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SIRdriftsalot

S15 Knocking only when engine is warm

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Hey guys,

 

Got a problem with my motor, it has a slight knock in it but only when the car is warmed up, on cold start will sound like its bloody perfect but once its warmed up it would start to make the knock, when i noticed the knock i definitely was not booting the car i drive my car like a sane person

 

Got told might be VCT but to my knowledge VCT knock usually goes away when warm and only knocks on cold, ill add a video that i took maybe it might help.

 

Any advice/info would be greatly appreciated as im quite worried about driving it around.

 

EDIT: also i remembered when im driving as the revs pick up the knock seems to fade away it does not knock through the rev range, maybe that would help.

 

Thanks in advance.

 

http://www.youtube.com/watch?v=2O5vwjGmOlQ&feature=youtube_gdata_player

 

Edit 2: another video with clearer sound and this one I didn't need to rev it to hear the knock.

 

Edited by SIRdriftsalot

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Fuel pump fixed mine but the motor still cracked a ringlanding a couple of months later :-/

 

Basically after driving for 20 mins or so and warming up it would start to knock. Issue was the pump getting warm and slowing down.

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Fuel pump fixed mine but the motor still cracked a ringlanding a couple of months later :-/

 

Basically after driving for 20 mins or so and warming up it would start to knock. Issue was the pump getting warm and slowing down.

 

Fuel pump?

 

i dont really see why a fuel pump would make the car knock...

 

not having a dig but would be nice to maybe get a bit more info to as how the fuel pump caused the knock.

 

thanks for the reply.

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My thinking;

As the car heats up the oil thins out, and some tolerences get smaller, while others get bigger. So maybe its a combination thats started up from something wearing/wrong oil etc...

 

When was the last oil change and what oil did you run? (i didnt listen to the vid btw)

 

 

-dan

 

Edit: listen to the video, sounds A LOT like bottom death rattle.

Edited by -LCD-

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My thinking;

As the car heats up the oil thins out, and some tolerences get smaller, while others get bigger. So maybe its a combination thats started up from something wearing/wrong oil etc...

 

When was the last oil change and what oil did you run? (i didnt listen to the vid btw)

 

 

-dan

 

Edit: listen to the video, sounds A LOT like bottom death rattle.

 

Prior to the problem the importer I bought it off said he will get it fully serviced before handing the keys over, but didn't seem like he did as when I changed the oil on the weekend the filter was still a Japanese brand.

 

Mate also told me oil loses its lubricating properties as it gets older.

 

I changed the oil after I heard the knock on the weekend using 5-40 fully synthetic as have a few stocked up cause its the usual I use, knock is still there.

 

Should of went thicker I know but it's what I had,

a mate suggested 15-40 and see how it goes.

 

Edited by SIRdriftsalot

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just put really thick oil in lol

 

Yeah as last post said mate suggested 15-40.

 

But I don't want to mask the problem if motor is on the way out I'll rather fix it befor the car isn't drivable and have to tow it.

 

Isit possible that oil pump is fkd or oil lines are blocked?

 

Not very advanced in mechanics so a lot if questions will be thrown here haha sorry fellas, only know my basics

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just put really thick oil in lol

 

Yeah as last post said mate suggested 15-40.

 

 

15-40 isn't really thick, it's the correct oil to be running!

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just put really thick oil in lol

 

Yeah as last post said mate suggested 15-40.

 

 

15-40 isn't really thick, it's the correct oil to be running!

 

I've Seen a few threads on oils in S15s and most use or suggest 5-40 or 10-40

 

Won't say your reply is wrong nor right, but it definitely doesn't help as the knock came on with the old oil.

 

Thanks mate.

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1. change oil to 10w-40

2. get it on a dyno and check for engine knock

3. if knocking persist then refer to pagge 11 of Nissan S15 Service Manual - Engine Mechanical

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Thicker oil only hides the knock as far as I know. You'll just hear the same noise in a month's time with a thicker oil and you're back to square 1. (lol page 11 of Service Manual - Engine Mechanical).

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^^ exactly what I don't want, just went to advance auto mech in enfield they reckon noisy lifter.

 

60-70 per lifter and 350-400 labour I thought get f**ked!

 

He also told me there's 16 lifters

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Err, there's something to do with if it's cam or crank noise depending on how fast it is as the crank is twice as fast as the cam (due to size).

 

Take it to a shop/dyno and see what they say - even if it costs for $100, then you know for sure.

 

Lifters tick, not clunk/knock. I only have solid lifters (so YMMV if they're hydraulic).

Edited by TheApothecary

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Death from below :( You can here the different sound rates from the top end to the bottom end (cams spin at twice crank speed). Start saving :(

 

Try unplugging coils one at a time, this will take the load of the bottom end. Will pin point which cylinder.

Edited by S15_Steph

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check the two bolts holding the cam sprockets on,

 

check the chain tensioner,

 

could possibly be the lifters too.

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Thanks for all replies guys.

 

will try all this over the weekend, on another note today after i got home from work i noticed the car was NOT knocking anymore?

