Nasty noise coming from engine/tbelt area VIDEO INCLUDED!

[desolateboosted]

91 TSi AWD automatic with 90k. Recently brought back from the dead from sitting 3-4 years. I re-ringed and threw a new head on. New t-belt.

The car starts, runs, & drives fine. I've driven it 550 miles so far. Bone stock.

Problem: car makes a nasty fast ticking rattle noise under a certain rpm window. It's louder than lifter tick and doesn't sound like rod knock. The noise isn't there when cold, but after warming up it's very apparent. The noise speeds and slows down with rpm. As soon as the rpms raise past a certain point (2.5-3k rpms) the noise goes away. The exhaust is stock except for a leak at the flex pipe. It's not the exhaust. The noise is literally coming from the area I am filming.

Here's the video on youtube. This is after the car has warmed up:

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[Paul@RTM]

Sounds like an exhaust leak. Far upstream, like maybe the exhaust manifold.

 

[Dsmkauai]

Id say time for a timing belt job. Look how much it moves while he revs. Sounds like somthing is hitting it, timing cover or shot pulley. Hard to tell but that belt seems to be alittle on the loose side.

 

[mercaholik]

You re ringed it huh, did it get honed? Also what head got put on, I've heard people putting 2g heads on 6 bolt block's without drilling the head bolt holes larger. It almost sounds like a oiling issue to a bearing or wrist pin. Was the motor gone thru and measured? Sorry it's just hard to tell but the fact that it kinda goes away at a certain rpm is why. If you already thoroughly checked the exhaust ( as you said its not an exhaust leak) then get a cheap mech stethoscope and try to pin point it better. Pull the timing cover and check the tensioner and pulleys as mentioned too. Let us know what you find as this will help my diag skills .

 

[linksys42]

I am also wondering if you put a 1g or 2g head on. And if it was a 2g if you had it machined for the head bolt clearance. Did you measure the head thickness of the new head to see how many times it has been cut/surfaced. And the depth of the oil supply tear shaped port (vid below) ? Also guys he already has the timing belt covers upper and lower off I am assuming to try to track down the noise. Also belt doesn't look loose, Its walking allover the cam gears. Check your gap between tensioner body and tensioner arm. Also check to see if tensioner arm assembly is worn out where it bolts/slides onto machined pin on engine mount. And check to see if you have a bunch of divots on the contact surface of the tensioner arm where the piston from the tensioner contacts the tensioner arm. One more thing to check since that T-belt is walking allover the cam gears, check crank shaft end play is in tolerance (I would start with this one first). Keep us posted on what you find because i am really interested in the final diagnosis.

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[jimsgsx]

I agree with dsmkauai. That is the first thing i noticed. Someone posted the same exact problem as this weeks ago. Its timing belt related for sure.

 

[jimsgsx]

Id say time for a timing belt job. Look how much it moves while he revs. Sounds like somthing is hitting it, timing cover or shot pulley. Hard to tell but that belt seems to be alittle on the loose side.

Remember we helped someone with the same exact problem a while ago? Same exact thing.

 

[desolateboosted]

It's all stock. I put a rebuilt 6bolt head on. The head was used shortly before in a good running engine. As for the bottom end it was a simple garage re-ring + hone job + new rod bearings. I've done these before with no issues. Unfortunately this is also the first time I have had the car running since I've owned it so I can't reference of how the car sounded before. Yes I'm not running any timing covers. Also the timing belt and balance shaft belt are both new. The timing components on the other hand, tensioner + pulleys were reused.

More observations, I can fully see the belt spining around when it runs and the belt appears to be loose. I can see it flapping/waving on the long runs on both sides if you get what I mean. However if the car is off and I check the tension by hand it feels tight, odd. Would a flapping belt make this loud of a noise? It sounds more mechanical vs belt noise imo..

I'll check the tensioner/arm area next.

Crankshaft end play and the belt walking around I'll have to check that too. But would endplay make a noise like this? Car runs great otherwise except for this annoying noise.

