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Is my T5 head cracked ???

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Vw bob View Drop Down
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    Posted: 15 Dec 16 at 18:34
Evening folks, I've been visiting as a guest whilst googling before but have just joined up so please be gentle, I've had my 04 174 T5, for about four years it's just turned 100k and has been causing grief over the past year or so needing a new water pump, turbo, aircon pipe, 5x very recent glow plugs , and lift pump in the fuel tank , for a while now it's been starting badly in the morning , hence the new glow plugs and lift pump , this didn't do much in the way of helping , so I started doing a few checks of my own , symptoms were poor starting if left over night , would turn over for ten secs then try and fire , then catch and miss for a couple of seconds , then run fine, once started would start instantly all day , so I fitted a non return valve on the fuel return line hoping that if it was injector seals this would by vacuum hold the diesel there , seemed to help, but no fix , so then fitted another nrv in clear pipe just before the tandem pump , thinking the tandem pump was letting fuel run back to the tank ,seemed to help but again no cigar, have now narrowed it down to this......if I start the van on the drive for a minute or two , in the morning it will start within half a turn of the engine, but if I use the van and it returns home hot, in the morning I get the poor starting again, I'm now thinking if the vans turned off cold it will hold pressure in the fuel rail , if it returns hot ,while its cooling down the fuel escapes from the rail due to the head being hot with the crack open until its cooled down , does this sound feasible to anyone ?? ,sorry for such a long first post but I'm at my wits end now wondering what to do next , cheers for any help , Rob.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote festa Quote  Post ReplyReply Direct Link To This Post Posted: 15 Dec 16 at 20:55
Turn the van around and face it down hill, it's known on the 5 pots that the injectors chaff the bores and effect the injector seals. Fitting a nrv on the return rail will only extend the inviable.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vw bob Quote  Post ReplyReply Direct Link To This Post Posted: 15 Dec 16 at 21:17
Hi festa , was hoping you'd notice this as I've seen you replying to loads of head stuff in the past on forums , forgot to say that it's always parked down hill on the drive , as I once reversed it on and left it for a week , I thought it'd never start again lol, also forgot to mention the sump level hasn't gone up , but then I wonder if it's only a slight crack by pure chance the diesel is going in at the same rate as it's using oil as the vans not used much, so what do you think of my theory of the crack opening up when used but staying shut tight when starting and stopping a cold engine ? , if the clear pipe stays full of fuel and it still "plays up" This must be either seals or head , do you agree ? What would my next thing then , get injector seals done and get them to pressure test the head while its apart? Cheers for the help .
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Post Options Post Options   Thanks (0) Thanks(0)   Quote festa Quote  Post ReplyReply Direct Link To This Post Posted: 16 Dec 16 at 19:00
The idea is not to throw money at it and a lot can be learned from checking fuel rail pressure. If air is getting in the fuel rail it wont run back down the flow but will return to the tank via the return. There is a o e way valve in the return rail but it's more of a flow restrictor to increase rail pressure. The heads do crack but it's more likely to be one of the injectors which won't necessarily raise oil levels unlike the tandem pump which leaks fuel into the oil around the spindle.
It might even be a damaged seal on one of the posts that connect the head to the rail.
The other place that fails is the seals in the push fit connectors that fit on the fuel filter as this is not really under pressure like the rail but once parked up can pull air.
Been where you are now a few times now.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vw bob Quote  Post ReplyReply Direct Link To This Post Posted: 16 Dec 16 at 20:08
Ok thanks , I'll put some clear tube on the return to the filter and see if I can learn anything there , also check the filter connections again as they didn't seem a tight fit when I checked last time , what do you mean by the seals on the posts that connects the rail to the head ? ,cheers
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Post Options Post Options   Thanks (0) Thanks(0)   Quote festa Quote  Post ReplyReply Direct Link To This Post Posted: 16 Dec 16 at 21:57
Between the fuel rail and the head there are extension posts that are two different length's. These carry the fuel to and from the head and there is a seal each end of the post.
I'm not trying to talk in riddle's but it come out like that sometimes
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vw bob Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 16 at 01:00
Hmmm, after keeping a more accurate mental note over the last few days it seems that it can be parked up hot and start ok the next morning doh, it's been good the last few starts fuel in the clear pipe up to the tandem pump , and fuel remaining in the return pipe albeit with a pea sized air bubble even with the extra nrv removed as it no longer held a seal, so I take it if the head was cracked it'd take loads of turns every morning to start ? But I'm still certain that when I get a poor misfireing start there's no fuel pressure !!, I don't know much about injector function , but as they're operated by the cam would it be possible that it wasn't the fuel rail seals leaking (remember the oil levels not going up ) but could it be a certain injector that was leaking into the cylinder only when by chance the cam stopped on that injector letting fuel leak into that cylinder losing fuel pressure that way , it does seem that when I get a poor start it does smoke loads more than it normally does , also I recently had my 16month old turbo go back to the suppliers for limp mode due to sooted up vanes again !!! , put this down to short journeys and lack of use , but could this indicate a duff injector overfueling
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vw bob Quote  Post ReplyReply Direct Link To This Post Posted: 23 Dec 16 at 10:06
Interesting very poor start this morning.......previously had to remove my nrv in the return line as upon checking found it no longer working , checked the clear fuel pipes before starting this morning as usual ,and first time since messing with it found the supply line full( nrv fitted) but the return line empty and slightly pulled together with vacuum , priming the system on the key did nothing at all , so obviously the engine needs to be turning the tandem pump to fill the rail , hasn't started this bad for a while now , so definitely seems dependent on where the engine stops on one of the injectors as to whether it leaks or not, so time to bite the bullet and off to the VW specialist in the new year
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Post Options Post Options   Thanks (0) Thanks(0)   Quote festa Quote  Post ReplyReply Direct Link To This Post Posted: 23 Dec 16 at 21:28
Could be a dribbly injector so that would explain the white smoke at start up. Mine smokes at start up but that's low compression on number 5.
Probably be best to pull all the injectors and send them away for testing which would cost around £25-£40 per injector for testing. If they need a rebuild then at least they would be setup as a matched set don't get exchange injectors as these are sometimes not setup correctly and you may find throwing £250 in the bin easier.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vw bob Quote  Post ReplyReply Direct Link To This Post Posted: 21 Jan 17 at 09:45
Right peeps an update ,as I hate it when searching these sort of threads just go cold once someone has sorted their own van gggrrrr, since fitting a better plastic OE type nrv into the return fuel line instead of a swanky but crap alloy one on
it and subsequently keeping the clear piece of return fuel pipe full of fuel , it seems OK , and has started fine    so it seems an air leak in the return line was in fact causing fuel to drain out of the system and fuel rail back to the tank .......reckon this could be why many people change ,pumps ,injector seals ,heads, as I have read on forums and then still have problems .

