Bought new, my F150 truck has not had any trouble for the 7 yrs I've owned it. I use it mostly for going to work (10 miles), hauling loads from lumber yard, and a tractor occasionaly. It's a 1998 and has only 55K miles on it. I planned on keeping it for at least 20 yrs if possible.

About 2 weeks ago I noticed a slight engine knock after starting engine when cooled down. Avg temp now is about 50F at night and 80 during day. This slight knocking sound can occur after resting 3 hours or longer during day or night. The sound grew a little louder over the 2 weeks and usually lasted only about 30 seconds and then went away, however, the other day it lasted about 2-3 minutes. It seems to be comming from the drivers side 3rd plug back area. I have noticed a slight antifreeze level change, but I think it's fairly normal now.

I parked the vehicle and changed the oil and filter. Inspected the plugs and changed them while I had em out. I kept some of the oil and all plugs. The oil looked ok. Did not look milky at all, but did need changing. (about 6 months since I changed it). The plugs looked ok also (normal wear on each).

I started it back up and the noise seemed about the same at first, but went away quicker (about 15 seconds). Tried again later about same.

I tried to pin-point the sound by using a wooden dowel w/o success.

Not sure wear the gas pump is on this vehicle or if a sensor could cause this sound. I've read/heard that it could be gas pump, exhaust leak, piston sleeve, sticky valves (which I'm hoping).

Anybody have next step ideas before tearing off the valve covers, etc?
Someone suggested redex.

 

Took it to a mechanic and they said the lifters are bad. $1100 to fix it.
I've done a fairly good job replacing the oil/filter myself, what would cause this?

Has anyone had any experience replacing them on this model or similar? I'd have to take off all that EFI stuff off which I'm not familiar with. I'm also worried that it would just occur again.

Any good manuals out there?

Somone suggested redex or reslone first and then worry about it afterwards if it still occurs.

Thanks for any replys

 

Jake,
Bad lifters is not a common problem with the 4.2. Not saying it isn't your problem, just saying it is not very common. Matter of fact, I've been lurking in the 4.2 forum for 6 years and do not have specific recollection of any case of bad lifters.
Occasional valve spring breaks, but other than that, the valve train seems to be pretty reliable.

What has been more common in these engines is slowly dropping coolant level. This is often a sign of a leaking lower intake manifold gasket or a leaking timing chain cover gasket.

See if you can determine the build date of your truck/engine. If it is before Dec 1997, then I'd definitely be checking further into the slowly dropping coolant issue.

If you have a small amount of coolant leak into a cylinder while the engine is off, it can cause slight knocking right after start up, until the liquid clears the cylinder.
Left unchecked, this can lead to one day a lot of coolant leaking into the cylinder and the result then can be a ruined motor when you try to start it.
Liquids are essentially noncompressible and when the piston goes through the compression cycle, it meets a brick wall and then metal things break. Not good.

There is much to be read about this in the 4.2 forum. Feel free to drop in there if you want to get much more of the skinny.

But, at the very least, I'd suggest you pay REAL close attention to the coolant level drop.

Having the problem (gasket) fixed is way less expensive than having to deal with what the end result might be.

 

Briain thanks for the reply.

I don't believe (though I've noticed a drop in coolant over many years) that it is leaking coolant into the engine. I say this becase the oil has always looked black when I change it and the plugs I just removed looked remarkably normal. I've read through the coolant leak problems that many 4.2L folks have and it frustrates me enough to want and trade it in for a Toyota, but I like this truck and would like to keep it.

Now, I could be wrong about the coolant and thus scares the heck out of me. I'm not sure, other than just changing the gasket, there is much else I can do about that?

However, Ford says the lifters are bad. How can they say that w/o opening it up? What's the worse that can occur if I continue to drive it?

I've taken out a carb on new T/A, fuel pump, changed out rotors and done timing on older models, however, I have not done anything like this yet. I'll have time over the summer to work on it if required, however, I need a little direction and maybe some help from everyone later:
- How can you tell if lifters are bad by looking at them?
- Any hints or manuals out there that may help me?
- Where should I get the parts? (not ford dealership I hope)

Otherwise I may drive it till it drops and swap out the engine or trade it in for a Toyota.
Thanks again

 

Well, if it is sticking lifters, then you can try any of several over-the-counter treatments, or go with the old school trick: Add a quart of transmission fluid to the crankcase to clean / loosen the sticking lifters.

As you mentioned, there are several OTC products you might try.
Ask 100 people and you'll get 100 different opinions.
If it were me, I'd try Marvel Myster Oil. I'd pour some in the crankcase and drive it and see if it helps.
Or I'd try the Risilone or similar engine flush products.
If it is a sticking lifter, then such an approach is, in my opinion, well worth trying. If it doesn't solve the problem, you haven't spent much money.
Some folks would balk at the idea of adding ANYTHING other than motor oil to their crankcase. But, fact of the matter is, it is done all the time without trashing the motor.

Just curious, what brand and weight oil are you running right now?

As far as the gasket and feeling bummed about your motor. I'd not sweat it right now. Again, try and determine the build date of your motor. I believe there is a tag on the valve cover that has the build date. If you can find the date, we can determine if yours is pre or post the date Ford changed to improved gaskets.

And, for what it's worth, I have owned all manner of vehicles over the last 30 years.
Chevy Ford Nissan Lexus Jeep Buick Toyota Mitsubishi etc.

Even WITH having to replace the lower intake manifold gasket at 155,000 miles on my 2000 F150, it remains the most reliable, trouble free vehicle I have ever owned.
I sold that truck at 170,000 miles and got an '05 F150 with the 4.2. It now has 44,000 miles on it and it appears it will be just as reliable and rewarding to own as the 2000 was.

My point being, you CAN get all bummed out over this, but I would not. At least not at this point. You might pour some engine washer or magic potion in the crankcase, a few sticky lifters free up, and you are good-to-go.

If not, we can take it from there.

Keep us posted and hope you get lucky.

 

I agree with Brian.Try the Marvel Mystery Oil first.That stuff loosens sticky lifters quick.If that fixes the problem ide seriously look into replacing the lower intake gaskets,if you decide to keep the truck.But,make sure the engine build date is before 1/15/98 before changing them.Good luck and keep us posted.

 

The build date is 11/97