Engine noise when cold

[Roger Blassberg 0]

When I start the engine (VR6, 209,000 miles) there is a knocking noise from the engine, directly related to engine speed. It disappears above 2000 rpm when the oil is cold, and completely at any engine speed once the oil is warmer than 60 degs.

 

If it were a bottom end bearing I would expect the knock to be more pronounced at higher engine speeds and at higher oil temperatures when the oil is thinner. It is totally absent once the engine is warm.

 

The engine goes very well, burns very little oil and the plugs are all clean. I use 10/40 Chevron oil and change it every 4-5000 miles.

 

The head, chains, tensioners and guides are all recently renewed - it's not a tappet or timing chain rattle.

 

2 alternatives come to mind piston slap or a noisy oil pump.

 

Any comments would be gratefully received.

 

Best wishes

 

RB

[Jim 2]

I suffer from something very similar with my VR6 which is on 189k. Like you, doesn't use much oil, apparently doesn't smoke under load, and pulls like a train. I've been told it's most likely piston slap.. so potentially not a big problem yet! Tis annoying though and does mean I'm super paranoid about not even going over 2k till there is lots of heat in the engine!

[floppyman 0]

It does sound to be tappets... But vr6 are prone to do piston noise due to the cylinder bore (especially number 1 cyl) mine does it when cold but does it no matter engine speed. Its 180,000 miles but ive replaced pistons on 140,000... Stupidly I never done a rebore.

[MoonlightVR6 10]

I suffer from something very similar with my VR6 which is on 189k. Like you, doesn't use much oil, apparently doesn't smoke under load, and pulls like a train. I've been told it's most likely piston slap.. so potentially not a big problem yet! Tis annoying though and does mean I'm super paranoid about not even going over 2k till there is lots of heat in the engine!

 

Mine is on 75k and have started to notice a noise that I suspect could be the same. I'm so worried about it. I do not know how to describe the sound (mechanically I'm a complete beginner, at best), except it sounds like it's not operating smoothly (as when warm) almost rough and rattle. I noticed it is there at idle, but fairly quiet, it seems to get more pronounced from maybe 20 - 30 on the rpm gauge. To be honest I thought it might be something to do with oil, maybe it wasn't getting pumped round as easily as the oil was cold, once it gets to about 55 it seems ok though. I always check my oil every couple of days and try and keep in the top half of the dip stick marking. Could it be from putting too much in, I'm sure I read in the manual that is bad for something and I accidently did that just before I started to notice it.

It is quite smokey when cold, but not really at all when warm.

I know your paranoia well, I am almost scared to drive her, I am worried I am just making things worse just using it but have no other choice.

 

 

What is this piston slap you talk of, sounds ominous!!!

What are tappers?

[jekel 10]

If anyone needs a new engine I can recommend my oold one which is now in the possession of Lilfuzzer on this site. Had a couple of worn valve guides I think, had mate who had a totally reconned/rebuilt VR6 got good deal, and easier to change whole engine, but bar valves was perfect, just had MOT'd before changed, passed emissions with no CAT, MOT man thought I was mad for changing it, even said quietest nicest sounding VR6 he'd heard.

I borrowed a mates VR6 with nearly 200K on it whilst changing and mine felt like a Formula 1 in comparison. Contact Lilfuzzer if interested but do allow for head/valve work (probs. just 2 guides but be stupid not to do whole head) it was mild, occasional puff of smoke after coasting down long hill. I think it was rebuilt just before I bought car bout 3 years ago, oil looked same coming out as went in at change, could see chains new, and had sump off once and like mirrors inside.

He also has gearbox which is perfect, I put new rebuilt one in when changed engine and you'd be hard pushed to notice any diff between the two running.

Contact Lilfuzzer and say your after Paul's VR6 from the white Corrado, as he has a few VR6's. He's from Co. Durham, down road from me

[Jim 2]

Mine is on 75k and have started to notice a noise that I suspect could be the same. I'm so worried about it. I do not know how to describe the sound (mechanically I'm a complete beginner, at best), except it sounds like it's not operating smoothly (as when warm) almost rough and rattle. I noticed it is there at idle, but fairly quiet, it seems to get more pronounced from maybe 20 - 30 on the rpm gauge. To be honest I thought it might be something to do with oil, maybe it wasn't getting pumped round as easily as the oil was cold, once it gets to about 55 it seems ok though. I always check my oil every couple of days and try and keep in the top half of the dip stick marking. Could it be from putting too much in, I'm sure I read in the manual that is bad for something and I accidently did that just before I started to notice it.

It is quite smokey when cold, but not really at all when warm.

I know your paranoia well, I am almost scared to drive her, I am worried I am just making things worse just using it but have no other choice.

 

 

What is this piston slap you talk of, sounds ominous!!!

What are tappers?

 

Best if you could record a video and stick it on youtube perhaps? Might help us identify what noises you're suffering from. Generally though if the noise starts to go once the oil is warming up to the 50 degree mark and it only does it from cold, then it's probably piston slap.

