I notice coolant pooling on my or under the intake manifold which is probably the reason for my mysterious continuous loss of coolant over the past year. Is there any special thing that I need to know about before I take off the manifold. Where do I release the pressure in the fuel rails?

As always, thanks in advance for your input.

 

The JTIS cd will give you a good step-by-step on removing the manifold. There is a sticky in the general help forum where you can download it, or else go to one of the member's uploaded files here:

http://www.mediafire.com/?sharekey=3...e4b9ac475cdcd3

Fuel pressure release valve is on the fuel rail at the front of the driver's side bank, just a basic Schrader valve. Before pulling the manifold, have you confirmed that it is not coming from the little dribble hole in the water pump or elsewhere? Might want to eliminate the easier things first before doing the more extensive work.

If you pull the manifold, be sure to post back here with the results. I'm interested to see how the job goes and what you find.

 

You didn't specify NA/SC but the NA has a propensity to leak around the plastic thermostat housing. Both my cars have had that. Everyone seems to be replacing leaking ones with an aftermarket aluminum one for less money.

 

And replace the 2 heater hoses while youre under there

 

Thanks all for the input. I changed the thermostat housing to the metal housing last year. I will check the dribble tube on the water pump. I finally found leaking coolant on the garage floor this evening coming from the right front part of the engine. I will look tomorrow morning to see exact location. The past few days I have been adding a quart of water every morning. Damn, it's a new water pump (aftermarket rebuilt) that I installed last year along with the thermostat housing. If the water pump is the problem, I may use a weekend and replace all the hoses while i have the coolant out since the odds are that some of the hoses may be ending their life at 168k.

I will post my findings.

 

Losing a lot of coolant with little on the garage floor is a sure sign of a water pump failure.

 

look very closely at the plastic crossover pipe on the front of the engine for cracks. Better yet replace it as the plastic "rots" and the orings at the block tend to fail as well. Best to have a cooling system pressure tester to isolate and verify where leaks are coming from

 

Brutal, thanks for the tip. I will take a look at them next weekend before i change some of the hoses. I did notice some dried fluid at the connections of the heater hoses running under the intake manifolds near the firewall on the passenger side and driver's side. Also, I got under the car today (unfortunately no visable leaking today) and seems like fluid is coming from a location above the alternator.

I took my car in to three independents specializing in Jags. Supposedly, the first two ran pressure tests but could not find anything. The first shop replaced the two hoses from the expansion (no charge) and the third shop said it was the radiator. I replaced the radiator six months ago and the coolant is still evaporating.

This forum is great and the people who contribute, like Bruatal, are a great help. It seems like I am having a better success rate in pinpointing the problem and resolving the issue better than the independents that I used.

Thanks everyone.

 

coming from the alternator is almost certainly the cross over pipe orings. this is a 10 min fix. replace these 2 and the stub hose to the t stat housing at the same time. you may just want to replace the pipe if you want to keep the car cause as i said earlier they do rot and split/break apart....also things brings up another thing I love about Jaguar coolant.....it has a tracing element in it that leaves staining and trails to help idenitfy leaks like youde never get with other coolants. It also seals small weepages. Those crossover pipe orings when they fail usually leak only when hot and not under a cold pressure test. You just really have to know the cars and what the failure areas are, something you dont get much with people that havent worked on alot of Jaguars yr after yr

 

Brutal, thanks again for the advise. I will tackle this fix this coming weekend as I gather the parts during the week.

 

Tackled the cooling system problem today. Took off the throttle body and unbolted the intake manifold. The manifold is on a pivot and pivot's up. The hose on the thermostat housing and the second hose on the water distribution pipes were leaking. The water distribution pipe I replaced 2 years ago and looks fine.

The opposite end of the hose from the thermostat housing to the firewall was also leaking. Apparently the stem on the rear connector was fractured. Also the coolant sensor in the overflow tank was missing an o-ring (i'm assuming it has an o-ring, otherwise it is plastic on plastic). Need to go the the dealership to get the replacement parts this Monday.

I replaced all the hoses running along the back of the firewall. It wasn't difficult, except to get the compression clips back on to seal the hoses. Since some were at a bad angle. It would have been easier if I replaced the compression clips with worm drive clips. Also, I replaced the breather hose that also runs under the intake along with new manifold gaskets.

Hopefully, my mysterious leaking coolant problem will be solved with the change of the hoses. I will know Monday after I get the remaing parts.

Slowly, I am knocking down everything on my "To Do List."

 

And thank you for the follow up. So many don't.

 

No problem, Test Point. Hope my post will help another person. Everything is straight forward in terms of removal, except I didn't know the intake was on a pivot until later. The JTIS CD I have doesn't give much information, unless I am using it wrong. Honestly, the cd I have is pretty useless. I usually can't find specific details in the JTIS although it contains good general information. For example, the engine is under the hood, the seats are in the cabin and the gas tank is in the trunk. The repairs I have done so far has been assisted by this board and diving straight into the problem. Is there a paperback repair manual like the good old days.

 

Hey all, just wondering if someone out there has run across an aluminum water distribution pipe. I upgraded my leaky thermostat housing to the aluminum one Saturday and I noticed that the distro pipe was deteriorating. Fortunately, replacing it will be a quick and easy job. I will be ordering a new pipe in the next few days but would like an aluminum one if one exists.

 

there is no seal on the coolant level sensor in the reservoir as its not exposed to coolant

 

thanks

 

Hi Brutal , Testpoint and all ... I have been reading this thread, and though the thread is a few years old... I was wondering if any of you could help with a question ... I too am going thru the same leak issues on my 99 XK8 (NA) and I have everything disconnected that all the threads and JTIS says, esp all 10 bolts on the manifold, throttle body off, and two bolts removed (one L, one R) from the bracket under the elbow, plus the 4 (2 on each side) below that loosen. The steel side plates are loose and top bolts are out. So now trying to lift the intake manifold, but it is quite "stuck" down. So this manifold is plastic, and one must be judicious, but just how did any of you "pry" yours up, or how did you pull up on it. It cannot be pulled up by hand alone. Car only has 58K miles. Help please, don't want to break anything, and all is disconnected, but where/how to safely pry or pull up? Many thanks for your help.

 

Got it ! I found a beefy place to pry against, and from there used the base of the thermostat tower to pry up from. Popped right up with a nice sticky release sound. Now to change out the hoses underneath, swap out the plastic thermostat tower with an aluminum one, replace the big plastic crossover pipe, and check out the source of the remnants of some coolant sitting (a slow trickle leak) on top the block and in the valley underneath. Will be looking for just which item has been seeping. The job will also get a new expansion tank .... which is where the job started! .... I found coolant seeping around the mid-girdle seam (where its two halves get glued together by factory). So from there, all these other things were noticed. so a whole bunch of stuff will get done. Anyway, I got the manifold up and I;m off and running. Thanks

 

Whilst you're at it: change your thermostat housing! Unless it is already metal. The plastic ones are biggest ***** going!

 

Thanks for the reply ... yes the tstat cover is also aluminum .... it all came in a kit, three parts, all aluminum, incl the screw cap lid. But just to make it all look really authentic as possible (ie for concours showing), I used a high temp flat black paint on all the parts. The rough casting texture made it stick really well, and even if you look closely, its hard to tell its not plastic. So the job is still underway right now.