I had a coolant leak which caused my 06 SV8 to lose coolant and get hot several times before I replaced the water pump and thermostat and repaired the two electric coolant pumps. Then it was OK for 3600 miles, but about 3000 miles ago on a trip, the top radiator hose backed off and it lost a couple of gallons of coolant and the Temp got up to 230F before I could stop and replace the hose and find an auto store to replace the Dex-Cool coolant. After that it developed another leak at a plastic quick connect fitting to a heater pipe which I replaced along with the top radiator hose assembly. Since then the new top radiator hose with a new spring clamp backed off twice (so I put two jubilee hose clamps on it) and now it loses about a cup of coolant from under the new 140 Kpa pressure cap per 100 miles due to high coolant system pressure, and it has residual pressure in the system even after parked for a week. A block test indicated combustion gas in the coolant.
So…I don’t know if the first time the top radiator hose blew off was a cause or a symptom of high system pressure, but I have a definite problem and have to decide if I try some Blue Devil head gasket sealer or bite the bullet and replace the head gaskets.
How big a job is it to replace head gaskets on a Super V8? And has anyone tried Blue Devil head gasket sealer on one of our V8 engines?
The ‘real world’ labor time is about 24 Hours for a 4.2 Supercharged X350 to replace cylinder head gaskets, ENGINE SET.
Jaguar Warranty time is 16.2 hours but unless you perform the task several times in a row, you will not come CLOSE to 16.2 hours!!! That is why 24 hours is more realistic.
You will need the timing tools to lock the crank/cams for reassembly.
I doubt that a ‘can-of-motor-new’ will help with your situation.
It’s a considerable sized job. I rebuilt my supercharger $2,200.00 US in parts, Polished the S/C housing and the intake runners on my XJR-100. It took me 60hrs to complete the process. Granted the polishing took a fair bit of time, as did the learning curve.
I was going to replace the tensioners while it was a part, but stopped because of the special tooling I didn’t have; and they weren’t making any noise, and I have cam covers that aren’t leaking. I’ve been told (by a Jaguar tech); that once you remove the Cam Covers they will for ever leak unless they are replaced with new. I guess they warp and cause their plastic they can’t be resurfaced. at $800 a pop for cam covers, and the lack of self-confidence, and special tools; I decided to wait. Simple case if it isn’t broken don’t fix it.
If you’re up for an adventure, and have pleanty of time, documentation and most important, self confidence - what do you have to lose? Take lots of pictures better yet GoPro the process, Books4cars.com does have a service manual available. That’s what I did, I strapped a GoPro on my head, and went to town. I did refer back to the video more times than I care to admit.
Thanks for all the input. I am still on the fence about what to do next and in the mean time emailed Blue Devil tech with some questions like could it be effective when the leak seems to be into the cooling system and not the other way, and the difference between the concentrate and Pour-N-Go. Here’s what he said.
“We manufacture two different head gasket sealers; the directions are different for each. The “Pour N Go” (16 oz./white label) is a less concentrated formula that does not require the removal of the thermostat or a flush of the cooling system prior to use. Whereas the “Mechanic Approved” (32 oz./yellow label) requires both the removal of thermostat and a flush before applying the product; the 32 ounce is the more concentrated formula. The product with the yellow label will give you best overall results as long as you can remove the thermostat and flush the system prior to use. With the use of either product you will want to use 32 ounces to treat your Jaguar.
To give yourself the best overall chance of BlueDevil working successfully is to remove the spark plug from the cylinder with the leak; this will be the spark plug from the cylinder with the low compression reading. If you are not sure which one that is, you may pull all of the spark plugs and will notice one will have a white-crystal-like substance on it and/or may look dirty; this is the plug you should pull. Leave the plug out for the 50 minute idle in order to relieve the pressure from building up and thus allowing the product to seal properly. If your vehicle only has a reservoir/overflow rather than a radiator cap, instead of pouring BlueDevil through the reservoir/overflow, with the car off and engine cold you should disconnect the top radiator hose and add the product there; do not pour it into the reservoir. It may be added into the hose or the opening on the radiator. Once BlueDevil has been added, reconnect the hose and start the idle from that point.”
I also emailed a relatively new outfit that sells BearsLeak (Get it? A play on Bar’s leaks) that offers a similar blue chemical head gasket sealer before I did the block leak test, and they recommended doing the test and if positive doing a similar flush, fill, and idle with two 32 ounce bottles of their product. They claim to have the best instructions in the market but, strangely, I couldn’t find those instructions on their web site.
An interesting side note is that I compared the before and after block leak test fluid side by side in identical shot glasses, and I left the “after” fluid in its shot glass on a bathroom shelf. A week later it had returned to the pre-test blue color and was perhaps even a little darker blue that before.
If you go the ‘remove spark plug’ route I wonder if it would be advantageous to disable the injector for that cylinder or whether it would throw a code?
Idk, if it were me, I’d start by getting a manual, figure out what special tools are required, depending on how handy you are and what equipment you have access to; see if you can make the tool, identify the tool and make it.
OH, DUH!
I have a service manual for the X308; but not the X350. What I do know about the two is the obvious, displacement, but the intake also changed. I don’t know how it changed but what I do know is the supercharger for the 4.0 is different than the 4.2 supercharger and the two aren’t interchangeable.
But for the 4.0 liter V8 Here’s a list of the special tools
The process is broken down into 40 steps, and there are a couple non obvious things to know when taking these engines apart. If you want to review the service manual(ish) for the XJ and XK1998-2003 4.0L V8 contact me off forum
I uploaded my Engine Repair Course Code 168 from Jaguar Training when I worked at the dealer to the internet on the OTHER jaguar forum and GUS has it on his site because I sent it to him.
The course is for the 3.0 V6 and the 4.0 V8 but all the tools and principles are the same for the 4.2.
Try a search for Jaguar Engine Repair Course Code 168.pdf
