1991 Grand Marquis strange noise issues after oil change.

[Duke Napalm]

Howdy guys,

Just registered a few minutes ago, but I've been pouring though all the information here since purchasing my land yacht a few weeks past. Simply put, I love the thing, and it's more comfortable than any car I've owned so far.

At the risk of this becoming an introduction thread in the wrong section, I'll get down to my little issue now. (Though I could maybe do a write up with pictures later if anyone is interested? You've all seen 1991 marq's of course but this one is almost showroom quality condition, inside and out! And with the pittance I paid for the thing, I'm probably disproportionately proud of it lol)

I've been sort of leisurely working my way through the typical tune-up items. Cap, rotor, plugs, changing out the factory wires, all that good stuff. Disassembled/cleaned the entire top half of the motor as a side project/learning experience. I'm used to working on ancient muscle cars so I figured this would be a decent way to sort of broaden my horizons. I wasn't really worried about the oil, however, because it looked fine. Couple days ago I just decided to go ahead and change it out.

Now, I've done a million oil changes before and I'm 99.9% sure I didn't do anything out of the ordinary. I used 10w-30 Rotella partially synthetic because I love that stuff, whilst substituting out a quart for Lucas oil additive. Manual calls for 5w-30 but I live in a hot climate (Arizona) so I figured it'd be fine. At first, when I went to autozone, they didn't have any Motorcraft oil filters on hand so I hastily (and stupidly) settled on a Bosch premium, completely forgetting it didn't have an anti drainback valve. Even so, I fully primed the oil filter before putting it back on. I've even tried swapping out the Bosch for a motorcraft, and putting a zinc additive in the oil and it still didn't help.

Now, for the noise. It's only present on startup and then only for a minute or two after as the car warms up. It's not hugely loud, but definitely noticeable. Closest thing I can liken it to is a quieter version of an idling diesel engine. No loud tapping or noticeable knocking, just a quiet to medium clattering/rattling sound. On anything other than idle it goes away completely and sounds perfectly fine. The car itself runs smooth as honey across all rpms, and I don't -think- it's an oil pressure issue.

I'm pretty stumped! Before the oil change it never made any noise when cold. I guess I'm curious as to what it could be, how to fix it, and if I should be overly worried. Gah, I hope not.

Sorry for the wall of text, it's sort of a bad habit of mine!

Any info would be greatly appreciated, thank you.

[P72Crazy]

Welcome to the site. Did you ask the previous owner what brand and weight oil he used? I've owned 76 cars (many of them SBFs), and SBF V-8s are generally sensitive to oil weight changes once they get some miles on them. I'd say you have the engine working on a thicker oil film than it's use to. The qt. of Lucas may have "pushed you over the edge" (too thick) and it's taking a couple of minutes now to get enough oil up to the lifters. I know many folks who have switched to high zinc oil and it's very subjective as to how much zinc is enough, but really I think you've over done it a bit. Give the folks you got the car from a call and see what oil they ran in it. If the car has over 60K miles on it, switch it back (even though it might not be your favorite brand). I'm sure you'll get a lot of good advise on this site, so let's see what you get from the "pros".

[Duke Napalm]

Welcome to the site. Did you ask the previous owner what brand and weight oil he used? I've owned 76 cars (many of them SBFs), and SBF V-8s are generally sensitive to oil weight changes once they get some miles on them. I'd say you have the engine working on a thicker oil film than it's use to. The qt. of Lucas may have "pushed you over the edge" (too thick) and it's taking a couple of minutes now to get enough oil up to the lifters. I know many folks who have switched to high zinc oil and it's very subjective as to how much zinc is enough, but really I think you've over done it a bit. Give the folks you got the car from a call and see what oil they ran in it. If the car has over 60K miles on it, switch it back (even though it might not be your favorite brand). I'm sure you'll get a lot of good advise on this site, so let's see what you get from the "pros".

I'm certainly hoping you're right! Unfortunately, I've lost the gentleman's number since the purchase of the car (got it off craigslist, and my horrible phone likes to autodelete things when it begins to run low on memory). It's got 69,xxx miles on the odometer. Are there any particular brands or weight of oil you would recommend? Should I maybe try draining some of the Lucas mixed oil out, and adding some more Rotella? Have anything in particular you would suggest?

