Engine noise when cold

[Jim 1]

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?

 

Any idea if the tappets have ever been changed either?

[GlosterOx 0]

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?

 

The recommended is 10W/40 so I would say that the 50 means it is slightly thicker and less viscous - Happy to be proved wrong though?

 

Ian.

[MoonlightVR6 10]

HI Jim,

 

Not too sure if the tappets were changed. The head gasket was taken replaced a few 1000 miles back, and I ASSUME that they did that as you have to take the cams etc off before you skim the block face (right)? When I saw it the head had just been skimmed and was just the aluminium head itself, not other parts attached? I can find out for sure but not sure 100% right now.

 

I do recall my mechanic saying that it was a pitty this had to be done as the inside of the head looked really good, his words.

So could have just put back in what was already there.

 

I will find out and update.

[Jim 1]

Has it made the noise since the replacement of the headgasket or was it since before that, or has just steadily developed over time? I'd be surprised if anything beyond specifically what was needed to be replaced as part of the job, was actually replaced. Tappets alone would add another £100 to the bill. Of course if they did change the tappets, they could have rebuilt with cheaper tappets, and anything other than INA branded tappets can be a bit of a lottery in terms of when they start getting rattly again.

 

Like you say, the head should have been completely stripped prior to being skimmed.

[dr_mat 0]

As for oil densities.. it's a balance. With an engine with very tight tolerances between all mating surfaces you want an oil that's sufficiently thin it'll squeeze in there (particularly when cold!). That's why all modern engines tend to come with ultra-light 5w30 oils. Old engines with between components, particularly when cold, don't need a thin oil to get it in there. In fact the thicker the better, as it provides better protection as it forms a thicker surface layer and hopefully plugs those gaps and keeps them plugged. In an ideal world the oil's density profile will thin steadily as the temperature increases and will follow the expansion profile of the metal used in the block/pistons/bearings.

In other words.. generally you don't want to go too thin on these engines, it'll just get noisier, though performance will improve a little.

[dr_mat 0]

The recommended is 10W/40 so I would say that the 50 means it is slightly thicker and less viscous - Happy to be proved wrong though?

 

Yes but bigger number == thicker and more viscous not less.

 

Don't think there's much in it between a 10w40 and a 10w50 though tbh.

[MoonlightVR6 10]

Has it made the noise since the replacement of the headgasket or was it since before that, or has just steadily developed over time? I'd be surprised if anything beyond specifically what was needed to be replaced as part of the job, was actually replaced. Tappets alone would add another £100 to the bill. Of course if they did change the tappets, they could have rebuilt with cheaper tappets, and anything other than INA branded tappets can be a bit of a lottery in terms of when they start getting rattly again.

 

Like you say, the head should have been completely stripped prior to being skimmed.

 

Hi Jim,

 

Yes it has, before (the H.G) it was drinking water like a whale haha! But, it still sounded sweet even from an ice cold start.

When I got it back they had not attached the exhaust manifold properly and it was blowing slightly. They have since tightened this up/filled the gap and that noise is no longer present. The time gap from having the head done to getting this fixed was about a month and I only really noticed (the suspected piston slap thing) after they tightened the manifold up (maybe it was there but I was more focused/paranoid on the exhaust blowing which over powered me noticing it - maybe because it (piston.S) goes after it has heated up... Idk) I have been real carefull with her since the gasket went as that cost a bloody fortune! I did over fill it with oil after getting it back from the manifold issue, I dunno if or how much that could have damaged her.

 

How much of a chore is replacing the tappets, is that a head & chains off jobbie?

[Jim 1]

It's not too much of a horror job to be honest. Stealth I think charge four hours labour at approx £60/hr plus the tappets themselves - you're looking at around £300.

 

For someone comfortable with the spanners it can be done in a half day easily but it is pretty involved and daunting.

[MoonlightVR6 10]

Do the tappets go quiet once the engine is upto temp, or are they always noisy if they are 'old and buggered'?

