Valve rattling under load in 99 explorer 5.0ltr.

[Jon Leone]

Hello all. Lately I've been having a problem with the valves rattling in my 99 Ford Explorer 5.0 L V8 all wheel drive truck. under normal idle conditions the rattling is not there, however once in drive and moving down the road upon giving the vehicle gas somewhere around 2000 to 3000 RPMs the valves start rattling like the engine is full of marbles. does anyone have this issue or know how to fix this problem. I am at a loss as to what to do. I'm afraid to drive the truck as I'm afraid it might blow up or cause damage. any help would be greatly appreciated as im only a shade tree mechanic.truck has 125,000 miles. Thanks.

 

[SWIGIN]

I'd pull the upper intake and take off the valve covers and have a look. If it is the valves and not the lifters you might find a broken rocker or spring.

 

[koda2000]

Are you sure it's you valves making noise? It might be pre-ignition? Try using a tank of premium fuel and see if the noise goes away.

 

[boominXplorer]

I'd start by cleaning mass air flow sensor as I've seen this cause the marbles sound a few times.

Any codes?

 

[Jon Leone]

Thanks guys. I'll give your suggestions a try next time I get a chance. I don't think I have anything broken in the valve train as she purrs like a kitten while in park and at idol. I have ran up the rpms while in this state and no rattling sounds at all. It's only under load when I hit the gas. Again thank and I'll post an update.

 

[koda2000]

Thanks guys. I'll give your suggestions a try next time I get a chance. I don't think I have anything broken in the valve train as she purrs like a kitten while in park and at idol. I have ran up the rpms while in this state and no rattling sounds at all. It's only under load when I hit the gas. Again thank and I'll post an update.

A rattling kind of noise under load is what pre-ignition sounds like. An overhead valve engine (like the Ford 5.0L V8) may develop a ticking noise if you have a valve related problem, but it wont rattle.

 

[drodgers421]

Mine made the same noise and never figured it out until I was removing the fog light assembly's to out in LED pods which look awesome by the way.

Anyways I was sitting next to the passenger side wheel when something caught my eye. The metal shroud on the furthest back spark plug was ever so slightly touching the manifold. Had a friend start it and revert the gas and asked if he heard anything and he said "yeah sounds like something broke or maybe loose in the engine area".

So shut it back off, let it cooled down and readjusted the wire set position and slid a heat shield sleeve down some to more a impromptu pad. And I haven't had a issue in a few weeks

 

[Craigerz]

I get the rattle in my 5.0 when I use premium fuel... so yeah I'd say try a different fuel also. Maybe even a different gas station if you always fill up at the same one.

 

[Turdle]

Hold up please.
check for exhaust leaks, particular attention to the passenger side bank and egr tube. Have someone powerbrake it a little while listening under the hood yourself. Some seafoam in the intake will be a good smoke test.

also, do you have a check engine light displayed?

does the check engine light even light up at all during the key on cluster bulb check?

 

[Jon Leone]

Thanks for all the info. I cleaned the throttle body, mass airflow sensor and filled with premium fuel. I'd say it's about 85% better than it was. I'm also going to change plugs and perhaps try a hotter one and see what happens.

 

[shucker1]

A hotter plug might make it worse.

Better chance for pre-ignition.

 

[MAS Tequila]

Run some SeaFoam through the tank to clean out any carbon build up.

Any build up can create 'hot' spots that will cause pre-ignition or spark knock.

It sounds like you have a bad case of pre-ignition.

My 2000 will do the same thing if I don't have the correct fuel to match the tune I'm running.

 

[Turdle]

Just a hunch but ignition timing is controlled by the pcm and input from the cranks sensor. The Harmonic balancers have been known to shift on the rubber since they are a 3 piece unit.

These engines have such low compression I really doubt octane is the root cause of any pinging, however higher octane may band aid the issue.

Still thinking exhaust (manifold) leak though. Tick under load.

 

[Blk2kXLT]

Adding this to watch list. I think I have something similar which might be an exhaust leak.

 

[MAS Tequila]

If I load one of the higher performance tunes and continue to run regular fuel, I will get detonation.

I just had to replace the harmonic balancer, it was causing the engine to vibrate but no detonation.

The only times I've had detonation is when I had the wrong fuel for the tune, once with some really bad gas, and occasionally when towing in the mountains with the 33's.

I need to re-gear.

 

[Blk2kXLT]

Adding this to watch list. I think I have something similar which might be an exhaust leak.

So got P171 and P174 CEL. The vacuum line that goes to the solenoid under the battery is falling apart. I grabbed the line and it nearly turned to dust in my hand. Also found a vacuum cap sitting under the intake manifold. Are there any capped fittings under the manifold?

 

[Blk2kXLT]

Fixed with adding RTV to the rear vacuum port that exits the right rear. The larger tube that hits 90* elbow then goes over to the PCV.