csh1234 Posted January 5, 2008 Report Share Posted January 5, 2008 Hi all, I replaced the thermostat on my parents 4.2Q sport before Xmas (cheers again for the 'how to' Lostkiwi!), the job went well except I had some problems getting the bleed valves on the heater hoses to reseal and lost some coolant over the next few days. I finally got them sealed and all was great. However, the last couple of days the car has started losing coolant again, probably about half a pint per day. I have had a good look round the engine and can see no obvious signs of leakage (inc the header tank, thermostat housing/hoses etc). The only area that appears to have some water driping is near the transission tunnel on the drivers side, roughly where the drivers footwell would be - I am assuming that this is an AC drain? Question is, are there any known areas I should check? If the waterpump was leaking, where would the coolant drip out? Don't want to tempt fate, but do headgaskets go on the v8s? Cheers Chris Link to comment Share on other sites More sharing options...
LostKiwi Posted January 5, 2008 Report Share Posted January 5, 2008 Any coolant leak except headgaskets will leave a trail somewhere. Headgaskets will show as a chocolate milkshake like accumulation in the oil filler cap and bubbles in the coolant tank. Its possible that if the heater matrix is leaking you may get water inside the car but half a litre is a lot to lose inside a car and you'd definitely know about it. For how many days has it been losing water? If its only one or two it may just have had a vapour lock somewhere and will stop again. One way to check if its the condenser drains causing the issue or if its the heater matrix leaking is to run without aircon for a day or two. If the water still keeps coming then its a heater matrix issue if it stops its drains. One cheap and dirty fix is to use a can of wonderweld. Fixes a lot of small issues and (in my experience) doesn't cause any problems. Also make sure you only ever check cold as the water expands when hot and contracts when cold so can give weird fluctuations in level. Also remember (and apologies if I'm telling you to suck eggs) to only fill to the marks on the side of the coolant tank and not to fill to the brim! Link to comment Share on other sites More sharing options...
nikw Posted January 7, 2008 Report Share Posted January 7, 2008 There is another possibility. There is a small pipe on the oil/water heat exchanger which can start to leak coolant and/or oil when the seals fail over time. As ever, PaulW is ahead of us and details the repair procedure here. Doesn't look like a nice job though so let's hope it's something else! Link to comment Share on other sites More sharing options...
csh1234 Posted January 7, 2008 Author Report Share Posted January 7, 2008 Cheers guys, I am starting to tear my hair out on this! I have had another really good look around the engine and underside (although I don't have access to a ramp so not as thorough an underside inspection as would be ideal) - can't find any sign of a leak. Car is losing half a pint per day, which appears to be just disapearing! Engine is smooth, no sign of water/oil mixing, so probably not a headgasket. Interior seems dry - plus no antifreeze smell - so I doubt a heater matrix. No sign of water on the ground when parked at my house all day today. The only thing I can find is a 'smell' of hot coolant around the front of the engine (I have checked/tightened all the hose clips disturbed whilst doing the thermostat, and checked the thermostat housing). I am loathed to take it to a garage as I really think it is something I should be able to sort myself! Link to comment Share on other sites More sharing options...
LostKiwi Posted January 7, 2008 Report Share Posted January 7, 2008 Try starting the engine from cold and leaving it to idle. Watch all around the area you smeel the hot coolant smell for drips. It may be the rate of loss is small enough that it evaporates as quick as it leaks. Whilst the engine is warming up and building up pressure you may be able to spot the area its coming from. Failing that you'll need to cold pressurize the radiator - not an easy task to do safely without specialist equipment although it is possible with a little ingenuity... If the leak is that slow some kind of radiator sealant (such as Wonderweld) will sort it no problems. Link to comment Share on other sites More sharing options...
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