I've a type 4 engine in a buggy and the last week it has started to emit a very high pitched (and embarrassing) squeal. It's definitely not the fan housing and this morning I've checked the carb and the exhaust for fitting. It's coming from the passenger side and only happens when I lift my foot off of the accelerator. There's no backfiring as you'd expect from leaking in the inlets, I'm just hoping I don't have to take the head off as it's a pain in the proverbial Could this be a leaking head? Please say no.
BTW it runs fine other than the squeal.

I had a high pitched squeak that was rev related.
Sounded metalic
Worst at idle and slowly disappeared the more revs.

Turned out to be a paper head gasket that had delaminated

This doesn't sound metallic but more like pressure related but only when the foot is taken off the accelerator or at idle when it's hot.

Could it be your passenger?

hth

lol.

worth checking for loose manifolds as the gasket can squeal under vacuum like a read does.

i'm with Vlad.

Foot off accelerator means you got your greatest vacuum pressure in the inlet manifold. a small leak can emit very high pitch sounds.
I'd be tempted to wiggle or put pressure on the manifold components while its running, wiggle hoses, look for change to locate the problem.

My toyota did that once, used to be painfully high pitch!

Maybe a pig..
Sorry......

I'd already checked the inlet manifold, to me a leak there would cause a backfire rather than a squeal so anyway the head came off, cleaned up and went back on again. The only thing I could find was that some of the head nuts seemed too easy coming off so hopefully that's what it was. Can't check it out until tomorrow as I'm sorting out a sticking brake at the moment....it's all good fun

spray some carb cleaner or start ya bastard around the manifold matting faces and see if the idle increases. if it does, you have a leak for sure.

My money is on manifold leak... head leaks normally more of a boom or choof than a squeak, as their on compression or power stroke rather than intake (both are way more pressure than intake vacuum)

So I reckon manifold gasket, or maybe a crack or pinhole in the manifold itself.

Vlad's tip would give a nice confirm tho.

so you tried it with the fan belt removed??
best to spray water around manifold's , less chance of setting you car on fire

breast plate rubbing behind the pulley maybe

All sorted now. It seems it was the head leaking due to the head nuts loosening. Everything put back together again and good as gold. I knew it wasn't the fan scraping as I've had that enough times over the years and didn't think it was the inlets either I was just hoping someone would come up with something way off the board to save me from having to remove the head i.e. an easy way out! Anyway it's all done now so thanks guys for your input.