Jump to the ***'s if you want to skip the long history narrative. For some, this may be helpful. Really, the punchlines are much further down...

Well, the good news is that the interior is all cleaned up and perfect with a brand new headliner (and sunroof panels) thanks to advice from the forum on how to accomplish this.

Also, was able to take the 1999 XJR for it's first real drive since I've owned it.

The bad news is that ended in it puking coolant just after I pulled back into the driveway. Lucky? I wouldn't go that far...

Here is the history:

I bought the car from someone who had owned it for just two years, and clearly wasn't that excited about maintenance costs. I viewed the XJR at the mechanic where it had some cooling hoses replaced, along with the pressurized expansion tank, which had cracked and developed a leak. There is a white coolant spot above the tank on the hood liner that attests to this.

The story was that the car needed a new radiator. Seeing the $700-$1000 for a new radiator and I guess judging the previous owner had me thinking the story fit.

The car was delivered on flatbed and I got to work troubleshooting the cooling system to confirm the radiator was actually at fault before sourcing one. To my surprise, once the cooling system was filled and burped - no signs of any leaks - other than massive oil leaks on both sides, including oil vapor/smoldering off the valve covers. No hint of coolant smell in the engine bay or exhaust. So, I order valve cover gaskets, secondary tensioners, a water pump, thermostat, and a whole bunch of other little precautionary parts.

While it was running and only leaking oil, I drove it around the block. Other than the oil vaporizing on the exhaust, all seemed ok at the time.

The oil leaks were truly massive. Spark plug holes filled to the brim, leaking around the entire periphery of both covers. Upon removal, I found that the valve cover gaskets were hard rubber, almost plastic rigid in feel. I got thinking at this point about what temperature/time it would take to do that, knowing that the valve cover gaskets had been replaced by the dealer for the original owner several times.

Anyway, I replaced the valve cover gaskets and reinstalled everything to see if that addressed the bulk of the oil. After bringing the car up to temps I waited patiently for all the oil residue (much of which was inaccessible with the engine in place) to smolder off - this took a good 30 minutes of burping the cooling system with the fans cycling on and off. There had been a huge puff of initial blue smoke when I started the car after the valve cover gasket job, but I attribute this to oil that I was unable to blow out of the spark plug tubes.

*******************Cooling system symptoms start here*************************

With no apparent active oil leaks and the engine bay smoking over with, I was feeling pretty good and took the car out for an increasingly spirited drive. In all, I put about 5 miles on the car. Temp appeared to hold stead at or below "half", and the heater seemed to work fine. Ambient temp was about 40F. The last thing I did was pull up a constant, nearly mile long 10% grade to my house. No sign during the pull of any issues. As I rounded the driveway and pulled in front of the garage, I saw the needle jump straight up and the red coolant light turned on. I shut off the car, and saw about a half gallon or more of coolant on the last 20 feet of driveway.

Immediate inspection revealed that the coolant came from what I guess is an open-atmosphere overflow tank located in front of the driver's front wheel. With the hood up, coolant was clearly boiling in the expansion tank, and perhaps elsewhere. Not good.

So, I put the car on stands and get to work. Maybe that radiator is clogged after all? Maybe the original water pump impeller is toast? Maybe the thermostat is original and stuck closed?

Well, 3 strikes for me. Drained the radiator from below and a lot of normal-colored coolant came out. I manually poured coolant in one side of the radiator to find it easily fill and then pour out the other side. No indication of a blockage in my eyes. No sign of stop leak gunk jamming everything up. Next, the thermostat - definitely not original, nice shiny, installed with valve upwards - unlikely cause there. Water pump was original in the end, but no signs of impeller failure. The gasket may have been leaking/weeping over a long period of time, as the complicated seal system literally disintegrated in my hands.

I've fitted my new metal-impeller water pump, and am on hold for a day until I get some nice new serpentine belts.

I also broke the quick disconnect off of the cooling system bleedline(?) that runs from the upper driver's side of the radiator back to the expansion tank. I haven't been able to find the part number - or at least one that the photo looks the same. I am thinking that the XJR line is different than the XJ8. If someone has the part number, I'll gladly buy new, but I have some adapter fittings that may work for a short time, to otherwise test the system.

So, I've spent the time reading the forum for a few hours.

