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After taking a short hiatus I find I am a bit over my noggin once again.
My Bronco II is on the way out for the engine. It’s been having oil pressure issues and I’ve decided (rather a painful choice) to retire it.
The new beast is anything but new. 1995 Explorer with the 4.0. 5 speed standard and 4wd. It has high mileage and the guy I purchased it from seems was less then honest. Mileage is actually about 230k. Normally that doesn’t scare me, depending on repairs and maintenance to extend the life of the vehicle.
Basic checks so far have the usual stuff: Brakes all need replacement, Tires as expected…..Then I come to the part that brings me here.
I did the cooling service and the oil change. New thermostat and coolant–and oil change using a MotorCraft filter and 10w30 oil. The former owner claimed he only used 5w30 oil, and that sense the truck was off the road for a while, he would start it up every few weeks..etc…
Long story short: Oil change and the engine sounded fine. Did the cooling service and normally I let the engine fully warm up and lock it in at 2k to ensure the coolant ‘burps’ out any air. Then I hear a light knocking metal on metal type sound that got progressively louder. The oil pressure gauge of course is one of those “Idiot Gauges” that ford figured was a good idea. So while the oil pressure gauge says “Good”….I now hear this once the engine gets warmed up.
Here’s a video of me under the truck with my cell phone camera nearest the oil pan where the noises are the loudest.
Any ideas or guesses? I’m pricing things out as well for the brakes and tires. That was an expected expense. If this turns out to need a used engine? This project just took a really odd and $$ painful turn of events.
Thanks all!!
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Sadly that would entail pulling the engine out. The 4wd and the cross member have that area pretty well sown up.
I know you say that the vehicle has an idiot light for oil pressure.
Could hook in a real oil pressure gauge and see if that is an issue.That’s next in the works. Although I’m not a fan of where Ford put the sending unit….. Have to go through the left wheel well from what I understand.
At least this isn’t a “Gotta get it done NOW” project.
Would be useful if the throttle is blipped a few times to hear how the noise changes with engine rpm.
Going strictly by sound, I’d say your engine sounds like a fine running diesel.
If it was a diesel I wouldn’t be as concerned.
I’ll be hooking up a oil pressure test gauge on it Sunday. Wish I could do it sooner, but Ford put the sensor in a tight spot. I’ll let it get warmed up and give it a complete once over twice. Even goose the throttle a few times and repeat under load.
Hard to blip the throttle and hold the camera at the same time :silly:
Looks like the test light will also come into play. I can ground out the spark at the coil pack for each cyc to isolate where it’s coming from.
Wife has already stated “find something else”. Issue becomes trying to recover losses. Might as well see how deep the rabbit hole goes first….
S-
Sadly sleeping on the sofa isn’t good for my back. Because that’s where I would be if I suggested that.
For the oil pressure guage, connect some tubing to the port and run it to a remote location where you can secure a Tee. Connect the tee to the line from the port, the sender for the idiot light and to the mechanical guage. That way the light can still get your attention, but the guage is also active.
Hope this helps,
That’s how I have it set up in my Bronco II already. That stupid gauge was one of the worst ideas FORD ever came up with. Just because people didn’t know how to interpret the gauge.
This just got a lot more interesting.
Did an oil pressure check. Stone cold we get about 65psi. All warmed up and at low idle we get about 28-32. Highly responsive to throttle position. (The Wife gets credit for holding the pressure gauge. That’s not my shade of nail polish)
We did a couple more videos of that noise.
Here’s where things get interesting. You can clearly hear the ‘knock’. Upon giving it some gas, the knock diminishes to the point it’s pretty well gone. Last time I had an issue with rod knock, it got louder and more pronounced when the engine RPM was raised.
Now where this blows my mind away….
I used a mechanics Stethoscope. I had that probe end all over the engine and transmission…and bell housing. NOTHING to report!! With that knocking sound? No place I touched the probe reported anything. The oil pan? I could hear rotational sounds, and even the ‘Wshoosssssh’ sound (best way to describe it) of the oil pickup! But no knocking sound.
Then I touched the probe to the exhaust pipes.
Bingo…… not as loud as I expected, but it’s clear as day. I then probed higher up to the manifolds. The noise isn’t “Loud” or as loud as what I’m hearing, but it’s very pronounced and the only place I could pick up that noise was when I had the probe of that stethoscope touching the manifolds and exhaust pipes.
Possible burnt exhaust valve? I’m guessing on this. I’ve heard rod knocks before, and they always get much worse with acceleration and they are clearly able to be heard with the stethoscope through the oil pan. The fact when it’s making this noise, I can hear all the “Rotational” sounds within the oil pan—and no knocking noise when I have that stethoscope touching various parts of that oil pan.
This isn’t a rod knock that I know of….
Any ideas? Am I totally off base with the idea of a burnt exhaust valve?
S-
Interesting …
If as you state you hear it on the manifold …
Might consider doing
1 A compression test to see if there is a leaking cylinder.
2 Pulling the valve cover and inspect the valve train
3 Leak down testYep, that’s what I have possibly planned for my next day working on it for Tuesday.
Going to the local pick and pull looking for assorted parts today.
With the noise seeming to be coming out of the exhaust manifold(s) it’s about the oddest I’ve heard. I will use the mechanics “ear” and probe the valve covers to see (or hear actually) if anything in the valve train could be doing this. If it wasn’t for the fact the noise is clear as day coming out the exhaust manifold? I might suspect a bent push rod or totally flat lifter. However given that noises can often travel down metal parts from one area to another….
While I’m not out of the woods yet, I feel a lot happier about the bottom half of this engine.
So tune in next time…. And find our hero probe the upper half of the engine (ahem…would have done this yesterday, but ran out of sun light). Using a “Scope on a Rope” (test light) to ground out the spark for each plug to isolate exactly what cyc this issue is associated with…
Love the leak down test idea, it gives me an excuse to purchase a small air compressor. We have 2 up in the barn I normally work out of, however one has pin hole leaks in the air tank, and the other one the motor, while not seized–just gives a loud hum and refuses to start, even if given a little helping nudge.
Thanks again!
S-
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