95TexasT4R

Blown plug
Okay so I recently traded my '01 Avalon grandpa car for a 95' 4runner limited 4x4 with the 3.0 and 185k miles. Took it to a mechanic to have it looked over top to bottom right after I got it and he said everything looked like it was in great shape, and that someone had recently redone the heads on it. A couple things that I had noticed, minor issues, was that the power steering belt was the wrong size and way too big, and that the A/C tensioner pulley had been taken apart and put back together the wrong way by PO. Had the mechanic go ahead and order parts to fix the pulley and belts, and got him to slap them on a couple days later. As I was driving away from the mechanic shop, I heard a pop sound and then what sounded like a slapping sound when I accelerated. My first assumption was that one of the belts had broken, so I turned around and took it back to the mechanic. Popped the hood only to see exhaust shooting out of the passenger side middle spark plug. The mechanic took the plug out, and found that it had basically exploded and in the process blew a portion of the threads of the plug off. (See picture). He replaced the plug and then took reading on the cylinder only to find that with the new plug in it was only firing around 50%, and told me that I pretty much am going to need a new engine. I really don't know what to do about it, but I have a family friend that is good with Toyota engines, and said that if I did end up buying a new engine he would be more than happy to help me put it in. What do I do? Is it possible that the blown plug could have also blown out a portion of the threads where the plug screws into, and that it is not sealing correctly and therefor I am loosing combustion due to that? Should I bite the bullet and look for a new engine? 3.4 swap? In need of advice please! Also, mechanic said that when he went to take the blown plug out that it seemed loose, and that may have caused it to blow.

muddpigg

iTrader: (1)

So let me get this straight. Mechanic took spark plug out and re-installed it then it blew out?? Sounds like it's on him.

Heli-coil it. Way cheaper than a new head or engine or swap. I had the exact situation happen on a dodge neon.

wyoming9

iTrader: (1)

Find a real Mechanic !!

Sounds like this one is over his head in doing any real work

Where you there and watched this spark plug being removed .??

As it must have vibrated loose and been bouncing around held by the spark plug wire

If it was still in the threads in that condition it would have been interesting removing it

Installing a new plug without repairing the threads in the head would have put you in the same position of having the plug vibrate out

I can only guess as I am sure there are things we don`t know.

How many miles did you drive the 4Runner before taking it there ??

Seems strange the spark plug vibrated out after you left and not during the test ride after the work was done

All I can say is the Warning Alarms are Going off!!

Maybe your wording is not correct and you mean the compression is 50 % of what it should be .
Well if the threads in the head are damaged of course the compression will be reduced .

For sure not a reason to need another engine

Unless the piston and cylinder wall has been damaged

95TexasT4R

The plug blew before the mechanic had touched the plugs, he only fixed the tensioner pulley. As I drove away I heard a pop (which was the plug blowing) and immediately turned around and drove it back to him.

scope103

You can probably helicoil the head so that it will seat a plug. While that can be done with the head on, it is a) difficult, b) hard to keep chips out of the cylinder, and most of all c) drilling for a helicoil "by hand" is a good way to get a sorta loose fit.

You should remove the head and drill it for the helicoil on a milling machine or at least a drill press. AND, once you have the head off, you can take a better look at it and see if more damage was done.

Even if you end up replacing the head, it will be much less expensive than putting in a used engine. And it's something you and your friend can do, if you're willing to stock up on a few tools, take your time, and replace each little part you break on the way.

95TexasT4R

The plug blew before the mechanic had touched the plugs, he only fixed the tensioner pulley. As I drove away I heard a pop (which was the plug blowing) and immediately turned around and drove it back to him.

95TexasT4R

The only work they did was in the belts, and I drove it approximately 3 miles between then and when it blew. I turned around as soon as it happened so I drove probably 2 miles with the blown plug.

wyoming9

iTrader: (1)

How many miles did you drive the 4Runner since you bought the 4Runner before the spark plug fell out??