XKR X150 coolant leak
Discussion
A colleague bought an older (2009 I think) XKR earlier this year with around 110k miles on it and it's been generally fine bar a couple of minor issues. Quite recently it started leaking coolant at a fairly prodigious rate, and he's concerned that this will be the infamous valley pipes. I've not yet seen the car or the leak, be he says the coolant seems to come from the middle of the engine area, he's pretty sure it's not e.g. the radiator.
However there are a couple of (IMO) unusual observations when taken together:
1) With a cold engine it doesn't leak, he can leave it for days and the level doesn't move. The leak starts as the engine warms up and it goes from nothing to a pretty large leak. It will empty the expansion tank in a matter of 30 seconds or so when it starts.
2) It doesn't appear to be related to coolant pressure, the leak still occurs even if the expansion cap is removed.
Can parts of the coolant system still get pressurised even with the cap removed? Has anyone seen anything like this previously?
However there are a couple of (IMO) unusual observations when taken together:
1) With a cold engine it doesn't leak, he can leave it for days and the level doesn't move. The leak starts as the engine warms up and it goes from nothing to a pretty large leak. It will empty the expansion tank in a matter of 30 seconds or so when it starts.
2) It doesn't appear to be related to coolant pressure, the leak still occurs even if the expansion cap is removed.
Can parts of the coolant system still get pressurised even with the cap removed? Has anyone seen anything like this previously?
LimSlip said:
However there are a couple of (IMO) unusual observations when taken together:
1) With a cold engine it doesn't leak, he can leave it for days and the level doesn't move. The leak starts as the engine warms up and it goes from nothing to a pretty large leak. It will empty the expansion tank in a matter of 30 seconds or so when it starts.
2) It doesn't appear to be related to coolant pressure, the leak still occurs even if the expansion cap is removed.
Can parts of the coolant system still get pressurised even with the cap removed? Has anyone seen anything like this previously?
I used to have an S-type R, and the valley pipe failed one time, so I speak with some experience (unfortunately!) ...and I work with industrial heating & cooling systems for good measure1) With a cold engine it doesn't leak, he can leave it for days and the level doesn't move. The leak starts as the engine warms up and it goes from nothing to a pretty large leak. It will empty the expansion tank in a matter of 30 seconds or so when it starts.
2) It doesn't appear to be related to coolant pressure, the leak still occurs even if the expansion cap is removed.
Can parts of the coolant system still get pressurised even with the cap removed? Has anyone seen anything like this previously?
Basically the cooling system only becomes pressurised when the coolant becomes hot, the fact that the system is 'sealed' allows the coolant to reach high temperatures, higher than the coolant's boiling point.
If the valley pipe has a crack or split, it's possible that it won't leak when the engine is not running, thus enabling the cooling system to be topped up. Once the engine is started, the water pump will circulate the coolant, the coolant will start to warm up & so will the valley pipe...as the temperature increases, so will the pressure...then the crack/split will then give way & the coolant will start to leak out. At this point it won't make much difference if the cap is on the header tank or not, as the system isn't really a 'sealed' system because of the cracked/split pipe, and the header tank is the high point of the system anyway, and the water pump is still circulating the coolant.
It sounds like your colleague needs to get the car trailered to a decent Jag specialist... where in the country are you?
Him you don't say whether it's the 4.2 or the 5.0 engine, the 5.0 came in 2009 model year.
If it's the 5.0, get him to STOP using the car if it's just starting loosing a lot of coolant. The water pumps on the 5.0 engine are famous for leaking then destructing.
My son's XKR indicated a low coolant level about a week ago. Topped up 2 litres. 2 days later low coolant warning again. I told him NOT to use the car again until we had replaced the water pump as I had similar with my 5.0 RR a few years back and the water pump shat itself on the M4 after the same symptons.
We replaced his pump earlier this week, the old pump was totally shot, the bearings were wobbling all over the place, and I reckon it had maybe less than 100 miles left it in before it destructed like my RR one did.