Edited by Vw bob - 21 Jan 17 at 14:32
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gregozedobe Quote  Post ReplyReply Direct Link To This Post Posted: 21 Jan 17 at 23:41
Thanks for coming back with an update, it is good to hear you have sorted your problem, plus knowing symptoms and the actual cure/s will help all those who come along after  Thumbs Up  Thumbs Up  Thumbs Up  Clap
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Post Options Post Options   Thanks (0) Thanks(0)   Quote T5 TDI Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan 17 at 17:56
Yes good news Bob.  I wonder if you may still have a tiny leak somewhere but the NRV is coping with it?

As you say, there are loads of threads on the net with the same sort of problems (can only start when facing downhill etc)  and they either peter out or end up with vast amounts being spent on new heads.  So it's really nice when somone bother to post the fix. :-)  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vw bob Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan 17 at 18:17
Hi mate, yes the leak would still be there undoubtedly, but have read that it may not leak fuel but still let air in thus draining the fuel rail , have read this on all types of Diesel engines and even diesel generators on the net, all I can say is that the nrv on the return is Definitely holding fuel in the system now ,it even starts facing uphill if left for days even with low fuel level in the tank whereas it wouldn't before ,I'm not for one minute saying this will fix everyone's problems, but for the cost of clear pipe and a nrv it's got to be tried first, wish I'd done it before I wasted money changing a perfectly good lift pump, but if I'd not tried this first , garage was on about changing the tandem pump next   "Cos that's what it was on another one they had in" lol
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Post Options Post Options   Thanks (0) Thanks(0)   Quote T5 TDI Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan 17 at 19:13
Never mind, the old lift pump will probably fly away on ebay!
    
