Glow plugs

Hi Anyone know the resistance of a glowplug land rover 90 2.5 TDI (year 86)
I have 3 at .5 ohm and one at 7.5 ohm
Bryan

Dunno I've never bothered checking resistance, just connect em across the battery an if you burn your fingers their OK.

The resistance should be VERY little, but rises smartly as the plug gets red bloody hot.

At half an ohm three of them might be OK, but at 7.5 ohms the other one is shagged.

The plugs will draw about 20 amps each from cold, so by Ohm's Law

V = I x R (volts = amps times resistance)

so R = V / I

so R = 12 / 20 or so

which is close enough to the half ohm you measured.

CharlesY

1986 - it will be a 2.5 TD, the TDI's did not come out until 1990.

When checking a glow plug take care not to be holding the tip when you connect it to a battery - it will get so hot so quickly you may be burned before you can drop it.

They get impressively hot - warm not. Orange hot is common.

CharlesY

Thanks all I will get a new set and keep the three as spares
Bryan

you can buy indivudal plugs u know.

chris_mack said:

you can buy indivudal plugs u know.

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Sure, but there's a certain good feeling as you climb into the car in mid-January with snow all around and it's minus ten outside, and you just think about those four lovely glowplugs that are just about to go red bloody hot exactly where it matters ....

or of course you could flatten your battery while wishing you hadn't been such a cheapskate.

Remember, "NO GLOW, NO GO" applies to lots of diesels on cold starts.

CharlesY

Hi I have the chance of four for under £15.00 so I took it
Bryan

Way to glow!

Cheaper plugs are not as good as the best quality ones, but they are surely a lot better than plugs that don't work.

Copper grease the threads before fitting and DO NOT OVERTIGHTEN them.
Nipped up snug and not a lot more is plenty.

CharlesY

charles when i recently fitted 4 new plugs i didnt copper grease the thread is this a problem? do u think i should take them off and put them on agen with copper grease?

chris_mack said:

charles when i recently fitted 4 new plugs i didnt copper grease the thread is this a problem? do u think i should take them off and put them on agen with copper grease?

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If I bought the car from you today and knew that, I would have the glow plugs out tomorrow, and coppergrease them and put them back carefully.

In answer to your question:
YES.

And if you get a little brush, keep it in your coppergrease can (I use a washed out beans can) and apply to every nut and bolt you put near your Landy.

One day someone will bless you for it.

CharlesY

ok will do so what does the copper grease actually do?

chris_mack said:

ok will do so what does the copper grease actually do?

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ermmmmm... grease things

bustersbus said:

ermmmmm... grease things

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yeh well done but why grease something that isnt a moving part?

chris_mack said:

yeh well done but why grease something that isnt a moving part?

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Maybe it's because it wont seize and be easier tae take oot in the future. That's just my guess

Think of it as an assembly paste for hot bits, it'll stop em siezing together an make it easier to get apart in fook knows how many years time. Copper Slip gets used for all manner of jobs it wasn't designed for but for glow plug threads it's ideal.

always copper slip your wheel studs, and when fitting disks(brake) use it on the mating serface(not the friction serface dummy) and when you take the disks off next time you won't have to smash them off with a lump hammer

I think the lad will be getting the general idea about copper grease now boys.

CharlesY

don't try to use it as a sexual lube its not good for that it will leave a mark