2.4t Blue smoke on acceleration after engine braking?

Willber · Post by **Willber** » 12 Oct 2021, 00:23

Good morning all (UK time anyway!)

My 2002 V70 2.4t petrol on 155k has started blowing a puff of blue smoke when accelerating again after long periods of engine braking and particularly when going downhill. It does not smoke after long periods of idling and does not smoke on first start up.

The full PCV was replaced 7k miles ago and is passes the glove test. All vac lines replaced and generally is a good stage 0 car.

The turbo appears fine with no excessive play or oil in either side or the pipework.

The plugs are all oily however and compression test shows 180-200 psi across all 5 cylinders.

It had always been run on 10w40 semi synthetic however I switched to 5w 40 fully synth and have done maybe 2.5k.miles on this oil. Could this be the culprit, or is it like my valve stem seals are going?

I am going to switch back to 10w40 and add a seal conditioner to see if it stops smoking.

Does anyone have any other ideas? I cant see how it would be PCV related but am open to opinions and I also am. Not totally convinced it is stem seals as no smoke on cold start in the morning. I really like the car and want to keep it, but if its means big money then its probably a no go to be honest. I do all work myself but not sure I could face taking the head off.

Thanks for any advice!

Will

Post by **abscate** » 12 Oct 2021, 02:57

Smoke after overrun , or high engine vacuum, is a classic symptom of worn valve stem seals

Coupled with the fact thst the Volvo white block doesn’t seem to have a history of piston ring problems, almost certainly stem seals are the culprit.

It is possible to do stem seals without removing the head, just the cam cover.

Willber · Post by **Willber** » 12 Oct 2021, 06:29

Thanks for your reply. It is certainly looking that way! I thought the head had to be removed to do the stem seals.... I will google for a DIY if there is one to do them without....

darylrobert · Post by **darylrobert** » 12 Oct 2021, 07:56

you need to remove the head to service the stems. Its a speciality job to remove stems special tools etc. Its labour intensive to remove the head but if you take your time and do a little everyday... it took me a week to remove mine but i then found wear to the cylinders and i decided it wasnt worth repairing.

Post by **RickHaleParker** » 12 Oct 2021, 08:10

Willber wrote: ↑12 Oct 2021, 06:29 Thanks for your reply. It is certainly looking that way! I thought the head had to be removed to do the stem seals.... I will google for a DIY if there is one to do them without....

The head does not need to be removed to replace the Valve stem seals. You remove the Cam cover, Cams and Spark plugs. Push compressed air into the cylinder through the spark plug hole. The Compressed air will hold the valves in place as you change the seals one at a time.

Post by **cn90** » 12 Oct 2021, 10:32

For 2.4 and 2.5T engines, worn valve seals are unusual before 200K miles.

I guess you can try thicker oil and see.

As long as the oil consumption is not excessive, you can "live with it"...

Willber · Post by **Willber** » 12 Oct 2021, 11:09

Ive changed it back to 10w40 semi synthetic today and have not been able to replicate the smoking despite similar driving conditions as before (long'ish periods of 50-60mph engine braking)

Have another 300 miles to do this weekend so time will tell. I am hoping it was just a quirk of the previous 5w40 fully synth oil but not convinced yet!

Post by **RickHaleParker** » 12 Oct 2021, 14:07

Willber wrote: ↑12 Oct 2021, 11:09 Have another 300 miles to do this weekend so time will tell.

ATP AT-205 Re-Seal will buy you some time.

Post by **erikv11** » 12 Oct 2021, 15:08

RickHaleParker wrote: ↑12 Oct 2021, 14:07
Willber wrote: ↑12 Oct 2021, 11:09 Have another 300 miles to do this weekend so time will tell.
ATP AT-205 Re-Seal will buy you some time.

+1, good suggestion from Rick. This is good stuff.

Willber · Post by **Willber** » 13 Oct 2021, 00:05

Thanks all.

I have seen AT-205 mentioned before and there is a similar product in the UK made by Forte which has good reviews. I will see how it goes at the weekend and possibly add that too, or maybe use Valvoline high mileage oil which has seal conditioners built in.

This is easily the most helpful forum I have posted on. Hoping I can get plenty of life out of my V70 yet!

Cheers

Will