Oil on Glow Plugs

Hi, I have a 90 fitted with a Disco 300 tdi engine and I have just fitted a new set of glow plugs and the two old ones I removed from cylinders 3 & 4 were covered in oil where as cylinders 1 & 2 were clean. I have had a problem starting from cold and when it does eventually start its pumps out blue smoke til its warmed up. Any ideas what the problem could be??

Regards Andy

That would be duff glow plugs then! If you have a multimeter you can measure continuity through the glow plug, you should get a reading around 1.5 ohms between the conector on the end and the body of the glowplug, if it is open circuit, like a blown fuse, the plug wont get hot and it will oil up. Assuming that the smoke clears once the engine is warm, it will be because there is no heat in the motor to help the diesel burn so you get more of a smokey smolder than a clean burn. It's worth buying the decent genuine glowplugs as the cheap ones off ebay don't last and don't seem to get as hot, as i've found out.

jump lead/battery and vice and test them

Sorry probably didnt explain it that well I have fitted a new set of plugs this morning it was two of the old ones that were covered in oil, were they covered in oil because they were not working or is it something else. Now the new set is fitted hopefully this will eliminate the problem

Andy

old ones will be shagged , but as I said before battery and jump leads you can test them-the oily ones will either not glow or not glow evenly.

Therefore the uneven glow won't be hot enough and you'll have got black smoke-simple

It's probably not oil, it will be diesel and soot, they are like that because they never get hot enough to burn it off, after a long drive they should be OK but if you had recently run it for a short time, then took them out, it's diesel.

He's asking what the reason for them being covered in oil is, not how to test them . Generally speaking your glow plugs should be BONE DRY, and at most, have a slight coating of dark black soot (carbon) around the very tip, which is the sign of a healthy engine. They should not, by any means be wet, and definitely not oily. The only liquid that should (in theory) be entering the cylinders, is diesel and only via the injectors. Oily glow plugs mean that there is oil getting into the cylinders, which is not what you want for a few reasons; 1) the engine will not perform optimally, 2) it could possibly lead to engine failure. Causes of this problem can be a few things, ranging from worn piston rings, leaking valve seals or a blown head gasket, even split piston crowns in some cases.

Before you start to worry yourself however, I'd suggest that you start with the simpler things. First of all, disconnect the hose between the intercooler and the air intake manifold and peep inside the hole o). Is the inside of the air intake manifold blathered in oil? Also check the air filter. If it's blathered in oil too, that wont be helping things, so swap it. I'd also suggest that you remove and clean the cyclone breather (here's a guide - http://www.landyzone.co.uk/lz/f41/cyclone-breather-76543.html) to ensure that the pipe between the cyclone and the air intake isn't drawing in pure oil, should the cyclone breather be gunked up.

If there is no significant sign of oil being 'sucked' into the engine, or forced into the intake manifold via the turbo, then you need to take it a step further and remove the head to inspect a couple of things, but we'll get to that if you need it.

One last thing that you can check is the following. Start the engine and get it up to its usual running temperature. Then, have a friend sit in the cab ready to accelerate when you need them to. Start by removing the oil filler cap. Place your hand over the opening and then ask said friend to rev the engine hard. Can you hear or feel any chuffing? Replace the filler cap and then move around the passenger side of the engine. Remove the oil level dipstick and press your thumb firmly over the opening so that it creates a seal. Have your friend hard rev the engine for five seconds, and then quickly release your thumb. Does the dipstick tube release any pressure (creating a hissing sound) or launch oil at you? If either of the above symptoms are apparent, you may well have a blown head gasket (which would explain the oil in the cylinders, oily glow plugs, blue smoke and struggle to start the engine). It could also be a couple of other things (as mentioned earlier) like worn piston rings, split piston crowns, worn oil seals or in the worst case scenario, a cracked cylinder block or cylinder head.

-Pos

pos said:

Oily glow plugs mean that there is oil getting into the cylinders.

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POS - it's diesel mate, the diesel on the soot can be mistaken for oil.

Even if it was, a little oil is not an issue anyway, and if it was bad enough to get it up onto the glow plugs he would have blue smoke, until there is an issue with blue smoke he is fine.

discomania said:

POS - it's diesel mate, the diesel on the soot can be mistaken for oil.

Even if it was, a little oil is not an issue anyway, and if it was bad enough to get it up onto the glow plugs he would have blue smoke, until there is an issue with blue smoke he is fine.

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He does mention blue smoke though I hope that it is just something as simple as diesel thats collected on a dud glow plug, that'd be a nice simple answer to his question!

when it does eventually start its pumps out blue smoke til its warmed up

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Ok I have checked everything as posted by Pos and they all seemed fine there didnt seem to be any oil in the inlet side or in the cyclone breather, I removed one of the new glow plugs that I fitted this morning and it was already covered in oil and its only been running for about 10 mins so I think there is a definate problem, if I did a compression test would this show up a blown head gasket??

13aldy13 said:

Ok I have checked everything as posted by Pos and they all seemed fine there didnt seem to be any oil in the inlet side or in the cyclone breather, I removed one of the new glow plugs that I fitted this morning and it was already covered in oil and its only been running for about 10 mins so I think there is a definate problem, if I did a compression test would this show up a blown head gasket??

