It started a little while after I got the car, as far as I can remember, the car was not making the noise when I got it. sometime around January or February this year I started to hear a sort of a clunky rattle noise, consistent in frequency and only audible at idle and just off-idle (but below 1000 rpm still). the noise was especially noticeable at first cold-start and also after the engine had gotten nice and hot after my 30 mile commute and I had pulled into my driveway. It seemingly didn't make the noise (more likely I just didn't notice it) after the engine had warmed up a bit and during the drive. My initial suspicion was the fan clutch given the seeming relation to engine temp and speed.
Sounded like an easy enough repair and would give me the chance to put the front carrier into service position for the first time (which was actually a lot easier than I thought it would be). Also was a good point to replace the drive belt as well since I had noticed a lot of cracking and missing groove-sections during the last oil change I did.
After pulling off the fan and clutch I inspected it and it actually seemed OK, but oh well, I had already ordered a replacement so a new one was going on anyway.
Just before that, though, was when I discovered the true culprit of the noise. It was as I took tension off the belt that I noticed something very strange, the crank pulley was wobbling like it was loose as i loosened the belt!
There was a lot of play on the crank pulley, something like a quarter inch of slop back and forth along the axis of rotation. I took a video of it.
That is definitely the cause of the noise that I heard, and it makes sense why (at least to me). At idle engine speed there is enough time between power strokes for the engine speed vary slightly and for a long enough duration that the pulley is able to slop back and forth as it's loaded then unloaded, etc. But that would be much less pronounced at higher engine speed! Right? Right!
Turns out that the reason the pulley was allowed to do this was because there were only 7 of the 8 bolts holding the dampener pulley to the timing gear. Looks like someone broke off a bolt during one of the previous Timing Belt services, of which I assume there has been two done in the car's lifetime (currently has about 140,000 miles before this work started).
As you can see, the previous Tech that did the last timing belt service wrote mileage and date on the air filter housing, how convenient! Now, if only he had done a better job on the service itself.
Here you can see, looking through an inspection mirror, the timing gear with the one broken bolt's threads still stuck in the gear (circled in Red).
My guess is that the crank pulley bolts were re-used after the last service. They must not have been tightened properly, either from the old dry threadlocker on the threads preventing proper torque from being achieved, or the bolts were a little stretched, or maybe the Tech just forgot to actually torque them, or maybe 7 bolts just isnt enough and it has to have 8 for it to work properly, maybe a combination of those things. In any case, after about 20,000 miles the bolts had been repeatedly hammered on by the pulley and vice versa that they ended up looking like this:
Notice the oblong shape of the bolt-holes on the pulley, also check out the widened out "key-way". This pulley is junked.
I decided the easiest fix for the timing pulley was to just replace it rather than trying to use an easy-out extractor on it or anything like that, just not enough room. Plus, the "key" that aligns the dampener pulley is machined into the timing gear and I didn't want to risk it with a potentially damaged timing gear key causing a similar issue in the future. Cost of OEM timing gear was only about $100 US anyway, the dampener pulley was the pricey part, I think it was something like $380 from ECSTuning. The timing gear, dampener pulley, 8 new bolts and 1 new timing gear crankshaft bolt totaled about $550 or so. My first major repair expense! yay!
well, after letting the car sit for a few days while I waited for parts to arrive I decided to take a closer look at a few other things. Some of the things I found are related to the timing service, others arent.
I found the water pump seems to already be leaking... only 20k since it was supposedly done (I have the repair history and bills from the prev. owner. the shop says they did it...)
I also found this power steering cooler return hose to be quite soft and showing cracks.
I'm gonna be cheap and do a home-brew fix for this with some hose I can get at work. as far as I can tell, its a "low" pressure line that returns to the power steering reservoir. What I have at work is some Goodyear Gorilla 3/8" hose and some worm-gear hose clamps. http://www.veyance.com/ProductsDetail.aspx?id=1072
Should be OK, it's 500 psi rated and has high oil resistance, the only thing I'm a little worried about is the temp range it's rated for. spec page says -20 degF to 190 degF. I'm not sure if the cooler return line will see that high of temps or not. Anyway, the OEM replacement cooler to reservoir hose is only like $90. It's the other one, the rack to cooler hose that's the expensive one and is the one most difficult to access!
Well, that's where I'm stopped at for now. I decided to completely re-do the timing belt service just for my own peace of mind, as they say, "if you want something done right, you gotta do it yourself". So I ordered Blau's Enhanced Timing kit. I also figured I'd pull the valve covers off and do the seals, gaskets and timing chain guides under there, again just for my own peace of mind, since I've seen posts all over the internet of crumbled chain guides and even worse, ruined chain tensioners due to totally worn off guides! The valve cover gasket kit with tensioner guides from Blau is actually surprisingly inexpensive for what you get, so that's on order too.
Stay tuned for more next week as I punish myself with more expensive and tedious repairs!
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Originally Posted by glennda5id
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