Stripped MDX engine block bolt hole for starter

[zullo]

I'm in a real jam! I intended to replace the starter motor on my 2003 MDX due to the starter noise at cold start. The starter is attached to the engine block with two M10 x 1.25 hex bolts. I had a hard time to take off the hex bolt at the top, but removed the old starter anyway. When I try to put the new starter on, the top one is not going in! So I tried spraying WD40 on the bolt and forcing it in, but not going well. I didn't want to drive the hex bolt too hard to break it in the bolt hole or mess up the engine! So the top portion of the bolt hole thread is stripped - see the picture. I have searched options: helicoil, tap/die, thread chaser... I don't think tap/die or helicoil is an option considering the tight space without taking the engine out (Errr! Just thinking bout it!).

I can't find a 10mm x 1.25mm thread chaser anywhere online or in tool stores in the DC area.

What are my options? If I bring the car to an ACURA dealer, what will they possibly do to fix it?

[ninor]

All you need there is tap/die 10 x 1.25 and chase it through. You might want to get 10 x 1.25 for the bolt as well just to ensure that it is clean.

This should be easy to find, you got NAPA in your area? any automotive place should have metric tap/die set available, sometimes it is cheaper to buy complete set as opposed to buying couple of pieces.

Anyway, just looking at that picture this is not a big deal, thread looks OK past 1/4" or so from the top, it should be just fine coupled with the other bolt to hold the starter in place...

Regards,

Nino

[zullo]

Thanks ninor. I did buy a 10x1.25mm tap kit. Because the TIGHT SPACE (between the radiator and engine, towards the bottom/front of the engine), I'm afraid the drill will not going in there straight, and mess up the bolt hole even further. I had to use a long (6") wobbly extention on the upper bolt (with stripped thread) while taking it out. So it will be very hard and inaccurate to tap/die. The good news is my two hex bolts are perfectly fine. I guess I'm just afraid to mess up the engine block - I only have one chance if I were to use the tap kit. So I chickened out on going the tap/die route.

Is the 2003 MDX engine block aluminium or cast iron? With force while tapping, I may crack the engine block or break the hex bolt inside the bolt hole. That's why I have been looking for a thread chaser (suppose a tap smaller than tap bit) to try cleaning the messed up thread in the bolt hole.

[ninor]

Originally Posted by zullo

Thanks ninor. I did buy a 10x1.25mm tap kit. Because the TIGHT SPACE (between the radiator and engine, towards the bottom/front of the engine), I'm afraid the drill will not going in there straight, and mess up the bolt hole even further. I had to use a long (6") wobbly extention on the upper bolt (with stripped thread) while taking it out. So it will be very hard and inaccurate to tap/die. The good news is my two hex bolts are perfectly fine. I guess I'm just afraid to mess up the engine block - I only have one chance if I were to use the tap kit. So I chickened out on going the tap/die route.

Is the 2003 MDX engine block aluminium or cast iron? With force while tapping, I may crack the engine block or break the hex bolt inside the bolt hole. That's why I have been looking for a thread chaser (suppose a tap smaller than tap bit) to try cleaning the messed up thread in the bolt hole.

NOTHING TO DRILL HERE!
just run that tap in and out by hand
10 x 1.25 tap IS a thread chaser, there is nothing to tap here, hole is already 10 x 1.25, once you run the tap through that hole, it will just clean the threads. Block is aluminum and since you are simply chasing threads with this tap it should go like butter. Tap has a lot of taper at the top and it will self center within the reason.

THE ONLY thing that you have to confirm here is that hole actually is 10x1.25, once that is confirmed, gently run the tap through it, it will clean the threads and you are done.

I suggest using a bit of anti seize on the threads as aluminum tends to 'grab' those bolts.

Attached picture is an example of a tap. This is what you need to use and turn by hand. (just to make sure we are on the same page)

Regards,

Nino

[TexasHonda]

It's clear from your post that you have never drilled or tapped a bolt hole. This is not the place to learn. Suggest getting professional help before you do more damage than already done. It's recoverable in present condition.

Those bolts are not that hard to align/start. I did this job about a year ago. Bolts should be started by hand using a socket w/ extension. I used a socket w/ wobbly extension on lower bolt to make alignment easier.

good luck

[zullo]

Yes Nino, that is the same tap I have (picture shown in your post). I have the MDX repair manual for starter, the bolt is 10 x 1.25mm. Just to be sure, I bought a set of same size nut and bolt to match.

With the new starter on, I did try to bare handed screw the nut in first, but no luck. Then with the starter off and help of WD40 and a wrench, I damage the threads to the current condition.

I'm so close to complete this project, but torn between save $$$ DYI and have the car towed to a dealer/engine shop.

[Tyler]

Just have a local mechanic come to your house and pay him well (cheaper than dealer/tow of course). This is like a 10-15 minute fix if you are very experienced.