Walnuts under the valve cover?

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bigsur100

bigsur100

Joined
Apr 30, 2024
Threads
1
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7
Location
Big Sur, California
Hi folks, new here with my 1999 Land Cruiser with 277k miles. Bought it with about 270k miles. Previously owned by a pilot who kept a hand-drawn spreadsheet of maintenance items. Lived its life in Arizona so no rust! I had a mechanic replace the valve cover gasket and the throttle body so far. Timing belt is not replaced yet, planned for 285k miles. Serpentine belt was replaced at 240k. I have replaced all the control arm bushings, shocks, ball joints, sway bar bushings, tie rods, and front diff mounts. Also just put on new Toyo Open Country AT III tires. It rides excellent now and runs strong. Figured it was ready for a big trip, like Baja.
IMG_2094.webp

But recently noticed this sound under the hood after it warms up. To me it sounds like walnuts rolling around in the valves.
See video and audio here:



Hoping someone can offer a lead on this, thanks!
 
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Assuming:
Fan belt off, no change.
Sound only started just after valve cover gasket R&R.
Possibly, socket or bolt left inside valve cover. Any missing tools or bolts/nuts

I'd first try stethoscope, to isolate aera. Then see if I could get a directional borescope through PCV port.
 
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Missed the part about VC replacement. Agree put a long screwdriver or stethoscope and see which side then pull VC. It's not that hard, especially since it was just done. Pray no damage was done if something was left in there.

No serpentine on check is quick and easy also.
 
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Wadepat2 said:
Missed the part about VC replacement. Agree put a long screwdriver or stethoscope and see which side then pull VC. It's not that hard, especially since it was just done. Pray no damage was done if something was left in there.

No serpentine on check is quick and easy also.
Click to expand...
Baja...may want to do a news search covering the last few days...
 
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2001LC said:
Assuming:
Fan belt off, no change.
Sound only started just after valve cover gasket R&R.
Possibly, socket or bolt left inside valve cover. Any missing tools or bolts/nuts

I'd first try stethoscope, to isolate aera. Then see if I could get a directional borescope through PCV port.
Click to expand...
Regarding assumptions. VC gasket was done, then noise started about 7k miles later. I’ve known the mechanic for 25 years so would assume to trust him. I will pull the serpentine belt and check components for loose acorns.
I’m so curious if someone has heard this noise before 😁
 
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If the noise occurred immediately following the repair then it's likely you'll find the culprit hidden in the valve train. Though, I hope it's unlikely that a mechanic would deliver the truck with that noise nor would you have left without noticing it. I have seen a lot of "coincidence's" after 30 years in the shop. Having had recent work doesn't always mean a current problem is related.

To me the noise was more noticeable towards the rear of the motor which sounds like a potential starter gear and flex plate issue, Just a thought and all I can suggest from a video.
 
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I haven't pulled the serpentine belt yet but I did put a long, thin piece of rebar to my ear and held it against all the drive belt components. Everything sounded smooth except the idler pulley. I looked at the maintenance log (previous owner was pretty meticulous with his spreadsheet) of what has been replaced here. Timing belt and water pump age is 75k, serpentine belt and "cooling fan" age is 38k, radiator and power steering pump age is 15k. Without more inspection, I don't know if "cooling fan" included the entire bracket. Do the fan and the bracket go together upon replacement?

So I'm leaning toward thinking its the idler pulley. I found this thread and when listening to the idler spinning in the video, I think I hear something similar. Serpentine Belt Replacement Interval? - https://forum.ih8mud.com/threads/serpentine-belt-replacement-interval.1233815/post-13516205

After more inspection, I've noticed the sound can be intermittent and vary in severity. Wondering if that is generally indicative of a bearing going bad...
 
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Ok my thought about the idler pulley has changed. I drove about 150 miles yesterday and then parked the LC on cement instead of the dirt. This morning I noticed coolant on the slab. Pulled the skid plate off and found coolant dripping from below the crankcase pulley and the coolant reservoir was empty.
So I guess I have to conclude the ten year old, 75,000 mile water pump has failed, right?
IMG_5293.webp


I looked at the maintenance log and found in 2014 the mechanic invoiced for a Timing Belt Kit With Water Pump CPK1231. Is anyone familiar with this part number or know if this would have included the idler and tension pulleys like this CruiserTeq kit? And would anyone like to lend their opinion about using this kit vs. a Toyota water pump?
 
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Sounds like a bad or loose pulley or bearing to me.

I don't know if I've seen a weeping water pump on a 100, but I don't think it shows itself only at the lower crank case.

Are you sure nothing is loose or wobbly in the belt accessories?

Curious to see what this ends up being!
 
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suprarx7nut said:
Sounds like a bad or loose pulley or bearing to me.

I don't know if I've seen a weeping water pump on a 100, but I don't think it shows itself only at the lower crank case.

Are you sure nothing is loose or wobbly in the belt accessories?

Curious to see what this ends up being!
Click to expand...
Yeah, the sound is most detectable when I listen directly to the water inlet housing assembly. So I'm assuming right now it's the water pump pulley on the timing belt. All the drive belt pulleys feel and sound ok, except I think I'm detecting the noise coming from the drive belt idler pulley. However, that is pretty close in proximity to the water pump so I may be hearing it propagating through to there.

The bottom of the crank case pulley is the only location I can detect the coolant leak at this time. It's looking like I'm just going to have to bump up the timing belt replacement 15,000 miles early and get in there to find out what's going on.

I'm not familiar with the anatomy and mechanics of the water pump but if the bearing on the pulley is shot perhaps the vibration has damaged the gasket or an o-ring? The vehicle is cooling itself so the impeller itself may still be functioning ok.
 
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bigsur100 said:
Sewing this up. Had the water pump and timing belt replaced. 15,000 miles earlier than the 90k due date. No more walnuts. Here’s the old water pump. I’m calling this puzzle solved.
Click to expand...

Ugggh! No water pump should ever sound like that! Glad you got your issue sorted.
 
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