Glow Plug Expected Life

[Big T]

How long due glow plugs last? My Suburban is having an awful time starting after sitting out in 27 F to 30 F temps overnight. Glows have been in there since it was bought from PO which was 50K miles ago. It's a little bit better starting if I plug in the stock coolant heater. Temps at our 2nd home in Big Bear lake are expected to be down around 5 F this weekend.

 

[SS FORCE]

How long due glow plugs last? My Suburban is having an awful time starting after sitting out in 27 F to 30 F temps overnight. When it does catch, it seems like just a few cylinders fire at first, very rough, then eventually all cylinders fire and it smooths out.

Glows have been in there since it was bought from PO, which was 50K miles ago. It's a little bit better starting if I plug in the stock coolant heater. Temps at our 2nd home in Big Bear lake are expected to be down around 7 F this weekend.

What glow's are you running? im curious about this as well. I put some in a little over 2 years ago and now my truck struggles to start in 30-40F. I was dumb at the time and bought autolights and now i feel im paying for it. Just bought the Duraterms from rock auto this morning.

 

[JayTheCPA]

How long due glow plugs last?

Am sure that others will chime-in with more technical responses . . .

My experience is that it depends on injector health. Good injectors will take the GP's to their rated life (which I am not remembering at the moment what it is for a 6.5 IDI). The last set were InstaHeats and all indications that at least one of them had grounded (harder and fussier cold starts) by 10K miles, but in fairness, when they were pulled the mechanic reported that none had swollen so I suspected that at least one had grounded due to carbon build-up from the marine injectors and use as a daily driver. Regretfully, I could not do a post-mortem as the mechanic threw out the used InstaHeats given that I supplied a set of new Bosch's. Only reason I am giving more information about the InstaHeat experience is that I know their reputation with the GM 6.5 and just want to offer a fair expression in terms of GP life.

In my CRDI rig, the GP's are at 75K miles and still going; plan is to replace at 100K.

Had an old Mercedes with the 'wired in series' style GP's, injectors that I knew were less than optimal (nailed when it was cold), and I had to clean the carbon out of them every 5K miles otherwise one would short to ground, cause an over-volt somewhere in the line, one would blow like a fuse, and take them all offline.

So, to come full circle, if the GP's are seeing a short life, might want to expand the search to see if there are other issues to go after. In the case of InstaHeats, the GM after-glow tends to kill them early with GM 6.5 owners experiencing about a year's worth of life.

 

[Big T]

I have marine injectors from Heath. The PO installed them in the year before I bought it with 150K miles on it. I have the receipt for them. I assume he did glows at the same time and I'll recheck the receipts.

So I don't know the exact miles on the injectors, or the glows. I do not know the manufacturer of the glows. I know on our now wrecked '95 we did not change injectors and glows until 150K miles and never had problems. This Suburban does have a Heath tune and the glow cycle has been extended from stock.

Our place up at Big Bear Lake is at 6,750' elevation, so wondering if that also has an impact. We did get down into the 30s here in Fullerton (north of Anaheim/Disneyland) this AM. Never had any starting problems in Fullerton which is basically at sea level (300').

 

[SnowDrift]

How long due glow plugs last? My Suburban is having an awful time starting after sitting out in 27 F to 30 F temps overnight. When it does catch, it seems like just a few cylinders fire at first, very rough, then eventually all cylinders fire and it smooths out.

Glows have been in there since it was bought from PO, which was 50K miles ago. It's a little bit better starting if I plug in the stock coolant heater. Temps at our 2nd home in Big Bear lake are expected to be down around 7 F this weekend.

I see the exact same symptoms, but suspected the starter was getting weak. It's been over 8 years, probably since I had it rebuilt. I think it seems as if it doesn't whip the engine over as fast as it used to.

 

[ak diesel driver]

good ones last quite awhile. the duraterms I'm using are about 3 years old including an episode of sticking relay that ran the batts totally dead on just the glows. I've had others only last 3-4 months (insta heats)

 

[tanman_2006]

My 60G's have 70K on them and seem to be getting weak but I think the injectors and IP are weak to. It started in 12* this AM and next monday and tues has a high or 7*.

 

[3500GMC]

I do know a cold timing advance circuit makes a world of difference on a mech-inj diesel. Helps to have the lift pump doing its thing during the glow cycle as well. Glow system is not that hard to diagnose.

