v8Dougie Posted October 24, 2010 Share Posted October 24, 2010 My father overheated his 300tdi on the motorway, didn't notice until he totally lost power. A local garage stripped it down and sent the head off which was badly bent. It has now been refitted with new head gasket set, skimmed head, new water pump ,new timing belt and new injector wiring as the original ones melted. The garage couldn't get it running and diagnosed that a couple of injectors had gone, they have now been changed as well. They finally got it running, but said that the turbo had gone as it was loosing oil, does that sound possible? I have ordered a new turbo (nice uprated kit from Allard Turbo Sport), but before they fitted it, they decided to do a compression test as it was running lumpy and found that it had no compression at all on cylinder 2. I now have it at home as the bill was getting too large, any ideas what it could be? Any help would be useful please as I do not really want to have to strip down everything I paid the garage to do! Cheers in advance Phil Quote Link to comment Share on other sites More sharing options...
BogMonster Posted October 24, 2010 Share Posted October 24, 2010 Turbo - yes unfortunately possible - I think when they overheat so does the oil, and gets too thin to properly lubricate the turbo. If the engine has been hot enough to melt the wiring harness I'm afraid I would have scrapped it, I have seen a couple like that and they were completely fked the last one was filled up with coolant to try it and when started it blew all 11 litres of coolant out of the header tank in about 3 seconds, never seen such a scattering match of all the people peering into the engine bay anyway it sounded like a stonecrusher and was dumped. Have they had the pistons out? if it has been really hot I'd be surprised if the pistons hadn't picked up in the bores but they should have checked that Compression is pretty simple in a diesel, assuming the timing's right then the rings need to seal, the head gasket needs to seal, the valves need to seal and there need to be not any effn great cracks in the head or the block. Any of those could be the problem - but I'd probably start with valves. If you take the hose off to the inlet manifold can you hear a "chuffing" noise when turning it over - this would mean a leaking inlet valve. If it is an EDC engine (presumably is if it had wiring to injectors) then has it been on a computer to check everything is ok on that side? Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 24, 2010 Share Posted October 24, 2010 Temperatures high enough to melt the wiring will cause other problems. For a start, the pistons might not be round any more but the normal problem is the rings losing their temper. If you have ever fitted a piston to a Tdi you will realise that the ring tension is quite great compared to a petrol engine. This may be a rumour, but I have heard that the alloy composition of the head(the grain?) can be changed by excessive heat and the head will not seal properly no matter how much it is skimmed flat. It is also possible that the top of the block is no longer flat. It can be skimmed, but then the tops of the pistons have to be skimmed as well to get the protrusion right. Personally I would be tempted to get a second hand worn (but not overheated) engine and recondition that rather than throwing money at the motor you have. Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted October 24, 2010 Author Share Posted October 24, 2010 Thanks for the replies guys, even though the potential news is not good! I have been out today and checked all the valve clearances, and they were all out bar two. I have set them to 0.08inch as per the manual. Then tried turning it over and it sounded happier, but still didn't start. Then checked the glow plugs, and all but one of them had no continuity and were not working. Hopefully that will make a difference. It is not looking good though by the sounds of your comments. Will let you know. Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted November 26, 2010 Author Share Posted November 26, 2010 Thanks for the replies guys, even though the potential news is not good! I have been out today and checked all the valve clearances, and they were all out bar two. I have set them to 0.08inch as per the manual. Then tried turning it over and it sounded happier, but still didn't start. Then checked the glow plugs, and all but one of them had no continuity and were not working. Hopefully that will make a difference. It is not looking good though by the sounds of your comments. Will let you know. Thought I would give you all an update as promised...got the new glow plugs fitted and turned it over, started after only a second or two but ran a bit lumpy with plenty of smoke out the back. Drove it around a little and it isn't too bad, but smokes more and more, taken the dip stick out when running and oil is bubbling up and flowing out of the tube, so I assume a piston ring is gone. So looks like they need doing now. Any thing I should look out for/do whilst changing the piston rings? Thanks in advance! Quote Link to comment Share on other sites More sharing options...
