[xj40] Water rail gaskets DIY -- w/o removing inlet manifold Part I

I have used this for advice regarding repairs and maintenance,
this is my first effort trying to give back.

The vehicle specifically involved was a 1989 XJ6 base, 3.6L
left hand drive.

Tools needed:
10 mm socket
13 mm socket
less than 8 inch long ratchet
less than 6 inch long ratchet
socket extensions
screwdriver and/or hose clamp sockets/driver
2 medium-size allen key
hammer with wooden handle or rubber grip
nylon/scotch abrasive pad
acetone and rubbing alcohol
lighting and a step
wire brush
rust remover
plastic bag large enough to fit water rail
2 EAC9745 gaskets
small bungee cord

To begin, I discovered that these gaskets frequently fail when
the water rail hose is replaced. The gaskets are more a means
of applying sealant to the mating areas then they are a classic
gasket. If the water rail securing bolts work their way loose
the gaskets will fail if you try to install a new hose. Do
yourself a favor and check and tighten these bolts before
attempting to replacing the hose.

  1. Displace and secure the battery ground lead.
  2. Remove the air box. Two securing nuts are visible.
    The third is in the front, down low and difficult to see. I
    removed the top half of the box first for ease of access.
  3. Unplug and remove the air meter. Be sure to disconnect
    the ground wire located on the front corner closest to the fan.
  4. Remove the bolt securing the oil filler pipe to the
    inlet manifold and displace the attached vacuum hose. Displace
    and secure the filler pipe to the inlet manifold using a small
    bungee cord.
  5. Jack up vehicle. To maximize drainage and to avoid
    getting wet, raise only the left front.
  6. Drain radiator.
  7. Displace the expansion tank hose at the water pump and
    move out of the way.
  8. Remove vacuum hoses from thermostat as needed for
    access to the water rail through the front of the inlet
    manifold. Label vacuum hoses as needed.
  9. Remove bypass hose from the thermostat to the water
  10. Displace heater hose from water pump and from the
    resistor located at the top center of the inlet manifold. Move
    hose out of the way to open access to the water rail.
  11. Remove hose from thermostat to resistor, noted above.
  12. Displace the vacuum hose from the cam cover pulling it
    down through the inlet manifold and out of the way.
  13. Unplug the wire from the device attached to the block
    below the water rail. It pulls off simply.
  14. From under the car displace the starter ground cable at
    the solenoid using the 13 mm socket and the small ratchet.

The teardown to access the water rail is now complete.

  1. Remove the water rail hose.–
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Is there a part II for this procedure?

Sorry about that,

Here is the rest of the procedure:

  1. Remove the water rail hose.
  2. Remove the four bolts securing the water rail. The front two are accessed through the front of the inlet manifold. Use the step and a light to look down through the manifold in order to better see what you are doing.

I used the less than 8 inch ratchet, a 3/8 inch to a 1/4 inch adapter and the 10 mm socket to remove the front to bolts. It gave me just enough room to clear the water rail. I used the butt of the hammer, pushed down through the gap in the inlet manifold onto the ratchet handle to release the tension on the bolts to avoid a potential knuckle busting experience.

The rear bottom bolt can be removed from under the inlet manifold using extensions inserted between the manifold and the heater hose. The top rear bolt needs to be released from underneath. There isn’t enough access to use wobble or jointed extensions.

  1. Remove the water rail through the front of the inlet manifold.
  2. Thoroughly clean the mating surfaces on the engine and rail using a nylon pad and acetone, finish clean with a towel and rubbing alcohol.
  3. If the bolts are fouled, clean them using rust remover and a wire brush, or replace with new bolts.
  4. To avoid having to locate the gaskets while simultaneously trying to bolt down the water rail, adhere the gaskets to the water rail using high-temperature coolant resistant gasket sealant, flat side down and allow to dry.
  5. Place the water rail in the plastic bag to avoid fouling the gaskets while feeding the rail back into position. Remember the gaskets are more a method of applying sealant than a classic gasket, they must remain clean.
  6. Remove bag while locating the rail to the block. This can be accomplished more easily by temporarily inserting allen keys through the rail into the bolt holes, one in front, one in back.
  7. Insert and hand tighten bolts into the open bolt holes, then remove the allen keys and insert the final two bolts.

