Jaguar Top Guy

As many of you know, I recently acquired a 2004 XK8 Convertible. During the hunt a number of members suggested that I look for signs of a “Green Shower.” At that point I knew enough to look for green stains at various places, but little else.

Since I bought my XK8 sight unseen, although I did have a pre-purchase inspection done, I wasn’t able to check for signs myself. Fortunately there are no signs of the previous owner enjoying a nice “Green Shower”, but I thought I might dig a little deeper into the “Douche Vert”, as the French might refer to it.

Much like the timing gear tensioner issue with the 4.0 vintage of the X-100, the “Green Shower” seems to be the bane of the XK8/XKR convertibles, especially the early cars.

Some of you, at this point, might be asking your-self; what is he talking about. I’m sure you ask yourself that question quite often when reading my column. Well the “Green Shower” isn’t a refreshing delight behind the green door, nor is it related to the rather large purveyor of savory canned vegetables.

It is a massive malfunction of the hydraulic system that operates the mechanism which lowers and raises the convertible roof, commonly referred to as the top (or the hood in British terms). It seems the weak spot in the system is directly over the rear-view mirror where the hydraulic hoses connect to the latching mechanism.

Power Packers (interesting name for a hydraulic top mechanism vendor) applied some rather questionable engineering to the hydraulic mechanism they supplied to Jaguar. Firstly, while hydraulics make very good sense for actually raising and lowering the top.

Lots of pressure is required and the mechanism is buried deep behind the seats so if it springs a leak the mess will be out of sight. If it does spring a leak, you will know soon enough because your top will either not raise or lower; or it will stop in the middle of either transaction.

You get it fixed and whoever fixes it can clean up the hydraulic fluid; or not (how would you know?). However, and here’s where the really questionable engineering comes into play, why would anyone design a system with a hydraulically operated latch mechanism over head when an electrically operated solenoid would fit the bill nicely.

After all, who ever heard of a Jaguar having an electrical problem? Worse yet are the hoses. Apparently the engineer who specified the hoses failed to communicate with the engineer who specified the pump. The pump puts out 1600 PSI and the hoses are rated at 870 PSI.

If these guys had de-signed the 4.0 V-8 the tensioners would have been made of papier-mâché. So, you have under-rated hydraulic hoses attached to the roof latch located in a tight space over the windscreen where significant heat builds up from the sun beating down.

What could possibly go wrong? Well, over unpredictable lengths of heat cycling and time, the hoses tend to dry out and begin to crack thus weakening their ability to contain the green fluid being pumped into them at twice their containment rating.

If you are fortunate, one or the other will begin to weep a bit leaving some green dots in the overhead courtesy lights and you can deal with it before it is catastrophic. However the more unpleasant scenario goes like this.

You and your significant other are all dressed up, perhaps she is wearing a brand new dress for a special occasion, and you decide it would be cool to arrive at your destination in style with the top lowered. Gazing longingly at her, you place your finger on the down side of the roof button and press it….. Oddly the top doesn’t move.

As you are pondering the cause of the problem, finger still on the button requesting the whirring pump motor to push more green flu-id to the latch at 1600 PSI, a spray of green gooey fluid comes out of the overhead courtesy lamp fixtures and, like it was laser guided, most of it lands on the now horrified, significant other’s new dress.

Day ruined, dress ruined, and, perhaps a temporary setback in your relationship with the lady in green. Worst case scenario, maybe, but it could also land all over your ivory leather seats.

The Jaguar’s Purr June 202010Speaking of Things Jaguar -June 2020 (cont’d.)What to do now. Well, let’s start with…. Take your finger off of the button!!!

First you must express greater concern for your significant other than for the car and helplessly offer her some assistance.

Next, grab an absorbent piece of cloth, perhaps a piece of your significant other’s dress. After all it is already ruined. A towel might work better; which from this point forward you will never leave home without.

