rather annoying and slightly worrying noise...

[garyp_E30_325i]

Mr car has developed a rather annoying and slightly worrying noise...

It's a high pitched whine, doesn't necessarily sound metallic but maybe an 'air rush'... I had fitted an Ecotek valve (not convinced by this thing, either way), after adjustment according to the instructions the valve would whine off-throttle (a little at tickover and a lot when shut-off - changing gear / deccelerating). However the whine got worse (at first sounded like it was coming through the speakers but you can hear it outside the car too). The Eco-valve is now off, but the whine is still there - and getting worse! It goes away when driving with the throttle open (maybe 'cause of air movement...?), but is there whenever I change gear, deccelerate or hold a steady throttle. So I just have to accelerate constantly and no problem then, eh?winkeye When stationary it's always there, no matter of throttle position. I just fitted a larger throttle body (at same time as removing Eco-valve), but it was there before and after.

Anyone got any ideas...?

[beardymat]

just a thought but have you checked the rubber hoses for splits,could be one of those sucking air in and squeeking. might be worth a look especially as youve been messing with them

[garyp_E30_325i]

I checked all the hoses, they're all degraded but none split. Thanks for the suggestion though.

Had another look at lunch time there, it's definitely more of a whistle than a whine and seems to be coming from the inlet manifold or thereabouts. Though I had the head re-built with a cam and a complete head gasket set less than 2K miles ago, surely it shouldn't be a blown basket?

I need to get a couple of bits n pieces from my local BMW dealer, so I might ask them to take a look - what will they say when I turn-up with an E30 parked next to all those shiny new models?8O They should be jealous!:D

[beardymat]

it does sound like its pulling air in somewhere but what is it running like? if its sucking air after the afm then itll be runnin lean and might tickover badly!

someone else out there must have some ideas before you resort to the stealers

[Brianmoooore]

Take a 3 foot length of garden hosepipe, stick one end in your ear and move the other end around the engine untill you locate the noise.

[MONSPORT42]

Is the sound coming 100% from the engine bay? because what you describe could be the fuel pump.

[garyp_E30_325i]

Is the sound coming 100% from the engine bay?

Yeah, it's getting louder and you can clearly hear it whistle from around the inlet manifold.

Took it to my local BMW dealer, one of their service guys came out for a look and, after slagging off my Power Boost Valve and other mods, concluded that either a gasket has gone or the inlet manifold has cracked. He recommends letting the engine get up to temp, then soaking each cylinder inlet in turn with WD40 to see where the leak is.

He also reckons it's a cheap fix, that is 2 hours labour @ Ԛ£67+vat each plus parts. Yeah OK mate, I'll find the leak, get the parts cheaper any multitude of places and either do it myself or pay and independent Ԛ£20-25 per hour cash, thanks anyway.

Oh well, sounds like a good excuse to get that "Alpina" type inlet manifold & rocker cover I've been thinking about... just have to convince the wife: "yeah love, the car won't work without these parts and the 'black' ones were cheaper..."

[MONSPORT42]

Ah, a whistle not a whine! If you can do without the car for a week, you could get your own manifold and rocker cover professionally powder coated (had mine done in Diamond Black to match the car) which would be a whole lot cheaper. Could also do a little Dremmel work to match up the inlets to the gasket before it goes away. Also a good time to get your injectors properly cleaned while the fuel rails accessible. You see, every cloud has a silver lining!