New pumps are £80 , fitting a couple of hours. This pump has been superceded 8 times with re-designs and part numbers.
If it's the 5.0, get him to STOP using the car if it's just starting loosing a lot of coolant. The water pumps on the 5.0 engine are famous for leaking then destructing.
My son's XKR indicated a low coolant level about a week ago. Topped up 2 litres. 2 days later low coolant warning again. I told him NOT to use the car again until we had replaced the water pump as I had similar with my 5.0 RR a few years back and the water pump shat itself on the M4 after the same symptons.
We replaced his pump earlier this week, the old pump was totally shot, the bearings were wobbling all over the place, and I reckon it had maybe less than 100 miles left it in before it destructed like my RR one did.
New pumps are £80 , fitting a couple of hours. This pump has been superceded 8 times with re-designs and part numbers.
This ^^^^
Assuming it’s the 5.0, the first few years of production saw them fitted with water pumps not up to the task. Our old 2011 XF 5.0 being an example. Caught it nice and early after noticing the pulley wobbling all over the place (easier to see with the plastic engine cover off).
Considering the car was out of warranty at the time, it was a surprisingly cheap fix.
If it’s the 4.2, then it’s likely the valley pipes, a whole other ball game to change….
Assuming it’s the 5.0, the first few years of production saw them fitted with water pumps not up to the task. Our old 2011 XF 5.0 being an example. Caught it nice and early after noticing the pulley wobbling all over the place (easier to see with the plastic engine cover off).
Considering the car was out of warranty at the time, it was a surprisingly cheap fix.
If it’s the 4.2, then it’s likely the valley pipes, a whole other ball game to change….
Just had the valley pipe done on my XJR. If it's this be prepared for a chunky bill. While the supercharger and inlets are off it makes sense to have everything in the valley replaced. I had every hose plus the knock sensors replaced along with the water pump. Not cheap but at least I know it's done and I won't be looking at a similar bill for the sake of saving a few quid.
flying-banana said:
Basically the cooling system only becomes pressurised when the coolant becomes hot, the fact that the system is 'sealed' allows the coolant to reach high temperatures, higher than the coolant's boiling point.
The head scratcher for me is how can the cooling system become pressurised when the expansion tank cap is not fitted?Thanks to all for the responses, the car has the 4.2L engine.
Just spoke to him, he says that from cold he removed the expansion tank cap to watch the level (hence no coolant pressure build up) and the coolant leak then starts after about 5 minutes of running.
To me this simply doesn't reflect the usual behaviour of a leaky hose or pipe that would be pressure sensitive, but more like a crack or insufficiently clamped sealing surface opening with thermal expansion. This goes back to the question I raised in the OP, can parts of the cooling system be pressurised even when the expansion cap is not in place?
To me this simply doesn't reflect the usual behaviour of a leaky hose or pipe that would be pressure sensitive, but more like a crack or insufficiently clamped sealing surface opening with thermal expansion. This goes back to the question I raised in the OP, can parts of the cooling system be pressurised even when the expansion cap is not in place?
It's not neccasarily a pressure related issue, but a flow related thing.
The supercharger has it's own cooling system connected to the main cooling system, those two big lumps either side on the top of the engine are the intercooolers, one each side of the S./C body itself. With the S/C being at the top of the engine it's possible that the pipes level or above the water tank are leaking, but it's only when the pump is physically pumping water through them that they have any coolant to leak out. When the car is off the pipes may drain down and not have any water left in them to leak out without the pump running.
On the 4.2 the usual suspect is the valley pipes that run under the S/C between the S/C and the engine. I had a 4.0 S/C XKR a few years ago and had the S/C off several times to replace some bearings in it. I saw the valley pipes and mine had already been replaced with silicon versions. I found removing and refitting the S/C that first time was a pig of a job, the second and third times I did it it was much easier and quicker!
But still a good few hours.
ETA. The time delay you mention is probably the delay in flow of coolant whilst the thermostat is allowing the engine to warm up. Once the engine gets to temp (90degress or whatever the thermostat on these if set to) , the thermostat opens and water starts to flow through rest of coolant system.