My problem sounds disturbingly similar to this case... https://www.jaguarforums.com/forum/x...a-fixed-62429/

Hoping that I either didn't bleed properly (I have the official instructions now) or that the lines feeding the expansion tank are mixed up somehow.

******** Specific Questions - Help Desired! ******************

• Does anyone have a photo or diagram of what the lines going into the expansion tank on a 99 XJR should look like/ where each of them goes?
• Does anyone have the part number for the radiator bleed line that I broke when taking the belts off?
• Any other thoughts or suggestions? Am I missing something obvious?
• Anything else to check before I break down and go for the head gaskets?

 

I just bought the pipe you're talking about for my 2002 XJR. It was MNC4583AB. I'm sorry to report it cost $58 from the Jag dealer.

Easy to break off, isn't it?

I think that part changes at some point, the later part like mine has an extra T piece and connection near to the header tank. I'm afraid there really is no substitute for taking your pipe to the Jag dealer, and checking it matches what they list.

 

There seem to be two possibilities :

1) it really did overheat and then boiled over.

2) The expansion tank opened prematurely and let all the coolant out.

2 could easily be due to a faulty header rank cap.

If 1) I have a question : are the electric fans working?

It is kind of behaving like the thermostat is sticking. Maybe put a new one in? Or test the current one in a pan of hot water?

 

My jag dealer actually faxed me the parts diagram to check against.

 

Mark, thanks for the PN. I can't find a clear picture or diagram on the internet to confirm, so I will be making that dealer trip you mention.

I would be eternally grateful if someone with an XJR could snap a photo of their expansion tank line situation - all the diagrams I see online and in the manual look different than how mine is currently plumbed.

Header tank cap looks new, like it was replaced with tank. If they are available separate, perhaps I will just pick another one up. Anyone know?

The electric fans were running like mad when when and after I shut off the car. While doing my static warm ups, I heard the low and high speed fan speeds. Not sure if both fans were on, but definitely two levels of airflow.

I have a new thermostat on hand it will be fitted when I put everything back together.

 

The first image shows where on the radiator the broken bleed line attaches to.

The second image shows my current expansion tank setup. The broken line connects to the open nipple shown on the tee in the second photo. There is a 3 inch long section of rubber tube with clamps that attaches to the nipple. The nipple is a bit obscured by the elbow and line that feeds to the pressure cap. The nipple points to the throttle body.

 

I just looked at mine. It's the same. That part number I gave you is right. What you get is the pipe, the bit of rubber, and the T.

 

Thanks, for anyone else later on, the PN is MNC4583AB, which appears to have been superseded by MNC4583AC.

Images for MNC4583CB look the closest to what I'm looking for because it has the tee and rubber section.

 

Connections look correct -- The XJR is different as it has the extra bleed going to the SC intercooler radiator. That is why the main radiator connection has the "T".

Did you check the thermostat to make sure it opens.

I have a set of those hoses for my 02 -- they get very brittle and are easy to snap. If you have any questions I can go look at the numbers on the parts.

When you look at the diagram for the small hoses: The hose to the SC radiator is supplied in two parts .. I guess it made it easier to manufacture the car .... This extra hose makes it confusing when you look at the parts diagram. One part connects to the radiator and the other to the expansion tank and they snap together in the middle.

Also... the early cars had the connection to the thermostat housing going directly to a plastic connection -- the later cars had a small length of curved rubber to absorb the flexing of the hose from the motor. Some of the diagrams show both old and new.

I thought that the hose you broke was the same for both the NA and the SC and went on the end ... but it could be the one supplied with the "T". I can't remember.

My dealer gave me a discount -- I paid a bit over $100.00 for all of them. Check the online prices.

 

Ok, an update.

I cobbled together a replacement bleeder line for the time being with some brass step down fittings and additional hose.

New water pump, thermostat, and goodyear gatorback belts were fitted, along with coolant. I followed the JTIS procedure. Wow, it took a long time running the car at 1.5-2k RPM to get the fans to kick on, but they both did. I'm hoping that before there was just a huge air bubble. No apparent leaks, excess smoke, or bad sounds. Oil looks good. Valve cover cap off doesn't show steam or blowby, cap itself is all oil. The overflow tank in front of the driver's side tire did fill slowly with about 2 cups of coolant. Not sure if this is because I overfilled or what. Cooling lines are not bulging or showing excess pressure. Heater works great.

