Whining engine
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Whining engine
I changed the valve cover gaskets on my 1990 F-150 302 EFI today. TO change them I had to remove the intake, after stripping it of throttle body and egr valve. A changed the valve cover gaskets and used all new gaskets on the intake, but when I started it up it made a continuous, high pitched squeal. It squeals at idle and at highway speed, and everything in between. It seems to be an air leak somwhere. I removed my belt and ran the engine for a second and the squeal was still there. Any idea what this is? It is extremley annoying!
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Joined: Jul 1999
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Whining engine
It sure sounds like you have a vacuum leak ...verify all the vacuum lines are attached , its easy to miss one . Its possible you left a bolt loose on the lower intake or the gasket got damaged during reassembly ? If you cant locate the exact area of the leak by simply listening and looking , a mechanics stethescope with the probe removed and a piece of 1/4 copper pipe in place of the probe . Its great for locating the exact area of a leak vs using a flammable liquid to locate a vacuum leak . More than likely its just a vacuum hose you forgot , but it never hurts to make sure .
Paul
Paul
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Whining engine
I also figured it to be a vacum leak. Can't find any lines loose, so I'll probably have to get a hold of a stethescope. Also, I forgot to metion that the noise is LOUD. almost enough to hurt your ears under the hood. and it goes away as I'm accelerating, then comes back when i level off my speed. Does that point to any more specific area? Thanks
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Whining engine
Oh yeah, that includes vacuum hoses to other stuff, but if its very far from engine, I would think you could tell. everything you took apart thats under man. vac. should be suspect. Intake and throttle body gaskets, hose connections. On a 302, isn't there a vac hose tucked up underneath the upper intake man. thats hard to get to? what if it was split?
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Whining engine
Turned out to be a tiny piece of the old gasktet was left on the throttle body which held it just the slightest bit off the intake. A simple mistake, but it sure was annoying! Soon as I got that fixed I heard an exhaust leak and had to change a header gasket! Bad week or something.
