Knocking - 4.6L - Rod? Other? | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Knocking - 4.6L - Rod? Other?


May 27, 2014
Reaction score
City, State
Northern IL
Year, Model & Trim Level
2002 Explorer XLT 4.0L
:(Well, I might be done with Explorers and / or Ford for awhile after this one (although part of the problem was my own doing)...

I've had a 2002 4.0L XLT (4WD) for a little over a year now. Fixed her up a bit and put new tires on - she's a very decent vehicle now. But I do have the beginnings of the dreaded timing chain rattle - and I know what the end holds with that. That, plus an issue with the trans slamming into reverse from park (solution - shift from P to D, then to R), told me that if I wanted to have an Explorer to carry my band gear in (and maybe tow a small boat one of these days), I better get a V8 model. So I did.

Found a 2003 V8 Limited (2WD!) with the D4 axle (3.73 LS) and tow package, meaning I've got the max tow / haul capacity available on a 3rd-gen. 218K on the clock, but if it runs well, I'm not worried about the mileage. Was so stoked. Drove to Indy to get it (about a 3hr drive each way). When I started it, both me and my driver remarked how quiet the engine was. Ran a little rough, but the scanner indicated a IAC problem along with likely a DPFE sensor. I've done the DPFE on the 4.0L, and I know the IAC is right up top on the manifold. Cake. Paid the owner and drove it home; it was basically sitting until last evening, while I was waiting for the title, etc.

I got out of the vehicle last night and left the engine running after having driven it for 15-20min at suburban speeds (30-45mph)...and what do I hear?

Thump...thump...thump...about 1 sec apart, sounding low in the engine. Low pitched, not really 'metallic' sounding. First thought... rod knock. But after researching a bit, people on other Ford sites have posted with other potential causes... loose flywheel bolt, piston issue...even a loose harmonic balancer.... yada yada.

Now, I know it's my own fault for not starting the vehicle again (or leaving it running) after the test drive (even took it on the interstate). So I only have myself to blame. But - I'll ask the resident experts here - and I don't have a sound file to post (yet) - won't for at least a day or two - what are the chances this is *not* a rod knock, which I know is the kiss of death - new engine time or scrap the vehicle.

Opinions / instructions are welcome...especially from those who may have had this issue. I know it's easier to drop the oil pan, etc, being a 2WD (one reason I decided to forgo 4WD this time; we do plow here in the winter, and I do not go off-road at all - so, less to maintain.) :)

As far as how the vehicle was maintained... apparently, pretty well. It's had 3 owners before me (just got the title in the mail today), but I had maintenance receipts from two of them, including the original owners. Carfax came out clean (for what that's worth) as far as major parts replacement and accidents. Being a Limited, it has the info center with the OLM in the dash, so there's no excuse there for not knowing when to change the oil. And as I said - the top end is *dead* quiet, warm or cold. So I don't suspect anything with the heads, lifters, valves, etc.

I'll be watching the Blackhawks hopefully winning their 3rd cup tonight on TV, but will check in tomorrow for any responses (and 'thanks' to those who do).

PS: The 4.0L also has the D4 axle, tow package, etc. Wondering if I could just put a pre-oiler on like 2000StreetRod (?) described, and keep the engine going for awhile (187 on the clock there, got it with 176, and the noise hasn't gotten any worse over the year (goes away after warm-up, but is present while coming up to speed (say, 2000 RPM and above, although I don't run her hard at all - 2500RPM is the most she tends to see). And I know a solenoid kit would likely (?) take care of the slamming issue in Reverse (although I *always* shift P > D > R, when I want to go in reverse...have done so for 20yrs on various vehicles).

Neither is my daily driver - I use the Explorer (whichever one I keep - ?) about once or twice a week, and I'm usually just hauling gear around from here <> there. Ain't nothing better / roomier for the price, IMO. Or at least I thought so until now... :(

Sorry for the rambling!

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

my 4.6L engine

For a future project I purchased a 4.6L DOHC V8 that had been pulled out of an Aviator because of a knock. When I disassembled the engine I found that two different rod bearings had been spinning for quite a while.


The crankshaft and two rods are unusable. I'm beginning to suspect that the 4.6L has a tendency to spin rod bearings.

Worst fear confirmed

Update - took it to a local mechanic. Soon as I started it for him, he confirmed that it was indeed rod knock.

Here's the quandary... I described both vehicles to him - and he recommended keeping the 6 cylinder - says he has customers driving them for years - if I put in the pre-oiler, he thinks it will last a while.

Looks like they only install reman's...and quoted me a price about $3K to install one (5yr unlimited warranty). Thinking that I don't want to go that route - I'd have $6K into an '03 with 200K on the clock. I see a couple online in the metro area on car-part between $1000 - $1500, depending on mileage (question - anyone know what 'CT done' is? I see that in the description of some of them). Then I'd just need someone to install it.

May post the V8 in the classifieds, if anyone's interested. Nice vehicle otherwise. Has the white pearl tri-coat in Limited trim.

Only $3,000 for a reman??? Thats a deal! It's $3,600 for the reman motor only for our 2007 Chevy Suburban... Oh yeah, we are the middle of a motor swap on it :p Pain in the butt!

If the truck is in good shape enough to do A Swap, I would. $3k for a reman'd installed is a good deal considering.......a remand tranny on Rockauto is a hair over 2k....

looking a truck with similar problems....rod knock...can a new crank/bearings be installed? or is the whole engine junk?

Back with the end of my story

Well, if you're pulling the engine to replace the crank / bearings, you may as well freshen up the rest of the engine, IMO, if it's got a lot of miles on it.

As for my outcome - I wound up selling the V8 for junk - I didn't have the time or inclination to rebuild it or the desire to lay out another $3K to put a reman in. As for parting it out, that was off the table, too. So it's in a junkyard somewhere, happily providing parts for it's Explorer sibs. :roll:

After reading good things about the GMT360s / 370s (Trailblazer, Envoy, etc) - I went and found a loaded '03 Envoy XL - with a 5.3L V8, 4L60E trans, 3.73 LS - and only 125K on the clock. Problem solved. Used the 4.0L I had as trade, and that ends my time with Ford, I'm afraid. That was last year - the Envoy has been trouble-free since.

I wish you all well, and that your Explorers keep running well & providing you with many more years of service. I loved the first two I had.

Well, if you're pulling the engine to replace the crank / bearings, you may as well freshen up the rest of the engine, IMO, if it's got a lot of miles on it.

its an 02 limited, with 180k on the clock, no rust that I can see. Guy only wants $700 for it, it drives, so I'll at least be able to get it back to my garage (with a lift). Maybe I'll find a junkyard 4.6 and just put that in