 

I'm rubbish with a spanner but would like to try it if I can manage it with minimal knowledge. Do I need any special tools to get to them? How do I know if they are to be replaced?

£300 isn't as much as I'd have thought it would cost to fix them, it is a lot sure, but easier to swallow than the bloody H.G!

 

Regarding oil, would it be better to try and get the thickest engine oil i can find? Would the thicker oil help prevent anything getting much worse down the line?

[Jim 1]

I really think it'd be worth taking it in for the opinion of a specialist like Stealth. They can have a listen to the noises and see if they think it's normal, or whether it's worth investigating further and / or taking any corrective action.

[GlosterOx 0]

Yes but bigger number == thicker and more viscous not less.

 

Don't think there's much in it between a 10w40 and a 10w50 though tbh.

 

What about the Mobil 1 Extended Life 10W/60, is that too viscous and has anybody tried it?

 

Ian.

[seanl82 23]

I think a few of the Turbo folk use 10w/60. I wouldn't just go trying to get the thickest oil you can find though, 10w/40 as standard was meant for a reason, so going too far off that is asking for trouble imo. Not sure if its been mentioned further back in this thread, but leaking exhaust gasses from the manifold can cause a noise very similar to the tappets. If they've just chucked a load of gasket sealer on the join where it was leaking previously, they may have only partially sorted it. Get a socket extension and put on your ear, and the other end around the engine. You'll be able to get a rough idea of where the noise is actually coming from. Also get a bit of bog roll and pull it in half so you only have a single ply piece. Get it in a garage with the door closed so theres no wind, and from cold so you don't burn your hand accidentally, put it next to the manifold in various places, especially where they've "repaired" it before. You'll see it blowing slightly if there are any leaks mate.

[dr_mat 0]

Thing that bothers me here is that the noise started when the manifold was bolted up to the back of the head. Taking the head off to do the gasket you don't need to take the cams out at all so there's no reason tappets might have got messed up in that process. However if the new gasket blocks or partially blocks an oilway somewhere you might well have issues coming up that weren't there before.

Who did the gasket and where did the replacement come from?

[dr_mat 0]

What about the Mobil 1 Extended Life 10W/60, is that too viscous and has anybody tried it?

 

Ian.

Won't make any difference on a cold start (still 10W) but will be noticeably thicker when hot.

 

I've not tried it, I just put up with the "natural" sound of a VR6..

[MoonlightVR6 10]

Hi All,

 

Cant get through to my mechanic yet for confirmation, I think he is on holiday though.

 

When I went over to partially pay, the head had just come back and had been skimmed, it was gleaming. The cams etc were not in it 100%, it was just the aluminium shell...

I thought they had to take all the valves, cams etc out before they skim the engine block face of the head (or do the valves sit slightly de-bossed to the head's block/bottom face? -otherwise wouldn't the skimmer just hit the valves aswell?). They deffo took it all out though.

 

With regards to the exhaust manifold. When I initially got the car back it sounded fooked! There was a month before this was tightened up and 'fixed'. I cant say for sure that the (suspected) piston slap thing came after, as it may well have been exhibiting this when the manifold was blowing, but the blowing was obviously over-powering the slapping (sound), I only noticed the slapping thing after the exhaust had been made quieter. The suspected slapping was 100% not there before they touched the head though.

They used the same exhaust gasket, I can see some white filler between the head and manifold and it doesn't look new... Would you reccommend I try and replace this with a new gasket, however, could this even make a difference? Could the engine getting hot and expanding slightly seal this off (making it sound right)which is what I maybe thinking the slapping is? If it isn't the poorly fitting gasket making the slapping noise, I'm happy to leave the exhaust gasket as is.

I just want to fix this awefull noise primarily, all the other little things can wait.

 

Not sure on the head gasket used, I think its an pinkish/red rubber looking material, pretty sure its not the copper one. Will have to confirm though.

