I bought a 1999 4.0 sovereign from a Jaguar specialist on the south coast of England earlier this year. It had covered 100k and seemed in pretty good nick to me. Soon however, I noticed the car was prone to giving a puff of smoke on acceleration. This was particulary noticiable when descending a hill where I live. If I gave the accelerator a bit of a poke when the car was gliding down the hill a cloud of smoke would be emitted. This was accompanied by the need to put 1litre of oil in it every 1000 miles. Naturally I assumed bore wear and suspected Nikasil. (The engine is a Nikasil variant) I would have taken it back to the garage but I had to go abroad for a few months and by the time I returned to the UK they had disappeared. (Bust, relocated?? If anyone knows the whereabouts of JAGTech of Chichester I'd be glad to know as they still owe me an ignition key)
I decided to give the car a catch up service and duly sent it to a well known Jag specialist near London. I asked for the water pump to be changed and the drive belt too along with a standard 60k service. I made a point of explaining the smoke issue and asking for a blow by test to be conducted before any servicing was done as I didn't want to pay for a service on a car with bore wear. The garage told me the test proved the engine to be fine but I wasn't convinced. When I asked how many litres were passing I was told the test is pass or fail and that they couldn't tell me an exact figure. I'm not on here looking to point fingers at people. The point i'm demonstrating is that I am still not convinved that the car does not suffer from bore wear.
Having had the car serviced at a cost of over £1100 I managed another 1000 miles or so before a headgasket blew. So I am now in a bit of a mess. I've got a car that may or may not have worn bores which definietely has a blown head gasket. I'm inclined to go for a second hand engine but I would be grateful for advice.
If i did change the engine i've been told there are potential compatabilty issues. I'm told this is to do with the location of VVT units and oil pressure sensors. None of the experts I have contacted have managed to sucessfully describe what i should be looking for. Does anyone have the ability to publish a photo with nice big arrows superimposed?!
I'm thinking about asking the mechanic who will do the job if he would mind me taking some photos of an engine transplant in practice. I reckon it would make a handy webpage for XJ8 enthusiats experiencing the same heartbreak.
Ed
Engine Change
Engine
E PITT.......sorry for the informal approach but there is no other name you post...........the reasons you give are breaking every rule in the book when buying a car im sorry to say.....but that doesn't help with your current problem. You talk about an engine replacement with the details you have given its a solution, but until you get the correct diagnosis its hard to tell............i have sent you an email to the effect with some solutions.............we dont know where you are geographically as you dont put it in your profile (we ask for members to do this) It does help a lot we want all members to change the detail in their profiles to help with the new information booklet........ALL MEMBERS .please try to help with this .............Joe 
Ed,
Sorry to hear about the blown head gasket. I don't know where you took your car to for a service but £1100 is extortionate unless there were loads of faults that needed fixing over and above basic servicing. You may be interested to know that there IS a range of figures for the blowby test. I have had mine done several times over the years by my local dealer (Guy Salmon Jaguar Gatwick) just for peace of mind that it's wearing gracefully.
The serviceability limit for engine replacement under warranty by Jaguar, in the days when they were prepared to do that, was 40 litres per minute.
The test can vary due to temperature and other factors, but mine is usually between 12 to 20 litres per minute, which is average for a normal engine apparently, so it seems all right so far.
Don't forget oil smoke can be from poor valve stem seals (as well as piston rings) and is most pronounced on the overrun when the throttle is shut suddenly. I don't get noticable smoke from mine, except a puff onstarting if it's not been used for a couple of weeks. It does use about a half a litre of oil in about 1100 miles; Dave Marks answered a similar question recently in the club magazine and thought 1L/1000 miles was not unreasonable.
I recently had a scare when it did 300 miles to a litre on a run up to north Yorkshire and I thought that the dreaded Nikasil had finally struck. I had a blowby test when I got back home and it was an unusually low 9 litres/minute. The oil problem turned out to be a leaking cam cover gasket - not obvious because there was no puddle of oil when parked etc. - and the oil was burning off on the exhaust manifold. So that's another cause of high oil consumption.
Regarding a second-hand engine, unless you get one from a late write-off, probably most around are of questionable condition. A Jaguar recon one is going to cost about five times what your car (and mine) is worth! If you go looking for a second-hand one, as your car is a 1999 you must get the AJ27 engine. The earlier AJ26 is very different and will not work with your engine management ECU and wiring loom, plus lots of other differences. You can tell the difference between them as follows: at the front of the engine the AJ26 has the VVT units and connector protruding forwards (i.e. towards the radiator) from each head; the later AJ27 has no protrusion from the front of each head and the connector is on the top, sticking up through each cam cover.
