It could be because all of the oil has settled in the pan from sitting so long. It takes about 30secs or so for the pump to send it up to the engine. It gets worse as it gets colder and the oil becomes thicker from the cold. The best thing to do is to use synthetic oil which sticks better the engine parts. They say most engine wear occurs on startup when all of the oil is sitting in the pan. The use of synthetic oil should help.
I had the same thing happen to me(3.5se) ..The car was only sitting overnight..the noise lasted about a minute and diminished as time went on...it was scary since it was definitely an engine knock...this happened about a month ago, and has not happened since, but it leaves a bad feeling
Sorry guys, but unless you have the TDI (Turbo Diesel Injected ) model that I haven't heard about....you have problems. This should not happen! At minus 40 maybe for a few second but it hasn't been that cold. You should report this to the dealer ASAP and make sure that you get a copy of the work order, just in case the engine goes when it's out of warranty. Something to listen for is a rattle (resonant vibration actually) between 2000 and 3000 rpm.
Try this while parked (neutral,in park, brake on, etc....you know). With the drive door open, (so you can hear) gradually raise the rpm up to 3500 and then back down. If you hear a rattle that sound like a loose heat shield, chances are that the pre-cats are bad. This will not be the same sound as you heard on start up. When the pre-cats go bad, they sometimes damage the engine, and that COULD be your problem. There is a recall on now for the 2.5's and there are some 3.5's with this problem as well, but no recall or even a TSB for the 3.5's at this point.
Yes synthetic is great but that is not the PROBLEM in this case.
Also use the block heater. That and synthetic oil (changed regularly ) are the best things you can do for an engine short of installing an Accusump.
Also leaving you car for a week will/should have VERY little effect. Yes the oil will drain back, but it only (normally) takes a second or two to repressurize the galleys. That will take care of the bearings. It takes a few more seconds to coat the cylinder walls.
Please post your findings. I would like to know the results
Just called my dealer and a technical guy there told me that it was because all the oil went down in the oil pan and it can takes a couple of second to the oil pump to distribute the oil in the engine...
It is very weird??? I had in the past a Civic and this never happen even if the engine was started once per month...
The only way to prove them that the engine is knocking, is to leave my car in the dealer parking lot for at least 5 days and start my car with one or two mechanics...
I had the same problem on cold morning. First, the car would start with a loud "Sreetch" like sound and then the rattle came in play and disappeared about 1 minute later. After a tune-up, i've been told that there was something wrong with belt pulleys. I've never heard any noise since then.
I get a knock like that for a couple seconds on start up in cold mornings somtimes also. One thing I have noticed in the past week is by turning the key to the "on" but not "Start" position and wait for a few seconds, then turn to "start", it doesn't knock and usually start up very smooth. Don't know what that would be doing though. (could be just coincidence so far too)
My 02 2.5S does this now for about the first 30-60 seconds...its a rapping noise that I've only heard before on cars that are low on oil...very deisel-like. My oil level is correct and it only happens when the car is cold. I've questioned my dealer about it and its (naturally) been written off as "normal"...I disagree, but got it in writing so when the motor blows I can hold them responsible.
Haikus Are Easy
But Sometimes They Don't Make Sense
I think that you guys should contact the dealership service department and have them take a look. Rattling .. knocking at start up is NOT NORMAL. The car should be propery designed to not do this. Yes it is most probably due to lack of oil or the pump just taken a few seconds to distribute the oil properly, but the bottom line is it should not be occuring. Its like what the f*&k did we all buy NISSANS or chevys or something.... I dont know...
2004 3.5 SE Manual Transmission--Stillen CAI/Exhaust/Race Pipe(ni)/Mesh Grill/Full Body Kit (tour style lip),/rear windshield lettering,HELLA HID's7500K(ni), JL Audio 0 guage hyper grounds, Stillen Sport drilled rotors/Brake Pros Pads Interior..Valentine One, Pioneer 8500 head unit w BOSE amplifier/6 disc CD changer in glove box (custom)/Pioneer Class D 1000 watt amp w 5 farad cap, CIPA auto dichromatic rearview w/comp, JL Audio 10W7, Dakota Digital Custom gauges in cubby(ni).
I just found out that one of my friends has the same problem with his altima. I told him to park his car on nose down on the hill infront of his house. The next day he started it, the noise was gone and it was the oil level that was causing the problem. Really weird problem and very common on altimas. Not sure about the new models.
It is a very weird problem and should definitely not be happening at all on newer cars. When mine did it when it was parked uphill and I know for sure the oil level was correct. Now I notice a slight rattling sound when I start it up occassionally....
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