You would have thought it would have leaked. I have seen the fuel coolers damp and even dripping.

There is an aftermarket diesel priming tool you can buy that connects to most plastic fittings.  It's simple rubber bulb with a NRV and plenty of different short pipe lengths and fittings.  I think it's really aimed at common rail pumps which can easily be damaged by running dry. I wonder if it could be adapted to pressurise most of the low pressure side in order to find a leak like yours.

NRV = Non return valve just in case anyone doesn't know. Wink


Edited by T5 TDI - 22 Jan 17 at 19:20
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Post Options Post Options   Thanks (0) Thanks(0)   Quote T5 TDI Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan 17 at 19:26
This sort of thing.  http://www.ebay.co.uk/itm/LASER-JANUARY-SALE-Diesel-Engine-FUEL-Primer-Priming-Bleeding-Tool-Set-Foam-/181353982896?hash=item2a398a2bb0:g:SfMAAOxycmBS1mqW

You can probably cut the cost considerably by buying just the VW adaptors and the bulb separately.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Maxb10v8 Quote  Post ReplyReply Direct Link To This Post Posted: 29 Jan 17 at 20:45
Wow!! Thanks so much for this! (Maybe I'm being premature here!?)...but mine has the pretty much exactly the same problem.   And yes, I've forked out loads of cash trying to sort it. The last thing the garage did as the injector seals...maybe it made a difference, maybe I'm just more used to it now? But it seems really random, sometimes it hard to start, sometimes not.
But I'm really keen to try a NRV out.
Is this a DIY job? Or would I need a special fuel pressure thingy?
Thanks, Max
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Post Options Post Options   Thanks (0) Thanks(0)   Quote festa Quote  Post ReplyReply Direct Link To This Post Posted: 29 Jan 17 at 21:38
It's also a flow restrictor so the fuel pressure is able to rise when the rpm rises. I had a 5 pot from a friend of mine which the same thing was done ( nrv on the return) and it was only a temporary fix before it started with the symptoms again a few months later.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vw bob Quote  Post ReplyReply Direct Link To This Post Posted: 25 Mar 17 at 16:09
Hi all back again , still having starting problems if left overnight , so with your help I'd like to establish some base line points , first off van uses hardly any oil and the level is Defo not rising , drained the fuel filter and was clear diesel , not contaminated with oil so hopfully this rules out the tandem pump , waiting to get the thing back from the garage (another unrelated fault ) to reinstall my nrv and try again , garage has had a look while in there but I've been a customer for years and they're a bit worried I'll get them to get the injectors out and it not be that . So I'd like to do some tests myself , so I'm thinking nrv just before the tandem pump and clamp the fuel return line over night effectively trapping the fuel in the rail , if it doesn't start well in the morning then surely this means injector seals , remember oil level not going up so hoping it's not a cracked head, secondly , if I put a pressure gauge into the return line before the filter , and pressurise the fuel line that goes into the tandem pump , what sort of pressure would I need to test ? , and would this test even work , pleeeease any advice as I'm getting really pissed off now , what other tests could I do , before I bite the bullet and just get the injectors pulled , oh p.s if I hold the revs at a steady 1500 rpm in neutral I can feel a very slight vibration and I've seen on threads this is common but I'm not sure why ?? Cheers Rob .
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TEA FIVE Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jul 17 at 20:14
Hi im new to the site but i also have the very same issue..I have a 2008 2.5 T5 with only 143thousand miles and have spent almost 2.5k trying to solve the fuel in oil.I have had a new tandem pum injectors checked and new seals,new battery ect...Yet after all the work carried out by the garage my van will only start faicing down hill no problem but if left on the flat or facing up hill it takes ages...there is a build up of fuel in the oil still and im just and my thederd end trying to get it sorted...would you suspect a crack in my head .........any advice or help would be great...thanks
brydoolz
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