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Kev0607 · Oct 31st, 2020, 02:04

A slight popping noise & a bit of white smoke is normal for a D5. A loud popping noise isn't, as explained in this video;

https://www.youtube.com/watch?v=QHLyubTrIQ8

*Note, I don't think your car has vacuum engine mounts (my car doesn't & its identical to the V70 in terms of engine layout & suspension & the XC is similar too). I'm fairly certain you won't see a vacuum pipe going to the engine mounts from the turbo control valve (like shown in the video on a euro 3), as yours is a euro 4 & it doesn't have vacuum mounts as far as I know (double check this though). The turbo is electronically controlled on the euro 4 & not by vacuum like the earlier euro 3's (this is why vacuum issues don't affect performance as such on the euro 4's). However, if you hear quite a loud popping noise from the oil filler cap, there's some sort of vacuum leak somewhere else in the system (rule out the vacuum engine mounts though possibly because as far as I know, there isn't any (double check).

This video shows how to directly test the vacuum pump. If you do this test as shown & the needle on the gauge is flickering, then that indicates a leak with the vacuum pump itself. The seals in the pump can be replaced, or you can buy a new pump. If the needle remains steady, then the pump is fine.

https://www.youtube.com/watch?v=-lgYAS3GoiE

If there's no vacuum loss at the pump, then you need to test each part of the system by checking the pipes for any wear as you go along (which would cause vacuum loss) & hooking up your vacuum tester to each section of pipework to check the reading (check for a flickering needle, which indicates a leak in that particular section of pipe. If the needle remains steady, that section of pipe is okay). Then its a case of keeping going & testing each section of pipe as you go on, until you eventually find the culprit(s). You may come across split pipes, which have just worn out due to age & being in a hot engine bay. If you're lucky, you might see split pipework early on. Its not a five minute job testing the whole vacuum system, so allow time.

https://www.youtube.com/watch?v=0zsIa4Y2Tcs

Note, these videos are from a euro 3 car. The process is more or less the same in the euro 4, except you don't have vacuum engine mounts (as far as I know) & the turbo is electronically controlled (so there's no boost solenoid).

Thanks to cheshired5 for these helpful videos too.

Oct 31st, 2020, 02:04	#4
Kev0607 Premier Member Last Online: Yesterday 23:44 Join Date: Apr 2019 Location: Manchester	A slight popping noise & a bit of white smoke is normal for a D5. A loud popping noise isn't, as explained in this video; https://www.youtube.com/watch?v=QHLyubTrIQ8 Note, I don't think your car has vacuum engine mounts (my car doesn't & its identical to the V70 in terms of engine layout & suspension & the XC is similar too). I'm fairly certain you won't see a vacuum pipe going to the engine mounts from the turbo control valve (like shown in the video on a euro 3), as yours is a euro 4 & it doesn't have vacuum mounts as far as I know (double check this though). The turbo is electronically controlled on the euro 4 & not by vacuum like the earlier euro 3's (this is why vacuum issues don't affect performance as such on the euro 4's). However, if you hear quite a loud popping noise from the oil filler cap, there's some sort of vacuum leak somewhere else in the system (rule out the vacuum engine mounts though possibly because as far as I know, there isn't any (double check). This video shows how to directly test the vacuum pump. If you do this test as shown & the needle on the gauge is flickering, then that indicates a leak with the vacuum pump itself. The seals in the pump can be replaced, or you can buy a new pump. If the needle remains steady, then the pump is fine. https://www.youtube.com/watch?v=-lgYAS3GoiE If there's no vacuum loss at the pump, then you need to test each part of the system by checking the pipes for any wear as you go along (which would cause vacuum loss) & hooking up your vacuum tester to each section of pipework to check the reading (check for a flickering needle, which indicates a leak in that particular section of pipe. If the needle remains steady, that section of pipe is okay). Then its a case of keeping going & testing each section of pipe as you go on, until you eventually find the culprit(s). You may come across split pipes, which have just worn out due to age & being in a hot engine bay. If you're lucky, you might see split pipework early on. Its not a five minute job testing the whole vacuum system, so allow time. https://www.youtube.com/watch?v=0zsIa4Y2Tcs Note, these videos are from a euro 3 car. The process is more or less the same in the euro 4, except you don't have vacuum engine mounts (as far as I know) & the turbo is electronically controlled (so there's no boost solenoid). Thanks to cheshired5 for these helpful videos too. __________________ 2007 S80 2.4 D5 - 110,000 miles* Last edited by Kev0607; Oct 31st, 2020 at 02:19.