As it says, got a new ticking or knocking noise coming from the area under the UIM behind the Alternator. I have an 04 with 55K-all recalls done, and I premix. I ran WOT from about 4.5K and around 6k got a odd rattle/scrape sound at 6k for just a second. No power loss. No idle issue, but as I pulled into my drive I could hear a distinct whonk, whonk, whonk noise. Got out to pop the hood and it was pretty loud and distinct. It sounds like lifter tick, or an injector, but with a little deeper tone like rod knock. I shut the car off and restarted after 5 mins-still there but fainter-drove fine with no power loss or idle issue (or CEL). Let sit again for 25 minutes, and the noise is still there. Cold or hot, makes no difference. I'll take her in Monday, just thought I'd share. Since it happens even after hot running, the airpump seems to not apply, and I check the plugs/boots and they were all attached. Oil level was fine too. any thoughts? I was thinking exhaust leak, but see 0 smoke. Bad injector?

 

Started up today and warmed up to idle with no noise. Took it for a 10 minute run, and came home-the noise is now present again. It is fainter than the first day, but it is there. A very distinct tock, tock, tock that sounds like its coming for the Alt/UIM area.

 

Is it a repetitive "tock tock tock" and always there after you run your car hard? Usually, the cracking/ticking noise are produced by the metals cooling down and contracting after a good hard run.

 

this is not the same crackling my midpipe makes. This is a repetative tock, tock, tock that has a rythm. This is a new noise. I'm pretty sure that I would have noticed it after 55K if it wasnt.

 

Got it to make the noise for the service manager and tech (they couldnt duplicate 1st time.) It is a really distinct knocking coming from under the UIM somewhere near the alternator and is only audible after the car has been drivin moderately. If you leave it at idle for 5 minutes, the noise increases. It goes in Monday. The car is 1oo percent normal otherwise. Will update. FWIW, the noise sounds exactly like a collapsed HLA (anyone with an early year miata can relate) of all things!

 

UPDATE:
Got my car back for the time being. The tech line suggested the dealership change out my 5-30 royal purple and install factory filter and 5-20. They have suggested that I may have gotten air bubbles in the omp lines... how they came to that conclusion beats the hell outa me. I am supposed to run the 5-20 around for a week to see if it clears the noise. I have serious doubts.... But, I have to do what they say till the problem is revealed. The tech line had the tech check the omp, too, and it was fine. I pre-mix with Lucas UCL to the tune of 3/4-1 oz per gallon so I would say if the omp is on the way out, I ought to be ok. The weather is really bad at the moment, so can't get is out to drive enough to check for the noise..soo....

EDIT:
Drove for a bit when weather cleared, the noise is very much still present. I got a recording on my cell phone, but have no way of loading up here. Anyone curious, I can send it to them-or better, if anyone knows a way to load it, that would be great.

 

sounds like a intake or exhaust type leak to me
olddragger

 

i talked to the tech who worked on my car and he said he traced the noise to the lower IM. the techline had him open up the omp to max for 5 minutes then drive. He did and the noise was still there, so they had him check the fuel trims and they were within 2%, so they had him ditch my 5-30 and pureone filter for the eom filter and 5-20. I have logged 3/4 tank of hard driving and had no change. It is only present once the car is hot. I am getting ready to drive to Florida and they seemed to think it was ok, so well see. I have no noticable powerloss, idle, hard start issues.

 

max5radster I may have the same sound...when it 1st occurred for all the world it sounded like the start of a sticking hydraulic lifter. Preposterous of course, but thats what it sounds like. I notice it off and on, but it may always be there I don't pay attention anymore. Weird, but so far harmless, like a wart. Hopefully it stays that way and like you I have no other strange happenings I can detect.

 

Same thing happening to my friends 8! It sounds like its back near the firewall... I will let him know about this thread so he can keep track of the outcome.

 

I've heard that noise before. I've tracked several times since then. No problems with mine.
And I do not alway have the noise.

 

I just drove my car to class tonight and had something along those lines. More like a shhhhhhhhhhh at normal driving but went away when I did a quick WOT blip. Anybody ever had this?

 

check your sparkplug wire boots and make sure they're pushed fully onto the sparkplugs, it's not uncommon for one to be loose and the ticking noise is the spark jumping the gap, had it happen myself even ...

 

Thanks for the suggestion Team! I actually checked that first off because I......SEARCHED (it really does work :p ) the forum and found that as a possible cause.

Well... I logged 2500ish miles on my trip in her without a problem. I switched out the dealers 5-20 before I left to my Royal Purple 10-30, (left the mazda filter on though) as it was in made 0 difference. The OMP was always functioning and did so on the trip as I used about 3/4 to 1 quart during the trip and had no powerloss issues. I premixed as always and managed to get 21-23mpg each tank while cruising 80+ with the wife, baby, and 400+lbs of luggage. In between fill-ups, I checked for the noise and it was inconsistent, but for the most part not as present. I will take her back in though as I would like some resolution to this.. I think I can almost hear the tonking through the exhaust. I also had a few elongated hot starts while there, but I have always gotten these every so often since she was new. (yes uprated batt/starter)

 

its probably the oil pressure release valve.