Bought a 03 FX4 with a rebuilt motor done by the dealer in 2019, not sure what maintenance to do

[Ahirtz]

Hello friends,

As the title says, back in 2019 I bought a 2003 FX4 from the original owner with about 90k miles (now at 125k) but the motor was replaced earlier that year with a ford rebuilt unit from the dealer; apparently the previous one succumbed to the dreaded timing chain issue. I was given the receipts for it but they aren't the most specific as to all the work that may have been done. The motor did come with a 3 year warranty, which I thought was a good deal and basically seemed like I was getting a "new" truck. Well it started leaking oil toward the end of that 3 year period and they replaced the oil pan twice chasing the leak. Ultimately they determined the leak to be the rear main seal right outside the 3 year mark. Its not too bad so I decided to just let it be. Fast forward to today and there also appears to be some oil coming from higher up, and possibly around the intake manifold/pcv system. There's also a noticeable ticking, and is generally running a little rougher. A few weeks ago I got the 0171/0174 codes and found a bad leak in the pcv elbow by the throttle body which fixed the code. At this point, I'm assuming I'll need to do a general work over to get it running proper. I have already replaced just about every fluid minus a coolant flush.

My overall question is, what all might the dealer have done with the engine swap? Is it possible they didn't put new gaskets on things when the original was dropped and everything put back together? Things like spark plugs/wires, thermostat, sensors? The rear main really annoys me as that is something I'm pretty sure would have been new on a ford rebuilt motor. Oil is definitely coming from higher up though as there's a trickle visible from the passenger side wheel area going down the engine block, almost like its from the head gasket. I'm assuming this is the valve cover which requires a decent amount of work by the looks of it. The intake manifold would be on the list as well, as the knock sensor wire came apart when I was fiddling with the pcv hoses and had to splice it back onto the connector.

So overall, just not sure how far to go with the maintenance. What is original vs replaced with the engine swap?

I wish I had confidence in the work that was done, the dealer is well regarded it seems. The ticking has me worried as that is typically a warning sign of the timing chain issue, but I thought Ford "fixed" that with better guides, ect. What are the odds of that happening on an "new" engine they rebuilt? Am I just overreacting here? Any advice would be greatly appreciated!

 

[superj]

whats a bummer but i bet when it says replaced, it was just a crate motor and all the original accessories were bolted back in place. it probably should have lasted longer but who knows with stuff now days?

if you can verify those leak points, change the gaskets and while in there, check the timing stuff, i suppose

 

[gw33gp]

An oil leak on the passenger side at the rear of the engine could be from the bolt that holds the rear cam timing chain cassette. That bolt has an O-ring as a seal. When I did my cam timing chain system rebuild, that O-ring did not come with the kit. I could not find the correct size O-ring for it. I also did not want to reuse the original O-ring because it did not look good. Maybe the mechanic that did the rebuild ran into the same problem and just reused the original O-ring.

I ended up using an O-ring that was thicker than the original. I put it on a mandrel and used a lathe to sand down the O-ring. It ended up being a tight fit in the counterbore in the back of the engine, but it sealed very well, and I have no leaks there after over 50K miles on that rebuild.

Unfortunately, the transmission has to be removed to check to see if it is leaking. If your rear seal is leaking, that seal could be replaced with the transmission out.

 

[Ahirtz]

An oil leak on the passenger side at the rear of the engine could be from the bolt that holds the rear cam timing chain cassette. That bolt has an O-ring as a seal. When I did my cam timing chain system rebuild, that O-ring did not come with the kit. I could not find the correct size O-ring for it. I also did not want to reuse the original O-ring because it did not look good. Maybe the mechanic that did the rebuild ran into the same problem and just reused the original O-ring.

I ended up using an O-ring that was thicker than the original. I put it on a mandrel and used a lathe to sand down the O-ring. It ended up being a tight fit in the counterbore in the back of the engine, but it sealed very well, and I have no leaks there after over 50K miles on that rebuild.

Unfortunately, the transmission has to be removed to check to see if it is leaking. If your rear seal is leaking, that seal could be replaced with the transmission out.

Ouch I would hate for that to be the leak. I really don't want to drop the transmission just to verify that. Looking back over the paperwork, it says they used an entirely "new" motor assembly (likely a crate engine) but had to replace the passenger valve cover with it so maybe that could be the leak? I'm not sure what a leak from the cover would look like. Is it possible the oil could drip down all the way and look like a rear main leak as well? Or is that wishful thinking haha

 

[Ahirtz]

whats a bummer but i bet when it says replaced, it was just a crate motor and all the original accessories were bolted back in place. it probably should have lasted longer but who knows with stuff now days?

if you can verify those leak points, change the gaskets and while in there, check the timing stuff, i suppose

Is there a chance that the ticking could be just worn out spark plugs and wires? I read in another post that changing those out sort of fixed the noise

 

[Shran]

Is there a chance that the ticking could be just worn out spark plugs and wires? I read in another post that changing those out sort of fixed the noise

Could be a bad wire that's cracked and arcing out on something near it. I have seen spark plug boots leak spark out onto cylinder heads and stuff too.

