Coolant hose replacement plan - 2005 STR
 

I had a leak from maybe the DCCV or auxiliary water pump. Decided to replace most hoses and finally have the parts after several rounds of orders from several sources. Car has been down for a couple of weeks and I've been able to drive the 1972 XJ6 which also developed a coolant leak then a faulty alternator (GM unit). Had to drive the F250 for a while too and just returned from Death Valley vacation with the truck so can get to fixing the STR.

Good decision - expensive, but the peace of mind is worth it.

Have a look at the under the supercharger hose. It's notorious. If that one blew posting a photo of it here and in the main thread for that issue would be helpful as evidence of what goes wrong.

I've not been hit with this so far but based upon what I've read this hose is not made right. So check out that thread and think about doing something preventative. One guy talked about having it made up in silicone and he was in the automobile manufacturing business.

I'm looking at that collection of hoses and gasping just thinking about what it all cost.

And if you haven't learned by now be forewarned any plastic involved in the cooling system (probably elsewhere as well) is of very poor quality. My second coolant tank is leaking once again at the very same spot.

Yikes!

Thanks. I just started my teardown yesterday and have included the removal of the supercharger to replace the hose underneath. I was originally going to skip this due to the effort however I have the luxury of having two other cars (XJ6 and F250) to use while I try to do the job right. I'm just now looking into sourcing the additional parts for this new effort.

It looks like he has the updated under SC hose. We don't know what was changed but the one I got from Jaguar is a one piece hose. No metal where it changed diameter. That spot seems to be where they usually start leaking.

I think you are missing a few hoses but maybe not?

I marked the SC hose in question.

https://www.jaguarforums.com/forum/a...1&d=1400016336
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????

I'm looking at the hose in that picture and I see two metal bands on the larger end so how is this now one piece?

Also, I have seen one(1) failed hose and it was in the larger section. I have been asking to see others and have not. So maybe I missed those?

Has it really been established that this is where the hose fails?

Sorry, no I was unclear. The one I have from Jaguar is one piece. But it looks like they have now changed it to a two piece hose with the metal bands on it.

I am hoping this was due to the difficulty in replacing this hose. I may even buy this new style one because when I checked it was less than $30.

Never been established but the pictures that I have seen posted, the failure is at the large end of the hose.
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Originally I was not going to undertake the SC hose replacement and apparently ordered the SC hose by mistake. I have not found a single comprehensive source that has: 1) exploded diagrams, 2)part names; and, 3)part numbers. So yes I am likely missing some hoses too.

I have now undertaken the work and have just gotten as far as removing the EGR valve. Couple questions:
1. My EGR looks to be in good shape. Should I consider replacing it?
2). Next step is to remove the two pipes from the air intake elbow. Pressing the plastic clips,does not seem to allow them to slid off. Any tricks? I hate to get too rough.

I sure hope I can put this all back together.

Better pic of my EGR.

Slow progress
 

Just thinking about have to replace the EGR at some near future date leads me to want to install a new one now since I have it out. Maybe I should replace the water pump too, since access is relatively good now. Took another look at the clip for the air hose to plenum and just followed the hose to the front where it has the same clip and is more easily inspected. Clip is "Norma" and I could clearly see how to remove it so after some fiddling go the rear off the plenum. That was the 1/2" or so dameter hose. The clip for the smaller hose (about 3/8" or so) is hader to get to back there so I just skipped ahead and began removing the four bolts holding the plenum to the back of the supercharger. Three are off, and the bottom one on the left side (USA driver) is a pain to get too. Got is loose however I'll pick up a few more fittings for my 1/4" drive socket set to manuver in there. Meanwhile, still driving my old '72 XJ6 daily.

Supercharger is off and just about time to start installing new hoses and gaskets. I tried to remove the plenum first since I read that it would be easier to get to the rest SC bolt. However one last bolt on the plenum proved to difficult to get to. So I just attacked the rear SC bolt and finally got it out.

Doing well. Did you see Brutal's advice to slot the rear bolt before putting the SC (I think it's the SC) back on?

Please post a good pic of the bad hose when you get a chance. Not just the failure part but another of the whole hose as there's an interest in how many variants there are of it.

Well your EGR valve and tube do look very good and I would be like you are now. Do I replace or not? If I had them on hand then yes I would change them. My personal plan is to have it all on hand if I need to do it. I have everything BUT the EGR stuff right now.

The tube looks to be stainless but several people have reported getting a hole in the tube so I wonder where it corrodes at?

