JB750 Posted December 22, 2014 Share Posted December 22, 2014 Well, after 'sorting' out the loss of coolant (or thinking I had, silly me!), when moving house recently, driving the Disco to the new place with caravan on the back, got just under half-way - around 12 miles - and the temp gauge started climbing again! Pulled over, lost around 1 1/2 gallons of water, topped it up again and it went down to well below half-way in a matter of minutes. Got recovered along with the van to the new house and now have the truck in the shed waiting for my attention. After all I have done/checked (see the links below) I have decided that there must be either a warped head or maybe even a crack so am going to strip down the top end and get the head checked out for the above. Can anyone suggest anywhere within the Bude area of Cornwall? I'm sure that there must be plenty of Landy places around the area but don't want to end up at some cowboy engineer who takes great pleasure in making many sharp intakes of breath Previous posts: http://forums.lr4x4.com/index.php?showtopic=90727&hl=overheating http://forums.lr4x4.com/index.php?showtopic=91507 Cheers and Merry Xmas & a Happy New Year, JB Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 2, 2015 Author Share Posted January 2, 2015 Well, taken the head off and the gasket doesn't look to have any breaks/leaks that I can see. I haven't got an engineers straight edge, but using two different thick steel rules there is the smallest amount of warp on the head but I cannot be 100% it is within limits so I will have to find somewhere to get it checked. But.....the coolant must be going somewhere, and I am sure there was none in the oil and no oil in the coolant. So I have checked all around the system to try and see if there is any evidence of leaks and I think my worst fear has been realised! Using a mirror and torch, it looks like the core plug at the rear of the block is pretty rusty on about 1/3 of the edge, and if it is that rusty on the outside I am betting it is going to be pretty grotty on the inside? So my money is on a leak from there once the system gets up to temperature. I am guessing that the only way to replace it is engine out? I have spent so many hours and long nights trying to sort this out, and feel like cutting a damn hole in the bulkhead so I can replace the core plug from inside the cab!!! Any advice/hints for replacing it and if I am making the right move? Sorry for the essay JB Quote Link to comment Share on other sites More sharing options...
alland Posted January 2, 2015 Share Posted January 2, 2015 hi before you do that it might not be core plug , have you tried the y piece that is on the pipe coming from the header tank and joins further down it is why my 300 used to over heat it got v hot and kept climbing untill it chucked out water , as i sold the truck as i was fed up to a mate and he said the y piece was blocked so changed it and it was fine hope it helps Quote Link to comment Share on other sites More sharing options...
stuck Posted January 2, 2015 Share Posted January 2, 2015 I have spent so many hours and long nights trying to sort this out, and feel like cutting a damn hole in the bulkhead so I can replace the core plug from inside the cab!!! Why not do exactly that? You could use a hole saw to make a neat job, paint the exposed edge with a rust preventative & fit a blind grommet once you are done. Good idea if you can guarantee the hole is going to be in the correct place. Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 2, 2015 Author Share Posted January 2, 2015 I have managed to take a picture of the offending core plug with the judicious use of a mirror, torch and some trickery pokery! I have also added a couple of pictures of the head and gasket along with the restrictor which came away from the gasket when I removed the head. As can be seen from the picture of the block, the heat shield between the block and the bulkhead is pretty rusty so I am guessing it has been getting pretty damn wet? Quote Link to comment Share on other sites More sharing options...
