Sounds like the bike from dumb and dumber.

[loogie1]

Hello,
My e30 325i is making pfutt pfutting noise like a low powdered steam engine. Reminds me a bit of the bike in dumb and dumber! Any thoughts as to what it might be? Is it the start of a potentially more disturbing/damaging pffut pfutting? It’s driving fine, idling and pulling well.

[ah]

What part of the engine is it coming from ?

[flybynite]

Normally that is manifold gasket blown on one cylinder. You should be able to narrow it down to within 1 or 2 cylinders by ear and sometimes feel the blow of the air from a reasonable distance away (dont get burned)

[loogie1]

What part of the engine is it coming from ?

Seems to be towards the back, I thought maybe exhaust manifold. It’s not a deep noise, but I suppose it could be signs of an early stages leak. It is a one cylinder sound. A small leak in the gasket of one branch of the manifold ?

[loogie1]

Normally that is manifold gasket blown on one cylinder. You should be able to narrow it down to within 1 or 2 cylinders by ear and sometimes feel the blow of the air from a reasonable distance away (dont get burned)

Ah yes, makes sense. Is it ok short term? Or is the school of thought to repair ASAP?

[Cloggy Saint]

My main concern is that you've seen dumb and dumber.

[flybynite]

Ah yes, makes sense. Is it ok short term? Or is the school of thought to repair ASAP?

If it is the manifold not so drastic, but a big leak can let air in and ignite any unburnt fuel resulting in backfire that can damage the exhaust.

If it is the gasket I would get it sorted, I have seen a blowing gasket make a groove in an alloy head. 325 head not known for strength.

My main concern is that you've seen dumb and dumber.

this also

[loogie1]

Ah yes, makes sense. Is it ok short term? Or is the school of thought to repair ASAP?

If it is the manifold not so drastic, but a big leak can let air in and ignite any unburnt fuel resulting in backfire that can damage the exhaust.

If it is the gasket I would get it sorted, I have seen a blowing gasket make a groove in an alloy head. 325 head not known for strength.

My main concern is that you've seen dumb and dumber.

this also

Ok thank you for that, my next job after replacing the OST wheel bearing, it’s making a really horrible noise!
You both knew what I meant referencing dumb and dumber though!

[Speedtouch]

Check that the nuts are tight on the exhaust/manifold before pulling things apart!

[loogie1]

Check that the nuts are tight on the exhaust/manifold before pulling things apart!

top tip! The nuts look really difficult to get to on the underside of the manifold, just from looking / locating the leak.

I've located the leak, when I pull the HT lead to no5. The noise ceases, it's coming from the bottom of the manifold/gasket.
To protect the ally head I have left No5 HT lead off until such time as I can repair it. Is this a good or bad idea? I am thinking in terms of fuel still being injected into the cylinder.
Thank you

[croqy]

Bad idea as your just washing the bore with unburnt fuel

[loogie1]

Bad idea as your just washing the bore with unburnt fuel

You’re right. Thank you.

[Speedtouch]

My first E30, a 1984 320i, had (unknown to me when I bought it), a stripped spark plug thread on #5 cylinder. It ran OK for the most part (spark plug held in with welding wire and JB Weld), but one day it failed the MOT on emissions being slightly too high.

To get around this, I sneakily disconnected the injector to that cylinder while the MOT tester wasn't looking, asked him to re-test it and it passed! He eventually sussed what I did, but allowed me to continue on my way with a fresh MOT pass certificate in hand.

It actually ran surprisingly well on just the 5 cylinders.

[Gert_8]

My main concern is that you've seen dumb and dumber.

IT'S A CLASSIC!

[loogie1]

Check that the nuts are tight on the exhaust/manifold before pulling things apart!

Yes, the nut below no 6 was loose. Others were also loose. Unfortunately when checking one of the loose looking ones it snapped like it were a twiglet! Is it normal practice to replace all the studs when replacing the exhaust manifold.? If one snapped that easily, the others must be similarly fragile. Still have the blowing noise I guess the gasket is goosed. Not looking forward to this job.....axle stands and rolling around underneath on the garage floor...with rusty nuts and bolts....so much fun!

[Speedtouch]

It is ideal, though not necessarily essential, to replace all of them, particularly if you're going to the trouble of removing the manifold.

Soak the studs in penetrating oil such as PlusGas for a few days prior to doing the job.

[loogie1]

It is ideal, though not necessarily essential, to replace all of them, particularly if you're going to the trouble of removing the manifold.

Soak the studs in penetrating oil such as PlusGas for a few days prior to doing the job.

Cheers Speedtouch. I am in Canterbury myself.

[Speedtouch]

Well, if you get stuck, I can recommend either Westbere garage or Oaten Hill Mews garage, which is in Canterbury near the Waitrose supermarket.

They have helped us out numerous times with awkward jobs!

If you tell them Maurice from Auto Body Care sent you, they'll probably give you some discount.

[loogie1]

Well, if you get stuck, I can recommend either Westbere garage or Oaten Hill Mews garage, which is in Canterbury near the Waitrose supermarket.

They have helped us out numerous times with awkward jobs!

If you tell them Maurice from Auto Body Care sent you, they'll probably give you some discount.

Thank you very much.

[loogie1]

Job done, thanks guys. Now I can hear all the other engine noises that upset me!
I wonder why the option of “double nutting” the studs is not mentioned in the wiki guide for removing sheared manifold studs. Worked a treat for me. Thinking the new manifold nuts will need re torquing at some point, not sure how long to leave it.

[Brianmoooore]

How can you 'double nut' a sheared stud? There's nothing to screw the nuts onto. If there's any of the sheared stud projecting from the head, then placing a nut over the remains and welding it in place through the middle of the nut often works, because of the thermal shock from the welding process.
I'd recommend replacing all the studs when things are apart, as well as renewing all the special copper coated nuts, but the studs aren't fragile. The problem is that the RH drive M20 manifold warps over time, taking the outer studs past their limit. The manifold face should be checked with a straight edge when it's off, and machined flat if found to be warped.

[loogie1]

How can you 'double nut' a sheared stud? There's nothing to screw the nuts onto. If there's any of the sheared stud projecting from the head, then placing a nut over the remains and welding it in place through the middle of the nut often works, because of the thermal shock from the welding process.
I'd recommend replacing all the studs when things are apart, as well as renewing all the special copper coated nuts, but the studs aren't fragile. The problem is that the RH drive M20 manifold warps over time, taking the outer studs past their limit. The manifold face should be checked with a straight edge when it's off, and machined flat if found to be warped.

Didn’t think to check the manifold for warping. I found the nuts or studs were loose, so hoping that was the cause of the leak and not warping. All new studs and copper coated nuts.
I had enough stud to get two nuts on it, thankfully it didn’t shear inside or close to the head. So no need to pull out the welder.
Not getting enough oxygen to my brain I think!