nickctp Posted November 23, 2011 Share Posted November 23, 2011 Hi, I appear to be burning coolant - the expansion tank is emptying out over a few days - it is not leaking, the temp is fine etc no sludge under oil cap. any ideas?? Quote Link to comment Share on other sites More sharing options...
Neilp Posted November 23, 2011 Share Posted November 23, 2011 Isn't this what happens when the head gasket is fooked? I wouldn't be driving it in the mean time until its been looked at. What year and mileage is the car? Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted November 23, 2011 Share Posted November 23, 2011 Top up the radiator and expansion tank to max. mark from cold and monitor. The level in the expansion tank will fluctuate so best always to check from cold. If you are not overheating and the coolant is not evaporating then you must have an external or internal coolant leak. Check for excessive steam form the exhaust, remember that the cats will burn up the coolant. Pressure and O2 testing should trace the issue if there is one. Alex Quote Link to comment Share on other sites More sharing options...
cefiro_drifter Posted November 23, 2011 Share Posted November 23, 2011 While Alex is on this thread i'd though id ask a question as its something ive seen people say a few times on this forum. surely the expansion/overflow tank is just that and is there to let excess pressure/water escape from the rad in to a container to make less mess. I didnt think a rad cap acted as a "two" way valve and let water/coolant/anti freeze get sucked in to the rad from the overflow if it needs it. tbh i havent ever had anything in my overflow bottle on any of my cars unless the car has overheated/pressurized and spewed it out Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted November 23, 2011 Share Posted November 23, 2011 While Alex is on this thread i'd though id ask a question as its something ive seen people say a few times on this forum. surely the expansion/overflow tank is just that and is there to let excess pressure/water escape from the rad in to a container to make less mess. I didnt think a rad cap acted as a "two" way valve and let water/coolant/anti freeze get sucked in to the rad from the overflow if it needs it. tbh i havent ever had anything in my overflow bottle on any of my cars unless the car has overheated/pressurized and spewed it out An expansion tank is exactly that, an expansion tank. Once the motor gets hot the coolant escapes to the expansion tank and once it cools the the coolant then returns to the radiator by means of vacuum. Alex Quote Link to comment Share on other sites More sharing options...
cefiro_drifter Posted November 23, 2011 Share Posted November 23, 2011 suppose it makes sence as the hose from the rad goes to the bottom of the tank. Most my other cars the hose goes to the top so would only ever suck air back in if it needed cheers alex and sorry for the hijack Quote Link to comment Share on other sites More sharing options...
nickctp Posted November 23, 2011 Author Share Posted November 23, 2011 Thanks all - hope its not head gasket -its only done 30k, I will get pressure test done etc and go from there - no steam from exhaust and no sludge in oil filler cap!! Quote Link to comment Share on other sites More sharing options...
rabbitstew Posted November 23, 2011 Share Posted November 23, 2011 If its not leaking it and no sludge under the cap then it could indeed be the head gasket blown. Same thing happened on my missus`s car and it slowly started using more and more water until it got to the point where it was using 1litre of water every 10miles. Pressure test usually helps narrow it down. Quote Link to comment Share on other sites More sharing options...
scubapics Posted November 23, 2011 Share Posted November 23, 2011 I've had this a long time back on another car. Turned out to be cracked cylinder head or bores. Jim Quote Link to comment Share on other sites More sharing options...
cefiro_drifter Posted November 23, 2011 Share Posted November 23, 2011 my old 5 series bmw was loosing water and pressurizing the system but not smoking , not burning oil and no sludge, not over heating. Turned out to be a partially blwn head gasket. Quote Link to comment Share on other sites More sharing options...
nickctp Posted November 23, 2011 Author Share Posted November 23, 2011 Head gasket - really?? No symptoms apart from he header tank emptying - the rad is staying full up. Sorry I am new to Jap engines I have previously owned Lotus with rover engines so just a tad on the different side. Let me explain fully. Basically I only purchased the car last weekend - took it for a test drive 20 mins or so all was fine. I then drove the car home (200 miles) only stopping once - pretty much all motorway. When I returned home I could hear a noise - looked under the bonnet and the little bit of water that was in the header tank was boiling and steaming. Topped it up and checked it again in the morning - it needed a little more so all was fine. checked again today and its right at the bottom of the header tank again. Of course I wont rule out head gasket until I have pressure test done etc the header tank does have a vent in the top right so as it gets hot I would expect it to steam and level drop slightly but just not sure how quick this should or will happen. any advances on H/G after explination? Aagin its only done 30k. Had clutch changed regular service etc - it has been looked after. Thanks again Nick Quote Link to comment Share on other sites More sharing options...
cefiro_drifter Posted November 23, 2011 Share Posted November 23, 2011 it doesnt matter on mileage mate.. an engine with 100 miles on it can do a HG if its had a problem with over heating/over heated in the past Fan failure is common on 350's so maybe your fans have/are not working resulting in repeated over heating and that could ahve killed the head. My zed has about 40k on it and its had two sets of fans previously and now its on aftermarket rad and aftermarke fans Quote Link to comment Share on other sites More sharing options...
Zugara Posted November 23, 2011 Share Posted November 23, 2011 I would say head gasket, worth checking if you have a creamy sludge on the oil filler cap. what ever it is, it sounds expensive Quote Link to comment Share on other sites More sharing options...
nickctp Posted November 23, 2011 Author Share Posted November 23, 2011 I would say head gasket, worth checking if you have a creamy sludge on the oil filler cap. what ever it is, it sounds expensive Thanks for that! as I have said no sludge no steam from exhaust no over heating rad is staying full - just the expansion tank!! thats why i'm finding HG hard to beleive - but I will have a pressure test done to rule it out! Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted November 23, 2011 Share Posted November 23, 2011 Take your car to a good indy for a professional diagnoses Also a second independent diagnoses is always a good plan. No point in just guessing what this issue is. What ever the issue I will have all the parts in stock to fix so a good saving to be had there. If the head gasket is indeed leaking the coolant can only go three ways. (1) Into the sump (2) Out the exhaust to atmosphere (3) Out the overflow on the expansion tank to atmosphere If you have a crack then the coolant can also go into the radiator. However we are getting way ahead of ourselves here as it may be something very simple and cheap to fix. You say that you have only had the car a few weeks, do you have a warranty or was it a private transaction? Alex. Quote Link to comment Share on other sites More sharing options...
nickctp Posted November 23, 2011 Author Share Posted November 23, 2011 Take your car to a good indy for a professional diagnoses Also a second independent diagnoses is always a good plan. No point in just guessing what this issue is. What ever the issue I will have all the parts in stock to fix so a good saving to be had there. If the head gasket is indeed leaking the coolant can only go three ways. (1) Into the sump (2) Out the exhaust to atmosphere (3) Out the overflow on the expansion tank to atmosphere If you have a crack then the coolant can also go into the radiator. However we are getting way ahead of ourselves here as it may be something very simple and cheap to fix. You say that you have only had the car a few weeks, do you have a warranty or was it a private transaction? Alex. It was private transaction - if indeed the HG has gone - what sort of money to replace on the Z?? Quote Link to comment Share on other sites More sharing options...
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