I posted this at another F150 site so sorry if you have already read this.

I have a 99 F150 5.4 4x4 with 173K.

I just bought the truck on Monday, and well I thrashed the hell out of it during my test drive, nothing out of the ordinary. No oil leak, shifts fine, drove fine, abs light on but other than needing a good cleaning it seemed fine; certainly no engine noise no loud knocks or anything out of the ordinary.

Drove the truck about 500 miles and then there was a severe knock that started on the way home on the highway, I don't know how it could have just showed up but as I said I flippin thrashed the mo fo during the test drive in attempt to find any problems such as this.

I understand without hearing the knock it is hard to identify, but it is audible at idle, gets louder around 1800 - 2600 rpm and becomes inaudible above 3000 rpm. The engine idles smoothly and still seems to have the same power. There is no smoke from the exhaust, but there appears to be a bit of metal in the oil, but I was inspecting at night and I could not do anything this morning.

I am assuming catastrophic failure is eminent and I am going to have to replace the engine, I am going to take it to a mechanic because this is a bit out of my shade tree mechanic realm.

I bought this assuming that this is a pretty reliable engine...well I have had this engine before and lots of miles without a problem. I know these engines can pile on the miles and usually the overhead cam becomes an issue but not a connecting rod, but I swear the noise sounds like a connecting rod.

Any insight or ideas would be greatly appreciated.

Today sucks but at least it is not my only vehicle, but it is the one I need in the winter.

 

Sounds like a rod bearing. Or possibly a broken timing chain tensioner or guide, sound anything like this?

This is just at idle, but when driven it would go away between 1500 and 3k and then show its ugly face after that.



This turned out to be the timing chain tensioner, guides and a few bottom end bearings.

Heres a quick clip of the motor out and the amount of slack in the timing chain..




Try to get a video of the noise. Use a mechanics stethoscope and try to pinpoint where it is coming from. Metal shavings in the oil is probably the rod or main bearings. If you think it is possibly the timing chain guides and tensioner which is fairly common, then remove the valve cover and check for slack in the chain, there shouldnt be any.

 

I can only hear the noise on the driver side, but the noise sounds very similar to your noise, and it acts nearly the same when reving the engine. Still beyond my capability but sounds like less than an engine.

 

By draining the oil and removing the pan, you can look at the rod bearings. Have someone turn the motor over by hand with a socket over the crank pulley, if there are bad bearings, you will see/feel them. If it is rod bearings, depending on how bad it is, Ive heard they can be replaced from under the truck with the engine still in? Someone can clarify that. I know its doable on some trucks. But the rod journals and crank journals must be inspected at that time and also measured to see if they are still within spec. If you catch it soon enough, you might get lucky. I have seen some pretty bad ones that were no repairable, which if new bearings are installed will eat them up very quickly. So, some inspection is needed to figure out what you have going on. Also make sure your not just hearing an exhaust leak at the manifold. Sometimes that can sound like metal on metal.

 

Ok, headed off to the mechanic today...I am guessing rod bearing but we will see. I will post up the update.

 

It is a nice looking truck in my opinion....I want to sell these wheels and get some different wheels and bigger tires. Thinking Hankook Dynapro MTs....had those on my FJ Cruiser and I loved them.

 

Survey says......new engine!!!! That is messed up, but at least I have a reason to put an engine in it...at least it is not trashed.

 

What was the diagnosis? Good looking truck. Those wheels don't look half bad with a good set of 285/70/17 on them

 

that sucks man, what ***** luck.

 

man what horrible luck. Cant you claim this on the lemon law thing? No way anybody should ever buy a truck and have the engine blow the next day and be stuck with it

 

New lemon law?
Not sure that would apply to a used vehicle with 170k :P Or we would all have new motors.

 

Hopefully you didn't pay an arm and a leg. Although you do have what some would say the best year 99, and it is a really nice looking truck. Just some bad luck as far as the motor goes.

 

I don't have much into it. I am looking into other options, right now looking like either Ford reman engine with 3yr warranty Unlimited mileage or a Jasper reman with 3yr 100K warranty..either is fine I won't be driving the truck that much. The mechanic shop that I took it to is supposed to be the best shop in town, I have had them work on other vehicles of mine and several of my racing buddies recommend them also...one of which owns all the NAPA stores in the area.

I know that the rod bearing could be replaced but is it worth it to just replace the rod bearing in a 173K engine....I don't know what to do because this is all beyond my abilities at this point. Sure I can change out the alternator on my wife's Jeep...it was nice enough to die on me today, but rebuilding parts of the engine are things that I have not done. So at this point I don't know what exactly to do, I have to rely on the mechanic's opinion....I have second opinion set up so I guess we will see.

$3500 for engine and $2000 for labor.....damn ***** sucks!!!!! There goes money for lift, wheels and tires!

 

Major bummer.......

Not to pry, but how much did you just pay for the truck, you need to think this through, you want wheels, tires and a lift, but NEED a motor..........

Doing some estimating as to options, (you told us the year and mileage) but I'm coming up with a street value of about $6,000 (with a good motor that you are about to spend $5,500 to get).

Simple math says at this point if you sell it for $600 "as-is" you'd be farther ahead, my guess you could probably sell it for $2,000 - $2,500 "as-is" to someone that could fix themselves.

Just my thoughts.......

Good Luck!
Ed

 

I see your point.

I don't have much into the truck at all. I am going to fix the truck regardless of whether fixing the engine or getting another. The truck is in great shape, not torn up. I need a winter vehicle/truck and I really like this truck. I will spend the money, within reason. I have an appointment set up with another mechanic and see what he says.

The way I look at it is that if I keep the truck for at least 5 years, which I am planning on keeping it for a much longer time than 5 years, then I feel that it is worth the money and effort.

Thanks for the input, good food for thought.