I am letting it cool overnight, and tomorrow I will check the header tank and S/C fill port and fill as necessary.

One big question- how high should I fill the black plastic header tank with coolant? I don't see a mark inside or out.

 

From all accounts the overflow to the fender tank is just that .. an overflow ... not a recovery tank. I was told it was installed to insure no fluid would ever be noticed. Jaguars were always leaked something .. and the x300 -x308 were designed to not leak .. or at least hide the leak.

To properly fill the system you fill it up to the bottom of the lip of the tank -- basically overfilling a bit -- the system will expel any excess .... now filled. The TSB on this says to only do this once ... I would think because of limited space in the fender overflow.

Did you really get 2 cups to go into the over flow ..16oz .... ?

 

The fluid in the overflow tank should be drawn back to the header tank as the car cools. If not, there is likely a air leak in the line or a defect in the pressure cap.

 

RJ237: If you look at the length of the tube to the fender overflow -- it does not reach the bottom .. the tank is not sealed.

I can't think of any car I have had in the past 15 years that had one of those -- a true recovery tank.

They all use an expansion tank -- like the Jaguar.

 

"One big question- how high should I fill the black plastic header tank with coolant? I don't see a mark inside or out."

You fill it right up, to the bottom of the neck. This is a system with a recovery tank, so the excess on expansion/warm up goes to that, and is drawn back in on cool-down.

Edit - now I'm not so sure. It should be possible by examining the expansion tank cap, to figure out if it designed to draw coolant back in, on cool down (or not)

 

Just looked at the hoses -- you are correct the radiator hose is the one with the T on the R .. strange that they did it that way. My part number is different .. but they keep changing them.

I bought all 5 hoses.

 

Alright - here's an update.

I filled up the coolant today (after an overnight cool-down), and it really didn't need much - maybe 4-5 ounces to bring the float up just to its highest position. I started out today with a small amount of coolant in the fender overflow tank, and this increased somewhat as I ran and warmed up the car for about 10 minutes in the garage.

After a moderate cool-down, this extra amount in the overflow seemed to be pulled back into the expansion tank. Felt good enough about that to take a drive.

I then drove the car about 30 miles. Not much info from the gauges, but it didn't overheat or show a low coolant light. No warnings or lights of any kind. Hard to tell because it started raining, but there is a possibility that some coolant made its way out of the overflow tank. Definitely a lot more coolant in that tank, enough that I couldn't see the level easily from underneath. Just after turning off, there was a continued gurgling that really sounded like coolant boiling in the expansion tank - I could feel the gurgling on by placing my hand on the tank. The expansion tank cap looks new, like it was just replaced along with the tank itself. There was very faint odor-free, colorless steam rising from both sides of the engine after shut down. Nothing evident out of the hood when driving around. From rain being splashed up? Hard to know.

Will see tomorrow how much coolant was drawn back into expansion tank (what is left in fender overflow), and what fill level is in the expansion tank.

Am I boiling coolant? Was that the coolant rushing back from the overflow into the expansion tank? How do I know if the cooling system is building adequate pressure to prevent boiling? Everything seemed pretty hot, but not enough to immediately burn myself. The whole intercooler coolant system seemed quite cool in comparison - maybe warm.

 

Another weird thing:

I drained the primary radiator (not the supercharger one), and replaced the water pump and thermostat. I didn't disconnect or drain anything else. Surprised that I used only a little over a gallon of coolant to refill - does this seem off?

 

It does sound like too little, but when I filled my system very carefully, I only added a gallon. Took it for a drive, and after about 2 miles on the freeway the low coolant light came on. Had to add at least a couple of pints. It seems air gets trapped in the system, and only driving will liberate it. Don't be too surprised if you have to add some.

I did have some problems with overheating and boiling over on my TR8. The problem came down to a leaky radiator cap that wouldn't hold pressure. Parts of the engine get hot enough to boil coolant if the pressure is insufficient. Do the hoses feel pressurized?

 

To be certain you have all the air out, the plug on top of the intercooler should be removed. 19mm hex key.

 

Not confident the system is building 15psi before dumping into overflow. I now have a spare pressure cap on order to test with. Hope that's it.