The rear bottom bolt can be tightened by using in extension inserted between the underside of the inlet manifold and the heater hose. The rear top bolt can be final tightened using the butt of a hammer press down on the ratchet handle through the gap in the inlet manifold. The front 2 bolts can be tightened through the front end of the inlet manifold using the less than 8 inch ratchet. The bolt ends are extra long, I had no problems tightening them down one-handed.

I tightened until my ratchet handle started to flex, the Jag spec is 25Nm, I believe.

  1. Reattach and reinstall the hoses, wires, plugs and air intake in reverse order. Refilling the cooling system will take a little more than 8 liters of coolant.

Thank you very much for the instructions!

In your opinion, what are the advantages of this method compared to the conventional method which involves removing the inlet manifold?

By the way, when feeding the rail back into position, should it be fed from under the car or through the front of the inlet manifold?

I am thinking the section 15 “Remove the water rail hose”. Could it be reasonable to remove the hose only from the water pump and then remove the water rail together with the hose? :thinking:

Here the rail was removed and replaced with the hose attached:

I renewed the hose three weeks ago and I will not renew it again while replacing the rail gaskets. Hence, it may be justified to remove the hose from the water pump only.

Sounds like a better plan. With mine the hose was essentially new and came off easy. It was the struggle getting the old failed hose off which caused the water rail seals to fail in the first place, due to the mounting bolts nearest the firewall coming loose. Fix one thing break another style.

The big advantage is you don’t have to remove and reseal the inlet manifold. Reading about that process was concerning, not because it was particularly difficult, but because so many people have had resealing problems.

I went through the front to reinstall the rail. Reach was the issue from down below as I recall.

Thanks for your views, GoCougs.
I believe I have the same case as you had: when I took the old hose off the rear water rail gasket failed. After having the new hose for two weeks the rear gasket started to leak. So, I have to change the rail gaskets but keep the recently replaced hose.

By the way, I have removed the oil cooler and associated hardware which means that I could get more space if I would take the oil filter off. However, I think it is not necessary since you have managed without removing the oil filter.

I have now completed this process excluding the part 24. The instructions are good, so, thank you, GoCougs.

Concerning part 4, I could not access the bolts without removing the oil filler pipe entirely.

Concerning part 16, the rear bottom bolt can be removed from underneath by using a 1/2 jointed extension. I just could not remove it from under the inlet manifold using extensions inserted between the manifold and the heater hose.

The rear top bolt was the most difficult to remove of the four bolts.
Overall, the rear bolts were not tight but loosened quite easily. The front bolts were a little bit tighter. It took a while to figure out how to break loose the front bottom bolt. I tried to loosen it by turning the less than 6 inch long ratchet with my left hand under the inlet manifold, but the bolt was too tight. The trick was to use the butt of a hammer, pushed down through the gap in the inlet manifold onto the ratchet handle to release the tension on the bolt as indicated by GoCougs.

Concerning part 21, I did not place the water rail in the plastic bag. I could feed the rail into position quite easily. I inserted and hand tightened the front bolts first. The rear bolts must be inserted and hand tightened from underneath.

Wow I never thought this could be done without removing the intake manifold … shows you what I know!

  • Attaboy to GoCougs’ detailed instructions back in 2016

  • Another attaboy to Otto on actually getting it done.

Is this a great forum or what :cowboy_hat_face:

Yes, Groove, it IS a great forum and thanks for providing such a great seguey: As a 20 year Jag owner and J-L member I can tell you owning and affording to maintain a ‘vintage’ Jag is made much more pleasurable and feasible - heck, let’s call it like it is - POSSIBLE - with the great help and advice of J-L members on this forum. I can’t speak from firsthand knowledge but I am sure maintaining J-L isn’t cheap, and certainly not without cost. SO - have you made a financial commitment to help support J-L? I’m sure pledging even $10 per month would be a help and greatly appreciated by those tasked with keeping J-L going. Think about it! :eyes:

Yikes, re-reading my post it sounds as though it was addressed specifically to Dennis a/k/a Grooveman. That was NOT my intent. It was intended for ALL J-L users and specifically J-L members. Sorry if this wasn’t clear.

