Slight Tapping Noise when cold

kawasaki

Junior Member
Messages
66
I haven't had the car at a shop as yet to determine what and where the noise is coming from. The price breakdown is worse case scenario if the seafoam Im going to run through the engine tonight to loosen up any sludge & varnish in the valve train fails.
The suction is very strong when the oil cap is removed. The engine sounds as if it wants to shut off and stall.
The video above is to show the strength of the vacuum suction. The lifter tapping only happens between 2K to 3K RPM.
 

Oneball

Member
Messages
11,069
Forget the sea foam. The suction shouldn’t be very much and the engine shouldn’t get close to dying. The vacuum should only be enough to lightly suck down a plastic bag placed over the filler hole.

There should be a valve between the inlet and crankcase that limits the vacuum, it sounds like yours has failed so it’s just an open circuit.
 

kawasaki

Junior Member
Messages
66
Forget the sea foam. The suction shouldn’t be very much and the engine shouldn’t get close to dying. The vacuum should only be enough to lightly suck down a plastic bag placed over the filler hole.

There should be a valve between the inlet and crankcase that limits the vacuum, it sounds like yours has failed so it’s just an open circuit.


Oneball,You just might be right.
I noticed lots of oil build up around that black hose that connects to the intake & part #1 . I quickly cleaned it last weekend after the oil change. You can tell where I missed on the hose clamps. The suction is very strong I'm not going to attempt to show with paper or plastic due to the fact it will be sucked in.
Would it be possible for you to post a short video of how much suction the engine is supposed to sound like. With the oil fill cover removed should the engine Idle any different?

6227462275
 

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Oneball

Member
Messages
11,069
If there’s that much suction the PCV valve isn’t working. There’s a rubber diaphragm and spring inside that limits the pressure.

When working correctly and you take a filler cap off you can’t normally hear it sucking air in above the other engine noise.

When you take the cap off there will probably be a slight fluctuation in rpm then the Ecu will compensate and return to normal idle.

Not a Maser but this is about the level of suction I’d expect.

 

kawasaki

Junior Member
Messages
66
I did remove Oil Disareator and cleaned it. The Vacuum in the crankcase is still strong.
Take a look.
 

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Oneball

Member
Messages
11,069
Did you check the red rubber diaphragm for holes/tears? Is the diaphragm seating properly?

It’s that diaphragm and spring that is supposed to control the vacuum
 

Oneball

Member
Messages
11,069
What's the sticky out bit like that seals the hole in the centre of the spring?

This is from a BMW but the principle is the same, when the vacuum is strong enough to compress the spring the rubber doughnut in the middle seals the hole in the valve body. If the diaphragm has a hole in it or isn't seated correctly or the doughnut is broken it won't work properly and you get too much vacuum.

p3624638_900_900.jpg
 

kawasaki

Junior Member
Messages
66
I washed it with dish washing liquid. I ran my fingers all over and didn't see or feel any tears or holes. This part is as good as new.
I was reading on other post about the crankcase vacuum on maserati 4.7, it will seem it is common for such a strong vacuum it also helps prevent oil leaks.


62284
 

Oneball

Member
Messages
11,069
Was the bit in the middle that seals the hole ok?

I’m surprised yours is sucking as much air in as it is but like I said video sound can be deceptive.
 

kawasaki

Junior Member
Messages
66
I'm going to try the two 4oz bottles of ZDDP in the engine today, I'll post the results.



63636
 

philw696

Member
Messages
25,113
That's a very informative guide that Duckhams have done.
Keeping that in my browser.
Thanks for posting.
 

philw696

Member
Messages
25,113
Greta Thunberg isn't going to like it. Another interesting read.
 

kawasaki

Junior Member
Messages
66
Mechanics in a bottle ;)
Be interested if it works.



Installed One 4oz bottle of ZDDP to the engine. The Tapping Lifter noise between 2 to 3K RPM did reduce quite a lot.

I'm Converting to the 5W-30 Red Line engine oil in spring which has Ester, Zinc, Phosphorus, all the good stuff for an engine.