Hi all, need some help please guys. I've had my z for about a week now and just got it back from the garage to fix a heater issue, and got a nice healthy service done too.

 

Before I gave it in I noticed the a rather loud tappety noise coming from the engine, it sounds like something spinning and hitting the silver metal cover on the engine, as I rev it higher the sound gets louder. And I can feel it too if I put my hand on the cover, like a grinding tappy sound It seems to die down when the air con is on...

 

I thought it was due to the car being sat for 4 months and just needed a good service (silly me)

But the noise persists, I thought it may be the timing belt, I hope it isn't.

It doesn't seem to be comming from the from of the engine but more on top near the front, if that makes sense?

 

I've also noticed the car seems to be revving quite low at idle around 700 and sometimes dips lower as I stop at lights etc to a point where it feels like it's about to cut out but them brings it self up. I have to give it extra revs to ensure it doesn't cut out when I move off. Drives stronger with Ac on as it's revving slightly higher and doesn't feel like it's gona stall bit obviously I don't wana drive with AC on all the time.

 

Can anyone please help me with this especially the noisy tappy noise coming from the engine, regarding the idle I've read that maybe the revs just need a slight adjustment to bring them up slightly, what do you guys think any advice on the engine noise would be most appreciated, and if anyone could point me in the direction of a good mechanic or someone who knows a thing or two about these engines that could take a look at the engine for me would be most appreciative and ill slip them a nice amount of beer tokens for there help. Cheers in advance guys!! Desperate to sort her out and have her purring just right again.

Hi,

 

sounds very strange, unfortunately I can't picture what section you are talking about " hitting the silver metal cover on the engine" may be a diagram or photo.

Or a video "with sound" of the offending noise.

 

you say the car has had a service done, by whom and what did they do, what parts did they change and what did they use? what did they say about the noise?

 

there are a number of checks that you can do...

run ecu codes (see tech section)... http://www.300zx.co.uk/forums/showthread.php?128845-Ecu-diagnostics

 

check timing and a number of other components and settings..

 

this is a good guide:

 

http://twinturbo.net/net/viewmsg.aspx?forum=technical&msg_id=922678

 

and this also for erratic idle:

 

http://www.300zx.co.uk/forums/showthread.php?126853-curing-erratic-idle

By metal cover I'm wondering if he means the CAS.

Most ticking/ tappet noises can be attributed to the lifters, these can become noisy although they function perfectly, oil changes and or the use of additive can quieten them down, however sometimes the noise will persist, use of the correct grade of oil is important as is regular changes.

 

You mention the very low tick over, this can also cause a noise of it`s own and that is vvc spring rattle, this will sound quite loud but will stop if the revs are picked up, try it and see, the low revs and stalling issue points to a set up issue with the base idle or a non functioning idle control valve, would be useful if you can get it on a ConZult diagnostic to check this and set it up, maybe a forum member close by with ConZult?

 

Jeff TT

Thanks for the replies guys, I'm sorry I'm making it difficult to explain where it's coming from, ok on top of the engine the silver rectangle which says Nissan on it and has the 4 chambers coming of it two on either side... Well it sounds like it's comming more from the first near side chamber. God I hope that makes, a good buddy from the forum said the same thing as above that it could be the noisy lifters and to try a oil additive.

 

And all also take to Jeff at Zed world in Birmingham he sounds like the man to go to.

 

under a tenner from Halford etc.

as Jeff said the other treatment i would consider is millers engine flush avaliable from opie oils followed by 5 literes of fuchs pros 5/40 engine oil and a new filter

Ah cheers guys and thanks for the picture Jeff I'm gona grab some today and maybe change oil again as you guys advised. So 5/40 is the oil to go for then.

 

Jeff ill book her in with you very soon mate. Thanks!!

Personally oil type for me is 10x40 semi synthetic as general rule but the fuch one is quality oil too.

 

Jeff TT

The fuchs is a good oil and dropping to a 5/40 on a fully synthetic oil of this quality gives better cold start protection with out hindering high temp thickness and due to its viscosity and lubricant benefits of this particular oil an increase in power and better fuel economy can also be seen on some healthy engines

 

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