Weird spark plug

[4ak]

I just replaced the spark plugs in my 2005 4-runner (6 cyl.) and I followed NGK's instructions to tighten plugs 1/2 to 2/3 turn after getting them finger- tight. When I attempted to do this with the plug that fires in the middle cylinder on the driver's side, I could only turn it slightly less than a 1/4 turn with the socket wrench before it became very tight. I thought it might be the particular plug, but I tried another new plug, plus one of the old plugs, and it didn't make any difference. I could see no sign of cross-threading and besides, the plugs screwed in and out easily. This was the first time the plugs have been replaced (19000 miles). Does anyone have any explanation for this anonmaly?

[ToyotaToday]

Originally Posted by 4ak

I just replaced the spark plugs in my 2005 4-runner (6 cyl.) and I followed NGK's instructions to tighten plugs 1/2 to 2/3 turn after getting them finger- tight. When I attempted to do this with the plug that fires in the middle cylinder on the driver's side, I could only turn it slightly less than a 1/4 turn with the socket wrench before it became very tight. I thought it might be the particular plug, but I tried another new plug, plus one of the old plugs, and it didn't make any difference. I could see no sign of cross-threading and besides, the plugs screwed in and out easily. This was the first time the plugs have been replaced (19000 miles). Does anyone have any explanation for this anonmaly?

the only thing I can think of is there is a washer from the original plug that somehow got stuck there. so, when you put new plugs in, you are using 2 washers and hence it tightened with only a quarter turn. That's the only thing I can think of

[humanoid]

Yeah, I'm thinking the same thing as what TT stated.

[4ak]

I thought of the same thing too and double-checked. I could find no left-behind washer. Any other ideas?

[jetwhine]

4ak,

Did you check to see if by some chance they told you the wrong info and someone has put a heli- coil in that cylinder? If it screws in and out easily that sounds like a heli- coil to me. I hope for you someone else did not mess up that thread. I have been trying to find a torque for you but have not found one. I looked in my books and could not find one. I did mine on my 03 but did not have that problem.

[4ak]

I'm the original owner, and although the vehicle only has 19,000 miles, I replaced the plugs because it's been about 4 1/2 years since I bought the 4 Runner (they all came out easily and all looked like they are supposed to). In other words, the plugs I removed were the ones installed at the factory (Denso on the passenger-side cylinder bank and NGK on the driver's). So, still eager to get an answer!