Hey guys I would appreciate some advice for my 2003 Chevy trailblazer 4.2 with 158,000 miles. My parents bought the vehicle new back in 03 and my parents gave me the car 2 years ago when i got my license. Here's the problem... My engine makes a really hard noise to describe and I'll try to describe it as best as possible. It makes a rattle/diesel sound. At idle you can hear the noise the most. Until about 2,000 Rpms the noise gets louder but after 2000 it stops. The funny thing is I am not throwing any check engine light codes, it runs great, it just makes this weird noise. Here's the other weird part, it has been doing it the past 5 years or so but until the last 6. Months or so you would only hear the noise randomly at idle, nothing else but now the noise is prevalent at all times until higher rpms. But after you get it up to speeds like after 25 mph you can't even hear the noise, like I said it runs great. I go to school for automotive mechanics and my instructor at school informed me he thinks it is my timing chain tensioner that has failed and I agreed with him because that is what I thought it was for the past year or so. My instructor told me that my engine is a ticking time bomb and the chain will break at any time and destroy my engine. I really do not want this to happen because I love my trailblazer and it's my first car. I would really appreciate some expert advice from you guys. I am really not about to replace this timing chain and tensioner. That is a ridiculous job and well beyond my mechanical abilities.
Timing chain tensioner gone bad?
- Thread starter Revans381996
- Start date
{tpc}
Member
- Jan 22, 2014
- 359
Might be the bearings in the water pump. This happened to ours not long ago. With everything off, and the battery disconnected for safety's sake, I would try and wiggle the fan up/down. I believe it shouldn't move. If it does, the bearings are probably going, hence your noise.
It was a while ago, but I believe this is how we diagnosed it in ours. Of course we had the dealer replace the fan clutch way back when, and they told my wife that something else was going to be a problem, but she could wait and fix it later. She couldn't remember the something else, but deduction led us to the fan clutch, which is attached to the water pump. A simple up down tug, and it was pretty evident. Replaced the pump, nasty noise went away.
Of course it could be another pulley bearing or something else. I'm no expert.
If you think its the water pump and you decide you want to do it yourself, look up the proper way to do it, which I think involves removing a bunch of stuff from the front end or the radiator or something. The way we did, I did not do this. Lots of swearing and cut up hands later, we got it done, but there must of been a much easier way.
It was a while ago, but I believe this is how we diagnosed it in ours. Of course we had the dealer replace the fan clutch way back when, and they told my wife that something else was going to be a problem, but she could wait and fix it later. She couldn't remember the something else, but deduction led us to the fan clutch, which is attached to the water pump. A simple up down tug, and it was pretty evident. Replaced the pump, nasty noise went away.
Of course it could be another pulley bearing or something else. I'm no expert.
If you think its the water pump and you decide you want to do it yourself, look up the proper way to do it, which I think involves removing a bunch of stuff from the front end or the radiator or something. The way we did, I did not do this. Lots of swearing and cut up hands later, we got it done, but there must of been a much easier way.
Defiantly not the water pump as it was replaced 20,000 miles ago but thank you anyways. Ill be posting a link to a YouTube video I will be posting later of my noise.
[video=youtube;xpcXrDEpZQ8]https://www.youtube.com/watch?v=xpcXrDEpZQ8[/video]
Here's the link to my YouTube video. Tell me if the link works thank you!
Here's the link to my YouTube video. Tell me if the link works thank you!
Hatchet
Member
- Nov 21, 2011
- 2,405
Hmmm thats a new sound to me. It sounds a little bit like rod knock, but not quite. I have a few guesses, but don't like to give off a guess. Hard to tell when i'm at work with sounds barely on. Hopefully someone can help ya with this.
Oh on a side note. Any engine codes thrown? I would think a broken timing chain tension er would throw the engine out of sink and have misfires.
Oh on a side note. Any engine codes thrown? I would think a broken timing chain tension er would throw the engine out of sink and have misfires.
No engine codes except for a po440 evap code that is irrelevant to the noise. Like I said the truck runs great which listening to the sound you would think it runs poorly but it doesn't.
Texan
Member
- Jan 14, 2014
- 622
Does not sound good. How is the oil pressure? It would be good to hook up a
mechanical oil PSI gauge and check. There was a resent thread about how to do this.
