Hi, I recently get a ticking noise about 30 seconds after a cold start of the engine which resembles the knocking noise of an old diesel engine although not as loud. Most of time it's tick-tick-tick with about o.2s pause in between the ticks and then again after 5s or so tick-tick-tick again . After that everything is normal.I'll try to link a (bad quality) sound file I've recorded. The file gives a wrong impression about the volume of the ticks though. It's not as loud as it seems.The whole thing lasts about 30s.
The car is a 99 C4 with 78300km on the clock. I already had my 80000km inspection done 2 weeks ago with oil change from Mobil1 0W-40 to 5W-50 done by myself last week. I only noticed the noise after I had already done the oil change. Should have noticed the sound if it would have been there earlier because I usually drive the car out the garage and then walk around it to load my luggage on the rear seats setting off to work. If have no idea though why the oil change or the inspection should be a cause.(Oil level is fine)
Any thoughts?
Thorsten
Click to download soundfile

 

Toddel,
I first noticed ticks, similar to yours when my oil was changed from 40 to 50 wgt (indy insisted 50 was best for TX heat). My guess is that is your root cause too. I am sure an oil debate will commence. I am tempted to go back to 40wgt especially with the falling temps.
IMHO of course,
RB

 

I have a '99 C4 and went to 5w-50 for the summer as a result of the oil debates on this forum. I noticed noise when I started the car in the morning as well. I recently switched back to 0w-40 for the winter and the startup ticking went away. I thought it was all my imagination, but maybe not.

edit: I just listened to the sound file. That does sound harsh, even keeping in mind that you said the ticking was magnified. I think mine went away after 5-10 seconds.

 

Have you attempted to locate where the noise is coming from by looking at the engine when it is making noise? Did YOU change the oil. What weight? What is your oil pressure at idle, cold? After driving the car to full temperature and shutting it down, will it make the same noise if you start it in 3 - 4 hours?

Sounds awful harsh for a valve unless one is either bone dry or broken.

 

I did the oil change myself, so it's definitely Mobil 5W-50. Oil pressure is almost full up on the scale when cold and drops to mid range when hot. Noticed no change there. Outside temp has been around 8 C (46 F) during the last days.
So far I could not hear any noise when the car was parked for a period like 3-4 hours but I've done that only two times since then. Hard to imagine that a change from 0W to 5W makes the difference.

Thorsten

 

Had to edit my last post because I had written 15W-50 by mistake.

The source o the noise seems to be the top area of the motor but that's really hard to tell.

 

Even running a 15W50 would not cause that kind of noise. I still have it in one of my 996's and I get no noise at all even after sitting for 1 week in 30F temperatures. However, a freind who runs 0W40 in his 997 gets it all the time at startup, but considerably quieter and with less duration than your sample sound file.

IF it is a valve, the only thing that would cause that kind of noise is dirt blocking the flow. See if you can maybe get a general feeling for the area of the engine the noise is coming from. Sometimes electical arching can sound similar to a mechanical noise. Look at the engine when the noise is present in total darkness.

 

The sound file is a little bit overdone on the relation of ticking noise to the noise of the engine itself. I guess it's the microhone characteristics of my PDA which I used for recording. Funny thing is that I tend to say that the usual valve lifter noise which I referred to in my topic title is much less now.


Thorsten

 

Also check the easy things, such as eliminating the secondary air pump by unplugging it before starting the engine, tools that may have fallen into the engine compartment and the electric resonance valve is not hitting against the alternator,

 

Damn, that ones got me stumped. At first, it sounded like a shredded accessory belt slapping somewhere but the fact the sounds goes away rules that out.

Since the sound goes away, I assume it has to do wth expansion from heat closing a "gap".

Weird ticks I have heard on cars:

1. loose spark plug (compression leaks past plug)
2. smog pump one way check valve (sounded just like a spun rod bearing, not making this one up)
3. of couse a loose rocker arm
4. worn out idler pulley
5. broke off valve stuck to my piston (too much boost, hard lean)
6. leaking header gasket
7. blown out head gasket (again too much boost, hard lean)

It is amazing how leaking compression or combustion can sound like a ticking or knock but I highly doubt any of these things would have occured on your car, just throwing out some ideas to stimulate someones brain for the cause.

 

Toddel,
I just listened to your sound byte. Your ticking does seem similar to what my car does only maybe a little louder. Hard to tell on the recording. But for me, it goes away completely in less than 10 seconds and does not cycle like yours. Could be your clearances are just more sensitive to the new oil. Just in case, I would let her warm up well before any higher revvs.
Good luck on a remedy.
RB

 

is your car a tiptronic?

 

Use 0w40 or 5w40...These cars do not need or want a 50wt. oil....There are very sprecific reasons for that...Do a search and you will see the topic disccused in the 996 and 997 forums extensively.

 

At start up, there is no difference between a 5W50and a 5W40, so your theory does not hold water, or oil for that matter.

 

Popcorn time! Come and get it!