citroen c4 hissing

[Steve]

I've got a citroen c4 on an 06 plate. 1.6 diesel (90 not 110).

It makes a hissing noise when first started up and for about 10-15 minutes thereafter. Is this a belt that needs changing? It has done 88,000 miles. The sound is coming from the belt on the drivers' side of the engine (which is exposed when you open the bonnet).

Also noticed when I opened the bonnet, there is a rubber pipe, maybe 8-10mm bore, hanging down at the other side of the engine. It comes from the back of the engine somewhere, but it is just hanging down towards the plastic scuttle at the bottom of the engine bay. Never noticed it before! Any ideas? The car runs fine, but the air con is shot (compressor wont even start).

Also, curiosity: Underneath the car, directly under the driver's seat is what looks like a small (250mm x 150mm?) heatsink with two pipes leading to the rear of the car. What is this? Its mounted on struts away from the bodywork.

 

[Burnerman]

The hissing could well be a drive belt, and usually we take the belt off, start the engine and see if the hiss disappears. Usually these belts are replaced with the timing belt, and yours isn't far off needing that done.
The small pipes could be fuel filter drains (but there's usually only one) so can you trace where they go? Another drain comes from the scuttle area, below the wipers but thats generally larger diameter.
The heat sink device is in fact a fuel cooler.
The air con won't work if its out of gas....thats the first thing to do when starting A/C work.
John

 

[Steve]

Thanks. I didn't think the engine would run without a belt on . . . doesn't it control something the engine needs to run?

Fuel cooler . . . new one on me. Would think with diesel the concern would be with warming it up, given our climate December to February . . .

The air con was filled up with gas in May by Evans Halshaw and dye added, but it hasn't worked since a day after that, never got around to taking it back to investigate.

Is the timing belt etc a major job?

I'm thinking of getting shut of this car start of next year, would prefer to avoid costly jobs now. I've had it 5 years, had my moneys worth. The paint under the bonnet (around the bonnet catch) is bubbling now (no corrosion underneath though), so I can tell its going to start costing me money soon!

MOT tomorrow. Lets see how much this £35 job will end up costing me . . .

 

[Burnerman]

The timing belt is a major enough job Steve and is usually in the 3 to 4 hour mark realistically......its also a good idea to replace the serpentine belt (the hissing one) and the water pump, tensioner and coolant too - which does work out expensive! Worth getting a quote from an independant garage for that one.
The engine can run quite happily without the hissing belt, but naturally enough it won't be charging the battery.
Without the fuel cooler, there's a risk of fuel aeration which would cause running problems. I have seen a VW where a trolley jack was used on exactly that spot
The dye in air con gas (together with some special oil) is used to check for leaks...under U.V light its easy to see where the leaks are.
If you are trading in I'd say nowt.
John

 

[Steve]

I've looked at another forum and citroen claim 150k miles or 10 years on the timing belt. That's reassuring but I've been driving it hard poverty the last year, 54 miles a day 5 days a week so that may have caused more wear than usual. I'll see if the garage say anything tomorrow.