Squealing V12 engine HELP!

[coalboy]

Well trying to get my car fully shipshape but have a high pitched squeal after recommissioning the engine. Ok the belts are a likely culprit I thought, but had the belts off the alternator, then steering pump, then air pump and therefore the water pump and still the squealing. Anything else anyone can think off, seems louder on the LH side of the engine bay. The rad fans are obviously not turning, just thought while typing this the heater fan unit is that side of the engine bay.

All ideas welcome. Hope it’s nothing internal

[bitsobrits]

Flywheel against the metal cover plate on the bellhousing?

Is the squealing somewhat muffled (as it would be for an internal issue)? Or more of an 'external' sound?

[coalboy]

Sounds more external than internal too me will eliminate heater motor today and look towards the rear of the engine as a possible source

[coalboy]

Ok the heater fan was a long shot not that, after turning off the engine the squeal subsides and there is a sound like a balloon deflating, wonder if I have an exhaust leak?

[John37]

Vacuum leak to servo or distributor?
Your's sounds like a US spec engine. My UK engine doesn't have an air pump. Is there exhaust recirculation?
It's unlikely to be an exhaust leak unless your system is almost completely blocked.

[coalboy]

Thanks for the suggestions. Disconnected the servo and reservoir and bunged the inlet manifold port, no elimination of the squeal,got my stethoscope on the distributor couldn’t hear it coming from there or from the black inlet manifolds.

Still to check the rest of the vacuum lines, mine is a later UK engine so has the air pump but not all the recirc stuff. Onwards I go. See what tomorrow brings.

[chris420sa]

Hi there
The squeal could perhaps be from the power steering system itself, not the belt drive to the PS pump.
That could result from a number of causes eg low TQF fluid level in the reservoir (test when hot but watch out for hot surfaces nearby), which may be caused by leaks in the PS (pipework...etc.)....
I had something which sounded similar to your squeal and fixed it only by a rebuild of the PS. I can point you in the direction of a guy who has spent 40 years renovating steering racks in his workshop near Chatham. The rack is a real bugger to get back in place especially as the pipework routing sucks.On this forum a contributor said he'd removed and replaced his PS rack without removing the radiator - impossible in my experience!
Good luck and please keep us posted.
Best
Chris

[coalboy]

Well bought a cheap smoke generator and disconnected the brake vacuum tank line onto the rear LH inlet manifold and low and behold from the right side of the rear LH inlet manifold there was a wisp of smoke, nothing else except out of the air box seals. Closer investigation and there is a line from the front rear LH inlet down to one of the carbs which had a slight tear from perishing. Replaced and all good. Just to be sure did the same excercise on the stubs on the other inlets on the RH side and nothing leaking.

Well just refitted all the belts and will test on Monday, just need to recharge my battery now lol.

[MarekH]

How is a vacuum leak related to a squealing noise?

kind regards
Marek

[coalboy]

Air being drawn in via a very narrow tear in the rubber makes the noise like a reed in a musical instrument. After belts, and leak via brake vacuum tank from passing non return valve AI suggested a leak in the inlet manifold area was the most likely cause in a V12 engine. Go figure my first application of AI in car repair.