9 replies to this topic

[SmellyGeekBoy]

Model: 1275GT
Year: 1974
Description of problem (please be as in depth as possible): Hi all!

Usually I'm pretty good with Mini issues but this one has me stumped... Basically it's started making a loud "hollow" blowing / sucking noise under acceleration and is very down on power at higher revs. I checked the exhaust over thoroughly yesterday and found it was blowing slightly at the Y piece, but I've fixed that and it's still making the noise. Doesn't seem to be blowing at the manifold either so I'm now 99% sure that this is some kind of induction noise.

I checked the cone filter over and blew it out with some compressed air but it all seems OK. The dash pot was dry so I topped up the oil in there which helped a little bit with the power but the noise is still there.

Any non-standard parts that might be involved with the problem?
MG Metro A+, K&N cone filter, Maniflow LCB system, modified head



Thanks in advance for any light you may be able to shed on this confusing issue!

Edited by SmellyGeekBoy, 11 April 2011 - 10:20 AM.

[xBR4DLEY]

Air leak? Check all hoses for splits and if they are on properly.

[SmellyGeekBoy]

Thanks for that, sounds like a plan. I'll give all of the hoses a good going over tonight but off the top of my head I can't think of any that it might be...

[yeti21586]

My mini made a similar noise to what your describing when my head gasket went.

YetI

[Scholes2012]

My mini made a similar noise to what your describing when my head gasket went.

YetI

+1... took it into Sleaford Mini Center today, it's blowing between Two and Three.

[ministar]

Maybe head gasket. but check everything else first. I wouldn't recommend driving it till you know exactly what it is.

[liirge]

Sounds like an air leak, check all hoses, and then when running see if the engine tone changes when you spray WD-40 or similar all around the manifold around the gaskets. I usually add grease to my gaskets on the inlet manifolds for 2 reasons..1. it keeps them in place whilst assembling, and second it seems to seal better.

[SmellyGeekBoy]

Thanks for your replies everyone.

I should mention that I had a water pump failure on the motorway a few months back which obviously caused some overheating (didn't want to stop on the hard shoulder as I was only about a mile from the exit so I carried on well into the red), the engine has been running fine since I got the pump sorted but I bet it's head gasket as a result of the overheating. I was going to change the oil soon anyway so I'll have a look and see if there's any evidence of any water in it. I've had head gaskets go before but never bad enough to make a noise!

Oh, and no risk of driving the Mini, it's not my daily driver so I can take my time to diagnose the fault properly.

Edited by SmellyGeekBoy, 11 April 2011 - 01:21 PM.

[Scholes2012]

Mine was blowing between cylinders Two and Three, so there was no water in the oil, and made a kind of WHARP sound coming from the carburetter area when i revved it. think a compression test would have picked it up.

[SmellyGeekBoy]

Yep, for anyone following this thread in future, I took the rocker cover off last night and sure enough there was the white emulsion-y stuff all over the inside of the cover and the rockers. Looks like I'll be having the head off at the weekend!