The supercharger has it's own cooling system connected to the main cooling system, those two big lumps either side on the top of the engine are the intercooolers, one each side of the S./C body itself. With the S/C being at the top of the engine it's possible that the pipes level or above the water tank are leaking, but it's only when the pump is physically pumping water through them that they have any coolant to leak out. When the car is off the pipes may drain down and not have any water left in them to leak out without the pump running.
On the 4.2 the usual suspect is the valley pipes that run under the S/C between the S/C and the engine. I had a 4.0 S/C XKR a few years ago and had the S/C off several times to replace some bearings in it. I saw the valley pipes and mine had already been replaced with silicon versions. I found removing and refitting the S/C that first time was a pig of a job, the second and third times I did it it was much easier and quicker!
But still a good few hours.ETA. The time delay you mention is probably the delay in flow of coolant whilst the thermostat is allowing the engine to warm up. Once the engine gets to temp (90degress or whatever the thermostat on these if set to) , the thermostat opens and water starts to flow through rest of coolant system.
Edited by Piersman2 on Friday 22 October 16:34
LimSlip said:
flying-banana said:
Basically the cooling system only becomes pressurised when the coolant becomes hot, the fact that the system is 'sealed' allows the coolant to reach high temperatures, higher than the coolant's boiling point.
The head scratcher for me is how can the cooling system become pressurised when the expansion tank cap is not fitted?Thanks to all for the responses, the car has the 4.2L engine.
If it’s a 5.0L I’m seeing more and more outlet pipes leaking (sits under supercharger and goes between each bank) as they’re a 2 piece construction plastic welded together.
Jaguar have modified them into a one piece construction and in order to change it you need to order 2 parts AJ813865 and AJ813917
Numbers 8 and 10
Jaguar have modified them into a one piece construction and in order to change it you need to order 2 parts AJ813865 and AJ813917
Numbers 8 and 10
Piersman2 said:
It's not neccasarily a pressure related issue, but a flow related thing.
The supercharger has it's own cooling system connected to the main cooling system, those two big lumps either side on the top of the engine are the intercooolers, one each side of the S./C body itself. With the S/C being at the top of the engine it's possible that the pipes level or above the water tank are leaking, but it's only when the pump is physically pumping water through them that they have any coolant to leak out. When the car is off the pipes may drain down and not have any water left in them to leak out without the pump running.
On the 4.2 the usual suspect is the valley pipes that run under the S/C between the S/C and the engine. I had a 4.0 S/C XKR a few years ago and had the S/C off several times to replace some bearings in it. I saw the valley pipes and mine had already been replaced with silicon versions. I found removing and refitting the S/C that first time was a pig of a job, the second and third times I did it it was much easier and quicker! But still a good few hours.
ETA. The time delay you mention is probably the delay in flow of coolant whilst the thermostat is allowing the engine to warm up. Once the engine gets to temp (90degress or whatever the thermostat on these if set to) , the thermostat opens and water starts to flow through rest of coolant system.
I did wonder if it could coincide with the thermostat opening. Thanks for the details on the SC cooling, I suspected the cooling circuit may be fairly complex. I've looked through a bunch of posts on Jaguar forums and removing the SC doesn't look quite a as bad as I'd thought, certainly something I'd be willing to tackle if the car was near my garage. However lives quite a way from me and last time I went to repair a car at his place and asked for a screwdriver he handed me a butter knife from his kitchen...not even joking.The supercharger has it's own cooling system connected to the main cooling system, those two big lumps either side on the top of the engine are the intercooolers, one each side of the S./C body itself. With the S/C being at the top of the engine it's possible that the pipes level or above the water tank are leaking, but it's only when the pump is physically pumping water through them that they have any coolant to leak out. When the car is off the pipes may drain down and not have any water left in them to leak out without the pump running.
