I am trying to locate GP for a 1999 JD 4100 gear tractor. JD sells them for $35 a piece and won't give me thier NGK #. The JD online catalog says the part # is AT110814. It is an NGK plug but noone seems to have it or can get it. NAPA gave me an NGK y-106-1 and said that it is the cross reference plug but it will not fit in the hole. I know that all 3 are bad, and can't start my tractor. Can anyone help?

Ed in PA, April 2009

iv,e looked up the model # and found that y 103 v matches the yanmar 3tne 74 $ 8.00 each at napa

scott, January 2013

call www.ytmag.com they have the glow plugs at little over $18 each

dan W., March 2011

Just went to the yesterday tractor website. www.ytmag.com and found the glow plugs. Just looked under John deere, all models and selected 4100 then all parts for 4100 and boom, there they were. $18.00 each.

Gene Friend, January 2011

I have 830 hours on my John Deere 4100
I have had it since it had 50 hours on it,,,,and have never had any starting problems till this winter 2010,,,,,and I am using a light bulb and fuel additive to aid my hard starting that came about just this winter 2010.
As I can see from the posts that my 4100 tractor Yanmar Engine has Glow plugs,,,,and I did not know it did. And I see that they will cost me from $32.00 to $35.00 each! OUCH !!!!!!!!!!
Anybody have any other ideas?????

Ron from Alabama, January 2011

Try this link http://www.ytmag.com/store/index.htm
I have bought them for about $18.00 Each. No problem at all. Good Luck.

Charlie, January 2011

The dealer parts received yesterday is the elusive NGK Y702U! Either JD stocked up on these before they became "obsolete" or they've got an exclusive. (As stated in a previous post, an extensive search of the web for this glow plug yielded none.) Looks like JD 4100 owners are on the hook for > $100 to replace all 3 glow plugs for now. As it's a Yanmar diesel engine, there may be other applications for it, and therefore other sources for the glow plugs. I probably won't be too motivated to search for them for at least another 2 years; I bought 3 at the JD dealer price.

Kevin, December 2009

The first time I replaced my JD 4100's original glow plugs (9 years ago) I examined them carefully. Although they'd been painted along with the rest of the engine, I was able to make out "NGK" and "Y702U 10V" and "0422" stamped on the lands of the integral nut. I had no problem finding these glow plugs on the internet for a third of the JD dealer parts price, UNTIL NOW!

I've replaced the glow plugs in my JD 4100 twice in 11 years and am going to replace them before using it this winter for plowing. I can't find the NGK Y702U anywhere! An NGK search shows it's "obsolete" with no replacement. I've ordered one from my JD dealer at $32 and plan to examine it for a new number. Hopefully the replacement for the original is available on the web.

It seems to take about 2 years before the 4100 starts hard and puffs a lot of white smoke during extended cranking. The colder it get, the harder the start. I always replace all three glow plugs when I have the thing apart and my starts a just like when it was new!

Kevin, December 2009