 

I've repeatedly been told that it's nothing to worry about on the VR - just make sure you drive the car respectfully until properly warm and you can manage with the 'problem' for years and years without any concerns.

 

It does just seem a fundamental design flaw of the VR6 engine unfortunately. I've heard plenty of meticulously maintained VR6's all sound the same way when cold.

[dr_mat 0]

VRs are known for piston slap when old. It's generally nothing to worry about and it goes away when you rev it (because the inertia of the moving piston prevents it slopping about in the bore) and obviously when warm (because, basically, the engine doesn't fit together until it's warm ...).

 

As per Jim's comment, it's something I've been hearing on every VR, ever, and has been mentioned hundreds of times on the forum over the years.

[MoonlightVR6 10]

Hi all,

 

Thanks for reply.

I actually noticed I had made a slight error, it only seems to do this really between 15 and 20 on the rev gauge, after that you can still hear it but it seems to quieten down a bit.

I will try and get a video of it, would it be better from inside the cabin or with the bonnet open looking at the engine? I will try and record 2 videos (of each).

 

Im glad that it should be 'live'able', howver, It does bother me a lot and I feel worried that its goign to get worse and worse and then have a hefty bill to accompany it.

 

Can it be fixed, assuming it is the piston slap? I don't remember it doing it when i got it, at all... Which I think makes me worry about it even more.

[MoonlightVR6 10]

Hi all,

 

Thanks for reply.

I actually noticed I had made a slight error, it only seems to do this really between 15 and 20 on the rev gauge, after that you can still hear it but it seems to quieten down a bit.

I will try and get a video of it, would it be better from inside the cabin or with the bonnet open looking at the engine? I will try and record 2 videos (of each).

 

The other thing I have noticed over the weekend is, that it seems louder when your in gear pulling away and the revs are betweens 15 & 20, than if uyou are in neutral and you just rev it upto 20, it is there on both but when its in gear actually pulling it seems louder.

 

Im glad that it should be 'live'able', howver, It does bother me a lot and I feel worried that its goign to get worse and worse and then have a hefty bill to accompany it.

 

Can it be fixed, assuming it is the piston slap? I don't remember it doing it when i got it, at all... Which I think makes me worry about it even more.

[Jim 2]

Increase in engine load rather than just revs does seem to increase the volume of the noise so that would, again, point to piston slap. I don't know why this is. This is a video of my car piston slapping away - not sure how it compares to your noises?

 

 

You can hear the volume / tone of the noise increase as I hold the handbrake on but then release the clutch to the biting point forcing the engine under some load.

 

If it's piston slap, that basically means the only way to fix it is to have the bottom end rebuilt - rebored block, and new / slightly oversized pistons.

 

As I say, whilst it's an irritation, it's not really a problem and is extremely common in the VR6. Engines exhibiting this problem will go on to do many more tens of thousands of miles without issue.

 

You may find you can reduce the problem somewhat with a thicker weight oil, such as the Silkolene / Fuchs Pro Race S 10w50 that a lot of people swear by on here. It does help quieten the engine down from cold quite substantially.

[Kevin Bacon 5]

What is this piston slap you talk of, sounds ominous!!!

 

It's when a cold piston is audibly loose in it's bore until warmed up. It's a lot more noticeable this time of year. The cold metals take time to expand. A rebuilt engine isn't necessarily a guaranteed fix either as it depends on the boring tolerances and quality of pistons used.

[MoonlightVR6 10]

Hi All,

 

Thanks for the replies.

 

I cant really hear the video at the moment as my work PC speakers are rubbish. I will deffo have a listen tonight with headphones and then upload a couple of mine to compare to yours.

 

I will also deffo try a thicker oil, hopefully it numbs the sound a little which will make me happier, a bit.

Would one of those oil treatment additives do any good, there is one which apparantly coats the metal surfaces of the engine with a plasic/oil layer (or along those lines) could this help?

 

What should I be on the lookout for, as an indication of it getting worse, louder?

Worst case scenario, what would happen if it completely broke down because of this?

 

What causes this exactly?

I had my head gasket done about 8 months ago and I am sure it started doing this after this. I don't think it did this before, even when it was loosing water... Could having this fixed have damaged the engine somehow?

[dr_mat 0]

Seriously, don't worry about it. It's completely normal and in extreme cold even brand new engines will do this. Just take care of it when it's running this cold and it's going to be fine. Owning a VR Corrado has plenty of other things for you to worry about..

[Jim 2]

Subject to confirmation that it is just piston slap and nothing more sinister, I agree with dr_mat - it's annoying, but just forget about it. I was reading old news group posts from 1997 for folks that had JUST bought their new VR6 engined VW, and after a few thousand miles was already doing it! It's just the way they are.

