Rattle sound uphill, highway speed

[ExplorerRandall]

Heya folks,

I've been doing a lot of reading on this forum for some time now, and finally decided to register. First off thanks for all the help.
I have a 1998 XLT 5.0 V8, AWD. Getting on five years of ownership. 188k miles.
Last month I did the timing chain cover, timing chain, gaskets, and this is the third water pump. Think I got it right this time. Leaky coolant no more!


I have a fearsome 'death rattle', but only noticeable when going up a significant hill, or sometimes at highway speed. Does not change speed with RPM. Consistent rattle speed through all RPM's. Might even be less noticeable when I drop the hammer.
Which leads me to think that it is not valve train or bottom end.
I just thoroughly cleaned the MAF sensor, and started changing plugs and wires. Usual tune up stuff. Still got the rattle as of now.
Noticed there are two bolts missing from the exhaust manifold. Driver side rear, and passenger side front bolts are gone. A small mirror confirms that the holes have threads in them.
I'll proceed with an update tomorrow. Not looking forward to doing the top end and hoping to resolve the issue without that, or redoing the entire exhaust.
I noticed that two, TWO exhaust manifold bolts are missing.
Also unresolved. Have a check engine light, which comes on more than not. Sometimes not. P0340, but I switched the cam position sensor a few years ago, and used the special tool. Might need another alternator.

 

[koda2000]

The 5.0 V8 does not suffer from the dreaded "death rattle" (that's a 4.0L SOHC issue). What you might be hearing is know as "ping". It caused by pre-ignition (fuel igniting before the pistons reach the proper height in the cylinders). Start by trying a tank of premium fuel. If the noise stops you have pre ignition. This tends to happen to older vehicles with carbon build up in the cylinders and on the valves. You can try a bottle or two of Chevron Techron in the fuel tank, it may help to clean things up.

Your engine also has something called a "knock sensor". It's job is to detect the pinging and retard the engine timing to prevent it, but it can't do anything when you have carbon deposits that get hot and pre-ignite the fuel. If you haven't changed your spark plugs in a while, you should do this too. The old spark plug will also tell you something about the health of your engine. A clogged fuel filter can also lean out the fuel mixture and cause excess heat in the engine's combustion.

I see you have already changed the spark plugs. How did the old ones look? Were they bright white, or have deposits on them? They should appear tan'ish and clean.

 

[4rd Xplora]

What Koda2000 said . I had an '96 Impala SS that pinged (us older ones used to call it "labor knocks" because you usually heard it when the engine was under a load), I changed to midgrade gas and it went away.

 

[ExplorerRandall]

The plugs look like it is running hot and lien.
It may be a ping. However, the sound does not increase or decrease with RPM. I tightened what bolts remain on the exhaust manifold this morning before headed off to work, and still hear some rattling sound.
I will change the fuel filter, pump some premium (gas prices aren't bad right now), and add some fuel system cleaner.
Any other recommendations would be appreciated, and I'll do a follow up this evening.

Thanks!

 

[chefduane]

Run some Chevron Techron through it. Two bottles (one at a time with a fill up.) It's the only additive that actually makes a perceived difference IMO. The other stuff is snake oil - although I did smoke out the neighborhood with some Sea Foam once. Didn't really make any difference but MAN what a smoke bomb!

 

[koda2000]

I've said it before - IMHO, SeaFoam treatment is snake-oil and potentially dangerous, as feeding it into the engine can cause hydto-lock/bend rods if you pour to fast.

 

[ExplorerRandall]

I changed the spark plugs and a few of them had a lot of white build up on them. I'm surprised those cylinders were firing at all.
Changed the fuel filter, and the fuel pump relay.
Cleaned the MAF sensor.
I think the rattle went away after I filled the tank with premium and added bottle Chevron Techron.
Filled it up with regular gas and the rattle came back.
Any ideas on how to clean out the buildup from the cylinders, without removing the heads, and without using Sea Foam?

Thanks.

 

[koda2000]

white buildup on spark plugs could mean you're burning some oil or perhaps leaking a little coolant into the cylinders. This buildup can cause hot-spots (just like carbon buildup) which will cause pre-ignition.