Drape the towel or dress fragment over the area that is still receiving the dripping hydraulic fluid from the lamp fixtures. At this point you will be in the car alone as your significant other has left screaming very disrespectful descriptive phrases regarding Jaguar cars.

So now what? First, determine if the latch did, in fact, unlatch. Of course if the top is half way down, the answer is obvious. Unless you want another shower (one a day is generally sufficient for good personal hygiene), do not touch the top button again.

You will need to manually lower or raise the top from this point. If you have a garage, lower it since you will need it lowered to deal with the cause of the deluge. How does one manually lower the top?

You could just try to push it down, but that would also cause a repeat shower and not work. Better to follow the proper procedure for manually lowering of the top as outlined in your owner’s manual.

You know, that little book has not been previously read. If you wish to manually lower your top as opposed to raising it, disregard the boldly printed caution that reads: “Do not attempt to open the convertible top manually, as damage to the linkage mechanism may occur.”

There’s a thought to ponder as you make your way around the car to open your boot. You will be going to places in your Jaguar’s boot where you may never have been before. Open your boot and remove the right tail lamp covering.

Next, with a good deal of force, remove the fuzzy panel on the right wall of the boot. Most likely the space behind it has not been entered since the car was built.

It’s a bit like entering an Egyptian tomb…treasures and all. There you will find a couple of important things. You will see the pump motor and fluid reservoir as well as the other end of the hoses that connect to the top latch way far, far away.

Actually it is only about six feet away, but Jaguar chose a route that requires about forty feet of hose to get there. Also visible are the hoses connected to the rams that actually move the top up or down.

Right there in front in its nice little clip is the roof latch key. Hopefully no one has raided the tomb before you and removed the key. If that is the case, you will need to find a hex key or allen wrench that fits.

Won’t that be fun? You will also no-tice a petcock near the hydraulic reservoir. Turning this petcock 3.5 turns anti-clockwise will relieve the hydraulic pressure and allow the fluid to return to the reservoir as you manually lower the roof.

Now return to the shower stall or passenger seat with latch key in hand. If you look up toward the dripping lamp fixtures, slightly to your right you will notice a small button. Carefully pry that button off to reveal the hole leading to the roof latch. Insert the hex key into the socket and turn it fully clockwise to raise the latch.

Once the latch is raised, the roof will lift to the raised position. This would be a good time to verify that all four windows are fully down. If not, lower the door windows in the normal manner.

To lower the rear windows, a quick tap of the lower position of the top raising and lowering switch will lower them. Now look up at the center of the front edge of the roof headliner to find an oval shaped opening just big enough to slide your fingers into.

Slide them in and gently pull the roof up and toward the rear of the car to lower it to its fully lowered position. If you encounter resistance you may need to push the rams down. They will be the poles of the small tents forming at the corners of your top.

What now? Well, if by this time your significant other has returned wearing another new dress and you have cleaned up the green mess, you can proceed to your destination with a great story to tell.

I suspect there will be little conversation along the way. No problem, as you will probably be a bit distracted anyway thinking about how to fix this, how you could have prevented it, and why you didn’t know this could happen. It might also cross your mind to remove the hex key from the hole in the windscreen frame before it falls into your significant other’s lap.

Let’s deal with those questions starting with “Why didn’t I know this could happen?” Un-like the tensioner issue, the “Green Shower” issue with the X-100 is similar to a widely known but somewhat well kept family secret.

Unless you specifically ask, it is assumed you know about it. Strangely the issue does not surface in the books on the X-100 I’ve read, including the “Essential Buyers Guide.” Guess they didn’t want to scare anyone off.

As if the tensioner issue hadn’t already done that. One of them talks about the problem with the hydraulic fluid used in the very early models that had a tendency to gel requiring it to be fully purged from the system and be replaced with Pentosin CHF 11S fluid.

Pentosin CHF 11s is used in all cars subsequent to late 1997. So, with a vague understanding of the dreaded “Green Shower” I decided to do a short survey of XK8/XKR owners within the club to see where I stood within the lot. I got a fairly good response. Of the responders it seems most (87%) had some awareness of the issue.