Many years ago, I had a similar sound which turned out to be the bolts for the torque
converter had somehow come loose (backed out). Use a stethoscope to try to localize
where the noise is coming from.
mechanical oil PSI gauge and check. There was a resent thread about how to do this.
Many years ago, I had a similar sound which turned out to be the bolts for the torque
converter had somehow come loose (backed out). Use a stethoscope to try to localize
where the noise is coming from.
IllogicTC
Member
- Dec 30, 2013
- 3,452
I edited the YouTube link post to just have the player right here in the forum instead of having to jump to another site.
I would definitely use a stethoscope to try confirming location. If it's the tensioner, it's a time-consuming job that will cost you a bit of money (not a whole ton I don't believe, but it's more than just dropping a Lincoln at Advance Auto and calling it a day for sure). And if it ISN'T the tensioner, you just put that money and all that time in for (nearly) nothing.
I would definitely use a stethoscope to try confirming location. If it's the tensioner, it's a time-consuming job that will cost you a bit of money (not a whole ton I don't believe, but it's more than just dropping a Lincoln at Advance Auto and calling it a day for sure). And if it ISN'T the tensioner, you just put that money and all that time in for (nearly) nothing.
I actually already used a stethoscope at school for the noise. The noise was loudest when I put it on top of the valve cover. Also when I put my hand on the top of the valve cover there's a small vibration
Sparky
Member
- Dec 4, 2011
- 12,927
Rod knock would be typically a deeper noise that also goes away after a rev and the engine speed is slowing down. That doesn't. Sounds like something valve train related to me. I definitely wouldn't be driving it until that's fixed!
BTW, looks like the infamous steppers bit you too.
BTW, looks like the infamous steppers bit you too.
Well I'm gonna have to drive it because it's my daily driver. Yeah stepper motor in my speedometer broke last year unfortunately. Thank you for your input!
Yes, top of the valve cover at the furthest front part of the engine, farthest away from the firewall.
IllogicTC
Member
- Dec 30, 2013
- 3,452
Then it might indeed be the tensioner, maybe. Not the tensioner itself making the noise, but a tensioner not providing proper pressure allowing the chain to hit something. But then again, it sounds way too rhythmic, increasing linearly with engine speed...
I dunno, I'm lost. Where's May03LT
I dunno, I'm lost. Where's May03LT
Thank you guys for all of the help! I'm lost as well. At this point I'm just scared the chain is going to snap and break my engine completely. I love this truck and I don't want to see it going to the junkyard.
IllogicTC
Member
- Dec 30, 2013
- 3,452
Revans381996 said:
Then it may be best to just roll with what your instructor said if nothing else, and diagnose/repair/replace the tensioner. It would afford you some great wrench time and at least a crude understanding on how to retain timing (if you don't end up having to remove your chain). And at your place of learning do they allow you to come in and get free/reduced-cost tool time in? Or maybe have other people help you? Could be a learning experience for everyone!
There may be other replies cropping up here and there before your next drive, hopefully they could help pinpoint other possible issues.
Yes I can work on my trailblazer at school. I go to high school half day then to my technical school the other half for auto mechanics. The problem with me bringing a huge job to my tech school is I would only have 2 hours max to work on it per day and that is only if we don't have anything else to do considering it is a school and I still need to get my other work done before I can work on my own car. Doing this job I really wouldn't get much help and I have never done a job this big. My instructor who diagnosed my car is only in class one day a week and my other teacher who is there the other days isn't much help to be honest. If I was to do this job I can just see my car sitting in the shop over a month with me getting frustrated. It is my daily driver and I really can't see going a long period of time without a car. If I really knew what I was doing I think I would've already tackled this job but I really don't think I have the skills necessary to do it yet.
Sparky
Member
- Dec 4, 2011
- 12,927
If the rest of the truck is in good shape, I'd be tempted to throw another engine in it if that one did blow up. But hopefully it can be fixed instead.
Can you take it to a reputable shop, have them give a 2nd opinion, and see how long it would take to get fixed? Sometimes it is worth just paying someone else to fix it as you'll get it back a lot faster also.
Can you take it to a reputable shop, have them give a 2nd opinion, and see how long it would take to get fixed? Sometimes it is worth just paying someone else to fix it as you'll get it back a lot faster also.