I find the water pump to be pretty easy to get to because it's on the front of the engine. The 4.2L does not have many water pump problems aside from a few that have leaked. I would not change it now.

It interesting to see the new 5.0L engine is known for water pump failures. Sometimes with 50K or less miles.
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Remember that my leak was the DCCV or maybe Aux Water pump not SC hose. I've not yet removed the DCCV or Aux Water Pump to confirm which is leaking however will be replacing both anyway. I will certainly share inspection results of my SC hose on this thread including pics. Meanwhile, on for my preventative maintenance my plan I might now be looking at:
- replace EGR
- retain EGR tube
- leave water pump alone

Now, what about SC oil replacement? I've not studied the procedure however it must be easier with SC off car.

Most likely the leak is a hose near the DCCV but the DCCV can leak too. Doubt it's the AUX coolant pump because they do die but I have never heard of one leaking yet?

It is but I did it on the engine. We have a couple of very good threads on how to exactly change the oil. You do know that we use the same SC oil as Ford and GM so you can get the right stuff almost anywhere?

I found the GM stuff cheapest on EBay.

It would be worth your while to search for the SC oil change threads. Just for background information.
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Pic from last night. Will inspect the hose more carefully upon removal.

Heh, just asked the XFR folks, over on their list, about their coolant hoses and learned that they are just as crappy as ours...
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Jaguar: Grace, Pace, and Space - Sir William Lyons

Gots to keep those dealerships eating.

All the ones I've seen photos of are the two piece design with the metal bands and it's the large portion that fails.

So I'm still confused by your comment???

Right that is the updated hose. Look at David_h's picture of his 2006 STR. It came with the updated hose. There is a one piece hose out there too. I don't have a picture of it handy. Not sure when Jaguar changed it?

Here is a picture of one under SC hose that let go. It is in the larger diameter section as you said.

https://www.jaguarforums.com/forum/s...sc-hose-65682/

Oops! I found it! Yes the two piece is stock but someone found a different style hose ion this thread.

https://www.jaguarforums.com/forum/s...r-yikes-97095/
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Your post confuses the situation even further!

Which is the later updated hose because if it's the two piece it clearly didn't work!

Long delay due to family stuff. I went ahead with preventative replacement of EGR valve (not tube though) and water pump. Also decided to take off inter coolers (really after coolers aren't they). Cleaned one with carb cleaner today (see pics). Ordered new gaskets. Also shown is swollen hose from under SC. It was not leaking but has been replaced with identical new hose.

More pics

Great pic!

Not trying to create confusion here but I still can reconcile this post's claim about which style is new vs old. I't the only place I've seen what "looks" like a one piece hose.

https://www.jaguarforums.com/forum/s...95/#post755109

The hose pulled out of this car is bulging and I guess the chording eventually lets go leading to to the spit & leak?

Thanks for the photos and documentation of your repairs.

Spent a few more hours on it this weekend. Intercoolers and SC back on. Went to install EGR and tube assembly and realized I did not have the metal gasket between the exhaust manifold and tube. However Had a couple extra metal gaskets for between the tube and EGR and looks like they would work with minor modification to the hole spacing. Decided to try dealer first.

Meanwhile decided to tackle the hoses which is what started me on this journey in the first place. Out with SC pump and hoses (see pic). Out with DCCV and hoses. Now cannot determine which arrangement for new hoses on DCCV. Two of the hoses appear identical although they have different part numbers (XR850719 & XR850720). I cannot read any numbers off the old hoses and was tempted to install anyway however I decided to take a break (I've had many) and confirm with the dealer. If anyone has a diagram showing the relative fiitment location of the two hoses it would be helpful.

See if this helps??

https://www.jaguarforums.com/forum/s...-hoses-102914/
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With everything back together I've made a few good runs including along the highway and all seems well. A couple of hiccups included the throttle body electrical connector cracked and partially disintegrated. I went ahead and used PVC tape with zip tie to secure it. The one hose I did not originally purchase was the expansion tank vent hose because I mistakenly believed that I had replaced it with the tank two years ago. Well after my first test run it sprung a leak and I picked up a new hose at the dealer. I guess the replacement plan was very timely.

David thanks for this thread. Since I may facing this I'm wondering what your mileage was?

My 2005 STR is at 89,000 miles. I had one part left over if anyone can help identify it (pi attached). A grommet about 1/2 inch diameter and presumably from the area of the cowl and/or wipers. Next items for me are:
- spark plugs
- replace front wheel well liners
- source and install front valence
Thanks.