 

 

IDK, I would like to take it to stealth but its a proper mission from me and besides, it will be v.hot by the time I get there (over 100 miles away) so the matey wont even be able to hear the cold start noise... Anyone know any Corrado specialists in or around n.w london?

[MoonlightVR6 10]

Hi All,

 

Cant get through to my mechanic yet for confirmation, I think he is on holiday though.

 

When I went over to partially pay, the head had just come back and had been skimmed, it was gleaming. The cams etc were not in it 100%, it was just the aluminium shell...

I thought they had to take all the valves, cams etc out before they skim the engine block face of the head (or do the valves sit slightly de-bossed to the head's block/bottom face? -otherwise wouldn't the skimmer just hit the valves aswell?). They deffo took it all out though.

 

With regards to the exhaust manifold. When I initially got the car back it sounded fooked! There was a month before this was tightened up and 'fixed'. I cant say for sure that the (suspected) piston slap thing came after, as it may well have been exhibiting this when the manifold was blowing, but the blowing was obviously over-powering the slapping (sound), I only noticed the slapping thing after the exhaust had been made quieter. The suspected slapping was 100% not there before they touched the head though.

They used the same exhaust gasket, I can see some white filler between the head and manifold and it doesn't look new... Would you reccommend I try and replace this with a new gasket, however, could this even make a difference? Could the engine getting hot and expanding slightly seal this off (making it sound right)which is what I maybe thinking the slapping is? If it isn't the poorly fitting gasket making the slapping noise, I'm happy to leave the exhaust gasket as is.

I just want to fix this awefull noise primarily, all the other little things can wait.

 

Not sure on the head gasket used, I think its an pinkish/red rubber looking material, pretty sure its not the copper one. Will have to confirm though.

 

 

IDK, I would like to take it to stealth but its a proper mission from me and besides, it will be v.hot by the time I get there (over 100 miles away) so the matey wont even be able to hear the cold start noise... Anyone know any Corrado specialists in or around n.w london?

[Kevin Bacon 5]

It could be the manifold still. Either a slight leak (on one cylinder), or a crack. As mentioned previously, a slight leak can sound very similar to tappet noise. Piston slap definitely goes when it's warmed up. If this noise is constant, I'd get the manifolds / gaskets rechecked.

[dr_mat 0]

On further thought, yes I agree with Baconator. It'll sound really really bad if there's a bit of a leak around the exhaust manifold and that hole MIGHT close up as the engine warms.

[MoonlightVR6 10]

Yes, it did, it sounded terrible! It sounded like the go carts at thruxton (if anyone has been there).

I am hoping the it's an exhaust thing, but I have a feeling it's not. I had a look but since the heat shield thing is in the way I could only see one corner. The manifold itself looks pretty worse for wear (rusted) , I wouldn't be surprised if it is cracked. But then it does sound different to the blowing manifold...[ATTACH=CONFIG]83081[/ATTACH] a weird question, is something meant to screw into the bolt looking port next to the spark plug? Looks like something should be...

 

Get paid tomorrow so will change the oil and filter first. I think I understand, but can you confirm? The first number and w, is how free flowing it is when it's cold, is 5w, 10w or 15w better for a piston slapping?

If the second number is the same viscous value but for when it's hot. Would I be right in assuming the 40 (as she has 10w40 halfords in her at the moment) should stay the same as the sound goes away when above 50 ish degrees?

If that doesn't work I think I will have to contact stealth and see if they can schedule an appointment somehow, I'll haven't drive up and stay over night and stay in a b&b but will be worth it just for the closure.

 

This noise is a nightmare! Does anyone else have a video of a piston slapping, to sort of cross reference? Was your video definitely a piston slap Jim?

[dr_mat 0]

Yes the first number is the cold viscosity, but you won't cure piston slap with oil. The only way to cure that is to never start the engine from cold..

 

The exhaust is often quite rusty (it gets very very hot..), but this doesn't mean it's more likely to be cracked. The fact it's been on and off a couple of times and tightened up after-the-fact does though.