4.7L Valve work - having issues

Hello, all.

About a month ago, my 2003 Dakota with the 4.7L, ejected a rocker on the #5 cylinder. Happened when I finished work and started it up... immediately ran rough and gave misfire codes. I pulled the valve cover and found the rocker sitting unscathed and luckily, no damage anywhere else. I found that the cause was a seized hydraulic lifter (lash adjuster), so I went about the task of replacing all the lifters. Along with those, I'm replacing all the valve springs and stem seals. The thing has about 314K mi on it, so way overdue for these things.

So, I got the passenger side bank done using one of those Miller tools to compress the valve spring. I used one of those valve holders that you thread into the spark plug hole and hook up an air compressor to keep the valves from falling.

I'm now on the driver's side bank, which is cylinders 1,3, 5 and 7. When I air up each cylinder on this bank, I'm losing loads of air coming out the throttle body. It's flowing out so fast that I have to hurry and get the spring compressed and the keepers back on before the valves fall. The compressor will drop to zero while running eventually. So far 3, 5 and 7 have exhibited it, so I'm sure 1 will do it too. This was not the case with the other bank, as they held the pressure. The fuel rail and injectors are removed, if it matters. Also, all the rockers are removed, so the valves are all closed. Any idea why I'm losing all this air? The truck drove fine, with what felt like loads of compression, prior to all this.

What am I missing here?

Thanks in advance

That is odd for one bank only. If you can, give a listen to tailpipe, intake throttle body and crankcase for source of leak. It could be blowing into cooling sys from head gasket too. Sounds like you may be pulling a head.

Yeah, very odd. I tested the head gasket a few months ago with a block tester and it passed with flying colors. I will check for that, but it seems that all the air is escaping out the throttle body and when I open the butterfly, it rushes out. The only thing I can think is that valves aren't sealing, but these are new springs etc. Maybe I should hook everything up, put rockers back in etc, rotate the engine a few times to see if things seat?

If the air is coming out of the throttle body, it pretty much has to be a problem with how the intake valves are sealing.

I would look into borrowing a leak down tester and seeing how bad it really is before going any further.

Actually, before I did that...... while I had the hose hooked up, I’d use a brass hammer and tap the intake valve a few times and see if it improves.
It could be as simple as some heavy carbon deposits on the valves, keeping them from properly seating.

I’d still do the leak down test afterward though.

This is great advice. I'll see if I can get my hands on a tester. I'll try tapping the valve. Not sure which is intake from exhaust though. I'm guessing the uppermost of the two? The thing that stumps me is that they are all showing the same symptoms.

I'm hoping that the slow manual manipulation of these things may have things out of line a bit and they will all vibrate into place and seal properly once the engine is run.

Yeah the intake valves aren't sealing, why is a mystery though. But 314K on a 4.7? You should win some kind of award for that!

This may sound like a silly question, but what weight oil are you running in it?

The factory recommended weight is 5w-30 and I've been told by another Chrysler Retiree that if you run heavier oil like 10w-40 it will spit out the cam followers on start up.
What he told me was that the heavy weight oil won't flow through the lifter (too thick cold) and pump it up and that's why the cam follower spits out.

A buddy was having the same problem with a 4.7 and we installed some rocker arm retainer clips on his.
It seemed to cure the problem.
They use the same clips on a Ford 4.6, they have the same problem.
They install on the cam follower and keep it centered on the lifter.

Got nothing but praise for the 4.7L. All I do is keep it full of oil and coolant. Its a very hardy engine. Scoped it some years back and could still see hatch marks on the cylinder walls.

I actually run a lighter oil, QSUD 0W-20. Standard dealer fill has been 5W20 for all 4.7L for many years now.

I pulled out all 16 lifters and a lifter for #5 cylinder had seized solid, which is why it spit the rocker. I couldn't budge it even with channel locks. All the rest were loose, albiet with dead springs. I'm replacing all of the lifters.

Fast68Plymouth, I tried tapping the valve with air applied.

Actually, I placed a block of wood of top of the spring and tapped that with a steel hammer because I didn't have a brass one. The change was not what I was expecting, but it confirmed my initial suspicion. When I tapped it, air began gushing right past the valve itself. I removed the spring and hooked it back up again and it sealed. So that's telling me that there is a small bit of play in the valves that can cause them to not be perfectly aligned when manipulated. It could be that the spring is off center or whatever, after manually compressing it. So I believe I just need to run the motor and hopefully things will vibrate into place.

Just in case there is carbon buildup affecting things, I'm also going to run a can of CRC intake valve cleaner through it, right before I change the oil. I'll also run a compression test after I drive it for a while. I say all this, with the hope that it even freakin starts, after all this work.

I do appreciate the help fellas.

If the valve doesn’t seat when closed because of some sort of alignment issue....... then the valve guide would have to be pretty worn out(or it’s something like the valve seat is loose in the head).

There should be no situation where the valve is opened, then closed....... where it doesn’t seal after closing.

I have never seen anything vibrate into place. Vibrate out of place sure, but never into place. Oh and valves don't vibrate.

You're right, vibrate was a poor choice of words. Anyway, I got it all buttoned up this evening and when I started it up, it ran like absolute crap, for the first few minutes... knocking sounds and all. I thought all was lost, then it smoothed out and began to run like the truck I knew. I guess the new hydraulic lifters took a while to prime and maybe the valves are seating a bit better now. Tomorrow I'm going to spray a can of CRC GDI Intake valve & turbo cleaner into the intake, run some motor flush through it, then change the oil.

Well I'm glad you got it running good. I want to see that 4.7 go 500K!

Completed all this today. Ran the CRC through the brake booster vacuum hose. After the oil change, I went for a half hour drive on the highway with O/D off, so the higher RPM would blow out any crud on the valves. I reused the motor flush from the truck in a Hyundai, right before I changed the oil in that.

Did I mention that I love the quiet cold starts with no lifter clatter. This completes the fix and the truck is running really well. The beast is back and ready for another 200K!

Thanks, all

What is that Hyundai and how many miles are on it? I'm a Hyundai tech.

2007 Sonata, 2.4L with 155K. Got some more work to do on that tomorrow. It's giving a small evap leak code and the ignition is sticking. Got a used ignition from the junkyard and I guess I'll be tracing hoses for any cracks.

I never see those hoses crack. I mean it's possible, I have just never seen it. Small evap leaks on them can be a PITA to find. Usually it is either a purge valve, canister close valve or the canister itself. Once in a while a filler cap.

Hey, guys.

Just wanted to thank everyone and leave you with a tip I came up with for installing the valve cover gaskets. I searched the web, but could find nothing on not having to use RTV or gasket maker to to prevent the gaskets from falling out. I was able to pretty much throw the covers around while installing them and they stayed in place, till I pulled the rubber bands off. I actually greased up the valve cover groove and gasket with dielectric grease, as well as the head surface and they seated real nice.

Should work on just about any valve cover. Hope this helps someone.

I used to rebuild chemical pumps with O ring seals. We would superglue the oring in the groove. It worked great, just a few spots to hold it, not the whole oring

So what happens when the o-ring that you superglued in needs to be replaced down the line?

I saw a mechanic do that to a customer's cars on youtube. Works for him, but does not bode well for the customer in the future.

It's just a few spots to hold it, not the entire seal and it comes off easily with a pointy stick and some acetone.

Yeah, I can't see using a hard glue on soft rubber. Maybe RTV, but crazy glue? The rubber bands made it super easy for me and I don't have to deal with any glue down the line.