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Mercury Grand Marquis mystery leak

2006 Mercury Grand Marquis. Hi Guys, please help, with your expert opinion because you might know of this Ford/Mercury leak, that the mechanics are not ‘seeing’-even though I brought the leak substance to them.
It’ not good when the Ford Dealer Service people keep putting us off. See, this leak began right after they did the Tune-up. Are they going about it backwards? The leak is a little oily, a little clear, and a little thin, but none the less still like a thin salad dressing vegetable oil that’s runny. I caught it on a stainless steel pan, positioned under and a foot in and a foot behind driver tire…sometimes I get a wiff of radiator hose smell when I turn off the car and open the door.

What do you think the problem could be?


What color was the fluid? Did it have sort of a sweet smell?

I had an engine mount leak a few years ago where the fluid matched this description, so that’s my guess here.

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Sounds like a leaking shock absorber or strut.

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Maybe it’s mystery oil.


It could be a small leak in the brake line, or a very small fuel leak.

To get a better picture, placing a piece of white paper under the leak would tell us more of the color.
And you can sniff if to see if it’s gas or not.
If it ends up to be pink to red…it could be a small leak in a tranny line.



If they added any fluids as part of that job, maybe they spilled some. If so, it will go away on its own w/time. The best way to find a mystery leak is to clean the engine using an engine cleaning product, then track it on a daily basis to see where the leak is coming from. Sometime they’ll also add a dye to the engine oil, coolant, etc which they try to spot using a UV light source. If you are willing to pay for that – which might be somewhat expensive – that’s the way to get to the bottom of it. I expect they think you aren’t willing to pay, so that’s why they are “not seeing it”.

It looks mostly clear but does have a slight yellow tint.
( so it feels like mineral oil, too)

Was this what you found in the pan that you used…or did you use a white paper towel???

We ask to use a paper towel, because different fluids will show different colors!!!

The best I can tell you, is to raise the car and use a “jack stand” for safety reasons. Then crawl under and take a look at that area in question. a brake line will be about a 1/4 inch diameter. A fuel line or tranny line about 3/8 inch to 1/2 inch.