I have a Vauxhall Corsa "C" (2003)(EU) which is a standard 16v 1.2 petrol, the engine is chain driven and sits at 50k. I don't think it was well looked after (service wise) in previous lifes.
Recently it sounds a bit more like a diesel when cold, but not too loud -and a common issue with the Corsa, however at the moment when the engine hits ~80-90 degrees it starts to "tick" loudly, to the point I can hear it in the cabin.
Observations
When I accelerate the ticking gets faster, if I depress the clutch and throttle, it gets faster, once the ticking starts it doesn't go away till the engine is cool. It will be audible when Idle and parked too.
"slight" loss of power, hardly noticable not anything serious though, and no misfiring or overheating. Taking ~10min to get to temperature in 20-35mph traffic.
prior to the ticking starting, when moving off in 1st, it sounds a bit "throaty" like an exhaust rattle but being in the car I can't work out where this is. No noticable smoke or anything from the exhaust as far as I can tell.
Plenty (almost full) oil and coolant. Oil is fairly dark and theres a bit of gunk around from a bit of moisture (Not HGF, a common mistake when diagnosing things with this engine!) It's from doing short journeys and the build up of condensation. Multiple owner forums confirmed this.
Conditions:
Engine is warm and has typically being driven for ~15min
Starting in cold weather ~0-4 degrees c.
Used for short journeys (~6 miles each way)
Notes
When I start the engine, it goes to about 2K RPM, sounds rough for about half a second then it's fine. This has been diagnosed as normal though for this car.
When I move off when the engine is cold, I get slight revving for the first couple of seconds, again this looks fairly normal for this engine looking on owner forums.
Thoughts?
My first though would be that it could be the oil, as it gets warmer the vicosity changes and it's not as effective? I thought it could be the timing chain, but it doesn't happen from cold. My third thought would be tappets. I'm not brilliant with mechanics so not a clue.
I recently put some Wynns Hydraulic Lifter fluid into the oil with no success. Sounds the same. The car did have some gasket work done and I'd be suprised if they did a full flush of fluids.
Tried to include as much info as I thought was relevant, but if theres anything else let me know
EDIT: Conclusion?
It got a bit worse when the engine got to 85-86ish and the ticking was getting louder, it was also happening on some cold starts for 30seconds.
It went in for a full check hoping it was the Ex. Man. gasket, and they found that the timing chain had a small amount of slack on it, and on an unrelated note the oil pressure switch needed replacing, the old oil in the system probably didn't help the longevity of the chain.
Update Months on and the car still does the same thing.
I have checked the oil, changed it, had the chain done and still after a 15-20 min drive it will tick away to itself. I think its the tappets, and occasionally the sound will go away again before returning later in my journey.