It might be worth contemplating changing the head gasket. One benefit is that with the head off you will be able to see the state of the Nikasil borerather than just guess. If you are going to change one gasket it might be worth changing both to inspect the other bores as well. Also, while doing the head gaskets it's worth doing cam chains and tensioners while everything else is off.
Good Luck!
Sorry to hear about the blown head gasket. I don't know where you took your car to for a service but £1100 is extortionate unless there were loads of faults that needed fixing over and above basic servicing. You may be interested to know that there IS a range of figures for the blowby test. I have had mine done several times over the years by my local dealer (Guy Salmon Jaguar Gatwick) just for peace of mind that it's wearing gracefully.
The serviceability limit for engine replacement under warranty by Jaguar, in the days when they were prepared to do that, was 40 litres per minute.
The test can vary due to temperature and other factors, but mine is usually between 12 to 20 litres per minute, which is average for a normal engine apparently, so it seems all right so far.
Don't forget oil smoke can be from poor valve stem seals (as well as piston rings) and is most pronounced on the overrun when the throttle is shut suddenly. I don't get noticable smoke from mine, except a puff onstarting if it's not been used for a couple of weeks. It does use about a half a litre of oil in about 1100 miles; Dave Marks answered a similar question recently in the club magazine and thought 1L/1000 miles was not unreasonable.
I recently had a scare when it did 300 miles to a litre on a run up to north Yorkshire and I thought that the dreaded Nikasil had finally struck. I had a blowby test when I got back home and it was an unusually low 9 litres/minute. The oil problem turned out to be a leaking cam cover gasket - not obvious because there was no puddle of oil when parked etc. - and the oil was burning off on the exhaust manifold. So that's another cause of high oil consumption.
Regarding a second-hand engine, unless you get one from a late write-off, probably most around are of questionable condition. A Jaguar recon one is going to cost about five times what your car (and mine) is worth! If you go looking for a second-hand one, as your car is a 1999 you must get the AJ27 engine. The earlier AJ26 is very different and will not work with your engine management ECU and wiring loom, plus lots of other differences. You can tell the difference between them as follows: at the front of the engine the AJ26 has the VVT units and connector protruding forwards (i.e. towards the radiator) from each head; the later AJ27 has no protrusion from the front of each head and the connector is on the top, sticking up through each cam cover.
It might be worth contemplating changing the head gasket. One benefit is that with the head off you will be able to see the state of the Nikasil borerather than just guess. If you are going to change one gasket it might be worth changing both to inspect the other bores as well. Also, while doing the head gaskets it's worth doing cam chains and tensioners while everything else is off.
Good Luck!
Brian
2006 X350 3.5 V8 Sport Premium in Midnight / Ivory
1969 Triumph Daytona rider
Previous XJs:
X350 2.7 TDVi in Westminster Blue / Barley
X308 4.0 V8 in Meteorite / Warm Charcoal
X300 3.2 in Spruce / Barley
XJ40 3.2 Sport in Gunmetal / Saville Grey
2006 X350 3.5 V8 Sport Premium in Midnight / Ivory
1969 Triumph Daytona rider
Previous XJs:
X350 2.7 TDVi in Westminster Blue / Barley
X308 4.0 V8 in Meteorite / Warm Charcoal
X300 3.2 in Spruce / Barley
XJ40 3.2 Sport in Gunmetal / Saville Grey
Brian,
My thanks for your response. With regard to the high service costs, I forgot to mention that the service also identified that my rear pads needed renewing and a new water hose was also required. It was quite pricey but I believe in paying experts a higher rate of labour on the basis that it takes them less time to do the job and there is less likelihood of having to pay for mistakes to be rectified. Being new to the Jaguar community I didn't know how many other perfectly capable Jag specialists there are out there who don't charge £55 per hour labour.
The points you raise about your blow by/leakdown/blow back tests only serve to highlight my suspicion that I had the wool pulled over my eyes. Discussions with other people in the know today has also raised the point that my oil burning may be caused by degraded piston rings rather than nikasil erosion. I suppose it is important not to jump to conclusions!
The predicament I find myself in sees the cost of the follwing options all working out in the thousands:
a. Fix head gasket. Address oil burning issue (piston rings/valve stem seals etc) replace timing chains and tensioners
b. Buy used engine with good service history and latest generation tensioners. Install
c. Fit rebuilt engine with latest generation tensioners (A source of an economical rebuilt engine has been identified)
Giving this further consideration especially in the light of some things I have heard today I have developed a fear of pouring good money after bad. Option C looks the way to go at the moment. As I see it, by going for a rebuilt engine i'm reducing the number of unknowns that are inherent with repairing an engine with 100k under its belt or swapping in a second hand unit.
