XK8 overheating
Discussion
I have had Jags for many years and recently bought a 2000 XK8. I thought it would be my dream car but it is turning out to be my worst nightmare and rather than proudly driving it around, it is sitting in the garage and I have no enthusiasm for getting it out and I regret buying it.
I have a problem with the cooling system. When it was first delivered to me, I drove it no more than a couple of miles and when I stopped, water was pouring out of the drivers side wing/sill. I later found out that it has an expansion tank in the wheel arch, which obviously I have never come across before. My mechanic found that the thermostat was u/s and changed that for me and I thought that had solved the problem. I have not taken it for a good run, but it appears that the problem has not been solved.
My wife took the car out last week to give it a run to see how it was. She did about 30 - 35 miles up the motorway, at no more than 60mph, to her destination and then stopped for about 30/45 minutes. When she went back to the car she checked the water level and it was low, so she put probably about a litre of water in it and carried on her return journey. En route she stopped after about 20 miles, she was parked for about 15 minutes and then checked the water level again and needed to put in about another 2-3 litres. She drove about 400 metres and parked up again and water was pouring out of the tank in the wheel arch. Once again she let it cool down for about an hour and then put more water in and got back home.
All of the time she was driving the temp guauge was showing normal and it did not go above that at all and no warning lights were on.
I thought that maybe the fans were not working but my mechanic has confirmed that the fans are operational.
It is going into the garage to check if there is a problem with the water pump and cylinder head gaskets.
I have just been talking to an acquaintance who said he had a car that had the same problem, albeit not a jag, but it was still a nightmare to try and find the problem. Eventually they found that it was an airlock in the radiator and once the system had been bled he did not have any more trouble from it.
I was going to check this but the manual says that it is not advisable to take the bleed cap off as it is possible that it could break and it needs to be tightened to a specific torque.
Does anyone have any idea what could be causing this problem, any suggestions would be much appreciated.
I have a problem with the cooling system. When it was first delivered to me, I drove it no more than a couple of miles and when I stopped, water was pouring out of the drivers side wing/sill. I later found out that it has an expansion tank in the wheel arch, which obviously I have never come across before. My mechanic found that the thermostat was u/s and changed that for me and I thought that had solved the problem. I have not taken it for a good run, but it appears that the problem has not been solved.
My wife took the car out last week to give it a run to see how it was. She did about 30 - 35 miles up the motorway, at no more than 60mph, to her destination and then stopped for about 30/45 minutes. When she went back to the car she checked the water level and it was low, so she put probably about a litre of water in it and carried on her return journey. En route she stopped after about 20 miles, she was parked for about 15 minutes and then checked the water level again and needed to put in about another 2-3 litres. She drove about 400 metres and parked up again and water was pouring out of the tank in the wheel arch. Once again she let it cool down for about an hour and then put more water in and got back home.
All of the time she was driving the temp guauge was showing normal and it did not go above that at all and no warning lights were on.
I thought that maybe the fans were not working but my mechanic has confirmed that the fans are operational.
It is going into the garage to check if there is a problem with the water pump and cylinder head gaskets.
I have just been talking to an acquaintance who said he had a car that had the same problem, albeit not a jag, but it was still a nightmare to try and find the problem. Eventually they found that it was an airlock in the radiator and once the system had been bled he did not have any more trouble from it.
I was going to check this but the manual says that it is not advisable to take the bleed cap off as it is possible that it could break and it needs to be tightened to a specific torque.
Does anyone have any idea what could be causing this problem, any suggestions would be much appreciated.
The temperature gauge is driven by software and isn't always a accurate reflection of coolant temperature. Providing the cooling system has sufficient coolant in it and the thermostat hasn't jammed shut it will self bleed via the coolant return hose to the header tank.
You have replaced the thermostat and know the cooling fans are working.
There is a possibility the water pump is failing. Unlikely, but there's a chance a 2000 car may have the earlier type fitted which were prone to shedding vanes and loosing efficiency leading to overheating, but from your description my best guess is you're looking at a head gasket failure.
You have replaced the thermostat and know the cooling fans are working.
There is a possibility the water pump is failing. Unlikely, but there's a chance a 2000 car may have the earlier type fitted which were prone to shedding vanes and loosing efficiency leading to overheating, but from your description my best guess is you're looking at a head gasket failure.
