Thys Posted March 9, 2008 Share Posted March 9, 2008 Driving home from work, my Discovery's engine temepature shot up to the red. I pulled over and found the expansion tank full to the top, and cold, so was the top radiator hose and the thin pipes to the expansion tank. Opened the bleed screws, and with a blurp the water was sucked back into the system, the temperature went back to normal, and all was well. As a precaution I replaced the thermostat with a new original one. Had no problem bleeding the system, and all went well, untill I opened the expansion tank, a week later, on a cold engine. I topped up to the top of the marker, closed the tank and started my trip to work, halfway (3km), same happened again. Bleed the system and back to normal. This now repeated itself 4 times, I replaced all old hoses, but no luck. This one really has me bogged down, can the second thermostat be the culprit? Quote Link to comment Share on other sites More sharing options...
Les Henson Posted March 10, 2008 Share Posted March 10, 2008 I would try it with no thermostat in, but it's unlikely that's the problem. You might have a head gasket leaking a small amount. Les. Quote Link to comment Share on other sites More sharing options...
Thys Posted March 10, 2008 Author Share Posted March 10, 2008 I would try it with no thermostat in, but it's unlikely that's the problem. You might have a head gasket leaking a small amount.Les. Thanks Les. I removed the innards of the thermostat and re-installed the outter ring and rubber ring. The fact that there is a small of amount of water dissappearing when I do short distances, but no loss on the open road, 150 km trips or more, sort of gives me the uncomfortable feeling the head gasket is giving notice. No water in the oil, but it may be a combustion chamber leak? Regards Quote Link to comment Share on other sites More sharing options...
Les Henson Posted March 10, 2008 Share Posted March 10, 2008 There are about 9 different ways a head gasket can fail, (I can only think of 7 though) Cylinder to cylinder Cylinder to water Cylinder to oil Cylinder to the outside Water to oil Water to the outside Oil to outside Tdi engines most commonly leak either cylinder to cylinder, cylinder to the outside, or cylinder to water Les. Quote Link to comment Share on other sites More sharing options...
Thys Posted March 10, 2008 Author Share Posted March 10, 2008 There are about 9 different ways a head gasket can fail, (I can only think of 7 though)Cylinder to cylinder Cylinder to water Cylinder to oil Cylinder to the outside Water to oil Water to the outside Oil to outside Tdi engines most commonly leak either cylinder to cylinder, cylinder to the outside, or cylinder to water Les. Les, I know with a petrol engine, the radiator specialists mounts transparent pipe on the radiator fill point, and fills it with a liquid that changes colour if combustion products are present. This is done with the engine running. Can this be done with the Land Rover Tdi engine as well, or can they do some kind of pressure test? Quote Link to comment Share on other sites More sharing options...
Les Henson Posted March 10, 2008 Share Posted March 10, 2008 I have a leak tester - this thing- The blue chemical changes colour if fuel/exhaust gas is present in the coolant. Green for diesel engines, and yellow for petrol. If you have a very slight compression loss, then a compression test might not be definitive. Detection of fuel or exhaust gases in the coolant is another way of finding out if you have a problem. Les. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted March 11, 2008 Share Posted March 11, 2008 Do not run a Tdi without a thermostat, as the thermostat works in a different way to most. As the thermostat OPENS with heat, it CLOSES the bypass. If you run without a thermostat, the bypass will stay open and the coolant will circulate around the head without going to the radiator. Quote Link to comment Share on other sites More sharing options...
Thys Posted March 12, 2008 Author Share Posted March 12, 2008 I took my Disco to a local radiator shop, they did the combustion leak test, the dark blue liquid started bubbling, and changed colour, head gasket or cracked head. I will stat stripping tonight................................ Quote Link to comment Share on other sites More sharing options...
Les Henson Posted March 12, 2008 Share Posted March 12, 2008 Make sure you get it crack tested Thys - I hope it's ok, but the 300TDi is known for this problem. Good luck anyway. Les. Quote Link to comment Share on other sites More sharing options...
Mark Posted March 12, 2008 Share Posted March 12, 2008 I think I am now suffering exactly the same set of symptoms as Thys on my 300... Having just done the head gasket, I suspected the water pump and/or the thermostat, so replaced both of those as well, but am still getting overheating issues. tonight I took the truck out and it got hot, then it cooled down and stayed at the right temp, then it got hot again, and then cooled down, before getting hot and staying hot. Intersting thing was that the heater in the car was hot when the car was at the right temperature, and stone cold when it was off the scale... :S Any ideas? Les, is that tester kit commonly available? might try and test the coolant for exhaust gas.... sorry for the thread hijack... Quote Link to comment Share on other sites More sharing options...
Thys Posted March 13, 2008 Author Share Posted March 13, 2008 Guys, thanks for all the advice and help with my 300's cooling system. I am in the process of stripping, got stuck when the standard Gedore and Stahlwillie sockets would not fit on the manifold nuts, looks like one requires a "thinner type socket and shaft. What did come up when removing the water pump bolts, was that the bolts were coated in a thick layer of Copper Slip. This indicated to me that the pervious owner had work done on the water pump/cooling system. The first thermstat I removed was also in an immaculate condition for an engine with 184000 km on the odo, maybe the cooling system played up before? Les I am fortunate to have a good friend of mine with his own motor engineering works, he also confirmed the tendancy that the 300's has to develop a cracked head. Will do the the "full Monty" on the head, and replace all the rubber hoses, thermostat, pump, head bolts and manifold studs, bolts. As will be recalled, I replaced the injectors a while ago, so lets see what comes out in the wash. Will do a photo history of the project. Cheers! Quote Link to comment Share on other sites More sharing options...
Les Henson Posted March 13, 2008 Share Posted March 13, 2008 Mark - I bought mine from Motaquip, here in swindon. The bigger motor factors should sell them. Les. Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted March 13, 2008 Share Posted March 13, 2008 .... Intersting thing was that the heater in the car was hot when the car was at the right temperature, and stone cold when it was off the scale... :SAny ideas? That's a common indication of air in the cooling system preventing coolant flow into the matrix (because it's full of air). Also preventing coolant circulating around the engine, because a big air bubble is just being squashed under pressure, rather than moving on to be self-bled away, OR coolant has been lost and the system simply doesn't have enough to go round. Not too good I'm afraid. Quote Link to comment Share on other sites More sharing options...
Thys Posted March 14, 2008 Author Share Posted March 14, 2008 Make sure you get it crack tested Thys - I hope it's ok, but the 300TDi is known for this problem. Good luck anyway.Les. Les, I did some investigation work, and traced the previous owner. I did this because when I removed the head, it was obvious that the head had been removed before. He then admitted that while touring in Namibia, two years ago, the serpent belt broke, resulting in the engine overheating. He nursed the LR back to the nearist town where LR only replaced the head gasket, without checking the head for warping. Looking at the leak, no obvious crack is visible, but a coolant flow path is crearly present from the coolant path, into both no 1 and 2. The head is currently at an engineerig shop for a pressure test. I will have the result on Tuesday morning. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted March 14, 2008 Share Posted March 14, 2008 Best of luck mate. At least if you need a new cylinder head for a Tdi you don't have to sell a kidney or two as with a TD5. If you need one, phone CCA at Kya Sands 011 708 0326. Mention my name and you pay extra Quote Link to comment Share on other sites More sharing options...
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