How long should a glow plug last ?
 

I know that there would be many factors affecting this but if you use the car for your daily driver how long can you run on the same plugs before they die ??

Thanks

As long at 27 years plus.

I never had one go bad until I replaced the originals.

JCD

Keep a couple of spares and if it ain't broke don't fix it. I did and regreted it ever after.

depends on useage, and who made them. I stay away from autolights & champions. I use the beru's and have had no problems with them. got'm in both the benz & my f-250. the problem with the autolites & champion is the tip swell so much that ya can't get'm out, or the tip will brake and fall into the engine cylinder.... and they won't pay for the damage there product did to you engine. I had to pull one of the heads on my truck to remove two of the gp's. :(

That also depends on the engine type. The later engines with afterglow go through plugs much more quickly. My OM606 is on its third set at 100K miles.

Just got out of replacing three last night, all Bosch. Lasted 18 months. About 32,000 miles. Not good.

I have one that went bad, just 5 months after being put in. They're all Berus. Any ideas why it would do this?
Thanks
David

Burning used engine oil from my fuel tank :rolleyes: made 2 of my GP's die.

Mine are original at 260K, as are the injectors. ~shrug~

I have had some luck cleaning out the precombustion chamber with a wire loop and compressed air. I have only ever removed small flakes of carbon, nothing big enough to hurt the engine if they fell in. Carbon buildup around the glow plug can shorten their lives.
Joe

I just did mine in Feb. they were 17 years old and had 233K miles on them. Their are other reasons to change them, on the newer engines with aluminum heads it is a good idea to at least take them out and put never-seize on them. That way when they do go bad you can at least remove them. Two of mine were very close to not coming out. Also on the 603's and some of the newer diesel's their harder to get to, so if your in their...

Bosch plugs
 

In my '99 OM606, the first set had to be replaced at 45K miles, the second set at 80K (and that included removing the head and having a machine shop grind out two of the plugs)

On set #3, one was already replaced under warranty after 90 days.

When I asked the dealer for an explanation, they shrugged and basically said "stuff happens".

How do you test glow plugs ??? What kind of tool do I need ?

Take it out and put 12 volts to it. The tip should get red hot within a few seconds. Don't burn yourself - glow plugs get hot.

So if I were to attach it to a battery would I just have to use the POSITIVE connector ??

Thanks

Positive to the connector on the end of the plug. Then hold the plug with pliers and touch the body of it to the negative post on the battery. I take no responsibility if you hurt yourself doing this.

No Problem..... Thanks for the help.
I am rather clumsy so my luck would be dropping the hot glow plug into my lap while it is on.

What if a glow plug is partially bad ? Would it still light up ?

Kamil,

You can test GP with a digital ohmeter. They should read about 0.5 to 0.9 ohms. Remove the GP cable plug from the GP relay and you can test by plugging ohmeter into connector holes. You have to remove connector anyway or you will get parallel readings which are innacurate.

This is an easy test because you don't have to remove the GP. It will find a bad GP 99 out of 100 times.

Do a search on ohmeter and you should get more test instructions.

P E H

The original series loop plugs used on Mercedes diesels up thru the late '70s on most models lasted 75-100kmi. The parallel, rapid heat plugs introducted on the "S" class diesels in the late '70sm and in all the models in 1980 typically last 150-250kmi and occasionally longer. The introduction of extended glow after the engine started in the late '80s started the trend to reduced longevity, but this was largely a factor on the duration of the afterglow - 16 secs on early models with the feature extending to up to 3 minutes on the later indirect injection diesels. The plugs in OM606 engines typically last 40-100kmi but a few last longer and a few will of course fail prematurely.

The numbers I quote assume that OEM (Bosch/Beru) plugs are used. Other aftermarket plugs have exhibited MUCH shorter live in my experience (often months rather than many years).

Marshall

They'll last a long time if you keep the fuel clean and dry. A drippy injector is a death sentence to a glow plug.