If it helps, I've got a fairly detailed maintenance log. This was the quintessential "owned by little old lady" car, and apparently it saw regular services at one of the ford dealerships down here. Doesn't specify the oil type, unfortunately. When I got the car, I completely forgot to ask, aside from if it had been changed relatively recently . Most of the time I look up all of the pertinent info online and just go from there anyway.

According to her son, she bought it new off the lot, and when she passed away he decided to sell. I've even got the original bill of sale, which is kinda neat.

I've used Rotella for everything and never, ever had an issue so this whole thing definitely has me a little befuddled.

Thank you very much!

[TecNickal]

Call the dealer and ask them. Look online at your phone bill, most companies save the call history for the last 30 days of calls.

[P72Crazy]

All of our local Ford, Lincoln dealers us 5W-20 and 5W-30 oil weights. I can't believe they use a different supplier so likely all of them use Motorcraft Oil. Additive packages change from time to time, so you can't get the same oil over the life of owning a car. I thought about your problem a bit over night and I really feel that the car is running on a thicker than normal film and that's what's causing the extra noises in the valve train. Provided you didn't over-fill or under fill the crankcase, there is no good reason for the engine to complain about an oil change unless the oil has significantly changed in film strength. I know from owning many Nissans and Toyotas, the V-6 and I-4 engines I've had would break-down the oil in approximately 2000 to 2500 miles. Valve train noise in these smallish engines is greatly reduced with an oil change. It's just like magic for the imports. I also had a 1975 Grand Torino Elite (75K on the odo) that had the 351W engine, it would get noisy at 2500 to 3000 miles and an oil change would quiet it down. So does the oil thicken or thin with time and mileage? I believe the engine will "shear" the oil molecules with heat and time. If this is the case, you're GM will chew up the oil and thin it down with normal use. Now, if you leave the oil exposed to heat and pollutants too long, will it "cook" and/or thicken up? I believe it will. Ever open up the valve covers on a car that has not been maintained properly? Looks pretty bad, sludge and hard black coatings on the metal. I'd just try the straight up 10W-30. If you want the extra zinc, pick a brand that advertises it has enhanced zinc or racing formula. And, there's probably nothing wrong with Rotella 10W-30 alone in our Windsor engines.

[P72Crazy]

PS, I've had high mileage SBF's leak and use oil by changing the oil weight and additive package. I bought a 113K mile Chevy 4x4 (damn can't believe I admitted that!) and the guy had used nothing but Pennzoil 10W-30 in it. Guess what I change it with?? I also have 6 P72 Ford Crown Vic's that were purchased from the NC Highway Patrol. All of these had 30 HD run in them from "day 1"........you guessed it, I still use 30 HD in them (with SM api grade) for the enhanced zinc.

[gadget73]

5w30 is too thin for an older 302. The manual should even say 10w30 or 10w40 for most temperatures you'd find anywhere in this country. Maybe they changed it by 1991, but the internals of that engine didn't change from 86, and I know thats what my 86 manual says. My 1991 Mark VII has been running 10w30 for the last 244k and it doesn't make funny noises. I would probably replace the Mucous with real oil though. Not personally a fan of that stuff. The brand of oil isn't real particular, as long as it meets the API standards.

Might be just a sloppy bottom end. The non-HO engine beat its bearings pretty badly, and if this one didn't get warmed up regularly it may be even worse off. Still fairly common for a 120k mile engine to hammer a bit on cold startup. If thats what it is, theres really not much you can do about it. Might be able to confirm the sloppy bearing idea with an oil pressure gauge. Get it good and warmed up, and hook up a test gauge to see if you have any oil pressure when its hot. Fords don't really need much pressure to run, so I wouldn't get overly worried about it being low but at least you'll know what that noise is and why you need to upgrade the stereo to cover it up.

[miamibob]

Have always run 10W-30 or 40 in my '87 GM but since I can no longer do the oil changes, the dealer uses only 5W 20 or 30. Haven't heard any weird noises but time will tell.....I add a little bottle of Zinc to it when I get the car back so we'll see what happens.

