Hello @Lewis Barwick ,
Great news on the repairs, just for future reference here are some pictures I posted a year ago that I posted for another member who also had the exhaust plug blowout.

The question was then, and still was never answered by Yoghurtshotgun, is what has caused the plug or plugs to blow out,, to much back pressure in the exhaust, meaning a possible clogging primary CAT, secondary CAT, collapsed resonator, exhaust flaps not opening at hard acceleration...

I would hate to see you have the issue again, so please ask the mechanic for his interpretation of the cause, especially after I just saw what happened to your air filters, is that some kind of blow back.. ?

Sorry for joining late, I missed this thread somehow.

Johnny

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I think I just answered my own question while thinking about what I wrote above, it has nothing to do with the boost side (intake) of the turbo, but to do with the exhaust side, so if the boost solenoid fails, then the waste gate will not open to allow for free flowing of the exhaust to bypass the exhaust turbine/wheel, therefore to much exhaust back pressure builds up in the exhaust side of the head and runner/cast tube that runs to the SAI combi valve, that runner/tube has the 2 plugs in it, so all this pressure is before it even gets to the first main CAT, and that built up pressure most likely blew back through the intake with the cam overlap blowing out your air intake filter.

Just my thoughts, I hope.

Johnny

 

Are the plugs just clearance fit push in or threaded?
If pressed in, a severe back fire would most probable raise the pressure inside the SAI cast rail as to blow the plugs out. Especially with a hot engine expanding the aluminium that the plugs are pressed into.
It would however, take a huge amount of back pressure to blow the air filter in to pieces as it would have to pass through the plenum, boost pipes, intercooler, compressor side of the turbo and finally into the air filter housing. Thats a long path for back fire pressure to travel giving it time to loose energy as it travels and expands.
I suppose if it severly backfired through the intake system on full boost that might very well represent a lot of stored energy.
You would think that the intercooler having crimped on plastic ends would gave also been damaged, forced apart? Not to mention turbine and compressor blade failure.

 

Hello @Frank ( Sunnyside ) ,
The plugs are press fit, just like tiny freeze out plug.

All good points you make on the amount of travel to blow apart the air filter, I wonder if @Yoghurtshotgun ever had the issue again, or ever found out why his plug/s popped out ?

Johnny

 

Hi Johnny,

sorry I didn't reply to your posts. I didn't get any notification you had commented.

The specialist I used didn't make any comment on how the sai plug got blown out but did mention on the initial consultation that they had seen this before and keep the sai plugs in stock.

The old air filters were very brittle/dried out so I don't think it would have taken much of a backfire to blow it apart and i certainly don't remember hearing any such noticeable backfire when things went wrong.

I am still having an issue that I noted not long after buying the car that pre dates this thread and I wouldn't mind your thoughts if I could?

when cruising at 30-40 mph the engine isn't smooth there is a sort of 'jiggly' feeling through the car and I find it hard to get off the throttle and ease back into it smoothly as the car stumbles a tiny little bit.

I have started another thread for this but no replies of yet.

I noticed on the invoice from the specialist a note which says 'bank 2 charge cooler visual damage' this would go along with what I think Frank said about a backfire causing intercooler damage however the issues in this thread were on bank 1 not bank 2. (UK RHD car)

many thanks

 

Has a smoke or pressure test of that damaged intercooler been done. If there is a small air leak it will effect the running of the car. The ecu's require a monitored air consumption by using the air flow meters. Any air getting past the air flow meters ie a leak some where after them then theengine can't calibrate fueling correctly and at best will run irratically and at worst throw ecl's and codes.

 

Hi Frank,

No I don't believe any such test has been done. I did call on Friday but it was at lunchtime so I got the answerphone. Will try again this week.

Car seems to be ok other than the oddities I described above. No eml light and it accelerates fine as far as I can tell etc.

Here's a photo I took of intercooler (what I can see of it through the grille anyway) it definitely doesn't look to be in the best of shape so will definitely have it replaced.

 

TBH its looks more flattend than split. But a proper inspection and test is a must.

 

So this is the exact place Ive found myself after an alternator and infotainment replacement. It threw a check engine light, and fuse 7 was blown. Replaced the fuse, cleared the codes, and a single drive later over 2000 rpms, fuse was blown again. The error codes are a barrage of things including P0245 Turbo/Supercharger wastegate solenoid A low Lower Limit Exceeded.

Is it the dreaded n75 solenoid that you replaced?

 

Hi Virtual Law,

Its been a long time now since me and the Bentley parted ways however I am pleased to say after the works mentioned in this thread were completed by GT services the car proved to be completely reliable over the following 2 years of daily driving.

I do believe the boost solenoid I had replaced was the N75 yes. It was situated on the left side of the engine near the alternator (if stood looking at the front of the car)

Despite normally doing all my own mechanical work due to not being able to trust garages fear of the unknown made me send the car in to GT services and to be honest they were great!

I believe the total bill was £1500 for the items mentioned but that was back in 2021.

I believe they have relocated from Crewe to Knutsford now.

Hope you manage to get yours sorted Virtual Law, these are fantastic cars.

 

Wow Lewis, youve got a healthy memory! Much appreciated!
Sucks that I cant drive it even after a long wait for the alternator job, since this n75 sounds rather crucial.

I too have a fear of bad mechanics but the guy who did the alternator already knows how to get to the boost solenoid it seems. Shall update as its repaired!

 

Hello @virtual_law ,
Did you have this P0245 issue prior to the alternator replacement, if not, it's very likely that the mechanic who replaced the alternator caused the issue, as the N75 is right there with the alternator, as is the wiring harness for the N75, the code is for low voltage or short, therefore it is possible that the wiring for the N75 is pinched between the alternator and block, or other surface, hence the fuse blowing when it is time for the circuit to come into action at 2000 rpms.

Johnny