[g0ldf1ng3r 15]

Subject to confirmation that it is just piston slap and nothing more sinister, I agree with dr_mat - it's annoying, but just forget about it. I was reading old news group posts from 1997 for folks that had JUST bought their new VR6 engined VW, and after a few thousand miles was already doing it! It's just the way they are.

 

interesting Jim

 

any linkys for us to see pls?

[Jim 2]

Here:

 

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0ahUKEwiSldeOyLPKAhWF9x4KHQKHCw4QFghAMAM&url=https%3A%2F%2Fgroups.google.com%2Fd%2Ftopic%2Frec.autos.makers.vw.watercooled%2F3mNCnivYCbY&usg=AFQjCNFUSrFf-TZCZbZ41RsXO9zZZxeZ5w&sig2=oK9EA9T_eOAmblDRVa_-sA&bvm=bv.112064104,d.bGg

[MoonlightVR6 10]

Hi All,

 

Sorry for the delayed reply, took a bit of messing about to get the videos uploaded.

I have attached one from both inside and outside the cabin. The last 2-3 days (since they have been milder with less frost) has seemed to proove better on the old girl as the noise seems to be quieter, but it is still there. Not been able to swap the oil out yet, but get paid this friday so will do it over the weekend.

 

What oil would you recommend for said piston slapping. 5w/40 or 10w/50? or fully synthetic 10w/40?

When watching the videos back I cant seem to hear it very much but hopefully one of you will be able to notice the issue. Failing that I can try and get another clip of it on a colder morning when it becomes much more noticeable.

 

 

[dr_mat 0]

[ grr fecking Youtube autoplay ]

 

Hmm. Difficult to tell but that doesn't sound like what I think of as piston slap. That sounds much more like a constant metal-on-metal noise than a slap and doesn't seem to go away, only changing tone when the engine revs. Piston slap sounds like a short heavy clunk once/twice per RPM (heavily muted by the engine block obviously). I don't hear that in your video at all.

[Jim 2]

Gotta say it does sound a bit slappy to my ears. Not dissimilar to the sort of noise mine was making when cold. Always hard to tell on videos as phone microphones never seem to pick up the noise properly, and saying it's not as bad when it's been a bit milder in the last few days sort of backs that up.

 

The interior video seems to reaffirm that to me.

[dr_mat 0]

Ok. My speakers in the office made it sound pretty muddy and graunchy tbh, and I wasn't really able to pick out any slap amongst the general sound of a VR6 not quite fitting together yet because it's cold... Need a high quality mic to carry the way it really sounds and yeah as Jim says phone mics are pretty awful.

It's certainly true that it's at its worst in extreme cold.

[Jim 2]

It sounded very different coming out of my TV than it does on my studio grade headphones in the office!

[GlosterOx 0]

What oil would you recommend for said piston slapping. 5w/40 or 10w/50? or fully synthetic 10w/40?

 

I use Fuchs Titan 10w/50 fully synthetic in my high mileage engine, comes highly recommended.

 

Ian.

[MoonlightVR6 10]

[ grr fecking Youtube autoplay ]

 

Hmm. Difficult to tell but that doesn't sound like what I think of as piston slap. That sounds much more like a constant metal-on-metal noise than a slap and doesn't seem to go away, only changing tone when the engine revs. Piston slap sounds like a short heavy clunk once/twice per RPM (heavily muted by the engine block obviously). I don't hear that in your video at all.

 

I would say it is more of a constant noise, rather than a frequent tapping sort of noise.

The best I can describe it is it sounds rough (not smooth like when upto temp), sort of loose, and kind of diesel'y all at the same time. It is present at idle but gets more pronounced from 15-20ish on the RPM gauge, cant say if it is present higher up the rev range as I have been driving it carefully, I am sure it quietens down after 20' rpm. although it could well be just drowned out by the engine speed/noise

 

If you have ever been gokarting at thruxton, it sounds very much like their gokarts haha, chuffy and rough if that makes sense. In this I mean that when I had a problem with the exhaust gasket blowing some time ago, it sounded sort of chuffy (kind of repetitive like a steam train, but rough at the same time, almost lawn mowery/diesely) but I could only really hear that when driving past parked cars. This is similar I suppose, but only when its cold, but more rough/ diesely than chuffy... Wow its hard to describe, and it is driving me insane!

 

What do you think it may be? Metal on metal doesn't sound good!

[MoonlightVR6 10]

It sounded very different coming out of my TV than it does on my studio grade headphones in the office!

 

would you think this is piston slap?

I can try and get some more videos but I do not know how to get the audio better quality as I do not have a good mic.

In the exterior video, I noticed it sounded different as I moved round the car, should I try from all 3 sides, front , left and right wings?

[MoonlightVR6 10]

I use Fuchs Titan 10w/50 fully synthetic in my high mileage engine, comes highly recommended.

 

Ian.

 

Does this mean that at higher temps its a little more viscous (thinner)? So does this mean its thinner at cold temps too, so it can be pumped around quicker and easier?