Ntb08-014

[NissanTech]

A new entry has been added to Knowledgebase

Description: 2007 NISSAN ALTIMA; QR25 ENGINE RATTLE NOISE WHEN COLD

Rattling or knocking noise from the engine when all of the following conditions are met:
1. The rattle noise is not coming from the catalytic converter heat shield (refer to
campaign bulletin NTB08-001), and
2. The engine oil level is in the operating range, and
3. Engine is OFF for 2 hours or more (cold soak of 2 hours or more), and
4. Cold start with engine coolant temperature below 122°F (50°C), and
5. The noise lasts for 1 minute or more during engine warm up, and

6. At idle or low speeds—engine rpm below 2200.

To check it out, rate it or add comments, visit NTB08-014
The comments you make there will appear in the posts below.

[kameshward]

Can anybody tell me if this Rattle Noise can be applied to a Altima Hybrid Engine too? The altima hybrid engine has the QR25 engine. My car which is a altima hybrid has this rattle noise. I got the heat shields replaced and still the noise persists.

Is there any bad news accompanied with this noise? In sense is this a problem in the long run?

Please help me!!!

Originally Posted by NissanTech

A new entry has been added to Knowledgebase

Description: 2007 NISSAN ALTIMA; QR25 ENGINE RATTLE NOISE WHEN COLD

Rattling or knocking noise from the engine when all of the following conditions are met:
1. The rattle noise is not coming from the catalytic converter heat shield (refer to
campaign bulletin NTB08-001), and
2. The engine oil level is in the operating range, and
3. Engine is OFF for 2 hours or more (cold soak of 2 hours or more), and
4. Cold start with engine coolant temperature below 122°F (50°C), and
5. The noise lasts for 1 minute or more during engine warm up, and

6. At idle or low speeds—engine rpm below 2200.

To check it out, rate it or add comments, visit NTB08-014
The comments you make there will appear in the posts below.

[NissanTech]

No, that bulletin does not apply to your Altima Hybrid.

[kameshward]

If it is a non-hybrid 2007 Atlima sedan with Qr25, then how do we rectify this problem? Or is it really a problem?

Thanks

[NissanTech]

Is it a rattle noise or a rough idle? You post rough idle in the title of your las post.

I haven't had any rattle problem with the 07 Altima hybrid, and I'm not sure what could be the problem. What is your dealers opinion about the problem?

[kameshward]

I am sorry i didnt follow up.. i was out of country for some time. Now about the Hybrid... I took it back to the dealership service center and they say they hear the rough idle but they cant do anything until the check engine light shows up. They cant figure how to fix the problem. They tried replacing the heat shields and that didnt do much. the rough idle still persists. I guess generally you wouldnt notice it when the car is at stop as the EV mode is ON. But if the battery is almost out of charge and then when you idle the rough idle is very prominent. This rough idle also comes up when you start the car up on a cold day. I greatly appreciae any help on this issue. At this point I am only taking it easy as I have an extended warranty on the car. But the rough idle is rather irritating and and when you pay close to 25K for a car you expect good quality.

One more thing to note is that... I have still been getting good gas mileage. I am not sure this rough idle would affect the engine efficiency.