knocking sound from engine bay???

[mathew82284]

I'm hearing this wired knocking sound coming from the area in the red. It sounds like a can of marbles and gets louder as i drive. It only seems to make this sound when the car is cold though. Once warmed up the car runs fine and sounds fine. Anyone know what it can be and what needs replaced?

P.S this is not my cars engine picture i found it on here so i can show the location of the sound.

 

[Cs4g63]

I see where you circled but does the sound seem like its coming more from the engine or trans?

 

[mathew82284]

Nope transmission is fine turbo is fine and engine is fine, when i push on the accelerator the sound gets really load in that circle. Is that the thermostat? Ill use my camera and try to pick up the sound for you guys to hear. It wont be posted for about an hour though.

 

[Cs4g63]

Hmmm. Im stumped for now at least. You eliminated everything I was thinking of.

 

[GSTinCO]

It most likeky is your thermostat. Replace it with a genuine Mitsu part or you will have this problem again.

 

[mathew82284]

Ok here is the sound its making anyone ever heard anything like this? Again the car drives fine and the turbo holds boost all the way through the rpms. its not the turbo or the engine its something in that area. Sounds like somthing is broken inside of the thermostat?

http://home.comcast.net/~mathew82284/Sound.AVI

 

[drewvr4]

that sounds like an exhaust leak..even though its not

take a screw driver and put it at the end of the valve cover and see if you hear a knocking, you could have a really bad lifter tick...but its really hard to tell

 

[mathew82284]

that sounds like an exhaust leak..even though its not

take a screw driver and put it at the end of the valve cover and see if you hear a knocking, you could have a really bad lifter tick...but its really hard to tell

I didn't hear any ticking from the screw driver. What is there something in the thermostat that can break like this? Also like i said it only does this when the temperature is below the middle mark basically when the car is cold. The car still runs fine and strong. The cars temps are normal and the oil temp is also normal, There is no leaks anywhere and the ticking doesnt sound anything like an exhaust leak a exhaust leak doesn't disappear when the cars warmed up. Anyone else have any opinions or something else could try?

drewvr4 i'm not saying your info is false but it just doesn't seem like a lifter issue. but i wont count it out.

 

[96gstdsm]

Even though it sounds like it is coming from the engine it very well could be coming from the clutch and transmission area. I had the same sound. It was the throw out bearing bagging around. Does it ever go away when you push the clutch in? When mine got loose it did not affect driving or anything. It just was really loud and abnoxious and would get much louder when i stepped on the gas. The only way that i know of to really check that though is by taking the tranny off. Maybe someone else knows of a testing method.
--- Ryan.

 

[RedTurboEclipse]

Hey buddy, you are not alone. Mine, well my daily driver 95 GSX, not the black one in my profile, makes the exact same sound. Exact same symtoms as you described. Usually only when started up after not being started for a while. And increases as you showed in the video when revved. But drive it a while then the sound goes away?

Am I correct? If so, wish I knew myself. I always had this thuoght that maybe its the stock t25 going out, and it only happens when started because the oil/water needs to circulate in the turbo than after a while as we described goes away. Or maybe its just my head finding an excuse to upgrade.

It doesn't really bother me because other than that, after driving a bit it goes away anyways. It does not seem to affect drivability. Car holds boost like normal, my compression numbers are fine, I have no over heating issues. My car is bone stock btw. Not even free mods.

It does not seem like the TOB, that sound will go away when clutch pressed as already mentioned. As for an exhaust leak, shouldnt it keep making the sound even after the car is warmed up and driven for a while.

Let me know how it goes if you find out what it is.

 

[omnified]

Had the same sound awhile back in a car I owned and it ended up being the thermostat and someone that owned the car before me ended up running the car "dead on oil" then overloading it with oil after they decided to put oil in the car.


Bruce
omnified

 

[mathew82284]

Had the same sound awhile back in a car I owned and it ended up being the thermostat and someone that owned the car before me ended up running the car "dead on oil" then overloading it with oil after they decided to put oil in the car.


Bruce
omnified

Yeah im thinking of just replacing the thermostat. My car is 100% stock and just started making this sound after i had a oil change done. i never checked the oil level. Would to much oil cause this somehow?

