2.4D (2005 on) "Chuf-Chuf" Airbox D5244T5

[Piers1956]

Hi folks. Firstly let me apologise if this is an old query only I am still seeking a likely solution to a problem.

2007 V70 2.4D 205,000 miles of mainly motorway work and a good service record. Probably one of the nicest V70's I have driven/owned but 1 infuriating issue. On tick-over it sounds like a 1960's tractor. Starting from cold all appears ok with perhaps a vague suggestion of a missed beat or two. After a shortish run the "Chuf-Chuf" starts resonating from the airbox area. This makes the car sound awful. Pull away again and over say 1000rpm the car is perfect. I have done the following.

New belt & tensioner. Injectors out checked refitted with new seals & clamp bolts. Leak off test close to perfect. Fuel adjustments well within tolerance.
Swirl valves replaced and everything cleaned from air box to valve chambers. EGR removed and cleaned. Vida Dice shows no fault code other than an AQS fault.

Car drives better than my last 185 D5, returned 47.1mpg on a mixed road 170 mile run around today and accelerates without hesitation. There is no audible injector noise or tappet noise, in fact surprisingly quiet. Two people have asked me if it has a cat back exhaust and whilst I am not 100% clued up on these I can only say it looks like a standard system to me although it probably sounds like it has one fitted when on tickover.

If it didn't run so well I'd hang my hat on a valve issue but I can't find a compression tester (Old School Type) to mate to the glow plug ports. Vida was showing RPM measurements of 699-703 min/max across the 5 cylinders.

Two suggestions offered are:- Timing Belt out 1 tooth. Exhaust Valve Lifters Weak. Jury is out on this one so as most faults are generic, I am hoping someone can enlighten me.

Many thanks.

[37 RUBY]

Does this https://www.volvoforums.org.uk/showthread.php?t=223589 sound similar to your problem?

[Piers1956]

Thanks for that, I have glimpsed parts of this before. Ticking the boxes, I only relate to the boom-boom or chuf-chuf in the airbox. No metallic noises from cams, valves etc. Quality Semi Synthetic Oil 5w 30 in this one, I think, but would need to check. Last changed around 1500 miles ago in November. Top off and no visible signs or wear and tear or loose followers but plenty of carbon, syrup etc all cleaned and polished. As for weak lifters, a possibility but not sure how this would manifest in the airbox orchestra. Low Oil Pressure on Low Revs again worth measuring as just off tick over everything is rosey. I'll update in a day or two. Thanks again.

[sv70]

It really is a shame that you didn't search the forum for this problem before you did the work on the injectors etc,because you will find that the vast majority of members with this problem cured the tug boat sound by replacing the faulty hydraulic valve lifters-myself included.I had the exact same noise,engine ran fine though and i ran it like this for over 12 months till i decided to replace lifters,turned out i had 5 lifters which were weak or weren't holding pressure and were totally limp,after fitting all new ones,noise disappeared.The noise through the air box is caused by diverted combustion air escaping via the weak lifters.I know it's not what what you would like to hear as a fix but in my opinion it's the lifters,i hope though i am proved wrong for your sake.

[Piers1956]

I sincerely hope you are right. Pulling the injectors is a nuisance but at least they will pop out easily this time round. I'll run the thread for a week and evaluate the consensus before going again. Thanks again for your input

[AndyV7o]

Btw you should really be running fully synthetic, not semi, and 0w30. 5w30 is ok when 0w30 is not readily available, but if ya want your engine right, 0w30 Fully synthetic A5/B5 from a big brand.
Wont cure this issue, but it will look after your lifters.

[Piers1956]

Firstly, I checked back through my receipts and in fact the oil purchased on 02.09.19 was Comma 5W30 Xtech Fully Synthetic ACEA A5/B5. No plans to change that as I bought 40 ltrs. (For more than 1 car)

Now back to the case in question. Well no point putting it off so now a barn full of bits and 20 lifters and 20 rockers to be weighed in.

On initial inspection I would have replaced 8 lifters and 7 rockers. Putting my sensible head on all 20 lifters and rockers are being replaced with FAI units. Interestingly the exhaust side lifters were worse than the inlet side yet for the rockers the roles were reversed. The lift on inlet No.3 was so excessive that after cleaning it, it was possible to see the full diameter of the internal roller bearings yet in operation it was not noisy??

The lifters were Ina and the rockers look like FAI but were without stamps or markings I can't be sure.

So, if all goes to plan Saturday should be the day of reckoning. Thanks for your advice, it will teach me to look a little closer next time I play with swirl valves.

[sv70]

That's always good when you see some definitely faulty parts,and very wise to do all 20,including the rockers,when you've got it stripped to that extent,please post your good news when you have built it back up.

[Piers1956]

"The train left the station at 16:40 yesterday"

Thank you all so much for the clear pointer on this one, the car sounds or in fact doesn't sound 100% better.

So to sum up, if you have a chuf-chuf in your airbox, go for the hydraulic tappets and rocker arms.

Moral to the story. Keep your eyes wide open on the forum and under the rocker cover, it will save you endless time and money.

Off for a quiet spin and thanks again. sv70 to the top of the class

[sv70]

That's great that it did the trick,we all try and go for an easy fix but sometimes you've just got to bite the bullet,i know it can be a a bit of a toil going through page and page of forum q's and a's,but you can bet a particular problem has already been answered on the forum ,it's just a matter of finding it,happy chuf-chuf free motoring.