That's probably what I'm gonna end up doing is taking it to a shop to get a 2nd opinion. The truck is actually great for almost having 160,000 miles except the the speedometer stepper motor being broken.
triz
Member
- Apr 22, 2013
- 746
IllogicTC said:Just wait until you ever have to disconnect the battery...
I never used to give it a second thought when I work on my truck till I saw some post here. (knocking on wood)
At the OP, I would try and get it looked at ASAP. If the guide is on it way out from the chain rubbing through it, you can damage the chain and knock your engine out of time. The sound was a bit similar to en engine they brought it to a friends shop (although it was a Ford). It wasnt something I saw right away till he told me to look again. The plastic guide had rubbed over to metal. Keep us posted and as always I hope its not that expensive or serious.
{tpc}
Member
- Jan 22, 2014
- 359
I don't get the battery thing, but just recently I've been seeing posts about how disconnecting it can mess things up. In ours the battery was replaced maybe a year ago, and I don't recall anything happening as a result. But now I am thinking of looking into this "memory saver" thing before I work on the t-stat.
Anyways, that was off topic. Seriously, daily driver or not, I wouldn't be driving that again until I was driving it to a repair shop. I'm not good enough to diagnose what that sound is, but that is NOT what I thought it might have been. To me that sounds like something hitting something it shouldn't in the valve train.
I'm not saying its going to be cheap, easy, or quick, but I know what won't be cheap, easy and quick and that's if something major breaks before you can get it looked at. Been there, done that, been in your situation before. Turned into a motor replacement that went bad, that I "couldn't be without because it was my daily", that ended in me trading it in for what I owed on it which wasn't much, and eating the cost of the motor replacement on my credit card. I ended up with a brand new lease (that I paid way too much for never owning anything), not enough miles to cover, that resulted in my not driving "my" car for the last year before I turned it.
Word of advice. Find a reputable shop (ask your instructor maybe?) and take it in, ask your folks/friends for help in the meantime. Thats all I got.
Anyways, that was off topic. Seriously, daily driver or not, I wouldn't be driving that again until I was driving it to a repair shop. I'm not good enough to diagnose what that sound is, but that is NOT what I thought it might have been. To me that sounds like something hitting something it shouldn't in the valve train.
I'm not saying its going to be cheap, easy, or quick, but I know what won't be cheap, easy and quick and that's if something major breaks before you can get it looked at. Been there, done that, been in your situation before. Turned into a motor replacement that went bad, that I "couldn't be without because it was my daily", that ended in me trading it in for what I owed on it which wasn't much, and eating the cost of the motor replacement on my credit card. I ended up with a brand new lease (that I paid way too much for never owning anything), not enough miles to cover, that resulted in my not driving "my" car for the last year before I turned it.
Word of advice. Find a reputable shop (ask your instructor maybe?) and take it in, ask your folks/friends for help in the meantime. Thats all I got.
Mine makes a noise very similar to that, not quite as low-pitched, but otherwise very similar.
It is definitely coming from the timing chain cover and I've used a stethescope to check all the other pulleys, pumps, etc.
I think that mine may be the chain guide on the top of the cover and I'm waiting warmer weather to pull it off and see. Hopefully it is not the entire tensioner, that is a big job and I'd have to get another of my 5 vehicles running to replace the TB for a while.
It is definitely coming from the timing chain cover and I've used a stethescope to check all the other pulleys, pumps, etc.
I think that mine may be the chain guide on the top of the cover and I'm waiting warmer weather to pull it off and see. Hopefully it is not the entire tensioner, that is a big job and I'd have to get another of my 5 vehicles running to replace the TB for a while.
Very good advice tpc. I think my next plan is calling up my family's trusted mechanic and I'll ask him to look at it Saturday. I think I'm starting to realize now that this is not something that I can just keep ignoring. I need a pro to look at it/fix it.
IllogicTC said:I dunno, I'm lost. Where's May03LT
I was never here!
Revans381996 said:
I hear ya. If it is timing related, the inspection alone can be time consuming since you won't be able to see much unless the front cover is off. And just about every DIY'er who went that far into the engine has had a problem getting the crank pulley off. Plus I think someone already mentioned that if it is timing related, we'd expect a cam/crank code.