[P72Crazy]

Yes, we use 10W-30 in our Fox Bodies and the same would go if I had a 5.0 in a Panther. I'm not saying anything is wrong with 10W-30 for the 5.0s, rather stating what our dealerships carry in bulk pumped throughout the shop. Most 5-20 or 30 oils have little zinc (thank you EPA). Valvoline makes a racing version in 10W-30 with (I think 1600 or 1800 ppm zinc/phosphorous). Most of our Fox Bodies sit so it's not really a big deal what goes down the pipe.

[Duke Napalm]

Call the dealer and ask them. Look online at your phone bill, most companies save the call history for the last 30 days of calls.

That is certainly a good idea, the only problem being that I do so many craigslist deals and field so many calls from random people that his would be lost in a sea of unknown numbers. As for the dealer, there isn't any indication as to -which- dealer it was that did the servicing. The maintenance log itself is in the original handbook that came with the car, and is just a list of dates and things done/mileage with the word "dealer" written in pencil next to them. Upon closer inspection, however, 10w30 is written in tiny, tiny letters in a few of the boxes so at least we know that's right!

[miamibob]

Put what the owner's manual says and call it a day!!

[Duke Napalm]

PS, I've had high mileage SBF's leak and use oil by changing the oil weight and additive package. I bought a 113K mile Chevy 4x4 (damn can't believe I admitted that!) and the guy had used nothing but Pennzoil 10W-30 in it. Guess what I change it with?? I also have 6 P72 Ford Crown Vic's that were purchased from the NC Highway Patrol. All of these had 30 HD run in them from "day 1"........you guessed it, I still use 30 HD in them (with SM api grade) for the enhanced zinc.

You know, now that I think about it, I had a 2003 Crown Vic interceptor I bought for cheap, and I absolutely loved it. When I changed the oil on that, though, I added in lucas and it developed a little bit of an identifiable rod knock on startup that wasn't present before the change. In spite of being a ford guy, I've mostly owned and worked on older chevy's (I'm right there with ya on shame, lol) because somehow I usually always end up with them (Anything from a '79 z28 camaro to a '74 nova supersport. Even a giant '87 K-30 with the military 6.2 diesel)

Every time I used lucas in one of those, there would immediately be a noticeable difference in running smoothness/quality and it even seemed to up the oil pressure, especially in my camaro. I am now coming to understand that "newer" engines are a whole different ballgame (big surprise, right?) but maybe it's just a ford thing?

So short of hunting up a gauge, I suppose my only option is to drain the oil and stick some additive free 10w30 Rotella in there and see what that does. Should I maybe put some kind of zinc additive in there, though? If so, any suggestions on what kind? Bah, I hate wasting oil and resources when I'm on such a tight budget but I suppose I'm learning something.

Thanks guys for all the good info so far!

[91waggin]

On a 91, zinc is more or less unnecessary. 86 and up are roller cams, rather than flat tappet. Zinc is necessary on flat tappets, but I've got a 91 that hasn't seen any zinc additives as long as I've been driving it, which is almost 100k.

[gadget73]

Its a roller engine, so you don't need the extra zinc. Thats a flat tappet thing, 85 down.


I suspect the dealers have 5w20 and 5w30 in bulk because most things made in the last 20 years use it, and almost all of what they work on is well under 20 years old. Not much point having 10w30 for the occasional weirdo that still drives an old car and actually gets it serviced at a dealership. Frankly I'd be a bit scared of letting most dealerships work on my old stuff unless they had a guy that had been there since my cars were still current. Most people look at my old stuff and go "this is too old to fix, you have to buy a new car".

[miamibob]

Its a roller engine, so you don't need the extra zinc. Thats a flat tappet thing, 85 down.


I suspect the dealers have 5w20 and 5w30 in bulk because most things made in the last 20 years use it, and almost all of what they work on is well under 20 years old. Not much point having 10w30 for the occasional weirdo that still drives an old car and actually gets it serviced at a dealership. Frankly I'd be a bit scared of letting most dealerships work on my old stuff unless they had a guy that had been there since my cars were still current. Most people look at my old stuff and go "this is too old to fix, you have to buy a new car".

Spot on in reference to the oil weights and the reason/logic behind the dealers decision. My dealership (and I HATE not being to do my own work) has several techs that have been there since before electricity. They, in turn, have "schooled" the newer guys on the older cars so I am probably safe, at least in the short term! The dealer's owner is a good friend of mine and they take special care when I come in as there are not many cars as old as mine and in such nice shape.