 

[ExplorerRandall]

gmanpaint,
You got stock in Autozone or something?

Koda2000,
I believe you are correct sir.
I will try one more bottle of Chevron Techron.
Meanwhile I will pump premium to keep it from knocking, until I have everything gathered to do the head gaskets, and that way I can make sure to clean out the cylinders proper. Sigh.

Thanks,
Randall

 

[ExplorerRandall]

I think I have everything I need to do the head gasket.
Got a Felpro Head gasket kit, red rtv, molly based engine assembly lube, penetration fluid(liquid wrench), new cylinder head bolts, and a pcv valve. And lots of research.
The only thing that looks tricky is, I have to set TDC for #1 to remove the cam position sensor. Once that is done I cannot rotate the engine. However, when I torque the rocker arms down, I need both valves on that cylinder to be closed, so I have to reinstall the lower intake manifold, and the cam position sensor, before doing that torque sequence on the rocker arms.

Before I jump into the head gasket mess, which is time consuming, I'm looking into decarbonizing the cylinders without opening that can of worms.
Today I ran the engine warm (not hot), and added about 20 oz of distilled water into the break booster line, slowly over about 12 minutes, then I drove it really fast for a bit, but still hear some knock up a good hill.
Bought another bottle of chevron techron fuel cleaner and plan to pour it in and fill it up one more before weekend.

Is there a better place to mist water into the intake rather than the break booster vaccuum line? I bought a spray bottle and plan to try and mist directly into the throttle body. Wondering how bad it will run with the intake hose disconected and the MAF bypassed?

Thanks,
Randy

 

[JCat]

If you are going to take the heads off, you should get a valve job AND check the valve springs for fatigue. Weak springs will cause ping, and the Ford 302/5.0 engine is famous for this.

 

[ExplorerRandall]

I'm having trouble finding both the throttle body gaskets.
My cylinder head rebuild kit came with neither.
I see the 'throttle body mounting gasket', which looks like it is right behind the throttle body. However, there is another gasket going from the aluminum elbow, to the upper intake. Anyone know what that one is called?
EDIT: Nevermind. I think I found it. There are two different ones. "EGR Housing To Plenum", and "To EGR Housing".

 

[ExplorerRandall]

Update:
Pulled the lower intake manifold this weekend. Decided not to pull the heads yet, as I plan to have them serviced by a shop when I do. New gaskets for all the intake side will hopefully make a difference. Perhaps it is running hot due to a lean mixture, and I think it is running lean due to the white spark plug electrodes. Maybe getting it running right again, and not lean and/or hot, will keep it from pinging.

I busted a couple 'pintle caps' on the injectors pulling them out. Right now I am cleaning the assembly and tracking down new pintle caps, as the Autozone and O'reilly don't carry those parts. Hoping to get some from either Napa Auto, or the local Ford dealership.

I noticed that my throttle body to EGR elbow didn't have much torque on the bolts, and oil running out the bottom of the gasket. Prob a leak there. The lower manifold just slid off after removing the bolts. Prob lots of leaks there. Water in the lifter valley, may have been from removal, but something makes me think that lower intake manifold gasket has been toast for a while. No PCV valve was present.... Sort of disconcerting. Glad I got a new one to put in.

Not as gnarly as a dual overhead cam engine, with two heads, and four cams to worry about, but still very time consuming. I did not have to remove the cam position sensor, like the book says.

Hope to get everything sparkling clean tomorrow and begin the re-instillation. I took lots of pictures, that I can post up, but mostly to make sure I route all the wires and hoses properly.

 

[koda2000]

I had a thought, may have nothing to do with your lean condition (and in my experience usually causes a rich condition), but how man miles on your O2 sensors?

 

[ExplorerRandall]

If the O2 sensor is original, 189,000 miles...
Could the O2 sensor be contributing to the ping?

 

[ExplorerRandall]

To replace the 'fuel injector pintle caps', I ordered Bosch Type 3 Fuel Injector Service Kit from Mr Injector. http://www.mrinjectorparts.com/store/p18/Bosch_Type_3_Fuel_Injector_Service_Kits.html
Hope their shipping is fast. Need to get this project done this week. Now for some gasket scraping. Fun!