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Eric, Automotive Repair Shop Manager
Category: Mercury
Satisfied Customers: 32043
Experience:  20+ yrs. experience as repair shop manager and technician.
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Always after a cold night of 40 or below, both my 1995 grand

Customer Question

Always after a cold night of 40 or below, both my 1995 grand marquis GS & 2000 Lincoln towncar have constant high pitched, whining sounds I can hear with my stethoscope coming out of both car's left catalytic converter (listening with my stethoscope) that usually lasts until the cars warm up. The Lincoln oil light also comes on intermittently until the car warms up. Doesn't sound like a bad catalytic converter clunking sound at all...
Submitted: 1 year ago.
Category: Mercury
Expert:  Eric replied 1 year ago.


I am sorry that you have not been helped yet. I just came online and saw your question.

have you listened around the welds for the converter, as well as the heatshields? If not, we need to do that just to make sure that they are not the cause of the whining noise. If ok, I suspect you have a very small piece of honeycomb in the converter that is broken and causing the whining noise when cold.

Customer: replied 1 year ago.
Eric, I have to check the c.converter like you suggested. I forgot to mention that when I start the cold engine on my 2000 Lincoln Towncar it hesitates like it is trying to briefly stall every 5 seconds while the high pitched whining lasts, so I give the engine more gas. When I drive it the oil light comes on the screen until it warms up a lot.

Your theory about BOTH cars having the same problems with the same left c.converter whining sounds strange, because the Lincoln only has 85,000 miles on it and the Mercury has 187,000 miles on it...It is possible though, since both cars have the same window switch problems, both have the same 4.6 liter engines, and both are Fords. Is it possible BOTH Fords have the same small piece of broken honeycombs, too, if it's not the seams or heat shields. I will listen to those areas tomorrow, so you might want to think all this over until I can confirm your possible thoughts on the matter.

Also, one friend mechanic, Kelvin, suggested it might be a narrowing of the opening into the c.converter (carbon build up in the exhaust I suppose) squeezing the air flow and causing the whining. My brother saw a lot of white smoke coming out of the 1995 Mercury tailpipe yesterday when I accelerated up to 35 MPGs and dissipated as I got above that, or the white smoke may have dissipated by increased outside air around the tailpipe. Maybe those 2 symptoms coincide with Kelvin's idea...

A 2nd mechanic, Tim, said he had a similar problem on a different car of his, and it turned out to be a vacuum break due to a hole in the gasket leading into his c.converter. I have 2 c.converters on BOTH my cars. What do you think of that idea?

Thanks, Dale
Customer: replied 1 year ago.


I need more time on my end to inspect the seams and heatshields on my 95 Mercury before I can rate your answer and give you a positive score.

Last night it wasn't cold enough to get my 95' Mercury to start the continuos whining sound; however, I looked under my 2000 Lincoln though while it was whining and couldn't find breaks in the converter seams or heatshield, so I think I traced the whining to the airbag compressor, which is probably radiating down into the c.converter. I have to check the 95 Mercury on drive up lifts as soon as it gets cold enough to replicat the cold whining noise with that car. So, be patient until I can get a very cold night and hear whining noises.

Do have any new opinions about my last response and my new development with the 2000 Lincoln. I am sure you know the Mercury doesn't use air suspension bags, so it won't be a compression issue in the engine compartment. Thx in advance for any new comments you may contribute...