Ticking from engine bay at 1-3K RPM under load (not timing chain guides/tensioner!)

[chuonthis]

Hey guys, I normally try to figure things out myself but I'm stuck on this one at the moment. I just hope the answer isn't rod knock. :(

Description of problem:
NA KA24DE: When driving and under load between 1000 and 3000 RPM (in any gears), I hear ticking or fluttering noises from the driver side of the engine bay. It is slower at 1000 RPM and speeds up until 3000 RPM. After that, the ticking might just be so fast that I can't make it out over the other noises. Noise stops when I stop the load or disengage the clutch. I honestly can't remember when the problem first started which is weird because I usually remember these types of things well.

Things I've checked:
1) Timing chain guides (both guides for upper chain) were tossed years ago. Checked the tensioner and it was working fine but I replaced it anyway. Everything looked okay (as far as I can tell...which doesn't mean much) with the valve cover and front cover off.
2) Changed oil and didn't see any metal in the old oil. Made sure levels were good. Using conventional 5W-30.
3) I can't reproduce the noise by revving the engine with the car parked so I can't pinpoint where the noise is coming from but with a passenger's help, it is definitely from the driver side of the engine bay.
4) Wheels have no play and everything looks fine on the suspension side of things.
5) No leaks that I can find in the engine bay.

Check Engine Lights:
- I got a CEL code 34 (knock sensor) 2 months ago at a track event (also got code 25 (iacv) and 36 (egr valve)). Cleared it and it didn't come back with daily driving.
- I went to the track again 1 month ago and the CEL came back (got code 25 again but not 36. But also got code 108 (evap purge valve)). Cleared the code again. Checked the knock sensor (and ECU wires) with a multimeter per FSM instructions and everything seemed okay. Code hasn't come back since.
- No other codes or mechanical problems.

Again, it's weird that I don't remember when the noise first started. I can't remember if it happened before 1 month ago, so I can't remember if it happened before 2 months ago either.

So what do you guys think? Any other steps I can take without pulling apart the engine? Could it be something in the transmission?

Update:
Problem turned out to be a broken head-to-exhaust manifold stud. Replaced the stud and replaced the gasket and noise is gone.

[240=180]

valve train???

[KwKouki]

very quick ticking noise? you might have a loose gasket somewhere on the exhaust side.

[punxva]

exhaust leak is what it sounds like, i''d change the gasket where the manifold meets the head

[Teknolust72]

Its sounds like one of your solenoids related to emmission control and/or evap purge valve. I have the same IACV, EGR, and EVAP codes, and one of my solenoids is probably bad or dirty. Its more noticable when the car is cold and/or under heavy acceleration.

Check your vacuum lines also. I had some open vacuum lines, and when I capped off most of them, it sounded better.

I am sometimes in Irvine, so I will let you hear/check out my car to compare sometime

[punxva]

he said it sounds like it's coming from the drivers side, which makes it seem as if it is an exhaust leak, you'd be surprised at how exhaust leaks sometimes sound like broken valvetrains

[KwKouki]

also how loud it is, it made me nervous when I first heard it

[chuonthis]

Well, I went to take a look at my exhaust manifold tonight. I took off the heat shield and things looked okay so I decided to check the torque on all the manifold nuts. I did it in the order specified in the FSM. All nuts were already tight until I got to the nut closest to the front of the car (near the distributor). As soon as I touched it, the stud fell out and I was left with this.

http://i299.photobucket.com/albums/mm317/oglez/IMG_1993-1.jpg

Upon closer examination, there is a noticeable gap between the head and manifold where that stud broke off so that's probably where the exhaust leak and sound is coming from.

How do I get the rest of the stud out?! One of my friends suggested that I try to cut a slot in the stud bolt and then use a flat head and unscrew it out (by hand or impact). What do you guys think? If possible, I'd like to do this without taking the exhaust manifold off since that would be at least an hour's work.

Thanks to all those who suggested to check the exhaust gasket.

[89twoforty]

It's definitely possible, and is sure to be a pain. Probably your best bet though.

[mrmephistopheles]

Look for an EZ-out. Otherwise, you'll probably just have to drill a hole in it and twist it out that way.

[Sr2O-det]

Drill the stud with the proper size drill bit and use an ez-out for that size, it should show you on the set when you buy it. Or if the stud is not very far into the head and you have a friend that welds, tell im to weld a nut to it and the just turn your wrench to pull the rest of the stud out.

[240esux]

you might have to drill it and re-tap it. but check all your bolts through your whole exhaust system.

i started getting an exhaust leak from my test pipe on the way to willow springs on sun, and i thought i can get away with tightening them and them there was still a loud ticking under the hood. i guess the gasket between the exhaust mani and the turbo blew. sucks to be me rite now!

anybody selling steel braided lines for a t25??? please hit me up. thanks

[ericcastro]

Pour the EZ out in, then stop by a shop that will back it out for you. It will cost a few bucks, but at least you wont risk the head or lodging it in worse.

[chuonthis]

Gonna go pick up an extractor set from Harbor Freight after work (link (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40349)) and a new gasket. Might as well change it out since the old gasket set is probably 12 years old.

Any thoughts on Cometic (link (http://www.frsport.com/Cometic-MLS-Multi-Layer-Steel-Exhaust-Manifold-Gasket-KA24DE_p_12544.html)) vs. OEM? The Cometic is cheaper ($35 vs. $45) and looks nicer but hearing the troubles with their head gaskets (needing perfectly machined surfaces) worries me.

[chuonthis]

Awesome. The problem is fixed. I took off the manifold, extracted the stud, put everything back together with a new gasket...was torquing everything down...and SNAP! The stud closest to the firewall comes off. (well, it didn't really make a noise)

Lucky I bought extra studs. Took everything back apart, extracted the stud, put everything back together and voila! No more ticking noise! Thanks for the help everyone!

One other note, don't buy the screw extractor set from Harbor Freight! It couldn't drill at all through the head studs. I guess it was just that, a screw extractor set, and it wasn't rated for grade 8. Went to Sears to pick up their $40 set of Drill-Out bits (link (http://www.sears.com/shc/s/p_10153_12605_00952152000P)). Cut right through the stud. The thing was, I first started to use the M10 bit but was afraid I'd hit the threads if I wasn't perfectly centered. So on my first stud, I used the M8 bit. It worked but when it got to the extracting part, the bit broke. But it left a hex nut sticking out that I was able to unscrew and it took the stud with it. Then when I had to do the second stud, I used the M6 bit and the same thing happened. So there goes $20 in tools. Oh well. I guess my hands weren't steady or something.