850 1996 aircon makes a sizzling noise

When the car is stopped a sizzling noise from the evaporator occurs for up
to 15 seconds.
The aircon works in general without any problems.

Is this something to worry about?

Per

 

That's weird. I'm just wondering... is there any way condensation could
get on a hot part of the motor? Have you raised the hood and looked for
the sound? It seems unlikely it'd be freon gas escaping... Look for the
sound and get back to us.

FYI

 

Hi all.
My V70 makes this noise after driving with aircon on for a while, then
stopping the engine.
I believe it's just the compressed gas being released into the evaporator
through the orifice. Nothing to worry about!
Mine's been doing this for all of the 5 years which I've owned it! I take it
the noise is getting quieter all the time, just like pressure draining out
of the system?
This is where the compressed refrigerant is in liquid form, and is released
into the evap through a small orifice, which is where it becomes gas again,
and absorbs heat. The pressure in the 'high' side of the system can remain
pressurised for a few seconds after the compressor has switched off.
See volvospeed.com for more info on how the complete system works!
Hope to help.
Joe.

V70 TDI 238,000 UK Miles.
Cambelt/waterpump change next month! (waterpump is preventative maintenance,
not leaked in 238k miles!! ).
Joe Landy
Peterborough
UK.

 

Hi Joe,

Thanks for your explanation - its seems to be the same phenomenon that I
hear!

Another thing,
I drive a TDI too and I have decided to try to change the cambelt and
oilpump belt myself. My
car has 125K miles and it is the first time that I try on this type of
engine. I have bought a german
manual from AUDI covering the engine which is similar to the AUDI A6 2.5
TDI.
In the book I read that a special tool is needed for the tensioners both on
the cam side and the oilpump side.

Besides this is there anything else to care about before doing the work.

Regards and thanks!
Per

 

Hi again Per Groth Ludvigsen.
You're suggestions worry me, as I have been down the same route, with the
Haynes manual for the Audi A6
e.t.c. I understand that the procedure is far and above any Non-Volvo
mechanic,
such as myself.
I believe the volvo has a different injection system from the Audi, helping
it achieve 140BHP, instead of 110 from the Audi??
Anyway,
I have been changing cambelts on cars/4x4s for 10 years, but I gave this
one a miss! The equipment that the dealers use set up the dynamic timing
whilst the engine is running. Sure, you may be able to set the static
timing, and get it fairly near, but you need the proper computer equipment
to do the job properly.
I have seen the dealers do the dynamic timing setup, and they plug the car
into their computer system via the diagnostic socket, it revs up and down a
few times automatically, and the car then comes to a lovely, smooth idle at
something very precise like 847 rpm!
I can't find anyone else who has ever changed the cambelt on the TDI. Lots
of people point you to the instructions for the petrol-engine cambelt
change, but the diesel is a completely different kettle of fish I can assure
you!
Remember that there are no ways of locking the pulleys in position, so you
have to look for arrows on the pulleys.
At 125K, I had the camshaft pulley oil seal replaced too. This requires you
to remove the pulley, and it's not keyed to the shaft. It's just on a taper!
It's up to you to try it, but I fear you'll pay one way or another.
The bill will either be £400, or more like £4000 !!
The cambelt changes are expensive at the main dealer, but not too bad when
you consider that they last 80,000 miles each time.
The injection pump belt requires replacing at 40,000 mile intervals, so
should have been done at 120K ??
The waterpump is also an item of concern. Several have been known to seize
up at 150,000 miles or so, taking the cambelt (and camshaft, valves, head,
e.t.c.) with it. Volvo should have driven the waterpump from the
injection-pump belt. That way, if the pump seized and the belt broke, the
engine would just stop !!
Might be worth considering while you're at it? The pump itself isn't dear,
and labour should be low in cost, as they'd be removing the cambelt already
!!
Good luck should you attempt the task yourself. I also look forward to
reading comments from others on this. Perhaps someone else HAS tried it and
succeeded? I can certainly find no web-pages or ng postings to suggest that
anyone has.
I'm sure someone who is a bit more knowledgeable than me can help out
further. I don't work on Volvos by trade, but there are people on this group
who do!
Cheers for now.
Joe Landy.
Peterborough
UK.

 

Thanks for your answer, Joe!

Sorry to worry you! - but Haynes wil not help you with respect to this
engine. You will need a german book written by
H. R. Etzold called "Audi 100, Audi A6, So wird's gemacht". ISBN
3-7688-0702-9. This book covers all you need to
know about maintenance and repair on the diesel engines too including the
Volvo 850/v70 2.5 TDI engine which orginally is from Audi A6 2.5 TDI. The
engine code is AEL and it was used in the Audi 100 and A6 cars from 9/94 to
/97.
Searching on the internet for this Audi diesel engine will give you a little
bit more respons.
You are right that there is a weaker 2.5 TDI from Audi with the code AAT and
ABP(without catalytic converter) but this engine is not used in the Volvo.
If you take a closer look at your engine you will find the Audi name all
over - Volvo did not change this.
Despite that the Audi and the Volvo uses the same diesel engine, the Audi A6
is faster and more quiet compared to the
Volvo 850/V70 2.5 TDI. I live in Denmark and here are very few Volvo 850
TDI - I bought mine in Germany last year.

My plan is to change the cambelt myself! I have heard that this is no big
deal because the wheels have timing marks on - but a special tool for
tensioners is required (can be purchased in Germany for 14 euro at Wotan AG)
and the belt tension has to be set manually and within 3 mm from the
tensioner mark.
Your advice about changing the waterpump sounds like a good investment.
Further Audi suggest to use belts from Audi
or from Contitech. You can also buy the belts from Volvo at 2 - 3 times the
price from Audi/Contitech. The belts and tensioners on my engine is from
Audi so I presume to use Audi again. The 40 K change interval for the
injector belt is new to me - mine seems from the service book to have run
70K and it still looks good!!
With respect to diesel injector pump side - I consider to let Bosch Diesel
Service (they have much more knowledge about this engine compared to a Volvo
garage) do this task because the pump presure need to be fine tuned. Doing a
dynamic timing setup on this 2.5 diesel engine is new to me - but I am not
an expert. Bosch said that they normally uses the wheel marks and then
afterwards they check the pump presure - but anyhow I think it is worth to
invest in this check which requires a special measurement tool.

Best regards
Per