So what's the tick?

[Matt99man]

My 98 4.0 has a intermittent tick, it's fairly loud and speeds up and down with the engine as it turns over. Any ideas what could be causing it? I thought the manifold gasket but would that be intermittent? What else could it be?

[BarnFind]

Crack in either of the 4 into 1's

[Matt99man]

Would that not tick all the time though not intermittently ?

[PVN]

If the noise only appears when the engine is warmed up and never when cold it could, possibly, be bore liner movement where the liner moves with the piston and hits the head - hence the noise. Rare but not unheard of. Very common with Range Rover V8s for some reason.

[Dr Mike Oxgreen]

Can you estimate approximately how many times per second you're hearing the tick, and at what rpm?

This might help us determine whether it's once per revolution of the engine, or once for every alternate revolution - the latter indicating a valve train issue.

For example, if it sounds like it might be 7 or 8 ticks per second at idle rpm, that would be too slow for it to be every revolution of the engine but would be just right for a valve train issue (cam shaft turns at half the engine rpm). Obviously you can't count 8 ticks per second, but you can easily tap 4 per second with a pencil and then imagine what 8 would sound like and compare it with what your engine is doing. If the ticking is significantly faster than that, then it rules out a valve train issue.

[PRTVR]

Could be a problem with one of the valve lifters, its been reported on here that oil is not getting to some of the lifters in certain situations, what grade oil do you use? Mine was tapping but reduced a lot when I changed the grade of oil to something heavier, Valvoline VR1 20/50.

[s p a c e m a n]

Manifold/exhaust blow is normally more prominent when the engine is under load, it would have to be a big hole for you to hear standing next to it with the bonnet open. Get a stethoscope and see if you can narrow it down a bit?

[ChimpOnGas]

I had this tick.

Use a 15mm ring spanner just to take the tension off the belt, then slip the belt off the tensioner pulley only so you can spin it by hand to check the bearing.

Here's what mine was like with the belt removed:

http://www.youtube.com/watch?v=x8zj3TRGUmE

Actually this was my second tensioner with a failed bearing in four years, so rather than replace it yet again I replaced it with a JE alternator bracket.

Failure is very common, if 10 random Chimaera owners removed their serpentine belt to check their tensioner pulley bearing I'd put money on over half of them finding what I've demonstrated in my little YouTube clip.

When the bearing starts to fail the ticking noise starts, and it will only get worse, when it gets really bad like mine the pulley will actually momentarily lock up then free in a split second.

You can see this happening, watch the belt closely at idle and if yours is locking up you'll see pulley kick against the spring tension every few seconds.

But like I say the best way to check the bearing is to pop the belt off and spin the pulley to listen for noise, and to check the pulley for play on the bearing as I've demonstrated in my clip.

Let us know what you find.

[Mr Supercharged]

To check for exhaust leaks which can cause a tappet sounding "click" noise I did the following:

1) Block off one exhaust pipe with tape.
2) Disconnect the plenum butterfly hose and seal the plenum with tape
3) Make a solution of 80% fairy liquid / 20% water
4) Apply this solution to the exhaust manifold joints / welds and gaskets with a paint brush.
5) Using an air compressor / air gun fit the nozzle of the gun to the other exhaust pipe and seal around it with tape.
6) Squirt a small amount of air up the exhaust.
7) Use a torch to search for foaming bubbles where you applied the solution above, wherever there are bubble you have a leak site that needs attention.

Simples! :-)

[Matt99man]

I've had the exhaust manifold gaskets replaced but I still have this ticking, it's worse now if anything at low revs. Here's the sound:


http://youtu.be/3_4-SREjV-4

[carsy]

Ye thats definitely not exhaust manifolds. Difficult to say from the video but that sounds like a knock to me rather than a tick.

[Matt99man]

The gaskets needing replacing anyway, it's strange how the ticking/knocking is so much more prominent now they have been changed

[ChimpOnGas]

Honestly, it only takes two minutes to check that tensioner bearing.

Use a 15mm ring spanner just to take the tension off the belt, then slip the belt off the tensioner pulley only so you can spin it by hand to check the bearing.

Here's what mine was like with the belt removed:

http://www.youtube.com/watch?v=x8zj3TRGUmE

Try it.

[Matt99man]

ChimpOnGas said:

Honestly, it only takes two minutes to check that tensioner bearing.

Use a 15mm ring spanner just to take the tension off the belt, then slip the belt off the tensioner pulley only so you can spin it by hand to check the bearing.

Here's what mine was like with the belt removed:

http://www.youtube.com/watch?v=x8zj3TRGUmE

Try it.

Ok, will have a go of that in the morning. Would this still be that case with the noise only coming when the engine is fully warm?

[Matt99man]

Matt99man said:

I've had the exhaust manifold gaskets replaced but I still have this ticking, it's worse now if anything at low revs. Here's the sound:


http://youtu.be/3_4-SREjV-4

Anyone else familiar with a tick/knock like this when their 4.0 is warm?

[Dr Mike Oxgreen]

Matt99man said:

I've had the exhaust manifold gaskets replaced but I still have this ticking, it's worse now if anything at low revs. Here's the sound:


http://youtu.be/3_4-SREjV-4

As per my previous post, that sounds like about 6 or 7 ticks per second at idle, which is far too slow for it to be one tick per revolution of the engine, but is about right for a tick for every alternate revolution.

I would put money on that being related to the valve train.

[PRTVR]

For £9 it might be worth trying some of this, have no experience of it myself,

http://www.halfords.com/motoring/engine-oils-fluid...

Personally I would go for a oil change with an engine flush and see if things improve.

[Sardonicus]

That's cam related no question & sounds nothing like ex gaskets IMO early warning of cam wear with that amount of noise even a visual inspection form underneath with the sump removed will reveal all the frequency of tap relative to revs is just right for the above.

[BeastMaster]

Agreed with others, not exhaust related. It is difficult from sound only but my guess and worth a check is one or more rocker steel pad cracked and dropped off. The valve will rapidly drill into the exposed soft aluminium rocker, which the lifter will not be able to adjust as the gap gets larger.

[portzi]

Matt99man said:

I've had the exhaust manifold gaskets replaced but I still have this ticking, it's worse now if anything at low revs. Here's the sound:


http://youtu.be/3_4-SREjV-4

I pressume its the original cam? What mileage has your car done?