Topic: Tapping sound when cold (Read 4039 times)

Salty · « **on:** 07 September 2006, 21:04:26 »

Ok looking for a few opinions here. I have a tapping sound when the engine is cold, sounds like a badly adjusted tappet but as the revs increase it sounds more like a leak from the exhaust quite close to the engine. The thing that is confusing my thoughts on the issue are that it sounds louder inside the car than with my head under the bonnet. I'm sure it sounds worse under load as well, but goes away when the engine has warmed up a little. Further to all of this after the car has stood for ten to twenty minutes after a long run the sound returns on restarting and takes a couple of minutes to go away again.
I've checked under the car and can't see any obvious holes around the front end of the exhaust system, but the down pipes have a sort of double skin to them which is loose so i can't see if there are any holes here.
anybody any ideas? btw its a 3 litre v6

STMO123 · « **Reply #1 on:** 07 September 2006, 21:08:37 »

From what I've read previously it sounds like the dreaded manifold gasket,Salty

Salty · « **Reply #2 on:** 07 September 2006, 21:12:04 »

I was thinking that way myself, but it may be the easy side to do.

STMO123 · « **Reply #3 on:** 07 September 2006, 21:12:57 »

There's an EASY side?

Salty · « **Reply #4 on:** 07 September 2006, 21:14:47 »

Well maybe not, looking at it I think the drivers side may be easiest.

STMO123 · « **Reply #5 on:** 07 September 2006, 21:19:17 »

I have this theory about omegas:

Things go wrong, manifold gaskets, knock sensors, power sounders etc, but they dont STOP. they just keep going. So, ignore it

Martin_1962 · « **Reply #6 on:** 07 September 2006, 22:02:48 »

Definately gasket

Salty · « **Reply #7 on:** 08 September 2006, 06:47:44 »

well that's two votes for manifold gasket. does anybody know how difficult they are to change? Haynes book of lies suggests that the righthand/drivers side bank can be done in car, but that you need to remove engine/cylinder head to drivers side bank?

Salty · « **Reply #8 on:** 08 September 2006, 06:48:35 »

or any other suggestions as to cause of noise?

johnny.dee · « **Reply #9 on:** 08 September 2006, 11:33:02 »

do not the omegas have hydraulic tappets, it might be the oil drying overnight and when started sounds tappetty untill warm. could be your oil. this problem is overcome by using fully synthetic oil.
just another alternative thought, as it used to happen in my sports car until it was recomended I change to synthetic, tappy moise then stopped.

Salty · « **Reply #10 on:** 08 September 2006, 19:57:48 »

Quote

do not the omegas have hydraulic tappets, it might be the oil drying overnight and when started sounds tappetty untill warm. could be your oil. this problem is overcome by using fully synthetic oil.
just another alternative thought, as it used to happen in my sports car until it was recomended I change to synthetic, tappy moise then stopped.

It's a thought, currently using the GM semi-synth which was changed the other week. The noise comes back when the car has been stopped for 20 mins or so and restarted so everything is still warm at that stage but not up to running temperatures.

EddieX · « **Reply #11 on:** 08 September 2006, 20:35:33 »

Yes it could be a tappet draining down. On my last car, the hotter the engine was before parking, the louder the tappet noise the next morning. Which points to thin, hot oil draining from the hydraulic tappets. A change to the thicker 'racing' version of Mobil 1 helped.

Eddie.

Salty · « **Reply #12 on:** 09 September 2006, 15:59:49 »

If it were a tappet would it not go away as soon as normal oil pressure was achieved? Or does the oil struggle to get to the tappets?

nigsey1600e · « **Reply #13 on:** 09 September 2006, 17:37:16 »

I am sure i have read somewhere that knackerd EGR valves can make tapping noise when cold so for a easy check/fix try unpluging the connector on that whilst running when cold hope this helps :-/

Salty · « **Reply #14 on:** 09 September 2006, 19:45:53 »

Quote

I am sure i have read somewhere that knackerd EGR valves can make tapping noise when cold so for a easy check/fix try unpluging the connector on that whilst running when cold hope this helps :-/

Thanks, definitely worth a try and cheap

EddieX · « **Reply #15 on:** 10 September 2006, 00:07:04 »

Quote

If it were a tappet would it not go away as soon as normal oil pressure was achieved? Or does the oil struggle to get to the tappets?

It depends on how bad things are. On my last car they were very very bad.

