850 1996 aircon makes a sizzling noise

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

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maintenance,

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.

"Per Groth Ludvigsen" wrote in message news:409e69dc$0$453$ snipped-for-privacy@dread14.news.tele.dk...

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

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