That said if I was hearing a ticking noise I would first be looking at the timing chain tensioners (fairly easy to replace those, maybe best just to go ahead and do it) especially if you are hearing noise on startup.

The fuel injectors will always make a soft clicking noise, could be that. Totally normal

Could also be an exhaust leak. My Jeep has a leak around the exhaust manifold flange that goes away after a few minutes of driving... the Ram pickup I have at work had a cracked exhaust manifold and made quite a bit of noise.

 

[Ahirtz]

Could be a bad wire that's cracked and arcing out on something near it. I have seen spark plug boots leak spark out onto cylinder heads and stuff too.

That said if I was hearing a ticking noise I would first be looking at the timing chain tensioners (fairly easy to replace those, maybe best just to go ahead and do it) especially if you are hearing noise on startup.

The fuel injectors will always make a soft clicking noise, could be that. Totally normal

Could also be an exhaust leak. My Jeep has a leak around the exhaust manifold flange that goes away after a few minutes of driving... the Ram pickup I have at work had a cracked exhaust manifold and made quite a bit of noise.

Good to know, thank you for the advice. I will definitely look into the tensioners. The ticking is fairly consistent regardless of startup or after warming up but its not the loudest, so its possible that its just the fuel injectors. What relief that would be! The exhaust manifold gasket and studs/nuts were replaced by the dealer surprisingly so I don't think its that. At the minimum I think new plugs/wires will be on order. I'll maybe get some audio/video and post that if nothing else changes

 

[1991 Blue danger ranger]

Ouch I would hate for that to be the leak. I really don't want to drop the transmission just to verify that. Looking back over the paperwork, it says they used an entirely "new" motor assembly (likely a crate engine) but had to replace the passenger valve cover with it so maybe that could be the leak? I'm not sure what a leak from the cover would look like. Is it possible the oil could drip down all the way and look like a rear main leak as well? Or is that wishful thinking haha

definitely possible, my 1991 4.0 (ohv) is leaking from the passenger side valve cover and i recently did the rear main which was also leaking (yeah i know rear main but not valve cover??!) and it still looks like the rear main is leaking, but i used to loose like 3/4 of a quart between changes and now i hardly loose any, despite how it still looks.

 

[Ahirtz]

definitely possible, my 1991 4.0 (ohv) is leaking from the passenger side valve cover and i recently did the rear main which was also leaking (yeah i know rear main but not valve cover??!) and it still looks like the rear main is leaking, but i used to loose like 3/4 of a quart between changes and now i hardly loose any, despite how it still looks.

This gives me hope! I don't loose too much oil between changes and it doesn't actually drip onto the driveway, just makes a mess on the underside. The previous owner used high mileage oil on the rebuilt motor which I thought would need normal oil without all the seal conditioners, so when I put regular oil in I got worried that the rear main "shrank" and started leaking. I'm not sure if this is possible or not but I'm using high mileage now just to be sure. No change yet.

 

[Ahirtz]

An oil leak on the passenger side at the rear of the engine could be from the bolt that holds the rear cam timing chain cassette. That bolt has an O-ring as a seal. When I did my cam timing chain system rebuild, that O-ring did not come with the kit. I could not find the correct size O-ring for it. I also did not want to reuse the original O-ring because it did not look good. Maybe the mechanic that did the rebuild ran into the same problem and just reused the original O-ring.

I ended up using an O-ring that was thicker than the original. I put it on a mandrel and used a lathe to sand down the O-ring. It ended up being a tight fit in the counterbore in the back of the engine, but it sealed very well, and I have no leaks there after over 50K miles on that rebuild.

Unfortunately, the transmission has to be removed to check to see if it is leaking. If your rear seal is leaking, that seal could be replaced with the transmission out.

Just to circle back to this, would it be possible to verify this o-ring leak with a borescope camera or something without having to drop the transmission?

 

[gw33gp]

I don't recall any openings in that area that would allow you to do that. You could crawl under there and take a look though.

 

[1991 Blue danger ranger]

I don't recall any openings in that area that would allow you to do that. You could crawl under there and take a look though.

Just to circle back to this, would it be possible to verify this o-ring leak with a borescope camera or something without having to drop the transmission?

if your truck is a manual you can get in through the viewport on the left side of the transmission, near the slave cylinder line hookup, could be able to see something in there? don't know about an auto sorry.

 

[Ahirtz]

if your truck is a manual you can get in through the viewport on the left side of the transmission, near the slave cylinder line hookup, could be able to see something in there? don't know about an auto sorry.

I don't recall any openings in that area that would allow you to do that. You could crawl under there and take a look though.

It is an auto, but thanks for the insight. I'll see what I can find, but likely just replace the cover when I do the intake manifold/knock sensor.