The details you give about the differences between AJ26 and AJ27 are interesting. I'm sure many others in my position would be interested in knowing the difference in the various variations of the V8. I would like to investigate the possibilty of publishing some detailed photographs to help clairfy the differences for those in the market for used engines.
Ed
My thanks for your response. With regard to the high service costs, I forgot to mention that the service also identified that my rear pads needed renewing and a new water hose was also required. It was quite pricey but I believe in paying experts a higher rate of labour on the basis that it takes them less time to do the job and there is less likelihood of having to pay for mistakes to be rectified. Being new to the Jaguar community I didn't know how many other perfectly capable Jag specialists there are out there who don't charge £55 per hour labour.
The points you raise about your blow by/leakdown/blow back tests only serve to highlight my suspicion that I had the wool pulled over my eyes. Discussions with other people in the know today has also raised the point that my oil burning may be caused by degraded piston rings rather than nikasil erosion. I suppose it is important not to jump to conclusions!
The predicament I find myself in sees the cost of the follwing options all working out in the thousands:
a. Fix head gasket. Address oil burning issue (piston rings/valve stem seals etc) replace timing chains and tensioners
b. Buy used engine with good service history and latest generation tensioners. Install
c. Fit rebuilt engine with latest generation tensioners (A source of an economical rebuilt engine has been identified)
Giving this further consideration especially in the light of some things I have heard today I have developed a fear of pouring good money after bad. Option C looks the way to go at the moment. As I see it, by going for a rebuilt engine i'm reducing the number of unknowns that are inherent with repairing an engine with 100k under its belt or swapping in a second hand unit.
The details you give about the differences between AJ26 and AJ27 are interesting. I'm sure many others in my position would be interested in knowing the difference in the various variations of the V8. I would like to investigate the possibilty of publishing some detailed photographs to help clairfy the differences for those in the market for used engines.
Ed
An update for any who may be following this thread: After some consideration and advice from members of the JEC, I arranged for the car to be towed to CFS Motors in Coventry (http://www.cfsmotors.co.uk/index.htm) to have my engine stripped and repaired. The boss is a chap called Chris Forbes and I rate him highly. I am certainly no mechanic and perhaps my endorsement is not an accolade to be proud of but I found him to be straight talking and knowledgeable with the sort of professional credentials you would look for in a man who you would entrust with your pride and joy.
Chris examined the engine and identified that infact both head gaskets were leaking. The car had clearly been overheating for some time. The nikasil bores were fine but the piston rings were worn causing my oil burning issue. We opted to have a rebore and steel liners fitted anyway. The rebore and new bearings, new oil pump, new thermostat and two new heads came to £3.2K including VAT. I was fortunate that my chains and tensioners turned out to be the latest spec and my water pump was brand new or it would have been about £3.6k. Now you can buy a good Jag for that sort of money and some may question the sanity of forking out that sort of money but hey ho, I like my car and sometimes it is better the devil you know!
I am running in the rebuilt lump now and I will report any developments as and when. As it stands, I would suggest that anyone finding themselves with engine problems could do far worse than talk to Chris Forbes. I owe no small amount of thanks to Joe Turner too for steering me in the right direction. Chris Forbes doesn't really advertise (because he doesn't need to) and without Joe's help I would still be using public transport. Thank you both.
Chris examined the engine and identified that infact both head gaskets were leaking. The car had clearly been overheating for some time. The nikasil bores were fine but the piston rings were worn causing my oil burning issue. We opted to have a rebore and steel liners fitted anyway. The rebore and new bearings, new oil pump, new thermostat and two new heads came to £3.2K including VAT. I was fortunate that my chains and tensioners turned out to be the latest spec and my water pump was brand new or it would have been about £3.6k. Now you can buy a good Jag for that sort of money and some may question the sanity of forking out that sort of money but hey ho, I like my car and sometimes it is better the devil you know!
I am running in the rebuilt lump now and I will report any developments as and when. As it stands, I would suggest that anyone finding themselves with engine problems could do far worse than talk to Chris Forbes. I owe no small amount of thanks to Joe Turner too for steering me in the right direction. Chris Forbes doesn't really advertise (because he doesn't need to) and without Joe's help I would still be using public transport. Thank you both.
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