About 2 weeks ago I started to hear a strange noise right at start up. It's hard to describe. It sounds kind of like a screeching metal on metal sound. It's not very loud and it only lasts for about a second right when the engine is starting. It also only seems to happen when the engine is cold. The noise goes away right away and my car seems to run fine after that.

I thought it might be because I was due for an oil change so I got one yesterday. The noise didn't stop. I told the mechanic about it and he said maybe it's dry starting??? Has anyone heard of this or can anyone take a guess as to what it might be.

Thanks!

 

Dry starting is when the engine oil has drained down to the bottom of your oil pan due to gravity, and you start the car with essentially no oil in it. It starts to flow soon as you turn the engine over so it's not starved for long, just a second or two till things get flowing. It's why most of your engine wear comes from cold starts.

Do you get this noise if you drive around for half an hour, then turn the car off, get something to eat, then turn it on again?

 

It doesn't seem to do it unless the car has been sitting for a while, like a couple of hours or more. Dry starting seems like it could be the culprit, since it only happens right at start up and goes away immediately.

Is this something I should be worried about? And why would it have started only recently? The car has about 42000 miles and I bought it with 37,000. It's a 2008. If I bring it to the dealership they likely won't be able to replicate it unless they keep it overnight.

 

I wonder if it's a belt tensioner noise... I started getting that in another car when the bearings started to fail with in it.

 

Check your belt and tensioner. That could be the culprit as well. Any slippage of the belt will cause the screeching noise at startup.

 

Squeaky belts are probably the first thing you should look at, but...

You might want to check your power steering fluid level, too. Also check to see if it is dirty. Either can cause noise at startup.

I have an Acura MDX that had a squeal noise at startup. According to people on an MDX forum, the Honda PS fluid eats at the PS hose material, and that material contaminates the PS fluid. (I'm not saying that this is the case on the G37.)

I made the squeal go away by flushing the PS system in the MDX with new, clean fluid and refilling it.

 

I know this may be way out there but maybe you have dirty throttle bodies?? Maybe a squeak is coming from one of the two and you can't hear it after the car is warmed up? It probably wouldn't hurt to clean them anyway.

 

I have this same problem and it just started recently i cant figure out wat it is so im going to take it to infiniti

 

Try doing an oil change... I had this issue and switched over to the ester oil... regardless the noise is gone.

 

Not sure if you found the problem yet, haven't seen a recent post but I have a similar issue and it difinately coming from the exhaust system. I have no warranty and I'm trying to find out if Infiniti will still cover the cost with the following bulletin: http://www.infinitig37.com/TSB/1SB19.pdf

Let me know if this could be the cause of your problem.

Thanks. RG

 

Late bump to the thread. Has anyone been able to resolve this issue?


Cheers!

 

Sounds to me like your starter isn't fully disengaging or taking too long to disengage?

 

I thought of something similar to that but it only does that on cold startup

 

He already did an oil change, as previously stated. The ester oil issue helps with VVT ticking. One more vote for belt tensioner pulley.

 

something to do with the heat shields or catalyctic converter. its the exhaust making that loud noise at start up, my G has done it for a long time now after warm up and driving around it fades away and only comes back after sitting for a long time. just buy a new exhaust or replace the shields and converter .