Only one person had actually experienced the “Green Shower”, but a couple of others had experienced some signs of an imminent potential; spots on the headliner, slow or intermitted top action. Three members have had all of the hoses replaced (one DYI, one at a Jaguar dealer and one at Ragtops & Roadsters).

More on what that entails later. Four members have taken other preventative measures; each different. They included several DIY measures; replacing the o-rings in the latch connections, adding a resistor to lower the voltage to the pump motor and adding a relief valve to reduce the hydraulic pressure.

More about those modifications later. A few indicated that they only raise and lower the top with the engine off to reduce the likelihood of a full pressure surge. Several indicated that they limit the number of times they raise and lower the top and only with their fingers crossed.

All in all a mixed bag of knowledge levels, experience, remedy and concern. I now fall into the category of knew little, but now know a lot, haven’t taken any preventative measures other than raising and lowering with the engine off, and now limit raising and lowering due to some concerns.

While not being overly superstitious I don’t cross my fingers, but I sure hope that rabbit limping around my garden doesn’t look in my console.

Moving on to the question of “What can I do to prevent the “Green Shower”?” There are actually quite a few preventative measures.

They range from simple behavior changes to very extensive and expensive component replacements or modifications. These preventative measures also range from mildly effective to close to guaranteed confidence.

I’ll outline the ones I’ve found and where to access information about them. There may be others as the creativity of X-100 owners who frequent the Jaguar Forums can be quite impressive.

Raising and Lowering the Top with the Engine Off | Speaking of Things Jaguar
With the engine running 13.5 volts will be sup-plied to the pump motor. With the engine off 12.0 volts will be supplied to the pump motor.

The reduction in voltage will decrease the pump’s output pressure to by approximately 150 PSI. While the effect is slight, the cost is zero, but you may notice that your top will raise and lower slightly slower.

Also, if your battery is weak you may get your top down or up, but not be able to start your car. The potential for this is remote as a high percentage of warning indicators from the on-board diagnostic systems are actually indications of low battery rather than the actual message. So if your battery is low you should probably already know it.

Reducing Voltage to the Pump Motor

Inserting 0.25 ohm resistor in the power feed to the pump motor will supply around 8.0 volts to the pump motor with the engine off thus reducing the output pressure from 1600 PSI to 1000 PSI.

With the engine on, the reduction is to around 9.5 volts and pressure reduction to 1100 PSI. If your hoses aren’t significantly deteriorated from excess pressure and heat buildup, this may be quite effective in prolonging the wait for your shower.

The cost is minimal at less than $25, no cutting of wires is required and the reduced voltage may increase the lifespan of your pump motor. There are apparently two schools of thought on long term effect to the motor as you will see later.

Complete description, including test results, and installation instructions can be found at Here
Adding a Pressure Relief Valve to the Hydraulic System

This modification is considerably more involved and more expensive. Gus Glikas of is, perhaps, THE guru on XK8/XKR top issues as well as most anything else with these cars. His website is quite impressive and has a wealth of information on all late model Jaguars.

Gus has done very extensive research and testing of the behavior of all aspects of the hydraulic top mechanism which he has documented on his website. Gus developed a kit and set of instructions for adding a pressure relief valve to the hydraulic pump, thus reducing the pressure of the fluid in the lines going to the mechanism.

Gus’s pressure relief modification, according to his tests, reduces the pressure to somewhere between 950-1000 PSI. The kit consists of a hydraulic valve, an adaptor, two short hoses and a pair of zip ties. The installation is vastly more complicated than the resistor approach and includes removal of the motor and pump assembly and changing a number of fittings.

The description of the kit and test information is Here and the installation instructions are Here. Gus sells the kit for $300 and generally requires “a couple of weeks” to assemble the pieces to ship.

The claimed benefit from the hydraulic relief valve is relatively the same as that of the pump motor resistor modification. Interestingly, Gus shows test results from a pump whose motor has had its power input reduced by a resistor and it shows vastly smaller pressure reduction.