I've tested for rod knock by removing each spark plug wire one by one while it's running. Noise still there and doesn't seem to alter.

I've also pulled the cas plug and simply cranked the motor. No noise.

Crank pulley is intact and looks perfect.

While driving around the noise disappears around 3k rpms.

I'll make another video. It's pretty dead silent when it's cold until it warms up.

 

[pauleyman]

Feels tight? Are you kidding me? That job is wrong without question. Tension is almost certainly wrong. Check the pulleys. What is the orientation? Show us. 1g and 2g are different. Is the crank plate bent? All possibilities.

 

[desolateboosted]

Yes feels tight when motor is off. I would say it's loose if it was in fact loose. Orientation is also correct. Tensioner pulley was tensioned clockwise pointing up. I've done numerous timing belt jobs in the past 10 years working with these cars. How is this job wrong without question? If that was the case 16 valves would of bent long before these now 650 miles.

All possibilities yes, and there maybe 2-3 other issues at hand here. But which one is causing this dreadful noise? 27 years of mitsubishi and that's all the insight you're giving me? Thanks but the above posters have been pretty damn helpful.

 

[Lou98GSX]

take the lower timing belt cover off and inspect for something rubbing . it could be a loose timing belt flapping against the cover . when you have the cover off turn the motor by hand until all the slack of the belt is at the tensioner pulley then loosen and adjust to specs . i also noticed in the video that the noise goes away at higher revs cause the belt is moving away from something .

 

[Dsmkauai]

^^ bingo exactly what I've been saying !

 

[inthemidst]

Ya your tensioner for sure check if its hard to squeeze down and the two dots on the pulley should be on top and your belt should stay tight at all times

 

[pauleyman]

The tension spec needs to be checked. Does it have balance shafts? And my former questions still stand. Is the plate bent?
Is the crank bolt tight? The belt should not move like that. The problem seems to be the belt obviously but youre going to have to dig to find the root cause. And yes 27 years but what did you expect? Omnipotennt answers? I gave suggestions based on facts given. Im guessing youll find the issue if you take it apart. Last question what is the tensioner protrusion?

 

[Dsmkauai]

Reusing 1991 timing components!! Ya that should work out good . Get a new idler and temsioner pulley and new hydro temsioner and you most likely will be good. Unless it's just a loose bolt or bent plate!

 

[linksys42]

This is how I would go about, 1st - check crank shaft endplay to see if its in spec or excessive (piece of mind). 2nd - I would align all timing marks back up on TDC on compression stroke and wait 15 min for the lifters to bleed down and the piston in tensioner to stabilize then take .15" drill bit (5/32 I think cant remember of top of my head, just measure bit with calipers) and check the clearance between the tensioner body and the tensioner arm. If it slides in and just barely rubs your good. I'm sure that since you have been working on these cars for 10 years that you timed it right but you should always replace at least the tensioner even if it doesn't show signs of deterioration just piece of mind. When you put it back together I would replace tensioner with OEM new. 3rd - pull the T-belt off and check for tentioner arm play in and out on the machined pin that the tentioner bolts on to that could also cause belt to walk like that. Have had first hand experience with it replaced it and issue gone. Also check the bottom of the arm on the tensioner where it contacts the piston from the tensioner if it has a divot (pic below) it could be causing the noise at low rpms slapping against the piston and then once under load at higher rpms not slacking and noise going away by keeping constant pressure on it. but I highly doubt it. Never know though cheap fix if it is. 4th - I really think its oil starvation (the clatter) do you know if the head has ever been cut/resurfaced resulting in the tear shaped port being to shallow to supply sufficient oil? Aftermarket Oil pressure gage? Anyway to check/verify oil pressure at head and the oil filter housing? Also while having the T-belts off I would check oil pump/gear rotation with socket and drill and check the front balance shaft rotation also. Any how that is where I would start. Hope you figure it out. And let us know what the out come is.