Dennis, thanks for your feedback, and I agree, this forum is great.

I concluded the part 24 and finalised it by adding the coolant. I had filled seven litres when I noticed coolant dropping to the ground. I started to inspect the system and noticed that the right side of the front gasket had come out from the water rail ear! At first, I could not believe it. Still I wonder it. Well, I had to swallow it and start everything from the beginning again. This time I made the gaskets from gasket material and added RTV sealant. I have done everything else except filling the coolant. I drained the system with three litres of water. I will add coolant later. I hope the gaskets will not leak. Let us see.

Overall, this job is very laborous. The first time took around ten hours and the second time five to six hours.

Otto …


Please believe me when I tell you we all feel your pain. Doing a pig of a job is bad enough but having to do it twice is &$#!. Good man on you for turning right around and getting it done. Hopefully that’s the last time you’ll ever make the water rail’s aquaintance.

Thanks for your encouragement, Dennis. :smile:

I added coolant, started the engine and checked for leaks under the car for ten minutes. I did not notice leaks.

Having worked three days with this project in difficult postures I can feel it in my body. :sweat_smile:

After driving the car for short distances yesterday I checked for leaks this morning. Luckily, I did not notice leaks. However, I am thinking of replacing the inlet manifold gasket, inspired by this https://www.xj40.com/viewtopic.php?f=23&t=7573. That would give an opportunity to check the tightness of the water rail bolts once more. :smile:

Otto …

If you’re planning to remove the intake manifold after all now you’ll have perfect access to the water rail.

My advice would be to go ahead and remove it again and really clean the mating surfaces, redo your two gaskets and lightly coat both sides with some sealant. Now put anti-seize on the bolts and torque it down to spec (Haynes manual calls for 22-28 NM or 16-21 ft lbs). You can do the whole job in 10 minutes and you’ll be sure there won’t be any future leaks.

I use spray copper sealant, but my friend who owns a British auto repair business swears by Permatex
Ultra Black.

Your suggestion is relevant. However, I cleaned the mating surfaces with 3M Scotch-Brite Ultrafine and acetone and used Permatex Ultra Black sealant. I also put anti-seize on the bolts.

Based on this thread https://www.xj40.com/viewtopic.php?f=23&t=7573, the inlet manifold removal should be quite straightforward. Is there any precautions? It seems to be clever to clean the throttle body at the same time.

Otto …

Well it seems that you’ve already done everything I can think of to ensure a good seal on the water rail.

As far as removing the intake manifold. Last summer I did that when I replaced my head gasket and rebuilt the head. I can’t remember any real problems except little pain in the rear things.

One was disconnecting the electrical connectors to the fuel injectors. They have the old fashioned retaining clips that you have to pry off (very fiddly). Also the connectors themselves had become extremely brittle and tended to break apart. I bite the bullet and replaced all of them (and also the water temp sensor connector) with new style quick disconnect ones that had pigtails. So all I had to do was cut off the old wires and solder them on to the pigtails. I used two sizes of heat shrink. One size went over each wire’s solder connection and a larger size then went over both wires. Turned out very nicely.


The other thing was dropping bolts and washers down into the bowels of the suspension while I was taking things apart. I know this sounds like a personal problem but I started using a telescoping magnet and stuffing rags under the things I was disconnecting. An interesting bit of trivia, NO fasteners that accidentally fall into the engine bay makes it all the way through to the floor :neutral_face:

Dennis, yes, the retaining clips are fiddly. I removed them when I got my injectors tested and serviced. Your idea on replacing the clips with new style ones is excellent!

Is it a good idea to add sealant like Permatex Ultra Black to the new intake manifold gasket? :thinking: