Glow Plug Replacement 2.5Tdi - Not As Bad As I Thought

[CRC]

Hmmmm .... things that have crossed my mind that I would now be double checking. I tend to never trust myself when something doesn't make sense.

 

The resistance of the glow plugs seems low at less than 1 ohm (NGKs are in the region of 1.5 ohms.)

Am I misreading the multimeter?

Does the multimeter work correctly?

Have I got the two leads in the correct sockets on the multimeter?

Is it set on the correct scale or am I reading kohms?

What does the multimeter read when measuring an open circuit? (Some just show a 1 when there is an open circuit. Am I reading this as 1 ohm?)

What resistance reading do I get when I touch the two probes together with nothing in between them?

Am I touching right on the end of the glow plug or further down?

Does it make a difference if I put the negative end of the multimeter onto the negative battery post?

 

I'm sure you're doing all this right, but I once pronounced a 240 VAC live contact dead because I had the multimeter set on DC Volts not AC Volts, and another time I shorted out 24 VDC supply when I had the multimeter plugged in to measure current not voltage. Easy done.

 

If all the above check out, now I'd pull one of the plug caps off and, using the multimeter set on dc volts, test for +12 volts arriving there when an assistance operates the ignition key on a cold engine and the glow plug light comes on. It could be that the relay that energises them has failed.

 

Once I'd confirmed that the glow plug resistances are OK and that the voltage is getting to their caps OK, then I might be tempted to take one out, connect a good ground to it, cause the system to operate the glow plug light and see if it truly does glow.

 

If the car starts fine when warmish, and struggles when really cold, the glow plugs / circuit must be the favourite culprit.

[dieselV6]

I'm fairly sure NGKs take less current within a second from switch on, on account that they are thinner tipped and need nowhere near as much power to glow as the Berus. The slight downside is they cool down quicker too so start the engine as soon as dashboard lights settle. 

 

There is a very good way of checking that the glow plug circuitry is working and without dismantling anything (just lift bonnet and remove engine cover).

You need a DC clamp ampmeter for this (not so popular, mostly AC clamps around, but DC one can be had at a reasonable price from Ebay, this is exactly what I use).

Close the clamp around the wire of each glow plug and check the current flowing as soon as ignition is switched on (without starting the engine, just lights on the cluster).

 

For stone cold plugs and a helper switching on the ignition, you can see 7A-9A current for NGK, and 9A-10A for Beru. The current goes down very fast as the plug heats up, so for repeated tests wait at least 2min before applying ignition voltage again.

 

Prior to this, you can also check total GP current using this method by clamping over glow plug harness next to coolant tank (between the 2 cable ties, no need to unhook them, but make sure the clamp is fully closed around the GP cable bundle. For NGKs, 45A-60A is expected there right when ignition is turned on (I just measured this on my new plugs), going down very quickly, after 5s I saw less than 30A (and afterwards glow plugs were switched off by ECU).   So test cold engine (e.g. after overnight cooldown), best to look at ampmeter and have a helper operate ignition (or set ampmeter at windscreen if you happen to have a remote DC current clamp). If the current looks on the low side, best to check individual GPs to see if problem is localised or if they all are close to being worn out. 

Edited 14 December, 2014 by dieselV6

[oh_superb]

Thanks chaps.

Resistance readings are defo pukka, I double checked, all around 0.8 Ohm. Not showing "1", I know what you mean by that CRC :-)

Good idea to try a current clamp, I'll see if someone has one at work tomorrow. Thanks for that!

[Gaz]

Wouldn't start this morning and the battery had all but given up after three goes.  Clock on dash reset to 00:00.   Started fine jumping it from the CRX, although still belched and chugged as per Oh Superb's description.

 

Local GSF didn't have any on the shelf, so I've just ordered six NGK's for home delivery.  Will see what happens, but it looks like my battery might also be suspect.  Cranked over fine on the first attempt, but was goosed by the third.  ECP appear to be noticably cheaper on S4 Batteries.

 

Gaz

[dieselV6]

I have been using Exide EA852 for past 5 years in the Superb, still good as new. I have been using various premium Exides for last 11 years, and they age very well, also have a smaller EA770 in the Roomster.  Internal resistance grows slowly if at all, and they are truly maintenance free not the sticker on caps nonsense as with OEM and budget Vartas (note the Silver Vartas are good in that respect).

 

Check first if you have 096 or 110 size battery, both were mounted in the Superbs, though V6TDIs mostly have the larger size 110 battery. If you have 096 size, you can get a 110 sized bracket from dealer (<£10) or scrapyard and put a bigger battery in, much better for battery life and definitely worth more than the price of the bracket. Cleaning battery clamps prior to swap might be a good idea too.

Edited 16 December, 2014 by dieselV6

[oh_superb]

ECP sold me a 096, based on my reg. turned out was wrong size, I have a 110. Tip: saved around £40 by buying the Bosch 110 sized batt on ECP eBay shop as "buy now pickup in store". Worked out cheaper than the "shop" price of the 096 Exide that they originally sold me.

By the way, since re-arranging the glow plug wiring and obviously messing around with the connectors now my car starts mint every morning! I suspect that cylinder 4 GP cable might have been shorting on the head through exposed copper.

Edited 16 December, 2014 by oh_superb

[Gaz]

Glow plugs arrived a couple of days ago, but I decided to wait for my new torque wrench to arrive having seen how fine the thread is on the plug, and not trusting my rather ancient 'clicky' wrench.

 

Draper needle torque wrench arrived today.  Brand new in packaging and registering nearly 10ft lbs without load, so it's got to go back 

 

 

Two steps forward and one step back.

 

Gaz

[dieselV6]

No need to send it back, you can calibrate this one easily by pushing the indicator needle in opposite direction relative to the rest of the wrench, until it shows '0' when unstressed. It's not exactly a precision device, there is a reason why other designs overtook it. But for GP job it is perfect.

Edited 20 December, 2014 by dieselV6

[Gaz]

I'd be inclined to agree DV6, but I'd rather not try this technique for something that's new and still in its packaging.

 

If it was used, or said anything on the packaging about correcting minor deviations then yes, and I accept it's not a precision device.  But it's not plumb and it looks to be going awry from the base, so back it's going.

 

Interestingly, I've just had a gander at the glow plugs and looking at the way they seat, there's no room for manoeuvre/error when nipping them up, is there!  And looking at their shape is it even possible to cross thread them (Mr paranoid talking here!)?.

 

Gaz

[dieselV6]

Cross threading is possible if you apply force at an angle. Steel screw can bite into aluminium head's thread relatively easily, so do not apply force until glow plug is freely screwed in by at least 1-2 turns.

 

If you put PVC or silicone hose over glow plug contact and thread it using the hose, it will follow the head thread, it also is much easier to remove/insert the glow plug using a hose. But to be honest, whatever method you use, so long that you can feel the glow plug turning in the existing thread for the first 1-2 turns rather than cutting a new one, all will be OK.

 

Regarding access, despite the various cables, hoses and injection lines, GP mounting angles are such that after removing intake pipe from turbocharger, you have straight, head-on access to 5 out of 6 glow plugs. The last one, nearest to air intake, requires universal joint to mount/unmount, but once unscrewed, can be manipulated out/iinto place using a hose. I added 5Nm more to any torque applied there (so up to 40Nm to unmount, 25Nm to tighten) on account of universal joint losing some torque across it.

Edited 20 December, 2014 by dieselV6

[iob]

Hi guys, question on topic: I was arguing with my indy mechanic whether replacing only 4 out of 6 GPs, considering the remaining 2 were still working (I was in favor of changing all in one step). Was it a bad call from his side? Do the GPs work on the on/off principle or degrade over time?

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[dieselV6]

GPs degrade over time, though initially very slowly, then rapidly towards failure. After more than 3-4 years there is certainly a case for replacing all at once, as the longer you postpone it the more trouble you may have removing them later. No point e.g. replacing only 4/6 only to find out that you cannot remove the remaining 2 a few years down the line, or having to replace them a year later. 

GPs are relatively inexpensive considering how infrequently they are changed, so changing 2 more really makes little financial difference. Also, the more a GP is worn out, the longer it takes to glow and the lower the peak glow temperature.

 

Since it was only 4 GPs in your case, could it be the mechanic did not know how to remove the ones closest to intake and the turbocharger as access there is limited (1 requires universal joint, the other one undoing turbo air intake hose)? Just curious which ones he replaced...

[iob]

Thanks for your comprehensive answer dV6, I suspected the same on the GPs behaviour over time.

As for the real reason behind the mechanic's choice not to change all of them (I bought 6 so I do have 2 spares now) I think you are spot on, since the remaining ones are both mentioned by you(intake and turbo)... I don't think it was lack of tools on his side(he has a very well endowed service shack) , rather it was a pretty busy period at his service and he didn't want any complications that day...I will insist on changing the other 2 as well on first opportunity.

Have a great Christmas and a Happy new year guys!

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[Gaz]

Well today was.... glow plug day!! 

 

Glow plugs - check

 

New torque wrench - check

 

Tools, long reach stuff - check

 

Tubing - check

 

Thread release agent - check

 

Not raining - check

 

Not too windy - check

 

New Bosch S4 110 720cca battery - check (I decided after the third failed start that it was suspect, particularly given that after eight hours charging it ran out of steam on the third start attempt, yet the car started fine with jump leads).

 

So eyes down, look in...

 

Decided to do the battery first, as the 'easy' bit.

 

Now, bearing in mind the current battery was a full size 110 Unipart one, I was a little dismayed to see the carry handles were gone.  the little tabs for 'em were there, but no handles.  Remember I can't use my right arm, so this was a bit of a hindrance.

 

Even rolling the conduit off of the firewall, the battery wasn't going to clear the plastic scuttle, and I didn't think it'd squeeze past if I took the pollen filter off.

 

So off came the wipers and plastic scuttle, which I of course cracked on the way out   

 

Then out with the battery.  Bloody fiddly one-handed, without handles, and it only seemed to want to come out vertically coz of the flat bar between it and the firewall.

 

Once the battery was out, I was a bit surprised to see in situ....a rubber drain bung.  Surprised merely because when buying the car I'd been assured the plenum chamber recall had been done.  Suspicion raised I decided to check the pollen filter housing, which all but fell off and didn't feel at all adhered to the bulkhead.

 

Here be what I found:

 

 

And the foam seal, just about intact:

 

 

And here's some of the water that squeezed out of said seal:

 

 

Pesky bung evicted (no I didn't oust the one under the brake servo):

 

 

Needless to say, the pollen filter is now properly cleaned and sealed to the bulkhead 

 

And my nice Bosch battery is newly resident 

 

It was a bit of a race against time as the weather by this time had closed in.  The biggest bit I had trouble with was getting the bolt back in for the battery retaining plate.  Jeez what a faff - my puddy's too big to get down the access area, so I had to wedge the bolt in a deep socket with a bit of latex glove, then wiggle it around until I got the bolt, plate and thread hole lined up.

 

As I had some sealant out, I glued my V6TDI plate back on the beauty panel :sun: .  And then the rain arrived       so I had just enough time to get my tools away before they got wet.

 

The Glow plugs..... remain tucked up cozy in the garage  :'(  and will have to wait to fight another day 

 

C'est la vie.

 

Gaz

[jimbof]

What a hassle. I was also assured the water ingress had been sorted. Twice. First garage had done nothing. Second just removed the bungs. Ended up sealing it myself. Wasters.

[rotodiesel]

In my opinion, unless you push the bung which is positioned under the brake servo down (there's a pipe running through it) to make a large drainage channel which will take bio crud and rain water, the Mk1 Superb is not fit for the road.

 

I have seen various B5.5 clones with rusted servo vac chambers, which is caused by constant water immersion when this drain gets blocked. Eventually, the mild steel and poorly painted chamber rusts through, and water is sucked into the servo causing loss of brake servo action. This is effectively brake failure on a car of this weight, especially when used by a driver of small stature - and it also causes engine damage due to ingested water.

 

Despite years of these well publicised problems, VAG obviously don't give a toss about the safety of its customers and that of other road users as they have not recalled these vehicles. Their denial of all design and manufacturing problems (timing chains anyone?) makes the wisdom of further purchase of their goods highly questionable in my view.

 

rotodiesel.

Edited 8 January, 2015 by rotodiesel

[oh_superb]

I am not of small stature, but when my pedal went hard unexpectedly, even with my 15 stone grunt, it wasn't slowing down I tell you that much.

It was proper hair raising moment approaching a red traffic light!  Handbrake stopped me though.

Since then I keep checking the darn thing.

[jimbof]

Did you get a new servo fitted then?

[CRC]

MIne now "ticks" reassuringly when it's stationary and raining  .....the lovely sound of water dripping out of the plenum chamber and falling onto the undershield.

 

My pollen filter seal had also been "done" by the Skoda main agents after I asked them to do it under warranty (using the recall printout to prove the argument), but it wasn't that good and a visit to the main VW agents resulted in them giving me the correct length flexible mastic seal that VW have issued for the problem on Passats.

 

Strange experience .... sort of  a "Don't know what you mean, mate, but you could try this but don't tell anyone you got it from me" conversation.

[oh_superb]

Did you get a new servo fitted then?

No I didn't. Just drained the water that it was sitting in!!!

I think the servo has seen better days but it's still the original one.

[Gaz]

No I didn't. Just drained the water that it was sitting in!!!

 

Way t' go!!   

 

And next time it does it, I trust you'll remove it and beat the water out of it mercilessly.....and then put it back, yelling 'and let that be a lesson to ya!' 

 

G

[oh_superb]

Way t' go!!   

 

And next time it does it, I trust you'll remove it and beat the water out of it mercilessly.....and then put it back, yelling 'and let that be a lesson to ya!' 

 

G

You got it!  :clap:

But now I have an unavoidable list of things to do:

Auto box oil and filter

Front top mounts (hope this will fix suspension front left noise)

Brake hoses at front

CV boots

Flickering xenon

 

Can't be asked with the sporadic door lock problems TBH.  But the above are required 

Edited 10 January, 2015 by oh_superb

[jimbof]

...and you make sure you do them jobs and treat her right...  Don't think we can't see you in the Superb Mk2 forum, judas... :-p

[oh_superb]

...and you make sure you do them jobs and treat her right...  Don't think we can't see you in the Superb Mk2 forum, judas... :-p

 

Yes, yes, of course :-)

I'm getting too old for this **** though ;-)  But where there is a problem there is an opportunity to learn.

Anyway, HID fixed today.  Can't do anything else next weekend as the missus is away again so I'll be baby sitting… hm.

But must do the top mounts, assuming they cause the rattling, getting worse.

This is a properly hijacked thread now.

So I'll revert to glow plugs.  Mine has started misfiring on a cylinder on cold starts again.  But the glow plugs are fine.  In terms of resistance that is.  Baffled...

Edited 11 January, 2015 by oh_superb

[propeller]

Hi. im an owner of 2006 superb 2.5 tdi. Does anyone know where i can find glow plug relay ? this topic seemed ok to post this question so i didnt make a new thread  
thank you for reasonable answers .)