Hey all,

Have been chasing a few issues on my 2011 XFR and one of them is a slow coolant leak. It also consumes a little oil (not enough to worry me) and has a clonk when coming on and off the power. It's got a sticky brake and a buckled wheel, so I'm starting to plan taking it off the road for a while to address numerous issues. So this thread poses the question:

What should I be doing while I'm in there?!

I've stripped the front end of the engine a little over the last week to try and get to the bottom of the coolant leak but haven't quite identified the source yet. I've got some gruesome photos though For background, the car has a good service history and has been serviced ahead of what Jaguar recommend its whole life of 122k miles. It's had the 100,000 mile service done and at that point the gearbox had a fluid change, new sump, new filters etc. It now does about 4000 miles a year and has the engine oil changed at least once a year. However I don't think it's had anything more than that done in terms of preventative maintenance. Other than the obvious loss of fluids there are no performance or reliability issues.

I started at the bottom of the engine and worked up to try and determine the source of the leak... this is what greeted me at the sump

Grim looking sump

That's quite clearly both coolant and oil mixing. I've cleaned it up now so that while I work on the car I can figure out where the fluids are leaking from.


My money is on the vacuum pump leaking the oil, and I've seen that can be resolved in some cases by simply tightening up the bolts (the workshop manual says 12nm but that either isn't sufficient or the bolts are backing out over time). If that doesn't resolve that then I will drain the oil and replace the seal, and can loktite the bolts in when refitting.

Moving up to the top of the engine to try and locate the leak...





So there's clearly coolant in the V which has been running down both sides of the black timing gear cover. I don't know yet if that will be coming from:
A. the water pump
B. the plastic feed to the oil cooler in the V
C. the plastic rear coolant bridge
D. somewhere else?!

There's no evidence of any coolant at the rear of the engine running down the gearbox etc so I think there is a good chance it's not the rear coolant bridge. I am waiting on a coolant pressure tester to arrive so I can pressurise the system to try and eyeball leaks. If that's inconclusive I'll drain it, remove the pump and see what's going on behind it - I don't want to remove the WP unnecessarily at this point if it's still good.

I need to resolve this issue fairly quickly as I need the car in July for some booked trips. Come August or September I will be taking the car off the road and doing more in depth preventative maintenance. During that time I intend to remove the SC and replace the plastic rear coolant bridge, replace the water pump to oil cooler pipe with the aftermarket aluminium option, and replace the expansion tank, thermostat and water pump (if not already done as part of this work). Fortunately my engine is quite an early AJ133 so the front coolant pipes are aluminium not plastic. I also have the uprated Bosch AMG chargecooler pump sat around ready to fit so may as well do that while it's in bits.

Oh yeah and while I was taking the belts off I thought I'd check for play in the supercharger... that needs doing as well! I think that is the source of my clonk as the engine mounts and propshaft doughnuts are all solid. No rattle but the coupler spring is obviously gone. So while the S/C is off it will get a new snout, new oil and I will check the bypass valve is sealing and adjust if necessary. Am considering a solid coupler but I know the factory one has been redesigned to address the spring failure now.

Have I missed anything in the 'to do' list while the S/C is off the engine? The crappy little pipe from the expansion tank to the front coolant bridge is pretty new as that already failed on me. Both vac hoses on the top of the supercharger that run the bypass valve actuator are new as these crumbled to bits, as did the large front air intake pipe which is also new. I've read something about the thermostat plumbing being redesigned at some point - if I buy a new thermostat & water pump to go on an early AJ133 will I also need to replace some other pipework?

Cheers!

 

Just to update this a bit - the coolant leak was the water pump itself. I replaced the bridge pipe that goes from the back of the water pump to the engine oil cooler with an aftermarket aluminium part while I was in there. I also broke the small plastic pipe (not the fitting but the pipe itself) that comes off the front of the water pump and loops round the throttlebody coolant pipe - as most of you probably know, you can't get that part on its own anymore and have to move to the updated coolant pipe layout, so that all got done as well. Later in the year I will be pulling the supercharger off and doing the remaining plastic bits and pieces, some o-rings that I missed, supercharger coupler and oil service, and so on and so forth. I'll be back on this thread when I do!

 

Good to know. It was the water pump I am having the same issue as well !!

 

It's a pretty easy job on the V8 as it's right in the front with decent access. Air intake tube off, belts and tensioners and pulleys off and it's right there. I took the electric fan out for better access - if you do place some thick cardboard over the exposed radiator just in case you slip with a tool. Oh and there's no way you can get the coolant out of the water pump by draining the radiator so there will be a lot of cleaning to do.