Well, after trying everthing in my bag of tricks to remove plug #3, I decided that Berniescout was right. Just loosen the clamp that holds the steering column to the steering box and slide the column up and out of the way. Now there is plenty of room to get at that plug.

 

If you have a universal joint and about 36" of extensions you could get it from between the fenderwell, also you have to remove the plastic cover and then rotate the shaft so the flatspot allows the extension to get to the plug. I also used a piece of fuel hose on the end of the plug to get it started, this saves the head from being cross threadedif the plug does not start properly (never start a plug with a socket because you can not feel ifit is cross threaded!!!).(This was how I did mine last spring)

 

I used a swival type joint and a t handle, but you can use a ratchet with enough extensions too.

I didn't rotate the shaft to the flat spot when I did mine though, with a swival I was able to clear it and get the plug out

 

the 5/8 spark plug socket should have a hex head on the end where it attaches to the ratchet/extensions, u get the point. the reason for this is when u dont normally have access u can slip a 3/4 inch box wrench or a 3/4 ratcheting wrench over the socket and remove the sparkplug with ease. no removal of steering columns, no pita swivels, no wheel removal. just pure simplicity and ease. i got my plug changes down to a 10-15 min process. u may have to find the right socketdepth to clear the plugsshields.

 

Hi there 'yall

I have a 1991 s10-Blazer (Tahoe edition, just to confuse you) 4x4 with the 4.3 litre.
I just replaced all the plugs today, I hadn't changed them in probably a hundred thousand miles and the engine was beginning to stumble.

I guess the number 3 plug is the one where access is restricted by the steering column. However, I was able to use a small plug socket (2 1/4" long),and a smaller 3/8" ratchet wrench on it which added another 1/2".

All the plugs sure are difficult though, I used combination of going through the wheel well, and going from on top. I only removed the air cleaner for access, and moved the AC lines to the side for one plug.

I used one of the old plug leads to start threading the new plugs in as I was changing the leads too.

I did replace with Champion Platinum 3018, looking at the plug however, I see the nose was slightly longer than the originals. I checked up at championsparkplugs.com and they are listed as correct. Does this mean they have a different heat rating ?

Cheers
Dave

1991 S10-Blazer 225000 miles (so far)

 

The heat range is determined by the depth of the porclain insulaton on the central elecrode. The plugs withdeep porclain insualtion are hotter than the plugs with shallow porclain insualtion and thehigher the plug number the hotter the plug. The length (or reach) of the central electrode is specific for the design of the combustion chamber.Projected tip plugs such as AC Delco CR43TS are cooled by the incoming fuel-air intake charge and ignite the fuel at engineeered distance from the piston. Projected tip plugscanniot be used in all engines if thecombustion chamber is not the proper depth.

AC Delco RapidFire #1 (GM-25164639) or #2 (GM-25164640) platinum tip plugs are an excellent choice for the S/T-10 Blazers, etc. Use AC Delco #1 plugs for the first60,000 to 100,000 miles, replacingstandard AC CR43TS heat range. Thereafter use AC Delco #2 plugs, replacing standard AC CR45TS heat range. The AC Delco RapidFire platinum tip plugs can be obtained for $2.35 each if you can get a 50% discount.They retail for about $4.50 each because the GMprofit marginis excessive on those type plugs. Theylast and do not need frequent changing.

The heat range is also determined by your driving habits. For constant stop and go city driving you can use #2 plugs andforconstant highway drivingyou can use #1 plugs.

 

i went ahead and used an end wreck on mine and tied a strong string to the enclosed end of the wrench and attached the other end to the spark plug.... pulled up on it firmly and it came loose easy enough.

 

You could always just get a body lift