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A leakage / compression test will tell you whether or not a cylinder is loosing compression, but not an answer as to what is causing the compression loss. To determine whether or not your head gasket has gone, there are a few things you can try. First start with the test that I mentioned above (oil filler cap off & dipstick tube test). Also, when the engine is COLD, remove the expansion tank cap (engine coolant reservoir cap) and then start the engine. Watch the water for bubbles. If the level of the coolant in the expansion tank drops, or if it bubbles, that will also point towards head gasket failure. Another possibility is that you may well have a couple of dogey injectors with a bad spray pattern, or no spray what so ever. If your injectors are just spurting fuel into the cylinders, it wont burn because there will simply too much diesel and you'll have a 'wet' bore. There are some garages that will have the necessary equipment to test your injectors at a cost, just to double check hat they're not at fault. That would not explain the blue smoke though which is caused by burning oil, or at least an oil thicker or more crude than diesel as partially burned diesel, or too much diesel to burn produces white smoke, not blue. I think the best way forward is to do the checks that I suggested (to determine the head gasket). If there's nothing obvious there, then take it for a compression / leakage test to see how the two cylinders in question compare to the other two cylinders. I expect that they will return lower compression test readings, or a higher leakage test reading. If that is the case, then it's going to be a matter of whipping the head off and finding what is causing the problem. If it's the valve seals in the head, it wont look obvious, you'll maybe see oil around the valves at best. Replace the seals anyway just to make sure. If it's worn piston rings or even broken piston rings, you might see scratching on the cylinder walls or oil lines. Check the tops of the pistons (piston head / crown) for cracks too. They will open up enough to allow oil through / compression to escape when the engine heats up. I'd like to put my money on it being the valve seals because they're cheap and a garage will do it for a small amount of money. Are you willing to take the head off your self or have a garage do it for you? It could be the difference between £0 (just your own time) and £500 at a garage.

-Pos

Ah you do mention blue smoke. How many miles has your 300tdi done? At about 130,000 the valve stem seals seem to leak a bit in the 300's.

If you can be bothered take the inlet manifold off (easy one to do), have a look in the ports, is there oil in any of them, you may also need to take the exhaust manifold off if you see nothing in the inlet ports to look into the exhaust ports. You can also run the engine with the inlet manifold off and see if you see any oil sloshing about - but I don't think they sound like they are leaking badly enough if you only get some blue smoke on start.

If so, change seals (NOT a head off job).

Put a litre of white spirit in your tank the next time you fill up. It will help to clean any crap out of the injectors and is much cheaper than special injector cleaner. It wont do any harm and may solve the problem if you have a partially blocked injector(s).

discomania said:

....change seals (NOT a head off job).

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How, I have heard other people say this, but no one has ever explained how you do it

Take the rocker shaft off, then you can get to the tops of the valves, then you bring say the middle two pistons up to TDC by turning the engine over on a breaker bar etc, then you can work on valves 3,4,5 & 6 and know that they won't fall into the cylinder.

Caps and collets off, spring out the way, seal staring you in the face.

Satrted up this morning on the first spin, one puff of black smoke followed by clouds of whitish smoke..............any ideas??

Cheers Andy

13aldy13 said:

Satrted up this morning on the first spin, one puff of black smoke followed by clouds of whitish smoke..............any ideas??

Cheers Andy

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Did you try any of the ideas suggested throughout the topic before it fired up first spin? White smoke could be three things. 1) Water in the cylinders being compressed (steam with smoke from diesel) 2) Steam being produced by water or condensation sitting in your exhaust pipe 3) Partially burned (atomised) diesel. I expect that it is probably partially burned diesel. Try what was suggested earlier and whack two or more litres of White spirit into your fuel tank with at least ten litres of diesel. Also, buy yourself a new fuel filter and a bottle of injector cleaner. Fill the fuel filter with injector cleaner and screw it onto the filter housing. Fire up the engine and then rev it hard for thirty seconds. Turn it off and leave it for twenty minutes so that the solvent dissolves any crux in the injectors and then take it for a really good drive and give it some welly through all the gears. Does it cover long distances regularly or is it primarily used for short runs?

-Pos

Yes I did try all the things yu suggested Pos no chuffing from the filler cap nothing from the dipstick tube and no bubbles in the header tank, could well be water/condensation in the exhaust as it has a side exit exhaust that does poke upwards a little at the end so rain water could be getting in and yes it it used predominately for shot journeys. I will use injector cleaner and change the fuel filter and see what happens.

Regards Andy

13aldy13 said:

Yes I did try all the things yu suggested Pos no chuffing from the filler cap nothing from the dipstick tube and no bubbles in the header tank, could well be water/condensation in the exhaust as it has a side exit exhaust that does poke upwards a little at the end so rain water could be getting in and yes it it used predominately for shot journeys. I will use injector cleaner and change the fuel filter and see what happens.

Regards Andy

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Good stuff Well just to let you know I have been having a few running problems with my 200TDi lately, and i've fixed them all in one go today. I had a bit of blue smoke on hard revs which I've fixed by cleaning the breather hose that connects the cyclone breather to the air intake with brake disc cleaner. It was gunked up with old dirty oil, and some mayo which is what you get when water comes into contact with the oil, so it must have had some water in there at some point too. I also removed the very top cap off my injection pump (held o with four screws) and cleaned the boost diaphragm with brake disc cleaner. I no longer have any blue smoke. I also (as you have said) have a side exit exhaust which pokes up a bit It steams like a Delonghi carpet cleaner if there's as much as a thimble full of water collected somewhere in the exhaust. As for power, I found that my CAF (cold air feed) pipe between the air filter and the turbo inlet had collapsed, which was preventing my engine from getting as much air in as it needed. The turbo didn't whistle properly and the power on hills was crap. This has made a tremendous difference and it might be worth checking just as a matter of routine maintenance.

-Pos

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