Bolt size to cover up engine bay holes.

Hi all,

Would anyone happen to know what thread size bolts I can use to cover and seal the three threaded holes on the left side of the engine bay? (Facing toward the engine.) I noticed they were rusting and would like to plug them reduce exposure. Pic for reference. Also, if one can provide the size on the two on the right side next to the engine fuse box. I think they are larger that the ones on the left. TIA.

 

Thanks I'll go look for them. I'm going to clean out the threads with a bore brush and grease the bolts when I put them on.

 

M12 I think, recently used those holes when I installed fog lights.

 

It’s the same bolts as the bed rails iirc. They are not the same as the drivers side- they are smaller.

mine were rusting too so I bought some metal wire brush type things and cleaned the threads out then anti seize on the bolts and done

 

I used these and got damn near all rust out of the threads

 

I only had two holes- not sure what the middle one bolt to

 

M12 is huge compared to these lol

One side is m6x1 other is m8x1.25

 

Surprised no body told you to trade it in. Part it out or call Toyota about that large amount of rust

 

I found a box of misc. metric screws from leftover TV wall mounts. I'm going to see if any are the right size and pitch.

 

What surprises me is that they don't have any screws or bolt there in the first place. Who knows maybe they will do a recall or TSB.

 

They do, but you had to get the manual

 

My mistake, it’s a m8 bolt with a 12 mm head.

 

Thanks for the advice all, I can confirm the smaller ones are 6mm 1.0 thread pitch and the larger ones 8mm 1.25 pitch. I used a 6mm bore brush and cleaned out the holes for the three and another 7.62 bore brush for the other larger two. I put CorrosionX on the brushes and spun them low speed in the holes. Cleaned out the rust and showing clean threads. The TV mount metric screws worked fine for this. I used some Aeroshell 33MS grease on the screw threads and they fed in nice and snug. Used what I had lying around the tool box. Next I plan to clean the engine bay out and see if there any other spots to check.

 

How’s that corrosion x? Seems like a good stand alone product by the reviews minus those regarding plastic contact/damage. Is it a sticky film like fluid film or more of a oily (non sticky lubricant) like 3n1?

check the nuts/bolts behind the grille, battery tie down are the other places I’ve noticed but haven’t addressed yet

 

Clean them out and put some RTV in there to keep out moisture

 

I use CorrosionX pretty much for most of my lubrication needs even my firearms. Not sticky but is oily. Thanks for the info for the other places to check. I will take a look around them.

 

I just greased them in case I plan to expand to doing some other add ons maybe a auxilary fuse box or other equipment. I think the grease will work good enough for now.

 

Don't use Phillips head bolts for anything unless you have no other choice.

 

The screws are what I had on hand and I'll get some better ones later on.

 

Perhaps the bigger question is why yours are rusting so bad, though it's certainly not a huge issue either way. You shouldn't be getting moisture there to any degree.
My truck is about 18 months old and no rust. Perhaps your threads didn't get any paint for some reason.

Looks like some have a horn attached to the middle hole and some don't.