GP Question?

[sle2115]

What is the recommended change interval for glow plugs...not necessarily from a book, I got that, they want to sell parts, but from those in the know. I have a set in mine that have been there for over 2 years, approaching 3. The thing starts great and while I don't mind spending the money on a new set, I'm wondering if I need to? I guess put it this way, I've taken somewhat of the "if it aint broken, don't fix it" mentality on this truck, it aint broken, so should I fix it? If it matters, I've put less than 10,000 miles on it since I've owned it. I will be needing it to start in cold weather though, as it is our clubs hunting UTV!

I'm running the solid state system (came that way it's an 87) put a new controller on when I changed the glow plugs and found they weren't working (they were autolites, so they needed changed and everyone was swollen, but came out whole) and am running Motocraft plugs. Also, does Autozone still have the bullet style motorcraft ones? ZD1A IIRC. I know there were several posts about them clearancing the spade type, but just wondered.

Anyway, thoughts?

 

[Diesel JD]

You have the ZD9s and unfortunately Autozone discontinued them. There might be a member who'd be willing to share out of his stockpile, as a lot of us bought more than we needed when they were clearancing them at Autozone for very cheap. I bought 13 for a buck each but mine are either needed for spares or spoken for. As far as longevity, I converted to solid state almost exactly 4 years ago. I did a stupid thing and hooked the fusible links up so the plugs had constant, not keyed power so that first set was toast right away. After I fixed that with new plugs I have only had to change one since then..yep, the one right under my turbo but still, I am impressed and don't have to worry about somebody burning out my plugs. You said yours works great I'd leave them right where they are, maybe ohm them out and make sure you have a very good clean ground and tight connections if you want to help them out, but not to worry, I'd say you have MANY more starts out of them unless something goes weird.

 

[sle2115]

Thanks JD. Not sure if you remember when I went through getting this truck running, but I went through and installed multiple ground straps, etc. Made a huge difference in how the in dash gauges work, glow plugs, etc. I've not had a minutes trouble with it starting, other than the fuel filter that was full of gray stuff...I believe it might have been dust from the new rear tank, solvent or something! It was a diesel tank, purchased brand new, and has a brand new sender in it, so I don't know what else it could be. It is the rear tank and when I got the truck, someone had written "don't use" on the fill door for that tank, so who knows what was in the fuel system between that tank and the inline Perma Cool filter I installed.

At any rate, the truck starts in ANY weather, always cycles the glow plugs, even when 90 degrees out, for a short time, longer as it cools, so I'm thinking they are fine as well.

 

[lotzagoodstuff]

If your truck starts easy every time, I wouldn't do any preventive glow plug maintenance. My truck had 3 bad GPs when I bought it, and when it got colder it was very tough to start on only 5 good ones. Since then, I change about one per year, right after the first 50 degree morning when it takes more effort than it should to start.

 

[Agnem]

I look at it this way. There are 3 failures a GP can suffer.

1) become non-functional
2) swollen tip
3) tips worn away

Generally speaking, any one of the 3 is grounds for replacement of all 8 in my way of thinking. Otherwise, I'd pull and inspect them every 25K, and just keep running them if they are OK. They really are amazing devices. They get white hot and are as bright as the sun when operating. It's hard for me to imagine they work more than once.

 

[sle2115]

I look at it this way. There are 3 failures a GP can suffer.

1) become non-functional
2) swollen tip
3) tips worn away

Generally speaking, any one of the 3 is grounds for replacement of all 8 in my way of thinking. Otherwise, I'd pull and inspect them every 25K, and just keep running them if they are OK. They really are amazing devices. They get white hot and are as bright as the sun when operating. It's hard for me to imagine they work more than once.

Yeah, I've played around with them out of the vehicle, which was pretty cool. Mine will take years to see 25k, but will be years old. I don't drive huge drives with the truck, but it gets started regularly for short drives, etc. so they may get used as much as one with more mileage, but just wondered what to do.

 

[Agnem]

That's a good point. Obviously more frequent starts will shorten their lives, so reason #1 may come into play more often than anything else.