Dropped 8m solenoid bolt in engine block!

I have a 5.3 2021 Tahoe and was forced to do a dod delete. As I got into the guts of the engine, my lifters and camshaft are fine, no scratches, dings or wear (especially near valve 8). The culprit points to a solenoid issue for the p0308 code I got. So, I am going to leave the stock camshaft as BTR said the camshaft in the kit is identical to the OEM (kit cam is also a GM cam).

As I am putting the BTR plugs in, I dropped one of the 8m bolts thru! I manually turned the cam CCW and it seemed a little stuck. I then turned the cam CW and had no issues. I then went CCW and had no issues. I turned the cam in both directions manually so valve #1 went up and down 3 times.
I had a replacement bolt and put it in the middle plug, where the ORM screw fell. Then I started looking into the possibility of a screw in the block and that’s when the danger & reality hit me…

If the original CCW turn was the bolt, it went lower towards the crank. I put a borescope down the oil dipstick and don’t see the bolt. Pics of oil pan
The borescope does not go past the camshaft so I’m obviously worried because I can’t visually see the screw.
I tried running a magnet on the oil pan but don’t think it’s down there.


Any other suggestions to retrieve a bolt in the engine block?

I’m a YouTube mechanic so be nice pls. This is my first time doing something larger than an oil or brake pad change.

I want to avoid pulling the cam/phaser bolt as much as possible because that area of the engine scares me (even tho I mustard up the courage to get this far).

Thanks for any help!

The windage tray will keep it from dropping into oil pan area.

however, if you didn't hear any audiable impact sound from it hitting or dropping further into the engine, it may still be laying near the lifter bore casting area. See below. The red area is where gravity would pull the bolt down to.



This is a snap shot from I Do Cars L87 tear down.

Amusingly he dropped the same bolt in the same area. I checked video and he doesn't mention retrieving it.

Can you remove the lifters to get further view into cam area?

if you dropped it right onto the cam it likely rolled off and is on top of the windage tray.

blanchard7684 said:

The windage tray will keep it from dropping into oil pan area.

however, if you didn't hear any audiable impact sound from it hitting or dropping further into the engine, it may still be laying near the lifter bore casting area. See below. The red area is where gravity would pull the bolt down to.

View attachment 492996

This is a snap shot from I Do Cars L87 tear down.

Amusingly he dropped the same bolt in the same area. I checked video and he doesn't mention retrieving it.

Can you remove the lifters to get further view into cam area?

if you dropped it right onto the cam it likely rolled off and is on top of the windage tray.

Click to expand...

I purchased a cheap 25.00 borescope on Amazon and was able to see it laying on the cam. I pulled the borescope out and screwed the magnet attachment that came with it.
Went back in through the valley cover and got it!… for 2 seconds, then it fell to the bottom of the windage tray!!

After a couple hours of trying to get it, I gave up and went to Lowe’s looking to add another magnet to the attachment. I found a small wand with a 3/16 round magnet. At Lowe’s, I did my best to fit the magnet onto the borescope attachment and tried to lift as many screws as possible to see if it is worth Mickey-mousing the attachment… it worked. Strong enough to pickup a 1/2”X4” bolt.
Back on my rig, I retrieved the solenoid bolt in 10 minutes!!

I have since swapped out the new bolt with the retrieved bolt (orange’ish color bolt above the scope/screw pic)

Amazon link has the scope at 35.00 now.
When I purchased it, it was 26 and change.
I went with the 16’ dual camera and that 2nd view was very helpful. Once in the block, the side view gives you an idea of what direction to go. Highly recommend that 2nd view. Videos and pics on the scope are pretty clean. Also has a knob for light brightness that has already come in handy.

Well done. Thanks for the follow up.

Way to persevere!

Now thats a butt puckering moment alright. Good job gettin' 'er out!

Good job man!!!

Super. From disaster to success!!!

DON'T DO IT AGAIN!!!!!

blanchard7684 said:

Well done. Thanks for the follow up.

Click to expand...

You are welcome.
This is what I did to the attachment

DOD delete complete! Here is a link to BTR torque spec recommendation.

Original cam but swapped out the majority of the BTR kit, lifters, lifter tray,exhaust manifold gaskets, head gaskets, BTR solenoid plugs etc…
While I was in there, I swapped new spark plugs and wires. The alternator belt was a PITA and the zip tie trick worked better than the rented Tightener tool.

Tomorrow I’ll do new oil change (will likely use 10-30 from now on), radiator flush and try and torque down on exhaust bolts to block & pipes as I turned her on today and she drove smooth and quiet!

I do have 2 codes pop up that I can’t clear, U3007 & P25a2 which I can only guess is from the unlocking of ECU. I’ll see what the shop says about those 2 codes.
Update on codes: cleared codes and no longer have them.

I’ll wait a couple months then sell the BTR/GM cam and whatever gaskets I have in the kit leftover.


Just thought I’d update how the YouTube mechanic came out, hah!

After a couple days of the dod delete, I’m getting a consistent p2098 and a very small misfire on valve 7, hopefully the misfire addresses the p2098.
Took the truck in for a diagnostic and they said valve 7 at idle has a small misfire. He said to swap plugs and spark plugs to see if the issue follows. I Swapped SP 7 with SP5 and coil packs 7 w/coil pack 3. After swapping at home, I went back and now valve 3 was having a slight issue (from coil packs 7)! FOUND THE MISFIRE! I Bought Orilley Ultimate coil packs and nkg spark plugs and was recommended to get AC delco. So I got OEM spark plugs and coil packs. I Just swapped everything out and still having the small misfire without a check engine light. It’s a real small jolt but not enough to really hear anything in the engine, under the vehicle or on the sides.

I’m thinking one of the injectors could be having issues now? Prior to reusing them, I cleaned the rubber cup w/mineral spirits and the injectors of any buildup. They looked good before I put them back in w/the new GM fuel lines.

What’s the most inexpensive OBD II for live data of my valves? I’ve tried to look it up on the web but lack the verbiage to hone in on a scanner where I can see the valves acting odd.
Not sure what else could be the a problem, I’m open to suggestions.

I appreciate any help, tyvm!

Check out the Foxwell line of scanners with live data and bi directional capabilities. Or step up a bit more for an Autel. If you do, get the scanner with blue tooth capabilities for dongle plug in at DLC and carry screen. I wish my Autel MK808S had that.