On the 4.2 the usual suspect is the valley pipes that run under the S/C between the S/C and the engine. I had a 4.0 S/C XKR a few years ago and had the S/C off several times to replace some bearings in it. I saw the valley pipes and mine had already been replaced with silicon versions. I found removing and refitting the S/C that first time was a pig of a job, the second and third times I did it it was much easier and quicker!
But still a good few hours.ETA. The time delay you mention is probably the delay in flow of coolant whilst the thermostat is allowing the engine to warm up. Once the engine gets to temp (90degress or whatever the thermostat on these if set to) , the thermostat opens and water starts to flow through rest of coolant system.
Edited by Piersman2 on Friday 22 October 16:34
LimSlip said:
Piersman2 said:
It's not neccasarily a pressure related issue, but a flow related thing.
The supercharger has it's own cooling system connected to the main cooling system, those two big lumps either side on the top of the engine are the intercooolers, one each side of the S./C body itself. With the S/C being at the top of the engine it's possible that the pipes level or above the water tank are leaking, but it's only when the pump is physically pumping water through them that they have any coolant to leak out. When the car is off the pipes may drain down and not have any water left in them to leak out without the pump running.
On the 4.2 the usual suspect is the valley pipes that run under the S/C between the S/C and the engine. I had a 4.0 S/C XKR a few years ago and had the S/C off several times to replace some bearings in it. I saw the valley pipes and mine had already been replaced with silicon versions. I found removing and refitting the S/C that first time was a pig of a job, the second and third times I did it it was much easier and quicker! But still a good few hours.
ETA. The time delay you mention is probably the delay in flow of coolant whilst the thermostat is allowing the engine to warm up. Once the engine gets to temp (90degress or whatever the thermostat on these if set to) , the thermostat opens and water starts to flow through rest of coolant system.
I did wonder if it could coincide with the thermostat opening. Thanks for the details on the SC cooling, I suspected the cooling circuit may be fairly complex. I've looked through a bunch of posts on Jaguar forums and removing the SC doesn't look quite a as bad as I'd thought, certainly something I'd be willing to tackle if the car was near my garage. However lives quite a way from me and last time I went to repair a car at his place and asked for a screwdriver he handed me a butter knife from his kitchen...not even joking.The supercharger has it's own cooling system connected to the main cooling system, those two big lumps either side on the top of the engine are the intercooolers, one each side of the S./C body itself. With the S/C being at the top of the engine it's possible that the pipes level or above the water tank are leaking, but it's only when the pump is physically pumping water through them that they have any coolant to leak out. When the car is off the pipes may drain down and not have any water left in them to leak out without the pump running.
On the 4.2 the usual suspect is the valley pipes that run under the S/C between the S/C and the engine. I had a 4.0 S/C XKR a few years ago and had the S/C off several times to replace some bearings in it. I saw the valley pipes and mine had already been replaced with silicon versions. I found removing and refitting the S/C that first time was a pig of a job, the second and third times I did it it was much easier and quicker!
But still a good few hours.ETA. The time delay you mention is probably the delay in flow of coolant whilst the thermostat is allowing the engine to warm up. Once the engine gets to temp (90degress or whatever the thermostat on these if set to) , the thermostat opens and water starts to flow through rest of coolant system.
Edited by Piersman2 on Friday 22 October 16:34
Love it. There's improvising, and then knowing when you've hit the limit of improvisation Pulling the supercharger on the 4.0/4.2 is not a difficult job, just lots of fiddly nuts, bolts and screws to get to particularly at the back of the S/C around the inlet elbow. What did for me the first time was trying to re-assemble the inlet elbow, gasket and S/C back together. You need 4 hands the size of of a child and the strength of Superman to hold and push everything back in place. I was almost in tears after 2 hours until I fundemantally changed what i was trying to do.
IIRC the S/C actually has it's own separate electric pump in addition to the mechanical pump for the normal coolant flow in the engine. It might be worth googling a diagram of the 4.2 S/C coolant system to see what's there. But chaces are it'll be the valley pipes or maybe cracked thermostat housing?
This thread might help give some more information.
https://www.jaguarforums.com/forum/xk-xkr-x150-33/...
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