Engine "rattles" only on "Cold" start

When the engine is started after sitting overnight, the oil pressure takes 3-5 seconds to come up to “normal”. (It comes up instantly, not slowly.) The engine “rattles” until the oil pressure comes up to normal. After the engine has been run, the oil pressure comes up within a second the rest of the day. (No rattling) Does the oil pump have to stay primed? Is there a check valve in the oil pump intake? The pump has been checked ok by mechanic for pressure. Any suggestions? 2003 Mercury Grand Marquis with 85K miles.

I don’t know anything about the car or pump, and I’m sure you’ve checked the following:

  1. Oil quantity too low
  2. Oil too thick for the weather
  3. What defines a “cold” engine? 60 degrees? 30 degrees? The temp affects the viscoity of the oil. In other words, it takes it longer to reach the “rattling” parts.

Of course, when all else fails, turn up the radio.

Do you change the oil yourself? Whether the answer is yes or no, a good anti drain-back valve in the oil filter is a must. The OE Motorcraft filters are good in this respect and can be bought inexpensively at mass market stores so you don’t have to pay $stealership$ prices. If this rattle cropped up recently, I suggest that you install a new, quality, oil filter, top off the oil and see what happens.

Lots of information about maintaining and troubleshooting your car can be found at www.crownvic.net.

I have the same problem myself on my 94’ Chrysler. I get a couple of seconds of rattle if I get a bum filter that has a weak anti-drainback valve. Of course the engine has a quarter-million miles on it too, which may be contributing to the problem. I’d stay away from generics and from Fram–when using both I have the problem. Wix seems to make a pretty good filter. In the cold weather, a full-synthetic oil will enable the engine to get oil pressure sooner too, as the oil won’t be a puddle of jelly at below freezing temps. Good luck.

Chances are no damage is being done, but I think I would change out the oil filter.  It should be an easy change if we are right about the drain back valve, since those filters are usually on top of the engine and don't tend to leak out lots of oil when you change them.

Is One Person’s “Rattle” Another Person’s “Knock” ?
It’s difficult to hear the difference through cyber space.

It looks like you’re not the only one with this complaint.

A Mercury TSB (Technical Service Bulletin) pertaining specifically to 2003 - 2004 Grand Marquis, Crown Vic, and Town Car models addresses a “knock during initial cold start”. It talks about an engine knock that dissappears after the engine is fully warmed up.

I’m not sure what’s at work here, but the fix is the installation of an exhaust shield kit # 3W7Z-5E258-AA. Apparently shields are installed (top & bottom halves) over the existing catalytic converter shields and Voila! . . . the knock is tamed! It can’t be rocket science because the labor is only about a half hour for the kit.

I’m not sure if this is your problem, but I would definitely look into this. Your local Mercury dealer has probably done some of these and can maybe shed more light on it. Describe your situation to a knowledgeable Technician and see if he/she concurs.


O. K. Guys, I’ve Waited As Long As I Can! This Question And My Answer Have Worked Themselves All The Way To The Bottom! Don’t I Get Any Stars?

What does it take to get stars around here? I thought my answer was pretty darned good, eh?

Ken, Where’d you go? Was that a good answer or what? Anybody listening?


Thanks, I Needed That! Who Did That?

Thanks for all the help… By “Cold” I meant 12-18 hours between 60-80 degrees.
The Oil and Filter has been changed and the problem has gone away… Must have been the filter…

Thanks again…

I guess we need to find a way to take away CSA’s stars now.

Take Em. I’m Totally Humiliated And Humbled, But I’ll Be Back.

Besides, you never know if I fixed somebody else’s Crown Vic, Grand Marquis, or Town Car rattle. You know, somebody who hasn’t thanked me yet!