 

[linksys42]

take the lower timing belt cover off and inspect for something rubbing . it could be a loose timing belt flapping against the cover . when you have the cover off turn the motor by hand until all the slack of the belt is at the tensioner pulley then loosen and adjust to specs . i also noticed in the video that the noise goes away at higher revs cause the belt is moving away from something .

^^ bingo exactly what I've been saying !

He has already said and you can clearly see in the video that he doesn't have timing covers installed.

 

[RamenPride]

Reusing 1991 timing components!! Ya that should work out good . Get a new idler and temsioner pulley and new hydro temsioner and you most likely will be good. Unless it's just a loose bolt or bent plate!

Agreed. Was there a reason why the pullies and hydraulic tensioner weren't replaced when you did the timing and balance shaft belts? Would also be a good idea to replace the water pump while everything's out.

I also noticed that you're driver's side engine mount has been modified/cut? Not saying that this does/doesn't have anything to do with it, but just an observation.

 

[GsSkeeT]

That is the exact noise my hydraulic tensioner made when it went bad. When I pulled it off I noticed the little piston in it had broken inside and was flopping around. I also noticed a small divot like linksys42 picture shows. I went ahead and replaced the water pump, tensioner arm and pulleys, plus the hydraulic tensioner with oem components. I properly pre tensioned the belt per the shop manual and checked the protrusion of the tensioner piston, which was to spec. One thing that really made me want to replace the tensioner arm, besides the divot, was that it seemed to have excessive in and out play. All said and done, it all works as it should. Hope it helps as what these guys are telling you to check and verify is the exact thing that was wrong with my car making the exact noise yours is making.

 

[Maes]

Timing related that belt should not move back and forth like that should stay in one spot never seen anything like it

 

[GsSkeeT]

Also when I had heard the noise, and shut off my engine, it jumped a couple teeth when I shut it off as I noticed when I went to align timing marks before removing the old belt. You said you see it flapping around while it's running but feels tight when it's off. Trust me, it's loose somewhere, mine was loose down by the crank and oil pump gear which is where it jumped a couple teeth not up at the cams since they were still aligned with each other. There are still many variables to the cause of some problems and prevention of more, which is why pauleyman is asking what he's asking along with everyone else, no matter how many years experience or knowledge these guys have, we need to know all the variables. You can't call your mechanic and let him listen to your car over the phone and be able to diagnose it, right? As much info and pics of stuff is the best way to get the help you need.

 

[GsSkeeT]

Timing related that belt should not move back and forth like that should stay in one spot never seen anything like it

Mine moved in and out like that, I believe it was due to the tensioner arm having excessive in and out play. I had check my crank for end play and it was fine, gear and all was tight. The in and out movement of the belt went away with the replacement of the timing components, in my case anyways

 

[Dsmkauai]

Seems to be a pattern forming here!! Lol

 

[desolateboosted]

Finally got a chance to tear into it and found the culprit. Ended up being a faulty tensioner. Once everything was off I was able to depress the tensioner pulley with my hands. The tensioner gave just enough tension to push the tbelt back up when motor was off making everything appear normal. F me for taking a chance on reusing this tensioner. Luckily the belt did not skip a single tooth.

All new components have been installed and car is good now.

Thanks for all the insight and help! You guys pretty much nailed it. Hope this thread will help to serve anyone who runs into this issue! This is a first for me, but now I know faulty tensioner will cause this loud knacking noise! ha!

 

[linksys42]

Finally got a chance to tear into it and found the culprit. Ended up being a faulty tensioner. Once everything was off I was able to depress the tensioner pulley with my hands. The tensioner gave just enough tension to push the tbelt back up when motor was off making everything appear normal. F me for taking a chance on reusing this tensioner. Luckily the belt did not skip a single tooth.

All new components have been installed and car is good now.

Thanks for all the insight and help! You guys pretty much nailed it. Hope this thread will help to serve anyone who runs into this issue! This is a first for me, but now I know faulty tensioner will cause this loud knacking noise! ha!

Awesome!! Got really lucky it didn't skip! did you happen to look at the tensioner arm to see if it is damaged (divot)?