 

so it seems to come and go? will confirm with a couple more drives and checks.

 

EDIT: lets say the motor did let go, how much would i be looking at for a standard rebuild?, just so i know what to get ready to fork out.

 

thanks again all

Edited by SIRdriftsalot

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Disconnect the VCT solenoid and see if the noise goes.

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the factory oil for the sr is 7.5wt40 AFAIK, and you can buy it from nissan $50 for 5L or something? non trade.

 

its worth trying some engine oil flush, slightly thicker and different oil, and disconneting the vct, checking the cams etc. but do it systematically. disconnect vct>check cams etc>engine flush>new oil>

 

 

-dan

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^^ exactly what I don't want, just went to advance auto mech in enfield they reckon noisy lifter.

 

60-70 per lifter and 350-400 labour I thought get f**ked!

 

He also told me there's 16 lifters

Go to another mechanic that knows what he is talking about, there is 8 hyd lifters in an sr20, one for each rocker arm and the rocker operates 2 valves.

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Have tried the VCT solenoid thing and still knocks.

 

also did the engine flush aswell as i thought it could be blocked oil lines not feeding enough oil, but nada still there.

 

but will check sprocket bolts and chain tensioner this weekend for sure.

 

till then ill drive it conservatively

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Unless you dont have another way of transport i wouldnt be driving at all, as said above take the coilpack off cylinder 1 through 4 and if the knock goes away after pulling one out.......youre gonna have a bad time

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Unless you dont have another way of transport i wouldnt be driving at all, as said above take the coilpack off cylinder 1 through 4 and if the knock goes away after pulling one out.......youre gonna have a bad time

 

In other cases it the knock will get louder. Any change in the noise means a bad time. From the sound of the vid, its a big end. It will only get worse if it is, there is no stop gap solution. Its not a lifter.

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Well past couple of days knock seems to have gone away, have checked after driving to and from work.

 

Possible that oil lines were blocked and it eventually cleared itself after I serviced it?

 

Or isit just all a calm before the storm? lol...

Edited by SIRdriftsalot

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imo big end noises dont come and go, once the noise is there, its there unless its masked up (like thicker oil)

a hydrolic lifter can occasionaly come and go,

from the video it doesnt really sound deep enough to be a big end, expecially at those low rpms, yet its hard to tell listening on my laptop speakers

where abouts in sydney are you, i work in a workshop over at hurstville yet live at cabramatta, so if you were in the area and it starts up again you could come past and ill give you my opinion,

also as far as engines go, it depends if you want to rebuild or just replace,

if you replace the engine with a 2nd hand one, and wanted to do the swap youself you could find engines around the 1.5k mark complete, less for just a long motor.

if you want to rebuild then it depends on how bad the motor is when you do the rebuild,

as if the big ends go and it damages the crank, then if the crank can be machined its ok, if it cant then a new crank isnt that cheap, same with rods

if you drive it till it dies you can put a rod threw the block and need pretty much everything,

if you rebuild it before it lets go or gets to bad, and the crank and rods are fine, then you can get away with just linishing the crank, new bearings, new piston rings, hone the block, check of the rest of it,

so rebuild prices will vary alot depending on what actual work is required.

another option if you want the peice of mind of a fresh motor, if an exchange motor, basicly its a set price they supply you with a motor thats been rebuild to factory spec, and you give them your old motor.dunno what a sr is worth from those places though.

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*snip*

 

Thanks for taking the time to reply, I actually live in Liverpool and work in strathfield-ish.

 

Reckon you could shoot me a PM with your number and if it ever comes back I will come and see you.

 

Thanks for that mate.

 

Edit: here's another video where I did not have to rev the engine to hear the sound

 

Dark cause done at night but all you need it the audio a lot more clearer aswell

 

Edited by SIRdriftsalot

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Ummmmm the first vid sounds like VCT, but the 2nd vid sounds like bad-ness.

 

Where is kemp or Donny ?

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Well sound has disappeared and I got told could of been at sticky lifter due to the car not being serviced regularly.

 

Which takes us back to it was probably sitting in the yard for a while befor I bought it with old oil etc..

 

 

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Ummmmm the first vid sounds like VCT, but the 2nd vid sounds like bad-ness.

 

Where is kemp or Donny ?

It's not vct, I know that sound very well. Strange that it comes and goes. Big ends don't do that. Perhaps it is a lifter?? I didn't watch the second video

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i was chatting to my boss at work today (mechanic) and said pretty much the same thing, i showed him the video, he said sounds like a bottom end knock, then i said yeah but the noise comes and goes and has gone away, he replied with oh then its more likly to be a a hydrolic lifter playing up a bit.

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i was chatting to my boss at work today (mechanic) and said pretty much the same thing, i showed him the video, he said sounds like a bottom end knock, then i said yeah but the noise comes and goes and has gone away, he replied with oh then its more likly to be a a hydrolic lifter playing up a bit.

 

Yeah the noise returned today, so I'm guessing the only way to fix it is replace the lifters?

 

If so ill just go ahead with it, unless there's another way to maybe help it?

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