He claims that the resistor approach only re-duces the pressure by 3.5% while increasing the operational time by 25% which equates to about 4 seconds. This is a bit misleading as the pressure reduction of both modifications is about the same all the way through the top raising process until the very end during what is referred to as the “deadhead” period.

Which I thought was, at least for me, the late 60s through the 70s. Actually, in this case he is referring to the “deadhead” period after the latch closure which is the 2-3 seconds at the end of the cycle when the latch is closed and the pump motor is still running.

The hydraulic pressure peaks during these couple of seconds which contributes to hose deterioration and shower potential. His graph shows the pressure of the voltage reduced by resistor peaking at about the same as an unmodified system. He also suggests that reducing the voltage to the motor will have a long term detrimental effect on it.

If you take a look at the instructions for installation of the resistor modification you will see that Dennis White from the Jaguar Forums has countered this claim and has even suggested that the data shown “elsewhere” has been intentionally misrepresented and that his test data shows the claimed benefit and he reiterates his claim for the extended life benefit of the volt-age reduction to the pump motor.

Dennis goes on to indicate that he is not selling anything and therefore has no monetary interest in his solution. Both offer their email addresses for questions and I’m sure each will be happy to discredit the other’s claims for you. And that’s that.

Manual Latch Modification

Remember the process for manually lowering or raising your top using the hex key hidden behind the right panel in your boot. Well there is an eleven page string of posts on the Jaguar Forums that describes the trial and error engineering journey to perfect a modification to remove the hydraulic pressure from the latch mechanism (while leaving the hoses in place) and still allow one to raise and lower the top with the hydraulic system.

I’ll save you the lengthy and sometimes rather uninteresting eleven page read. Dennis White was also instrumental in development of this modification. The modification is fairly simple and involves disconnecting the hydraulic hoses that operate the latch at the pump end and capping the fit-tings on the pump.

The hoses attached to the latch are left in place and the disconnected ends in the boot sit in a small reservoir made from a plastic water bottle. The reason the hoses are left uncapped is covered in about 5 or6 pages of the development process.

In the end it was determine to be best to let them open and sit-ting on a pool of hydraulic fluid to ensure ease of latch movement and allow for the possibility of reconnecting them prior to selling the car.

I assume the plan then is to toss the caps and modified water bottle to the new owner just as he/she is sitting in the driver’s seat all smiley and let him figure out what to do with them. Mum’s the word on the “Green Shower” potential whilst in the midst of the sale.

Dennis suggests this modification can be temporary or permanent. While you may encounter leaks in the other hoses going to the top rams (pistons that actually raise and lower the top), with this modification you will definitely not experience a “Green Shower”.

Once the modification is completed, the process of raising or lowering the top, while not as elegant as the normal operation, is relatively simple. The first step in both raising and lowering the top is to insert the hex key into the hole and turn it fully clockwise to raise the latch.

Following that, you press the roof switch for raising or lowering the top as you would normally. When the top is fully up or down as the case may be, rotate the hex key fully anti-clockwise. Then press the roof switch again.

If you get a “Top Not Latched” warning, wait 5 seconds and hit the button again. Dennis offers a disclaimer that sometimes you may need to give a tug on the top in order for the latch to fully close. At last check he was still working on a remedy for that. There are some owners who have taken this path and attached very decorative knobs to their latch keys. All of the information on this modification is Here.

There was also a string of posts on the Jaguar Forums about an attempt to convert the latching mechanism from hydraulic to electric as it should have been engineered in the first place.

There were significant challenges in both finding a latch that would fit in the tight space of the header rail and getting it to interact with the rest of the top lowering system. The string was a few years old and seemed to reach a dead end.

Replacing the Hoses

Replacing the hoses can be either a preventative measure or a “post shower” remedial measure. Replacing the hoses is waaay easier said than done.

