[Fattyboombatti]

Hi Guys

The Large Disa Valve on my intake manifold failed last Friday.

I originally suspected it was a bad coil or spark plug as the code reader said misfires on cylinder 6 and i changed those without issue. However the issue still persisted and lead me to forums which suspected a broken disa valve which is correct.

Mine had fell apart and i now have bits of plastic and probably a metal spindle going nuts in my engine (and or manifold) and there is around 40 PSI on cylinder 6, i believe is should be around 140psi after taking it to a local independent BMW garage.

The car has done around 150k miles and is a e90 325i n52 2.5l 07 plate.

is it worth time and money replacing it and is it a job that can be done as a DIY?

Cheers

Matt

[tlow98]

I’d definitely take the intake cover off to confirm.

[RocketSurgeon]

Yeah, definitely confirm first. USB borescopes are dirt cheap, I think I'd want to take out the spark plugs and take a peek. While you have the plugs out, run a compression test across all six cylinders to confirm.

[robthewrench]

The PSI on cylinder 6 should be much higher. over 100. I would check the compression again, just to confirm. You could also pull the valve cover to see if there is any obvious damage to the valves on cylinder 6.

However, at 150k miles, a head rework is not really a good investment. Sorry to say that while it is possible to fix valve damage, it is not financially a good move. Removing, rebuilding, and re-installing a head is not a DIY level type job.

If the damage is in the cylinder wall, the engine is done for.

Sorry to give you bad news, I hope that this can help.

[mxchris727]

This was a very common issue on the E46. The plastic won't hurt the engine if it gets sucked in but the metal pin will. Keep us updated; hoping for the best.

[nsjames]

Originally Posted by robthewrench

The PSI on cylinder 6 should be much higher. over 100. I would check the compression again, just to confirm. You could also pull the valve cover to see if there is any obvious damage to the valves on cylinder 6.

However, at 150k miles, a head rework is not really a good investment. Sorry to say that while it is possible to fix valve damage, it is not financially a good move. Removing, rebuilding, and re-installing a head is not a DIY level type job.

If the damage is in the cylinder wall, the engine is done for.

Sorry to give you bad news, I hope that this can help.

this.

a decent condition used head is still 5-600 dollars.
you'd be into it for near a grand just to swap a used head on it yourself, after you replace all the stuff you should replace because you're there.

If the cylinder wall or piston is damaged, it's over.
Would second a USB borescope through the plug hole to look for damage.

Maybe you get lucky and it's just a stuck valve from a plastic bit in the seat.

[Fattyboombatti]

thanks for the reply guys

seriously i am still in mourning over this, loved the car and wish i read up on this DISA Valve bollocks long ago..

i forgot to add that after i replaced the spark plug on cylinder 6 it was damaged by the time i got to the garage and he removed it.

i am going to keep the car, just out of curiosity it is a simple swap if i replaced it with a n52b30a, rather than the n52b25a that is currently in my car?

[scanspeak]

Originally Posted by Fattyboombatti

i am going to keep the car, just out of curiosity it is a simple swap if i replaced it with a n52b30a, rather than the n52b25a that is currently in my car?

That's exactly what I would do. Just find one from a similar year and it should be straight forward.

Get a cheap borescope here https://www.ebay.com.au/itm/Waterpro...r=521626968514

[Fattyboombatti]

cheers for that. i may as well take the manifold off and have a look.

is it possible to remove the cylinder head without doing the engine timing again?

[tlow98]

NO

[2one3E90]

Originally Posted by mxchris727

This was a very common issue on the E46. The plastic won't hurt the engine if it gets sucked in but the metal pin will. Keep us updated; hoping for the best.

So if its a plastic pin and flap its fine going in the engine? Rather than a metal one?

[nsjames]

Originally Posted by 2one3E90

So if its a plastic pin and flap its fine going in the engine? Rather than a metal one?

mine ate an all plastic DISA valve without issue recently.

[2one3E90]

Originally Posted by nsjames

mine ate an all plastic DISA valve without issue recently.

Wait HUH? LOL What year and mileage? SO IT JUST DOWNED IT AND how long HAS IT BEEN LIKE THAT? Can anyone chime in and say this is okay or has had it also? Does the heat from the N52 really melt it? My disa was all plastic from the evident breaking point i saw on the disa.

[nsjames]

it was an original DISA valve that came with the manifold from an early 06.
prior to the metal pin revision.

this is what I found in the intake.
motor is 100% fine.

[2one3E90]

Originally Posted by nsjames

it was an original DISA valve that came with the manifold from an early 06.
prior to the metal pin revision.

this is what I found in the intake.
motor is 100% fine.

Wow. If it was a metal pin it be a different story?

[nsjames]

Originally Posted by 2one3E90

Wow. If it was a metal pin it be a different story?

probably.

[Ozzie335i]

Great news.

[webberg]

So this pic is from my 2006 330xi, build in 8/2005. These large DISA flaps may have been like this for years, so it must have had a plastic pin.

I am about to remove the cylinder head to replace the head gasket and will be checking the cylinders carefully as well.

[VehementCrom]

Originally Posted by 2one3E90

Wow. If it was a metal pin it be a different story?

Mine looked exactly like that as well, the metal pin was in my intake manifold plenum. No damage to my motor.