 

[omnified]

Possibly, but like I said Im not like 100% sure and dont want to give you the wrong issue. Im just stating that it's more than likely the thermostat from the sound of it and could also be too much oil. Those are basically the only two suggestions Id recommend on checking. If the issue still makes the knocking noise then Im basically all out of ideas.




Bruce
omnified

 

[RedTurboEclipse]

The too much oil is not the problem. At least in my car, and my car sounds the same and has the same symptoms as described by mathew. I put exactly 5qts, and hell when it had a leak even less, and sound is still there ONLY at start up usually when not for a while, and drive it a bit and it will be gone.

The thermostat is something I would never have thought, I however don't plan to replace it anytime soon because as I mentioned, other than the noise its fine, and this is my beater so its not a big deal, but if confirmed, I'll do it eventually.

 

[fwdeclipse]

I dont know how a thermostat could make a knocking sound like that. Check that side of your exhaust manifold and make sure the nuts are tight. That sounds like an exhaust leak to me. When the car gets warm everything expands and the exhuast leak will go away if its not a huge leak.

 

[mathew82284]

Ok thanks guys, Tonight when i get off work ill check the bolts. Im thinking of going to buy a thermostat today but probably cant install intill wed. So ill get back to you guys about this. It has a distinct sound and i used to own many mustangs that had exhaust leaks i have never heard a exhaust leak sound like a can of marbles, The only other time i heard this was when my friend blew his engine.

 

[GSTinCO]

That is definently not the same sound I had when my thermostat went out. It has to be a moving part because it seem s to be rev dependent. I would check your oil level just to be sure and try to isolate where the sound is coming from the best you can. I wouldn't imagine it's the throw out bearing either but could be. It sure doesn't sound like rod knock or anything shaking in the lower end. Have a friend or someone rev the car and see if you can isolate the noise.

 

[RedTurboEclipse]

Keep in mind the sound goes away after car warms up and driven for a minute or so.

 

[merqury]

I had the same sort of noise. Its the valves they are like that.................most of the time the noise is there in the beginning or if the car is cold and then it goes away as you start driving. What kind of oil do you use ? and do u use any kind of additives? becaz my mechanic once used mobile 1 and lucas at the same time............the combination was so thick that one lifter was not working properly. It started making that noise. We drained the oil and put just the oil no additive. So there is no real answer but thats how the motor is and the valves. I hope it goes away after a while becaz thats ### happens with me.

 

[linksys42]

That sounds like an exhaust leak, get underneath and check the flex section. And work your way up to the exhaust mani.

 

[mathew82284]

That sounds like an exhaust leak, get underneath and check the flex section. And work your way up to the exhaust mani.

Ok i went under the car and its not an exhuast leak from the flex pipe or the headers, The sound is coming exactly from that red circle spot. Its below the radiator cap. It sounds like a metal ball is moving around inside that thing below the radiator cap im not sure exactly what it is and im not sure where the thermostat is. Also i ran my car kinda hard to test to see if the temps stay normal and they did, I did however notice when i parked i was leaking coolant it was comeing from the overflow tank. It was full to the brim. and the sound isnt as loud anymore. Could air be inside the radiator and cause this marble sound? maybe air rushing past the thermostat?

 

[luvmygst]

Pull the heat shield off of the manifold. I am willing to bet that you have black soot on the head from an exhaust leak. (for some reason my #4 cylinder likes to come loose everyonce and a while) I can see no way that a cooling system can make a noise like that. Sounds like a leak to me. It just goes away when the manifold/turbo heat up and expand. If you are lucky you can just tighten the bolts and it will go away. Good luck

 

[silvawolfe]

How about rod knock.

 

[luvmygst]

How about rod knock.

Rod knock tends not to quieten down when the car warms up. I usually gets worse, or comes out of the block. I have had the same problem I am still betting on the exhaust leak.

 

[RedTurboEclipse]

Yea its not rod knck.

luvmygst, you know what, I forgot to mention when I was explaning how I was having the same problem as the OP.

I did remove the heat shield and tightened the exhaust manifold bolts and the sound did go away but then it came back. I totally forgot. Perhaps I didn't tighten it enough.