Boydie Posted January 3, 2015 Share Posted January 3, 2015 You don't need to cut holes in the bulkhead/firewall. If it is the rear welsh-plug you can access it by jacking up the engine and removing the gearbox an engine mounts and lower the engine slowly onto the front axle - to give you greater clearance you may want to raise the rear of the gearbox to give a slight degree of inclination to the front. Once this is done with a right-handed drill drive drill a hole in the middle of the welsh-plug and with a Phillip's head screwdriver inserted into the hole lever it out. With steel-wool clean out the port - make sure it is totally dry and paint it with liquid sealant (not silicon) insert the new welsh-plug and (and this is the doosy) strike it hard in the centre to cause it to seal. At this stage if you can beg, borrow or rent a radiator pressure tester fill the system and pressure test it to ensure that your plug has sealed, if not trust in all things mechanical , refit the engine and gearbox mountings, fill the system and run the engine up to temperature with fingers crossed - those that you have left without Band-Aids covering the nicks and cuts that you will have suffered. As I said, it is possible, I've done it but it wasn't easy. Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 3, 2015 Author Share Posted January 3, 2015 Thanks Iain I must admit, I am tempted to go for it using your method, but knowing the fun I've had in the past with core plug removal and refitting, I think I might be tempting fate doing it in the car. There is quite a bit of oil staining down the left-hand side of the block too so I think I might be as well to lift the engine, give it a good going over and clean up. I've already got the radiators out, turbo out, and I replaced the flexi plate between the torque converter and the flywheel not so long ago so I know I can get the top bell-housing bolts out which seems to be one of the worst jobs on the Discos. I should be able to leave the power steering undisturbed by just unbolting the pump from the mounting bracket I hope. It has Air-Con, so I will do the same for the pump for that too. Whilst it is all off, I will give everything a good going-over to try and nail any more issues that might be waiting in the wings Just need to get somewhere to check the head for me now. Quote Link to comment Share on other sites More sharing options...
Boydie Posted January 4, 2015 Share Posted January 4, 2015 If you drop the engine (you need to disconnect the front engine mounts anyway so just remove them) you will find that the top bell-housing bolts are more accessible Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 4, 2015 Author Share Posted January 4, 2015 Yep, I was going to remove them anyhow as it makes engine removal a fair bit easier apparently. I did manage to get the top 3 bell housing bolts out OK using 3 extensions on my ratchet going in from the transmission tunnel inside the cab when I did the Flexi plate, but if there is enough play in the selector cable I may be able to drop the front of the engine enough without disconnecting if from the gearbox. Quote Link to comment Share on other sites More sharing options...
Boydie Posted January 4, 2015 Share Posted January 4, 2015 If you can afford it a GOOD quality cordless hammer/ratchet gun is a boon - mine is a right-angled Bosche1/2" drive tool and it gets into 90% of the tight places and is soooo much quicker than a 1/2" ratchet spanner. I got mine on EBay Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 5, 2015 Author Share Posted January 5, 2015 I've got a 1/2" drive right-angle windy gun which could get into tight spots, it's not an impact gun but once I crack the nuts it will do the rest. Maybe I need to put a cordless gun on my next XMAS list? Quote Link to comment Share on other sites More sharing options...
Boydie Posted January 9, 2015 Share Posted January 9, 2015 Just a thought for your consideration. When re-built my 300Tdi motor I purchased a new head, (it came complete with valves & springs fitted) and I had it ceramically coated, when this was carried out they removed the valves & springs, plugged the valve guides and sprayed the external surfaces they then wiped the valve seats and welsh-plugs clear before baking the head, once the coating was baked and cured -- and to my relief the head didn't warp -- the head face was skimmed 0.001mm to remove any high spots on the coating and the valves re-fitted. The advantage of this process is that it keeps the combustion temperatures in the cylinders rather than passing into the head, I had the same coating applied to the(new) piston combustion chambers and crowns. The annoying thing I noted on re-assembly was that none of the pistons had the same "rise" above the block face, they varied from 61 to 72 thou, consequently I had the three shorter rods stretched to match exactly the longest one, small wonder that Land Rover recon that a combustion test of +/- 70 psi is acceptable- my variation over all four cylinders when the engine is cold is 10psi. The other "modification" I had carried out was to the three triangular water-ways between cylinders 1-2, 2-3, and 3-4. These do nothing as they aren't connected to a corresponding port in the cylinder head -- all they do is inadvertently reduce the sealing area surrounding the cylinder. Consequently I had a friend of mine who teaches welding at the Sydney Tech College to weld them up, he did this very, very carefully and the block only needed a skim of less than 0.001mm to remove any high traces of his work. The composite and multi-plate head gaskets STILL have cut-outs for these water-ways so obviously they were intended at some time to be open to the head and for some reason beyond my ken have never been changed/modified so when I fitted the head gasket I filled these openings with high temperature silicon. The engine has now done well over 300,000 kilometres without missing a beat. The timing belt gets changed every 100,000 kilometres and oil/filters every 10,000 and the water temperature never rises above 90 degrees C. Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 9, 2015 Author Share Posted January 9, 2015 Finally got the donk out last night and fitted to the engine stand. Had a pig of a job getting the front low enough to get the top bolts out of the bell housing because the damn steering box is in the way! Anyhow, took out the core plugs and I think it is safe to say that the rear one is foobarred! Had a heck of a job getting it out too, hence the rather larger than normal hole to lever it out. The others came out fairly easy. I'm 99% sure that this is where my coolant loss problem was. Under pressure it won't take much more than a pinhole to start losing coolant rapidly and there is a real string-of-pearls along the bottom edge of it!. While I've got the engine out I will try and find out where all the crud and oil is coming from, it's not leaving puddles under the truck but there is a pretty good coating on the right side of the block and all the running gear underneath. I've checked the rear seal and it seems OK, I think it might be from one of the ancillaries bolted to the right side of the block. Now need to get my order in for new head gasket, bolts, thermostat housing gasket, locating dowels are pooped too (inlet/exhaust gasket) looks fine. Think I'll treat myself to anew torque wrench too, mine is a little long in the tooth and probably well out by now. I've got an angle torque gauge so should be all set once I get a new wrench. Watch this space for the next episode........ Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 9, 2015 Author Share Posted January 9, 2015 I have cleaned the head up and checked for warping as best I can with what I have: I have a thick steel rule which I have checked against the engineers block I have and am confident it is true. I then used the rule on the head to check for bowing, and as far as I can make out, there is at most 0.02mm of gap in the centre of the head. I took some pictures shown here. What does the collective think? The white bits around some of the valves is just paper I used to wipe off the head after cleaning. What do you reckon guys? Quote Link to comment Share on other sites More sharing options...
Boydie Posted January 9, 2015 Share Posted January 9, 2015 In my opinion -0.02mm in the centre of the head is excessive, get it skimmed, if it was 0.002 I'd say it was okay. You will need to remove the valves if you have this done but that's not a bad idea as you can fit new valve stem oil seals at the same time as lapping them in (which of course you were planning to do) after the heads been skimmed. You will have noticed the pitting marks on the head where the three water ways are, before you re-fit the head consider painting these areas with a thin coating of high temperature resistant anti-corrosive paint. Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 10, 2015 Author Share Posted January 10, 2015 Thanks again Iain. Looks like a skim is in order then? I will take your advice on the 3 waterway areas, I have seen a video on youtube with one that has corroded very badly so junked the head! For all the hassle I've had in the past, I am not taking any risks again, if the head need skimming it needs skimming. I am on a 3-hole gasket at the moment, do you think I will need to stay with that thicknes (1.5mm) or go for the no-hole one (1.6mm) after the skim? Thanks again for your input JB Quote Link to comment Share on other sites More sharing options...
Rangy35 Posted January 10, 2015 Share Posted January 10, 2015 I would skim the head regardless, the surface is not in good shape. The valves dont need removing for the skim. But if you are going to do valve stem seals you are going to have to remove them so it would not matter before or after the skim, have the valve guides checked. Skimming the head does not influance the gasket thicknes, the piston pretrusion above the block does, measure it and see if the correct gasket was fitted and if not get the correct one. Quote Link to comment Share on other sites More sharing options...
Boydie Posted January 10, 2015 Share Posted January 10, 2015 JB, skimming the head wont make any change to your current head gasket thickness, but to make sure that you are using the correct gasket use your straight edge, turn the engine over so that pistons 1 & 4 are at TDC and with feeler gauges measure the gap(s) between the straight edge and the block and then turn the engine over and measure 2 & 3 if the greatest gap is over 65 thou and under 75 thou then a No.3 (3 hole) is the right gasket, if it's less than this then from what information I can glean from LR (and confirmation of this would be much appreciated) if the LARGEST gap is under 65 thou, a 2 hole and if the largest gap is under 55 thou a single hole, for OVER 75 thou gap the gasket has NO holes. I carry the "no hole" gasket as a spare when I'm touring in the bush as it is more likely to take up any minor warping that might have occurred due to the failure of the original 3 hole currently fitted. It's not bad practice to use a micrometre to measure the thickness of your old and therefore fully compressed composite gasket to confirm that the pistons will no come into contact with the cylinder head when they are at TDC. The new gasket will, of course be fractionally thicker to allow for that degree of compression. The head bolts have a maximum use of 5 "removals" as they get stretched during the torqueing procedure, I would advise a new set and put your old ones aside for future use / spares. Quote Link to comment Share on other sites More sharing options...