 

[tanman_2006]

My 95 has a few problems that dont help starting but here is my experience:

I did rebuilt injectors and 60g's at the same time and starting was perfect that winter. I showed off when the neighbors 24V Cummins wouldnt start on first crank by firing the my 95 up while -30F, sounded pretty pissed off but didnt miss a beat. Now another 3yrs/75K later and every winter it smokes more and shakes worse. I have suspected a couple bad injectors for awhile and now my IP is leaking fuel so none of that helps.

My opinion is replace GP's w/ injectors. Test and save any that are still good because you never know when a glow might ground out.

 

[WarWagon]

They are expected to last a long time and some do. Best to check them before winter every year. I usually change what's left of them along with the engine...

You absolutely need to know what is in your engine before extending the glow times. The the goal is the self limiting plugs that IMO heat slower then the original plugs. I like the Duraterms and have 3 years 30K on one set and 50K on the other set. I did not like the 60G's (slower to heat than duraterms IMO) and removed nubs with the entire tip gone when I cracked a piston.

Over-advanced timing will erode the plugs. Cycling them on when the engine is hot and running can physically damage them. Either can ruin them. Jumpstarting higher than 12v or booster units can burn them out.

The glow time is fairly long on the 1995 and it starts very good. The 1993 starts better the longer I glow the plugs.

You can ohm a few out and see if they are burned open. Start with ohm tests on the low hanging fruit aka the easy ones on the driver's side. I would pull one or otherwise read the part number and brand. Check a glow plug for 12v on each side with the WTS light on. Helper or clips with volt meter on windshield so you can see it from driver seat. Just to make sure fusible links are good to each bank. Check the controller nuts for corrosion. Then you are down to checking each plug for 12v and the plug's resistance.

The hardest to get to plugs like #8 may not match the rest...

 

[schiker]

Another insta heat low life story here about a year old gave a lot of smoke. AC 60G 's last quite a while. Mine are a couple of years old still going strong. OE ones lasted 5 plus years 120K miles and were ok just did them with injectors while there.

 

[Big T]

Just ordered a set of Bosch from Rockauto. $60 including shipping.

Remind me why #8 is a PITA to remove? Downpipe in the way?

 

[WarWagon]

Just ordered a set of Bosch from Rockauto. $60 including shipping.

Remind me why #8 is a PITA to remove? Downpipe in the way?

:hammer:

Do you know what is in the engine now?

 

[Big T]

No I don't know what's in the engine now. I do know they've been in there for at least 50K miles that I've owned it. The injectors were installed within a year of my purchase of the vehicle and they're Bosch Marine. I figure that I have 50K miles left on the injectors. Glows are so cheap that I just bought a new set. A tank of fuel is more than 2x the cost of the glows.

I've owned the Burb since January 2010. The past 2 years it has grown worse on the cold starts. Before that it was fine.

 

[JMJNet]

Remind me why #8 is a PITA to remove? Downpipe in the way?

#8 is fine once the fender liner is removed, it is there, only 1 min to do.

The one before #6 (?) located behind the DP with a shield tube, not too bad after the fender liner removal also.
Problem is more trying to get the clip off inside the shield tube.

 

[Big T]

I left it plugged while up at Big Bear Lake this weekend. Snowed 3" yesterday and it was 14 F this morning. It started right up.

 

[racedaymechanic]

Xs 2 on taking the inner fender out, It makes it so much easier

 

[TurboTahoe]

I find it helpful to have the following:

1) Good batteries
2) Good cables for the batteries, especially to the starter.
3) Synthetic 5/40 oil in the sump
4) Good cables going from glows to the relay

Good luck, my point is that it might not be the glows.

Rob

 

[Big T]

My answers as follows:

I find it helpful to have the following:

1) Good batteries

Brand new batteries this spring

2) Good cables for the batteries, especially to the starter.

All verified as good.

3) Synthetic 5/40 oil in the sump

Rotella T 6 5w40 Full Synthetic.

4) Good cables going from glows to the relay

I will start testing these.

Good luck, my point is that it might not be the glows.

Rob

 

[Big T]

Well left it unplugged and it was 28 F this am. Engine would not start. Pissed, I put the new glows in on the driver's side and it fired right up, but ran rough for about 20 seconds before all cylinders lit up. It was like half the engine was running. So I guess it was bad glows and I need to do the passenger side.