Losing that much water is ominous, but you should see some tell-tale signs elsewhere which are symptomatic of CHG failure.
I know this sounds daft, but is the coolant reservoir cap fitting properly ?
IME, a failed CHG makes for a rough-running engine. Plus, a lot of other tell-tale signs, too.
I know this sounds daft, but is the coolant reservoir cap fitting properly ?
IME, a failed CHG makes for a rough-running engine. Plus, a lot of other tell-tale signs, too.
Jaguar steve said:
The temperature gauge is driven by software and isn't always a accurate reflection of coolant temperature. Providing the cooling system has sufficient coolant in it and the thermostat hasn't jammed shut it will self bleed via the coolant return hose to the header tank.
You have replaced the thermostat and know the cooling fans are working.
There is a possibility the water pump is failing. Unlikely, but there's a chance a 2000 car may have the earlier type fitted which were prone to shedding vanes and loosing efficiency leading to overheating, but from your description my best guess is you're looking at a head gasket failure.
Get a cheap OBDN reader and Torque or similar so you can see the real temperature. The guage is just a damped switch.You have replaced the thermostat and know the cooling fans are working.
There is a possibility the water pump is failing. Unlikely, but there's a chance a 2000 car may have the earlier type fitted which were prone to shedding vanes and loosing efficiency leading to overheating, but from your description my best guess is you're looking at a head gasket failure.
No chance it will have been fitted with the dodgy early water pumps they had gone by 98. It should have had a replacement anyway by this mileage so who knows what dodgy one might have been fitted.
Sounds like the coolant is over pressurised try changing the cap on the header tank.
Get a sniff test done just in case it is head gasket.
Hi guys
Thanks to you all for your replies.
I must admit I am leaning towards head gasket, purely for the reason that whenever I have a problem with a car and that particular part "very rarely goes wrong", it always does with me, so I am being a bit pessimistic.
I will check if my garage can do a sniff test, as it is a small spanish garage and I don´t know whether he will run to such technology, although in all honesty he is pretty good.
When I had a head gasket go on my Daimler, many years ago, it would hardly suck the skin of a rice pudding, but my XK8 still has a lot of power and it does not hesitate, so that is one of the reasons that I am looking for something other than the head gasket.
The cap on the header tank is not old or worn and there is no evidence around it to suggest that water is leaking from there.
As the water is coming out at the bottom of the wing/sill behind the drivers wheel (RHD) then it leads me to think that something is pressurizing the water system and it is coming out of the expansion tank in the wing.
Does anyone know whether the water pump on this is likely to be the same as on a 1998 XJ8, as I bought one a few years ago when I thought my water pump on that was failing, but in fact the problem was one of the pipes running along the top of the engine that had sprung a slight leak, so I still have that in stock. I have read that some of the older XK8´s can have a problem with the impeller´s in the water pump, so I was going to get my meccy to check that out.
It is obviously a case of process of elimination, unless we can come up with something that tests prove positive for a failure, as in head gasket sniffer or something like that.
Will obviously find the problem eventually, but it is so frustrating that I can´t trust the car out of the garage. I work in the holiday rental industry so this is a very busy time for me and I don´t have the time to check things out myself. The garage is on summer hours, so only works mornings and he is backed up with work as well and won´t be able to look at it for about another week, if I can find the time to get the car to him.
I will try and keep calm and positive..... No it´s not working, I am stressed and negative, but I am sure I will look back on this with relief when it is all sorted.
Thanks to you all for your replies.
I must admit I am leaning towards head gasket, purely for the reason that whenever I have a problem with a car and that particular part "very rarely goes wrong", it always does with me, so I am being a bit pessimistic.
I will check if my garage can do a sniff test, as it is a small spanish garage and I don´t know whether he will run to such technology, although in all honesty he is pretty good.
When I had a head gasket go on my Daimler, many years ago, it would hardly suck the skin of a rice pudding, but my XK8 still has a lot of power and it does not hesitate, so that is one of the reasons that I am looking for something other than the head gasket.
The cap on the header tank is not old or worn and there is no evidence around it to suggest that water is leaking from there.
As the water is coming out at the bottom of the wing/sill behind the drivers wheel (RHD) then it leads me to think that something is pressurizing the water system and it is coming out of the expansion tank in the wing.
