C30 General : Strange noise at cold start

[Matchtx]

Hello from France !

I'm a French guy and, of course a C30 owner !
Mine is from 2011, with 230'000' km on the clock. It has a D3 (D5204T5).
Since this winter, a strange sound start to appear at the start, cold.
The timing belt and aux belt has been done 80'000km ago.

Any idea of the source of this noise ?

I'll really appreciate
https://www.youtube.com/watch?v=FrSqhJx2U3U&t=2s

[Matchtx]

Continuation of investigations: it seems that this noise is due to a leak coming from my LR jar.
Let me explain:
Since I have had the car, it has always had to be refilled with coolant from time to time and I have never found where it comes from. No water in the oil, no suspicious smoke..
While looking for my noise this morning, I removed the right front wheel and the mudguard in order to have a visual of the accessory belts. I realized that it was damp: it seems that my jar is oozing/leaking on the belts!
This explains a noise present when cold, which stops as soon as you tickle the accelerator and which disappears completely when hot: the water surely escapes at some point.

Do you find my theory plausible? In any case I believe in it

[Simmy]

check the coolant tank and hoses for splits /leaks fix any found leaks and check the belts for any damage if in doubt and the age of the belts is unknown it would be better to replace them also check all pulleys and idlers/ for any roughness / damage

[Teddy1975]

The coolant tank can develop small cracks in the plastic that can't be seen but will let coolant seep out either when the pressure builds up (engine heats up) or in your case while the engine is cold until the pressure builds up.

Replace the coolant tank with a new one, fortunately it doesn't cost so much.

[Matchtx]

Originally Posted by Simmy

check the coolant tank and hoses for splits /leaks fix any found leaks and check the belts for any damage if in doubt and the age of the belts is unknown it would be better to replace them also check all pulleys and idlers/ for any roughness / damage

Thanks for your advice. The timing belt and accessories are 80'000km's old (2-3 years) so they are fine.

I'll order on Skandix the tank and also the pipe under the tank

Fresh liquid coolant and there we go !

[Simmy]

aux belt is the one that can take the contamination .timing belt is fairly protected a failed aux belt can do untold damage to an engine if it gets wrapped round other moving components. change it for peace of mind. much cheaper than a replacement engine go it right do it once.

[PNM]

Originally Posted by Teddy1975

The coolant tank can develop small cracks in the plastic that can't be seen but will let coolant seep out either when the pressure builds up (engine heats up) or in your case while the engine is cold until the pressure builds up.

Replace the coolant tank with a new one, fortunately it doesn't cost so much.

I can vouch for this, I was loosing coolant without an obvious leaks and managed to convince myself that it must be the head gasket on its way out. I opened the bonnet when up to temperature and still running, and a small stream of steam was coming out of some numerous cracks that were barely visible to the naked eye.

Word of warning, there are 2 types of coolant tanks for these models, one with the outlet pipe on the same face as the inlet pipes and one with the outlet on the opposite side. I ordered the wrong one initially.

Also, to avoid having to drain the system fully, I just sucked all the coolant out of the tank with a turkey baster and put it in a clean tub to be reused.

[Simmy]

this coolant tank problem is the same on lots of models c30 v50 c70 s40 its very common.