JasonH · « **Reply #16 on:** 10 September 2006, 09:52:45 »

Try a long screwdriver on the rocker cover bolts. Put the handle against your ear and the tip of the screw driver on the cam cover bolts. You'll be able to hear each tappet.

You'll know if you have a bad tappet(s). Good ones don't make much noise, bad ones are loud when you do this.

Salty · « **Reply #17 on:** 10 September 2006, 11:19:24 »

Quote

Try a long screwdriver on the rocker cover bolts. Put the handle against your ear and the tip of the screw driver on the cam cover bolts. You'll be able to hear each tappet.

You'll know if you have a bad tappet(s). Good ones don't make much noise, bad ones are loud when you do this.

i have tried this, the tappets for no 1 cylinder sound marginally louder than the rest so I'm not sure if it's tappets. The tapping sound is not really noticeable at tick over but when you set off and the engine is under loud it is quite loud.

sounds2k · « **Reply #18 on:** 10 September 2006, 12:59:24 »

my old miggy - a 1999 2.5 V6 - had exactly the same problem when I bought it, sounded a bit like it was blowing - but only from cold or after the engine had cooled down. It only ever lasted for a couple of minutes, so I ignored it for the 6 months that I kept it ... and I don't think it got any worse during that time. My current one (a 2000 3.0 V6) is fine so far

JasonH · « **Reply #19 on:** 10 September 2006, 15:24:37 »

I don't think it's your tappets then. Mine aren't noisy when you listen to the engine from the engine bay, but listen to them individually some are really loud and some are almost silent.

Salty · « **Reply #20 on:** 10 September 2006, 17:35:01 »

I really hope its the EGR, i don't really fancy manifold gaskets.

Taxi_Driver · « **Reply #21 on:** 10 September 2006, 19:03:05 »

Manifold leaks are usually a ticking noise when cold....is it a tick or more a tap....if you see what i mean.

My only advice is really is if you do go for changing manifold gasket....is soak the manifold studs in penetrating oil the evening before you do the job....you dont want to go snapping a stud off....that will be bad

Salty · « **Reply #22 on:** 10 September 2006, 20:03:30 »

Quote

Manifold leaks are usually a ticking noise when cold....is it a tick or more a tap....if you see what i mean.

My only advice is really is if you do go for changing manifold gasket....is soak the manifold studs in penetrating oil the evening before you do the job....you dont want to go snapping a stud off....that will be bad

Ok a loud tick?? if I'm going to change the gasket i might try some that freeze type release stuff, can't remember what its called now i saw it on a thread somewhere??

a written thread not a bolt type thread

Salty · « **Reply #23 on:** 20 September 2006, 14:14:47 »

Tried unplugging the EGR didn't seem to make any difference, so looks like the manifold gasket

SHARPEY · « **Reply #24 on:** 21 September 2006, 21:53:14 »

Just a thought and I could be completely off the mark. I've had 2 previous Omega's and both of them had snapped exhaust stud/studs (which I was told was a common fault) which caused an eratic tapping sound.

jonny2112 · « **Reply #25 on:** 21 September 2006, 21:57:34 »

Sharpey, I take it this was somewhere about the manifold/downpipe area?

SHARPEY · « **Reply #26 on:** 21 September 2006, 22:01:57 »

Yes indeed. I never did anything about it to be honest and one of the cars I sold, the guy was a mechanic and noticed it straight away but said it would be easy for him to fix....alright for some !!

STMO123 · « **Reply #27 on:** 21 September 2006, 22:45:39 »

Can I ask a daft question? What exactly does a leaky manifold gasket do to your car? Do you lose performance? Is it an MOT failure?

Sorry, thats three daft questions

wigan pier · « **Reply #28 on:** 22 September 2006, 04:14:25 »

My Rover exhaust manifold is leaking (needs a helicoil job) but it goes quieter as it heats up (expanding metal I assume) though I have been told it could fail the mot on emmisions?

JasonH · « **Reply #29 on:** 23 September 2006, 11:56:50 »

A leaking exhaust manifold could cause the car to use slightly more fuel (lower MPG) and fail the MoT emissions test.

It does depend on how bad the leak is whether you notice it though.

The reason for this is that although mostly exhaust escapes some fresh air gets sucked in. The lamdba sensors detect the extra oxygen and assume the mix must be too lean because not all the oxygen is being consumed. The car ECU richens up the mix to try to compensate.

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Author Topic: Tapping sound when cold (Read 4039 times)

STMO123

STMO123

STMO123

Martin_1962

Taxi_Driver

STMO123