Does anyone know whether the water pump on this is likely to be the same as on a 1998 XJ8, as I bought one a few years ago when I thought my water pump on that was failing, but in fact the problem was one of the pipes running along the top of the engine that had sprung a slight leak, so I still have that in stock. I have read that some of the older XK8´s can have a problem with the impeller´s in the water pump, so I was going to get my meccy to check that out.
It is obviously a case of process of elimination, unless we can come up with something that tests prove positive for a failure, as in head gasket sniffer or something like that.
Will obviously find the problem eventually, but it is so frustrating that I can´t trust the car out of the garage. I work in the holiday rental industry so this is a very busy time for me and I don´t have the time to check things out myself. The garage is on summer hours, so only works mornings and he is backed up with work as well and won´t be able to look at it for about another week, if I can find the time to get the car to him.
I will try and keep calm and positive..... No it´s not working, I am stressed and negative, but I am sure I will look back on this with relief when it is all sorted.
spanspeed said:
LeighW - I have not noticed any steam coming from the exhaust.
I remember years ago, my Impreza WRX had a head gasket fail. The only symptoms were that it would get hot (temp gauge rising towards red) when it was driven hard (and only then), and the water level would rise in the header tank. It ran fine, no misfiring, no steam from the exhaust, no goo in the coolant or oil, no loss of power, no leaks, it even passed the sniff test! But after checking everything else, the gasket was changed and the problem was cured. I remember it well, because it cost me £2.5k to fix... 
Not helping much am I?
Is the car fairly exclusive where you are ?
How does it make you feel when it has worked (briefly)
Does it stand out or make a statement ?
Its a bit psychological really, been in the same frame of mind myself.
You have to answer the three questions, take a break from it for a week and go back refreshed, looking around on various websites these cars are not the moneypit some think, compared to german stuff for example.
They are underated and look spectacular, just have a break and perservere, its harder when its been your dream car...I know.
PS, just noticed your on the Costa del Crime, answer the fourth question, is it nicked ?
How does it make you feel when it has worked (briefly)
Does it stand out or make a statement ?
Its a bit psychological really, been in the same frame of mind myself.
You have to answer the three questions, take a break from it for a week and go back refreshed, looking around on various websites these cars are not the moneypit some think, compared to german stuff for example.
They are underated and look spectacular, just have a break and perservere, its harder when its been your dream car...I know.
PS, just noticed your on the Costa del Crime, answer the fourth question, is it nicked ?
Edited by Zippyworld on Thursday 16th August 19:29
Hi Zippyworld
In answer to your questions:
Yes it is fairly exclusive in the area and it would stand out and make a statement if we could take it out the garage.
As with all our jags, they make you feel great when you drive them, unfortunately we have not had the chance to feel this with the XK8 as it has not worked correctly since buying it in January. We bought it from the UK and had it transported over. It was not stolen.
We have been taking a lot of breaks from it as we do not have the time to do much at the moment.
Thankfully we do not live anywhere near the Costa del Crime. Lived there originally but moved about 9 years ago, to a much quieter, less commercialized area.
In answer to your questions:
Yes it is fairly exclusive in the area and it would stand out and make a statement if we could take it out the garage.
As with all our jags, they make you feel great when you drive them, unfortunately we have not had the chance to feel this with the XK8 as it has not worked correctly since buying it in January. We bought it from the UK and had it transported over. It was not stolen.
We have been taking a lot of breaks from it as we do not have the time to do much at the moment.
Thankfully we do not live anywhere near the Costa del Crime. Lived there originally but moved about 9 years ago, to a much quieter, less commercialized area.
I might be worth checking that the pipe from the header tank down to the expansion tank is not cracked/split.
I had an XJR of this vintage that used to display similar issues, lots of overflowing water and continual top ups.
Turned out to be because the pipe down to the expansion tank was not air tight so water would flow down the pipe to the expansion tank in the wing as the engine heated, but wouldn't get sucked back up again when the engine cooled.
So I'd top up the header tank, run the car, it would push expanded hot water into the expansion tank in the wing, but then couldn't pull that water back up into the header tank as it cooled as it was sucking air back in via a crack. After a couple of top ups the tank in the wing would overfill and dump water, and the header tank was always low.
Worth checking before assuming something more complicated.