Boydie Posted January 11, 2015 Share Posted January 11, 2015 JB, done some research for you, go to http://forums.lr4x4....showtopic=25408 this will explain piston head measurements and correct head gasket selection to you ---- enjoy Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 11, 2015 Author Share Posted January 11, 2015 Thanks for all the good info guys I have the Rave workshop and maintenance manuals so have all the good info you have about gasket thickness etc. With regards the skimming affecting the thickness of gasket, I thought that as material is removed, effectively the valve faces will be a little closer to the pistons which is why I wondered how much can be removed before needing a thicker gasket, if that makes sense? I have just ordered a 24" straight edge so in future I can be a little more accurate than my present methods! I also have a DTI so can measure the piston rise for gasket thickness. Doing a rough check with feeler gauges the other day pointed to the current 3-hole gasket being correct. Thanks again for the input, I will tray and get the skimming done this week. JB Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 11, 2015 Author Share Posted January 11, 2015 JB, done some research for you, go to http://forums.lr4x4....showtopic=25408 this will explain piston head measurements and correct head gasket selection to you ---- enjoy Boydie, not sure if there is a link issue but the one you gave takes me back here Quote Link to comment Share on other sites More sharing options...
Boydie Posted January 11, 2015 Share Posted January 11, 2015 JB, I understand your concern however both the inlet and exhaust valves are fully closed well before the piston is at TDC on both the combustion and exhaust strokes so skimming the head 0.02mm to get it back to perfectly flat wont be a problem. Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 12, 2015 Author Share Posted January 12, 2015 OK Iain, thanks for that. I know the valves will be closed before long before and after TDC, but I guess I'm just a naturally overthinking worrier When I looked at the range of measurement for piston stand proud for a 3-hole gasket is 0.71mm to 0.80mm. So assuming my estimation of the stand proud value of 0.76mm is correct, I still have 0.04mm to play with anyhow, so even skimming 0.02mm off the head should still leave me in the clear. Just finishing off cleaning down everything ready for re-assembly and waiting to get it skimmed now so I can start putting it all back together! Remind me again why we own Land Rovers? Quote Link to comment Share on other sites More sharing options...
Rangy35 Posted January 12, 2015 Share Posted January 12, 2015 OK Iain, thanks for that. I know the valves will be closed before long before and after TDC, but I guess I'm just a naturally overthinking worrier When I looked at the range of measurement for piston stand proud for a 3-hole gasket is 0.71mm to 0.80mm. So assuming my estimation of the stand proud value of 0.76mm is correct, I still have 0.04mm to play with anyhow, so even skimming 0.02mm off the head should still leave me in the clear. Just finishing off cleaning down everything ready for re-assembly and waiting to get it skimmed now so I can start putting it all back together! Remind me again why we own Land Rovers? No you are not skimming the head gasket, you are skimming the head.You can skim the head 10mm the gap will stay 0.04mm Quote Link to comment Share on other sites More sharing options...
JB750 Posted January 12, 2015 Author Share Posted January 12, 2015 No you are not skimming the head gasket, you are skimming the head. You can skim the head 10mm the gap will stay 0.04mm I think I've confused the issue I know I am getting the head skimmed, but what I was trying to say is that the allowance for the piston proud measurements from the block to decide which thickness head gasket to use states 0.71mm to 0.80mm. My concern was that when you skim the head, you actually bring the face of the valve nearer to the piston by virtue of the fact that the distance between the valve face and the head face is reduced slightly. But because I have 0.04mm piston proud allowance before I would need to go to the no-hole gasket, then I technically can remove that much from the head face before it would be an issue. The limits for head gasket thickness still apply whether I have an increase piston proud value or a reduced head face to valve face value. The end result is the same, the valve face needs to be a certain amount away from the piston face. I guess I am understanding the clearance thing slightly wrong, the reason for the head gasket selection is more for the pistons clearing the head face rather than the pistons? Hope I haven't confused the issue even more Quote Link to comment Share on other sites More sharing options...
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