Just replacing the latch hoses requires almost complete disassembly of the left side of the interior including removal of the seat, door treads, foot well panels, A pillar cover, entire back seat, right rear speaker panel, carpets and all panels in the boot. Oh, and everything attached to the windscreen support.

The hoses are paired and are zip tied every few inches. The price for a set of OEM latch hoses from the dealer is about $500.

The four ram hoses can be as much as another $1000 or more as they are each sold separately. Again, the process for replacing all six hoses is not for the faint of heart. A few years ago you could get the local Jaguar dealer to replace all six hoses for around $2500.

I’ve been told it is about twice that now, or more. Some restoration shops will also replace the hoses. Some caution should be used regarding the hoses a shop will use. If they use OEM, or worse some NOS hoses they happen to have on the shelf, you will be just starting over with a new showerhead.

There are some vendors who sell up-graded hoses with a Kevlar core. They should outlast the rest of the car. TopHydraulics sells a full set of all six hoses rated at burst pressure of 23,000 PSI for $600.

If you would like a preview of what is involved in replacing the hoses, Here is a series of videos on YouTube that take you through the daunting process. Not for the faint of heart….

So, not sure you want to go the expense of having a shop replace the hoses, yet finding the prospect of doing it yourself a bit daunting; what to do? There is a third option. If you search the web for Jaguar top repairs you might find or or

All of these websites offer the same services; hydraulic hose replacement on your XK8 at your home. Yep, that’s right, they make house calls. The reason their described services are uncannily similar is that they are all the same company.

All roads lead to Marvin Johnson. I had the opportunity to talk with Marvin the other day. It was a quite enjoyable conversation during which he related his story. He seems a very pleasant man with an air of credible confidence who truly enjoys his work.

Marvin aka “Jaguar Top Repair” provides full service repairs and preventative replacement of all top components right in your driveway or garage. Atlanta based Jaguar Top Repair was started by Marvin Johnson over ten years ago after he experienced the “Green Shower” multiple times.

After spending well over $4000 for ineffective repairs performed by dealers and shops, he did some research and realized that a good part of the problem was in the quality of the hoses and hardware that were being used in the repairs.

Initially he started the business ten years ago by selling upgraded hoses and fittings. A few years ago he got a call from an elderly gentleman who had had a “Green Shower.” With a groan, the gentleman said “I wish you were closer. My nearest Jaguar Dealer is over four hours away.” When asked where he lived, the gentleman replied, “New Mexico”.

In an empathetic response, Marvin said, “I’ll come out and do the job for you.” Since then Marvin Johnson has done close to 250 hydraulic hose replacements and other top mechanism repairs all over the country.

Yes, Marvin is a one man operation. He doesn’t want to trust his business reputation for service quality to anyone else. Regardless of your location in the USA, Marvin will arrive at your doorstep in his “Jaguar Top Repair” tee shirt and replace you hoses, latch, and/or rams; generally by the end of the day. He uses Kev-lar core hoses and offers a full parts and labor warranty; 5 years on parts and two years on labor.

His prices are quite reasonable as well. Replacement of pump to latch hoses -$1750. Replacement of all six hoses -$2500. Replacement of all hoses and the latch and the rams -$3500. His prices are all inclusive with the cost of travel and living built in.

Marvin, admittedly, knows how to travel cheaply. Just call 888-317-9340 or 844-524-6261. Both will be answered by Marvin and he will be more than happy to discuss you top.

So, there you have it then; the “Green Shower” story. There is a saying among the Jaguar Forums posters …”There are two kinds of Jaguar XK8/XKR convertible owners.

Those who have had a green shower, and those who are going to have a green shower.” After doing a bit of research I’m not sure I would agree.

Yes, there are some who will fall into the first category, but if you haven’t had the shower, there are ways you can prevent being in the second.

So, what am I going to do for my XK8 convertible? Aside from packing several towels in the boot and leaving the top down all summer, I’m not sure at this point. My present inclination is to have Marvin stop by with a set of hoses and spend the day in my garage. I’ll keep you posted.

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