Hi all. This will be long, please bear with me. I'm trying to help an old lady solve her car problems. She has a 2002 Grand Marquis with 90k original miles. Today she called me to say she's stuck in the middle of the road because her motor stopped and wouldn't start back up. When I got there, I asked her to try to start it, and the engine seemed to "get stuck" after turning over about 180 degrees. She did this twice while I observed, same result. So we towed it back to her place and the first thing I did was put a ratchet on the harmonic balancer. I got it to turn more than 720 degrees, so I figured it probably wasn't anything catostrophic. So I put jumper cables on it and had her fire it up. As soon as she did, it had a very pronounced, some might even call it loud, "tapping sound". I'm not an engine expert, but I've observed top-end and bottom-end problems. In my non-expert opinion it's coming from the top front of the engine. It may not be internal either. To eliminate all possibility of it being caused by a pulley or other ancillary device, I removed the drive belt and the sound persisted. The only other thing I can tell you about the tap itself, is that it's a regular interval, and it seems to tap about 2 to 3 times a second at idle, and of course a little more frequent for the first few seconds after cranking because of the additional revs before it settles down to normal idle. She also told me that she noticed the tapping sound when she started it up, and drove for about 10 minutes before this incident where her car cut off.

One more bit of history on this engine, which I believe is relevant. For some reason, her intake manifold (the first generation of the "new style" intake with hybrid plastic runners and a metal coolant passage) started leaking coolant out of the back of the driver's side coolant passage, down onto the driver's side head and then down into the V of the engine and down the back. Without doing any further analysis on the old intake (I assumed maybe her engine ran out of coolant and the pressure build-up caused the intake plastic to crack), I replaced her manifold with the Dorman intake replacement which has the metal coolant passage also. I never believed it might have been possible that coolant seeped into the adjoining air intake passage and into the cylinder, so the regular checks I did on her oil were visual only. I never did any of the usual tricks (blotter paper, or dripping dipstick oil down onto the manifold to see if it burns or crackles), I just regularly inspected the oil, visually, and I believe it was changed within the span of a 5000 mile interval, with about 2000 miles being put on the same batch of oil after the intake incident. I don't recall exactly when I did the intake, but I want to say it was about 82 to 83k miles (and it has 90 now).

One final bit on this particular motor, her oil gauge suffers from the classic "oil pressure switch" problem, whereby the oil pressure gauge is wired to the engine's oil pressure switch and has either two positions - in the middle, or dead. The pressure switches are notorious for going bad, and that particular problem with the oil gauge acting up, seemed to be very intermittent and sparse between incidents. I listened to the engine several times, and drove it, never suspected that it could actually be without pressure. I'd like to believe that coolant really didn't get inside the combustion chamber, and that she's had good oil pressure the whole time, but that may be wishful thinking.

Any ideas on the tick are appreciated. This woman is in the middle of a career change, she bought the car on my advice because I told her Ford motors are solid, and I'm ready to bend over backwards to help her out. Thanks all.

 

We have run into the PCV spring being too weak and the plunger inside just fluttering. Easy enough to check. Unplug it and close it off. Good luck.

 

Thanks for the reply. I've been reading through a ton of forum posts that Google knows about. In addition to the PCV issue that you mentioned, lash adjusters and cam followers (sometimes, mistakenly it would seem, referred to as "rocker arms") are common sources of the tapping sound. I called it a "tick" but it's much more than a tick.. it's a full-blown tap. I'm very scientific, and since I didn't previously own an oil pressure gauge, I put this off until I can get a gauge delivered tomorrow. I figure it's relevant, because people on forums seem to believe that these motors are very sensitive to oil delivery in the top end, with some people going as far as to say that the top-end of a Ford 4.6 can be worn out much quicker running 5w30 rather than the recommended 5w20.

I'll report back when I get deeper into it, probably with pictures to go along. Thanks again!

 

So I cracked open the bottom plug on the fitting at the oil filter, and I hooked up my shiny new oil pressure gauge without having to remove the oil pressure switch. It showed me 75psi on crank, and 60psi when it settled down to regular idle 30 seconds later. That's not to say that there wasn't ever a problem with oil pressure, so I'm gonna leave it hooked up for a while and continue to monitor it over a number of days. With 6 feet of hose, I have no reason not to.

