappear, and later, on... no idea what is wrong, is there anyone has same problem? Link to comment Share on other sites More sharing options...
ece_tim Posted December 15, 2009 Share Posted December 15, 2009 I have the similar sound, but comes from the driver side, and when apply brake, the sound disappear, and later, on... no idea what is wrong, is there anyone has same problem? You need to more exactly isolate when the noise occurs. Test if the noise comes on with brake, acceleration, turn, accelerate while turning, brake while turning, etc etc. But really I would just suggest you find a reputable shop and take it in. Finding and fixing front suspension/steering problems is tricky and time consuming if you don't know how to diagnose. It will be very difficult for people on a forum to tell you exactly what to replace. Link to comment Share on other sites More sharing options...
Bostonian1976 Posted December 18, 2009 Author Share Posted December 18, 2009 thanks very much. Is there anything in the actual steering rack that can work its way loose? I sometimes feel a looseness/vibration directly in the wheel at very low speeds Link to comment Share on other sites More sharing options...
ece_tim Posted December 18, 2009 Share Posted December 18, 2009 I suggest you look up some diagrams of how a front suspension/steering is actually laid out & connected. It's hard to understand what may go wrong if you don't have the big picture. Anything you're feeling is unlikely to be in the steering rack itself. As stated previously, things like ball joints, strut mounts and wheel hubs can all contribute to any vibration or looseness. Look at some of these diagrams and notice the ball joints that connect the wheel hub to the control arm and to the tire rod. The tie rod is connected to the steering rack. A ball joint is literally a bolt inserted into a larger metal receptacle and filled with grease so that it can rotate as needed. They do eventually wear out, or the rubber seal is broken and the grease leaks out, leading to premature failure. A bad ball joint leads to poor movement and response for the components it connects. http://auto.howstuffworks.com/car-suspension4.htm The strut is attached to the vehicle body via a strut mount - literally a metal frame that has a bushing of some type inside that cushions the vibrations of the strut from the vehicle body. When these go bad, increase vibrations can transmit and the strut mount itself can even move around as the strut moves. A wheel hub is a circular structure to which your brakes and wheel (via the lugnuts) attach to. These are two extremely critical components to driving your car (wheels and brakes are important, agreed?). The CV axles, in an AWD car, are driven by the transmission and thus turn the wheels via the wheel hub. Since there is metal on metal and it rotates, there is grease and bearings inside the wheel hub that allows things to rotate smoothly. Eventually these do wear out, or seals can break & grease leaks out causing premature failure. All of these can cause the very general symptoms of front suspension noise. If you lift the car up and lock the front wheels (tranny in park, or have someone sit on the brake pedal), then grab the entire wheel and try to wiggle it left/right & top/bottom. If it wiggles at all, then the bearings in your hub aren't doing their job and your wheel hub may be on the way out. Strut mounts are difficult to diagnose and rather are just a rule-out, as they are cheap and easy to replace. Ball joints are easy to spot if they've blown and leaked grease everywhere, but they can still be faulty and not show much on the outside. On an old car it's not a bad idea to replace all of these wearable items to ensure longevity of the vehicle. I don't remember about the late 90's Legacy's, if you replace ball joints individually or they come on the tie rod ends. Either way, those parts aren't terribly expensive if bought through an online OEM parts dealer and the labor to install isn't too bad either. Keep in mind you will need an alignment when touching any of the parts mentioned here (except the wheel hub). I think I also previously mentioned that if you take the car to be aligned, the techs can usually tell you pretty quickly what is wrong, if the car won't hold an alignment. Link to comment Share on other sites More sharing options...
Bostonian1976 Posted December 18, 2009 Author Share Posted December 18, 2009 very thorough - thank you very much for taking the time to post that Link to comment Share on other sites More sharing options...
Bostonian1976 Posted December 18, 2009 Author Share Posted December 18, 2009 alright - knock sensor replaced and check engine light off whew - now I can go back to something more than 18 mpg Link to comment Share on other sites More sharing options...
ece_tim Posted December 18, 2009 Share Posted December 18, 2009 Thanks. I touched base with a friend of mine who is far more of an expert than I and asked his opinion on what I wrote here. He added the following below. To give credit where credit is due, I highly suggest taking a look at his blog: Jim's Garage. He is an excellent mechanic, enthusiastic racer and very knowledgeable guy. He has a lot of posts on the work he's done on his Evo and other customer cars, as well as general automotive and racing posts. Without further ado: Check the antiroll bar (sway bar) end links and bushings for wear. They can produce a clunk if worn, loose, or missing (yes, they sometimes go missing). For checking the wheel bearing play I wouldn't lock up the brakes since that would prevent the bearings from showing their wear. I would grab the wheel/tire at twelve and six o'clock and see if there is play. With your Legacy we found the only way to find wear in the rear was to put it up in the air and use the drivetrain to spin everything. [My 06 LGT had a bad driver's side wheel bearing. I had a terrible howling noise that increased with speed and I thought it was just the summer tires wearing. We put an automotive stethoscope on each rear control arm and there was a VERY audible difference in the driver's side & passenger's side.] Clunks usually are not wheel bearings. Tie rod inner and outer ends can be checked by holding the wheel/tire at three and nine o'clock and feeling the play. It is often helpful to have someone watch as you apply pressure back and forth. They can spot the actual flex in the joints while you push and pull. CV joints (constant velocity joints) that have worn often manifest themselves at low speeds and in tight turns such as in maneuvering around a parking lot. At extreme lock they will clunk as the car moves. This is the ball and cage trying to pop out of place and if that is the problem it should be dealt with ASAP. Ball joints are a tough one unless the boot is obviously broken and leaking lubrication. On some cars it is best to have the suspension free hanging and squeeze down on the ball joint and hub casting with a large pair of channel lock pliers. On others the suspension needs to be loaded (on the ground or on an alignment lift) and a large pry bar engaged to flex the joint. On some cars you can spot a bad strut mount by just jacking the car up so the wheel hangs free and then letting the car back down on the wheel. On VW's, in particular, you can watch the mount stretch up and down. I often find clunks in this area after people have changed out for new struts and either put things together wrong or too loose. Link to comment Share on other sites More sharing options...
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