feldo Posted November 29, 2010 Share Posted November 29, 2010 Thought I would give you all an update as promised...got the new glow plugs fitted and turned it over, started after only a second or two but ran a bit lumpy with plenty of smoke out the back. Drove it around a little and it isn't too bad, but smokes more and more, taken the dip stick out when running and oil is bubbling up and flowing out of the tube, so I assume a piston ring is gone. So looks like they need doing now. Any thing I should look out for/do whilst changing the piston rings? Thanks in advance! Same symptoms happened to me, eventually found it to be a bent con rod on no 3 cylinder, ended up buying another engine!!!!!!!! Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted December 3, 2010 Author Share Posted December 3, 2010 Bent conrod, from over heating the engine, is that not a bit odd? Does that give all the same symptoms of failed piston rings? Any suggestions on best order of attack to get the engine up and running again? Reluctant to fit a replacement engine as this one was very good and "low" mileage at only 90k and has already had a new top end. Happy to spend the same amount as the price of a fully reconditioned engine doing this one up, at least I know it is done properly then! Quote Link to comment Share on other sites More sharing options...
fozsug Posted December 3, 2010 Share Posted December 3, 2010 Bent conrod, from over heating the engine, is that not a bit odd? Does that give all the same symptoms of failed piston rings? Any suggestions on best order of attack to get the engine up and running again? Reluctant to fit a replacement engine as this one was very good and "low" mileage at only 90k and has already had a new top end. Happy to spend the same amount as the price of a fully reconditioned engine doing this one up, at least I know it is done properly then! New Pistons New Big end bearings New Main Bearings Head set Bolts Sump sealer Check bores for scoring De glaze bores Check for cracks in bores , especially no 4(flaw detector) http://www.turnerengineering.co.uk/acatalog/300Tdi.html Good luck Tony Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted December 6, 2010 Share Posted December 6, 2010 If you have a bent con-rod the piston protrusion will be very different to the others or non-existent. 300tdi con-rods are easy to bend, I bent one with the starter motor on an engine that was hydraulicked. Engine did not turn over, but the rod was badly bent. Luckily new rods are not very expensive. Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted February 8, 2011 Author Share Posted February 8, 2011 Okay guys, sorry to resurrect an old thread, but have finally got round to starting on stripping the engine again after our Xmas break. I have taken the head off, and on first novice inspection the cylinders look okay, no scoring or cracks. Cylinder two was more oily than the others which matches the compression test, and continues to suggest a piston ring. I have a few photos and hoped someone could help me out as best you can to see if all looks normal. First image (1148) shows some black marking at the bottom of the picture on the cylinder head, this did not come off when cleaned with a cloth, and looks a bit suspicious to me, is it normal? It is not on the other end of the head, this is also showing the head above cylinders 1 & 2, so wondering if it could be related to a loss of pressure? Image 1135 shows cylinder number 2 which has significantly more oil smears around it than the others. There seems to be very minimal wear at the top of the cylinder, no real step, and the bores look clean. Image 1144 (last one) shows the block after cleaning, I do have more picies, so if you spot anything let me know and i can upload a zoomed one. Finally, next steps! I am going to take out the pistons, but am I best replacing just the rings or the whole lot? How easy are rings to fit? If it is easier to attach a new piston (with rings attached by manufacturer) to the old conrod I might just go for that option. Also am I advisable to change all the big and small end bearings? Sorry for all the questions, I have loads of knowledge on cars, but first time I have stripped an engine myself! Cheers in advance for any help. Phil Quote Link to comment Share on other sites More sharing options...
fozsug Posted February 8, 2011 Share Posted February 8, 2011 Looks like a head gasket failure between 1 and 2, causing the marking on the head. Get the head pressure tested and skimed, valves seat reground, new valve guide seals. The bore doesnt look too bad. The block looks ok I would fit new pistons with the rings already fitted . New small end bearings, new big end bearings, main bearings and thrust washers Hone the bores to let the new rings bed in New head bolts , head gasket, manifold gaskets, valve caps, check push rods are not bent. Good luck it will be worth it Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted February 8, 2011 Author Share Posted February 8, 2011 Looks like a head gasket failure between 1 and 2, causing the marking on the head. Get the head pressure tested and skimed, valves seat reground, new valve guide seals. The bore doesnt look too bad. The block looks ok I would fit new pistons with the rings already fitted . New small end bearings, new big end bearings, main bearings and thrust washers Hone the bores to let the new rings bed in New head bolts , head gasket, manifold gaskets, valve caps, check push rods are not bent. Good luck it will be worth it Hi, cheers for the response, however the garage already skimmed, pressure tested and refit the head with new head gasket set after it over heated, does that mean they did not do it correctly? Do you reckon the piston rings have still failed, or could the head gasket not fitting properly have caused the lumpy running, burning oil and no compression on cylinder 2? I assume now I have it at this stage it is worth changing pistons and bearings anyway, but wonder if I have any scope for getting some of the £1200 back off the garage? They gave me it back not working saying it would be another £1000 to get it fixed! The head Hadley does look in good condition, so what could cause it to fail? Cheers again! Quote Link to comment Share on other sites More sharing options...