The problem, whatever it is, is in the passenger side head. I've ascertained that with a mechanic's stethascope. I took off all but the rear-most, bottom-most valve cover bolt today. To get to that one, I'm either going to have to put a tiny 1/4" ratchet back there, or do what I've already seen at least one person do - remove the entire "air box" containing the evaporator and the blower motor. For a good pictorial, see Ford Crown Victoria Passenger Side Valve Cover Replacement

I'm expecting to find either bad lash adjusters, or bad cam followers, or both. Hopefully there's no damage to the cam or the valves themselves.. that episode where the motor seemed to hit a "dead spot" and stopped turning over, doesn't sit well with me at all. I'm hoping I can get the cam followers and lash adjusters out (and back in!) without a spring tool. That may be wishful thinking, and this turns into a week of waiting on Ford specialty tools to do this the right way.

As always, any commentary is appreciated.

 

I spent a good solid 5 hours today, removing things and moving things around. The last thing that needs to come out is the AC box, and it's getting stuck on the positive cable going from the starter to the battery, which seems to be bolted onto the back of the passenger side head. As soon as I raise the vehicle so I can get to that bolt, I'll have it licked. Interestingly, the URL I posted previously, indicated that this cable didn't have to get unbolted in order to remove the AC box. Although, that was a Crown Vic.

 

So I re-examined the URL I posted, and it appeared to me that they had the AC box off before taking off that battery cable from the back of the head. So I tried once more, and I was able to fenagel the box out with the cable still bolted in. But I discovered another problem. After not being able to use the door lock/unlock buttons since the day before, I discovered that power to half the stuff in the car wasn't present either. The overhead lights, the door lock/unlock, and part of the ignition (or things that get powered on from ignition voltage, like the chime module) don't work. And of course it won't start either.

I probed all over the fuse box on the front left fender, all of the fuses are good, but I might have ground problems. I checked the sockets of the 4 relays in that box, and neither position 85 or 86 (relay control circuits) have ground present. I guess I'll be detaching those boxes and cleaning the heck out of them and troubleshooting further. I want to resolve this problem first and foremost, before I crack open the valve cover. As I said in the first post, it's cut off on her 3 times, and me once, and it could very well be the same issue of getting power to various devices.

 

Finally, valve cover is off. I haven't removed all of the cam followers yet, it's raining sporadically here and I didn't want to take any chances. What I did find, was a bunch of shavings strewn all over the valve cover and the cam gear. I haven't determined whether they're metal or not yet, will need to buy a magnet. I couldn't tell what they were in my hand, but I'm leaning toward metal (though I realize they could also be plastic, from bad timing chain guides, right?)

If anyone has any comment on this, perhaps common failure modes, I'd love to hear it. I suppose I'll be taking her timing chain cover off next, for a closer look.

 

One more thing... her oil pressure switch has been acting funky lately. Car has 90k miles, and it's been acting up since about 85 or so. I previously looked at it, and determined that it was probably a bad switch, based on the fact that they tend to go bad after a few years. Now I'm not so sure. When it would act up, it'd "flicker", which is a condition consistent with either a bad switch, or a switch that's only seeing about 8psi of pressure, from what I understand. Maybe there are more shavings in her oil pan, wreaking havoc on the oil pump and the pickup?

 

I agree with the guide issue from the pictures you posted. If you had access to a bore scope, it may save a teardown, but I suspect a scope would confirm the guides are worn out. I would invest in tensioners while I was into it.

 

Thanks for the reply. I'll be getting back into it a little later today. Even with all of the tools in the world, I don't see any way possible that I won't be replacing something in the timing cover.

At this point I'm pondering whether I should do the chain too. You didn't mention that so I'm assuming the chains are usually good for a while longer? Also, do you have any opinion on the "S.A. Gear" brand of timing components? A local vendor has them in stock, though I think the consensus is that Cloyes has the best R&D. Your thoughts?