I had an XJR of this vintage that used to display similar issues, lots of overflowing water and continual top ups.
Turned out to be because the pipe down to the expansion tank was not air tight so water would flow down the pipe to the expansion tank in the wing as the engine heated, but wouldn't get sucked back up again when the engine cooled.
So I'd top up the header tank, run the car, it would push expanded hot water into the expansion tank in the wing, but then couldn't pull that water back up into the header tank as it cooled as it was sucking air back in via a crack. After a couple of top ups the tank in the wing would overfill and dump water, and the header tank was always low.
Worth checking before assuming something more complicated.
spanspeed said:
Hi guys
Thanks to you all for your replies.
I must admit I am leaning towards head gasket, purely for the reason that whenever I have a problem with a car and that particular part "very rarely goes wrong", it always does with me, so I am being a bit pessimistic.
I will check if my garage can do a sniff test, as it is a small spanish garage and I don´t know whether he will run to such technology, although in all honesty he is pretty good.
When I had a head gasket go on my Daimler, many years ago, it would hardly suck the skin of a rice pudding, but my XK8 still has a lot of power and it does not hesitate, so that is one of the reasons that I am looking for something other than the head gasket.
The cap on the header tank is not old or worn and there is no evidence around it to suggest that water is leaking from there.
As the water is coming out at the bottom of the wing/sill behind the drivers wheel (RHD) then it leads me to think that something is pressurizing the water system and it is coming out of the expansion tank in the wing.
Does anyone know whether the water pump on this is likely to be the same as on a 1998 XJ8, as I bought one a few years ago when I thought my water pump on that was failing, but in fact the problem was one of the pipes running along the top of the engine that had sprung a slight leak, so I still have that in stock. I have read that some of the older XK8´s can have a problem with the impeller´s in the water pump, so I was going to get my meccy to check that out.
It is obviously a case of process of elimination, unless we can come up with something that tests prove positive for a failure, as in head gasket sniffer or something like that.
Will obviously find the problem eventually, but it is so frustrating that I can´t trust the car out of the garage. I work in the holiday rental industry so this is a very busy time for me and I don´t have the time to check things out myself. The garage is on summer hours, so only works mornings and he is backed up with work as well and won´t be able to look at it for about another week, if I can find the time to get the car to him.
I will try and keep calm and positive..... No it´s not working, I am stressed and negative, but I am sure I will look back on this with relief when it is all sorted.
Yes same water pump, XJ8/R XK8/RThanks to you all for your replies.
I must admit I am leaning towards head gasket, purely for the reason that whenever I have a problem with a car and that particular part "very rarely goes wrong", it always does with me, so I am being a bit pessimistic.
I will check if my garage can do a sniff test, as it is a small spanish garage and I don´t know whether he will run to such technology, although in all honesty he is pretty good.
When I had a head gasket go on my Daimler, many years ago, it would hardly suck the skin of a rice pudding, but my XK8 still has a lot of power and it does not hesitate, so that is one of the reasons that I am looking for something other than the head gasket.
The cap on the header tank is not old or worn and there is no evidence around it to suggest that water is leaking from there.
As the water is coming out at the bottom of the wing/sill behind the drivers wheel (RHD) then it leads me to think that something is pressurizing the water system and it is coming out of the expansion tank in the wing.
Does anyone know whether the water pump on this is likely to be the same as on a 1998 XJ8, as I bought one a few years ago when I thought my water pump on that was failing, but in fact the problem was one of the pipes running along the top of the engine that had sprung a slight leak, so I still have that in stock. I have read that some of the older XK8´s can have a problem with the impeller´s in the water pump, so I was going to get my meccy to check that out.
It is obviously a case of process of elimination, unless we can come up with something that tests prove positive for a failure, as in head gasket sniffer or something like that.
Will obviously find the problem eventually, but it is so frustrating that I can´t trust the car out of the garage. I work in the holiday rental industry so this is a very busy time for me and I don´t have the time to check things out myself. The garage is on summer hours, so only works mornings and he is backed up with work as well and won´t be able to look at it for about another week, if I can find the time to get the car to him.
I will try and keep calm and positive..... No it´s not working, I am stressed and negative, but I am sure I will look back on this with relief when it is all sorted.
The fault could be the cap on the header tank , it is a pressure relief valve, if it fails the system over pressurises.
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