Start up rattle on 4200 - With sound

Andy4200

Andy4200

Member
Messages
143
Hi all,
I'm having a bit of an issue with a 'bag of spanners' rattle on start up. From cold it rattles loudly for about 5 to 6 seconds then fades away. It sometimes does it when warm as well. The car has good oil pressure, no other noises, drives fine and has no other warning lights.
I've tried to do some research on here and the other forum before posting.
So far:
  1. Checked variator solenoid electrical plugs. Oily so cleaned up and reconnected with electrical grease.
  2. Noise seems to come from front of both cam covers.
  3. Changed the small one way valve at the back of the right hand cylinder head - no change.

I'm wondering if the accumulator has failed. It seems this should provide oil pressure to the variators on start up. A new one is currently £700!!! I've contacted the manufacturer, Hydac, today to see if there is any alternatives. Will keep you posted.

Does anyone have any further thoughts??

Thanks
Andy.
 
FIFTY

FIFTY

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3,100
Where does the sound come from?

I had this for a while (strange rattle on cold start) and it turned out to be the Torque Tube
 
Andy4200

Andy4200

Member
Messages
143
It's definitely top end of the engine.
It sounds like a load of hydraulic lifters have no oil and need the oil pressure to come up to pump them up.
The sound fades out, rather than an abrupt stopping of the noise.
I'll try and record the sound over the next day or 2.
 
Ewan

Ewan

Member
Messages
6,812
There’s nothing new about a rattle on start up on the Maserati 4.2 V8 engine of 2003-2009 (approx). The better news is that it’s no big deal.
 
CatmanV2

CatmanV2

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48,789
Ewan said:
There’s nothing new about a rattle on start up on the Maserati 4.2 V8 engine of 2003-2009 (approx). The better news is that it’s no big deal.
Click to expand...

As the man says. As long as it's not really loud. A recording might help.

C
 
Andy4200

Andy4200

Member
Messages
143
Yes, that's the issue. I've found evidence on the forums that some sound is normal. I cant imagine this is though. It really makes you cringe when you hear it.
As you say, a recording would help.
 
Andy4200

Andy4200

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Messages
143
It happens on cold start and sometimes warm. To be honest I haven't driven the car enough yet (due to other issues) to recognise a pattern.
 
Geo

Geo

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Messages
616
FIFTY said:
Where does the sound come from?

I had this for a while (strange rattle on cold start) and it turned out to be the Torque Tube
Click to expand...

What exactly was causing the rattle, and what what was required to fix it?
 
Andy4200

Andy4200

Member
Messages
143
Hmmm, I had seen some posts about the manifold rattle but I kind of discounted it as the noise goes in about 5 seconds and the manifolds probably won't heat up that quickly.
Thanks for the suggestion though.
I'm hopefully going to record the noise later when I get home from work. Something to look forward to!
 
philw696

philw696

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25,455
You will certainly get a rattle on start up if the oil pump shaft splines have rusted away but as she runs fine after start up I don't think this will be your issue.
 
conaero

conaero

Forum Owner
Messages
34,631
No return valve in the rear of the cylinder head is where I would start.

If failed, the oil seeps away and basically you get a dry head startup till pressure builds.

It’s cheap and easy to do.
 
hashluck

hashluck

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1,523
conaero said:
No return valve in the rear of the cylinder head is where I would start.

If failed, the oil seeps away and basically you get a dry head startup till pressure builds.

It’s cheap and easy to do.
Click to expand...

OP says already changed

"Changed the small one way valve at the back of the right hand cylinder head - no change."
 
T

TimR

Member
Messages
2,731
Pull the fuel pump relay before you next start the car...crank it over for 10-15 secs, stop, repeat and watch oil pressure rise on the dash indicator...Once higher than off the floor ( it'll go all of a sudden to 2-4 bar)...replace the the relay and start as normal...If its quiet, its an oil-in-top end thing..
That gets the diagnosis sorted for a start off....
The accumulator doesnt provide oil pressure on cold so much as maintain a balance in pressure and oil feed when the variators are actuated...The solenoids open and the nitrogen oil bag pushes against the deficit in oil as this happens..Pressures are usually high, flow at the top end of available..there is a dedicated oil pump that works the oil to the top end I understand..Least thats been the understanding I have arrived at on these lumps..
The good news referenced is the fact that its not your valve train clattering. Rather, the variator has evacuated it's oil. If your solenoids' connection blocks are oily, its bleeding back, tracking the wiring because the seals ( in the solenoid valves) are blown...APPARENTLY. I say apparently because this in not proven in my mind...but mine rattles on one side; it happens to be the side that the solenoid leaks..
You can try swapping the solenoids (its cheaper) The variators are rattling and this will lead to wear- it has to. Eventually they wont rotate to alter cam position...I guess you know youre screwed at this point !!?!
In an ideal world, the variators, solenoids and oil bag would all want replaced....
I complained about it to McGrath. They shrugged and said 'we've heard worse...Its normal"...Part of me feels they arent interested in roling up their sleeves to do it...but I will concede they know way more than me and have constant exposure to these cars and their issues...
edit; The other thing to note IMO is the fact that you dont use the car a great deal...If you ran it evevryday as a daily driver, I reckon you'll notice that it doesnt happen nearly as often...I pull my relay as i use it only once a week as a rule...but leaving a warm engine in the sun to bake under the bonnet- thin oil can dissipate rather quickly and you can notice it after on a few hours sometimes too....!
Essay over.. Pull you r fuel relay and see if it happens with cold 9thick) oil after you work up pressure. I bet its quiet like a mouse !!
 
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Andy4200

Andy4200

Member
Messages
143
Thanks for your essay, very helpful. It was a thread you posted on that I got a fair bit of my info from.
I like the idea of cranking to bring up oil pressure first.
It's going to take a couple of days to try all these ideas. Tonight I want to do a cold start to record the noise. Then when cold tomorrow I'll try the cranking before starting.

There seems to be a fair bit of confusion how the system works. Some seem to say leaking connection blocks isn't a problem as long as the pins can make an electrical connection. Who knows.
Thanks again.
 
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