I like what tpc said. It might pay to get a second opinion before committing.
If you're going to try the stethoscope, here's where everything is behind the front cover.
May03lt: do you have any opinions on what this noise could be? Do you think it has to do with the timing chain/tensioner/guide? Also thank you so much for all of your YouTube videos. They have helped me immensely.
Revans381996 said:
That's one of those things that I'd have to hear for myself (and go over with a stethoscope) before condemning anything. When I saw you put your hand on the front of the valve cover it made me think that you had a feeling it was up front. I wish I had a "fast and easy" 3 minute answer but I don't.
I'm glad you got some use of the videos! Be sure to rate, comment, spam forums, donate to my patreon, and turn off adblock before watching. Just kidding, don't do any of that.
Yeah its defiantly up front. That's why I put my hand over the front of the valve cover. When I put my hand on the front of the valve cover I feel a vibration almost like the chain is hitting the top of the valve cover.
Well I've got some good news... I called up my family's mechanic and he said to just bring my trailblazer down tomorrow and he said he would look at it for free. I'm just happy I might get some more insight on what's going on tomorrow. Thank you all for your help and I'll keep the thread updated on what's going on. Also glad I finally realized this isn't just a problem I can keep on ignoring.
The mechanic I went to has no idea what that noise is. He said he's never heard a noise like that before in his life. So I guess I'm just gonna have to find a better mechanic
{tpc}
Member
- Jan 22, 2014
- 359
Ugg, sorry to hear, that sucks.
Don't want to be all negative nancy, but I would start preparing for the worst. I had an issue with a car once that according to a mechanic "friend" needed a "valve job". Well I paid said friend lots of $$ to do a full engine rebuild because I liked the car and wanted to keep it (and it wasn't going to cost me much more, plus I had the $$ on hand). I was assured how great it would be. Well months later after I got it back, and because he used all reman parts on it I made it a half mile down the street before it overheated and I had to shut it down...I ended up getting it running myself.
The point of the story is, after I got it running it made a weird noise. Not weird like yours, but weird in its own right. Every shop I went to told me it was either the trans or the engine and they wouldn't know until they replaced one or the other...and then it might be the other one! So I cut my losses at that point and sold it to the first person I could fine that wanted it, which was actually pretty quick. I'm sure they got a decent car with a little work (as I am fairly certain it had something to do with the clutch), but it was just becoming a money pit and I couldn't see going any further with it.
Your case is different, because to me that's definitely only an engine deal. The thing is I wouldn't be surprised if the "fix" involves something expensive that may not actually be the fix. Or that it could start off fairly inexpensive that leads to more expensive. But my experiences have led me to the more cynical path with respects to this so for the most part I plan for the worst.
Don't want to be all negative nancy, but I would start preparing for the worst. I had an issue with a car once that according to a mechanic "friend" needed a "valve job". Well I paid said friend lots of $$ to do a full engine rebuild because I liked the car and wanted to keep it (and it wasn't going to cost me much more, plus I had the $$ on hand). I was assured how great it would be. Well months later after I got it back, and because he used all reman parts on it I made it a half mile down the street before it overheated and I had to shut it down...I ended up getting it running myself.
The point of the story is, after I got it running it made a weird noise. Not weird like yours, but weird in its own right. Every shop I went to told me it was either the trans or the engine and they wouldn't know until they replaced one or the other...and then it might be the other one! So I cut my losses at that point and sold it to the first person I could fine that wanted it, which was actually pretty quick. I'm sure they got a decent car with a little work (as I am fairly certain it had something to do with the clutch), but it was just becoming a money pit and I couldn't see going any further with it.
Your case is different, because to me that's definitely only an engine deal. The thing is I wouldn't be surprised if the "fix" involves something expensive that may not actually be the fix. Or that it could start off fairly inexpensive that leads to more expensive. But my experiences have led me to the more cynical path with respects to this so for the most part I plan for the worst.
I mean I agree with you 100% but I really don't know what to do at this point. If no mechanic can figure out what the noise is idk how I'm gonna get it fixed. Maybe I'll just wait till it dies then I'll put a new engine in it. Might as well try as I would have nothing to lose and I'm sure I could get a little help at school.