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Hello, I have a 1998 pontiac grand am se with a 2.4 L DOHC engine. The engine has 117k miles on it and I have only owned the car for a few months. I changed the oil to high mileage part synthetic 5w-30 oil and platinum spark plugs within the first few weeks of driving it. The car ran smooth until a little over a week ago, I noticed a new sound during idle even though it was barely noticable. The noise becomes very noticable as the volume and velocity of the noise increases with the rpm, becoming pretty loud around 2500 rpm. It’s kind of a tick/clack noise and it worries me I may need a new engine or rebuild. My oil is full so isn’t low oil pressure, what can the noise be?
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3 things come to my mind, valve train, bottom end, or tct. If you cant tell where it is coming from, hook up a timing light. If the noise happens at a lower frequency than the light it is in the valve train and you should look at your valve lash, if the noise is at the same frequency as the light flashing, it is bottom end. To diagnose a bottom end noise, do a power balance test per erics video. If the noise does goes away during the power balance test, it is most likely rod knock, if the noise stays during the test, it is most likely piston slap. The last thing i thought of was possibly a tct and that is kind of a shot in the dark. The 2.4 L engine uses a timing chain and they tap sometimes, if none of the other tests i mentioned show you anything, the tct may be something to look at, I have successfully repaired them in the past. Let us know what you come up with.
[video]http://www.youtube.com/watch?v=bAOmUjAjNjE[/video]
Thank you sooo much guys for the advice! I’m going to go check things out but sadly it may already be to late. I went driving yesterday, not too far but enough just to test out the engine because I had somewhere a lot further to be in the next couple of days that would of required highway driving so didn’t want to be stranded on the highway. I realized the car lacked a lot of power, I pretty much had to floor the engine to accelerate like a normal car from a stop. As I approached home, the oil light kept flickering whenever I wasn’t giving the car gas and the car would tremble in die after a few seconds if I wasn’t giving it gas. Going to go see how bad the damage is but I already know I want a new engine, may have a few dead cylinders.
Sorry to hear that it’s worked out that way. In the future do not run synthetic oil in an old engine like that as it often causes problems like that. Synthetic oil has different flow characteristics and as a result it can cause engine noise and oil leaks in an older engine that was not designed to run synthetic.
As to the issue you have now you might consider checking the oil pressure as that will give you a good idea of what kind of shape the engine is in.
Thanks Eric for the advise, guess it was a bad idea putting synthetic oil in it Haha, just thought I could get it to run better with synthetic oil because when I bought it 4 months back, it had been sitting a good while and the oil was black when I changed it a week after buying the car. I did intensive research and discovered my engine bearings are probably bad. That would explain the noise and low oil pressure. When the oil light begins to come on that’s when the car shuts down so guess my car is programed to do that. I’ll be getting my engine replaced with a used one and will NOT be using synthetic oil again
Are you having the same issue collegeman? If you having a clacking/knock noise when reving the engine its probably an engine bearing according to my research and if one goes bad then all should be replaced. Instead of getting new bearings I prefer to get another engine in fear that I probably caused further engine damage.
[quote=”joser1994″ post=44481]Thanks Eric for the advise, guess it was a bad idea putting synthetic oil in it Haha, just thought I could get it to run better with synthetic oil because when I bought it 4 months back, it had been sitting a good while and the oil was black when I changed it a week after buying the car. I did intensive research and discovered my engine bearings are probably bad. That would explain the noise and low oil pressure. When the oil light begins to come on that’s when the car shuts down so guess my car is programed to do that. I’ll be getting my engine replaced with a used one and will NOT be using synthetic oil again[/quote]
I shot a video on this very thing last week partly because of this thread. It should be out in the next couple of weeks.
Thank you so much Eric and everyone else for taking the time to reply to me. I will definately be looking forward to your new video seeing where I went wrong.
Sorry to hear about the results, that’s never fun. 🙁
[quote=”EricTheCarGuy” post=44459]Synthetic oil has different flow characteristics and as a result it can cause engine noise and oil leaks in an older engine that was not designed to run synthetic.[/quote]
Hi Eric, while I love all the videos and information everyone is giving out, I have to strongly disagree on conventional vs synthetic. The engine really couldn’t care less as long as its the correct grade and the additive pack isn’t worn out (old oil).
This relates to the myth of switching to synthetics causing leaks. If anything, the switch from old used oil to fresh oil has done a good job of cleaning and protecting the engine. It’s quite possible that this could have been caused by a clogged or failed oil filter for example, causing related lubrication problems.
As far as engine noise, even switching between brands, but conventional to conventional, or synthetic to synthetic, can have a large effect on top end noise.
1998 isn’t really that old IMO (or I’m starting to show my age, although I’m not old yet either). I’m currently running a 1987 MR2 with over 200000 km during the summers. The complete history is unknown but it has seen a mix of conventional, high mileage, and is currently on synthetic (non high mileage). It hasn’t been taking care of perfectly all it’s life either, since I’m now discovering many factory parts that should have been changed quite some time ago. So far no oil related issues – good pressure, no leaks, etc. 🙂
Looking forward to the video, keep ’em coming!
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