fozsug Posted February 9, 2011 Share Posted February 9, 2011 I have had another look at youre pictures, the one of No2 cylinder i think i can see where the piston has started to melt and left a shiny aluminium residue near the top. I would say no compression is due to rings failing in that cylinder. For the sake of a few quid have the head pressure tested and checked for warping at a good engineering shop. As has been said above, sometimes when they get that hot they become porous and will never seal. I would clean the block face up with a gasket scraper and then scotch it with a scotch pad, then using a very good straight edge check that it is perfectly flat. If not then i wouldn't bother rebuilding it. If the block is ok and the car is a keeper then i would rebuild as i said above, with the possible addition of a new head. When rebuilding ,be meticulous about getting everything free from old gaskets sealers etc,hone the bores with a medium stone carefully, thouroughtly deagease and clean, and then clean again, assemble all bearings with good clean oil, use good quality components, not ebay or ***tpart , take youre time, use the workshop manual and enjoy it, its very satisfiying. Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted February 27, 2011 Author Share Posted February 27, 2011 Just thought I would let you all know that I have just finished putting the engine back together, and it fired up on first turn of the key and ran smoother and quieter than before. Not able to take it for a test drive as need to put the track rods back on...can't get the old ball joints off grrr. However I have a few other niggles I need to turn my attention to now, none of which were issues before it over heated. The ABS light is on The airbag light is on The air con cooling fans come on when tHe ignition is on, and stay on constantly even when air con button is off and heater fan is off. Any ides on these points? The wiring which runs along the top of the head to the sensor was damaged during the over heat and was "fixed" by the garage. What is tHat sensor and could that wiring be at fault? Any help greatly appreciated as I am stumped! Quote Link to comment Share on other sites More sharing options...
Niamh Posted February 27, 2011 Share Posted February 27, 2011 The ABS light will stay on until you're doing approx 5MPH forwards. If the battery has run flat the the airbag light says on until the relevant fault code is cleared from its control unit, we have Rocacom Lite with the appropriate module that fixed this for us. Niamh Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted February 27, 2011 Author Share Posted February 27, 2011 Niamh, you are a star! The car has been off the road so long I forgot about the ABS light doing that. The battt did go totally flat, new one now. Can I buy necessary equipment to clear the code myself. If so how much and where from? We are not planning on parting with the car so happy to pay more to buy the equiopment so we have it in the future rather than pay a diagnosis man. That just leaves the air con fans... This forum is amazing! Cheers Quote Link to comment Share on other sites More sharing options...
Niamh Posted February 27, 2011 Share Posted February 27, 2011 Rovacom came from Blackbox Solutions but has been superseded by Faultmate. I understand that there is also a product called Nanocom, but I've no experience of that. Niamh Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted February 27, 2011 Author Share Posted February 27, 2011 Just had a look on that website but cannot see the appropriate unit for a Disco 1, is yours a D2 or D1. Does the D1 have a diagnostics port? Quote Link to comment Share on other sites More sharing options...
Niamh Posted February 28, 2011 Share Posted February 28, 2011 IIRC the unit covers everything, you just select the appropriate leads (LDxxx codes) so check what connectors your Disco has, Our D1 with ABS and airbags has an OBDII connector in the drivers footwell. Niamh Quote Link to comment Share on other sites More sharing options...
v8Dougie Posted March 28, 2011 Author Share Posted March 28, 2011 Thought it would be nice to let you all know the end of the story/saga! The Disco is back on the road, fully MoT'd taxed and working great. After fixing all the problems, air con fans was a result of the garage putting the sensors on the wrong way round, found there was a water leak. Diagnosed to be the "P" gasket. The local dealer thought it may actually have been the cause of the initial overheat. Annoying that a £4 gasket caused all these problems, but hey ho. Thanks for everyone's help throughout this, would have been much more difficult not to mention the expense if it were not for you all! Cheers again Phil Quote Link to comment Share on other sites More sharing options...
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