Hi,

My 2004 VDP with 159K has a slow coolant leak that I am having a hard time locating its source. I can see the coolant leak coming down one drop at a time at the passenger side bottom corner of the radiator, but I think the source is somewhere above that. From what I can see and touch from the top and from under the car, I have not been able to locate any part that is wet or has an indication of a leak. The expansion reservoir and the radiator hose were replaced over a year ago and no sign of leaks from either. All visible hoses are in good condition. I’ve attached 2 images, one is just a view of what I can see from under the car and the other is the leaking coolant that I am able to see at the bottom corner of the radiator. The coolant stops leaking probably half an hour or less after the car is parked and leaks one drop at a time as shown in the picture.

Any thoughts of where the source of the leak might be?

Thanks.

 

I had a slow leak in my 05 VDP that I finally traced to a hairline crack on the overflow reservoir. It couldnt be seen until the car heated up. When I took it off to look at it I couldnt even see it at all and it doesnt leak until under pressure. I hope you find it.

 

Actually removing the overflow reservoir is a good idea regardless. It will give me more access to see what's going on, if it does not end up to be the source. I'll tackle it this weekend.

 

Have you considered a coolant dye and the associated googles to find this leak? Almost all car parts stores carry them.

 

Mine was the overflow tank also, Most develop a hairline crack at small tube on left side at top where the nipple is molded into top of tank. If this area is getting old and you grab that hose by the tank and wiggle it; this action will usually go ahead and break it off. This area just deuterates over time and becomes brittle. Also at the bottom where the Quick connect hose goes on can leak from the O-ring that's inside, which is also a very slow drip, FYI . Jag does not have a replacement O-ring, only sell the whole hose assembly. You can use a #212 O-ring which is an 1/8" X 7/8" X 1 1/8".

 

I had to replace the overflow bottle for a leak. Damn recirc tube connection on the bottle is too long and if you lean on the hose, it will bend the connection and it will break. Very difficult to see as it breaks on the bottom side. The plastic bottle is also a bit pricey, but easy to replace yourself.

 

The first thing that I would definitely do would be to examine that small diameter plastic nipple to the overflow tank. For the life of me, I don't know why Jaguar would make something as flimsy as that. I mean, chances are good that the nipple will break if the rubber hose is pulled out of it.

By the way, I'm assuming that you did insert that rubber hose all the way into the nipple when you replaced the overflow tank last year. If it wasn't, a small leak would be all but guaranteed.

 

Thanks for the suggestions. I'll tackle the issue this weekend and will report back.

 

I did a lot of additional investigations into the coolant leak. Initially, I thought it was the hose that connects from the auxiliary water pump to the thermostat as it was wet and it felt soft. Once I removed it, I realized it was not the source, but I still replaced it with a new one. I then borrowed a coolant pressure test kit from Autozone and was able to reproduce the leak but still was not able to find the source. Next, I bought a blue UV flashlight and a coolant dye. Poured the 1oz dye into the coolant reservoir, drove for 20 minutes, then parked the car in the garage and in the dark used the blue UV flashlight to look for the dye, and there it was. The leak was coming from the upper left corner of the radiator, next to the upper coolant hose (see attachment). When I started investigating the leak, I noticed the change in the color on the plastic edge part of the radiator, but it was not wet when I felt it, and I tried it multiple times, so I dismissed it as being the source. The coolant dye certainly confirmed it is the radiator.

Thanks rsa760041 for pointing out the dye method. For everyone else looking for a coolant leak, this should be your first approach, easy, cheap and effective. Now, on to tackling replacing the radiator.


Location of the leak. Upper radiator corner

location of the leak. Zoomed in image.

 

Mine was a small hairline crack in the overflow tank. I used to drive a BMW 325i and they were notorious for catastrophic failure of the expansion tank with often engine damage as a result. To me, the extensive use of plastic in newer car cooling systems is a problem. If you pull the tank you will find many of the coolant 'hoses' are really plastic pipes with snap connections. For my money it was worth replacing all those pipes on my '08 vdp while I was in there.

 

I've replaced every hose except probably 2 over the last 2-3 years. Will see, might take care of them during this maintenance.

I have a related question. While investigating the coolant leak, I had the car parked with the front wheels on a ramp for almost a week. While driving the car afterward, I got the air suspension failure message with no suspension issues that I can see or feel. The message goes away after the car is parked for a short period of time, possibly less than an hour. I've replaced one front and one rear strut in the last 2-3 years.

I am wondering if there is a chance the suspension failure message that I am getting now is the result of the car being on a ramp for a week, or it was just a coincidence. I don't have a jaguar specific scanner to retrieve the code.

I will be replacing the radiator once the new one arrives in two days, and the front wheels will be on a ramp again. I will most likely take my time replacing it over few days to a one-week period, so my question is, will it better to disconnect the battery while the front tires are on a ramp for multiple days, or it does not make a difference?

Thanks.

 

I am a firm believer that with Air Suspension going down, one should wait and monitor it for a few months at least. Mine used to go down over a week, for perhaps a year or so, and doesn't now. I did nothing. I put it down to "valves" randomly not sealing when we're talking about AIR.
I won't disagree with any other comments about this or that needing replacing. I just say: monitor it for as long as you can stand. Assuming it's working whilst running, worst case is wearing out the compressor faster than "optimum".
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The manual says, if the car is not level when parked, it will kindly let air out of the suspension to level it at various wakeup times. But it can't pump stuff up when parked.

 

Thank you all for your feedback.

I fixed the coolant leak by replacing the radiator and while it was out, I also replaced the drive belt. Here are some notes and pictures:

I replaced the radiator with one from 1AAuto. Part # 1ARAD01018 for $150 with life time warranty. The radiator looks very well constructed and an exact fit. It is working fine so far, but too soon to tell if it was a good decision or not.
I replaced the transmission cooler lines O-rings using parts from the dealer. Part #C2C6713 for $6 for each, which probably costs 50 cents at the auto parts store, but I wanted to make sure I had the correct size.
Once I had the radiator out, I had full access to the drive belt. It looked a bit worn from the outside, so I replaced it with a belt from Autozone for $30. They have two brands that fit, their own brand and continental, so I bought the continental brand. Replacing it took 10 minutes. I borrowed a serpentine belt tool from Autozone for the job which needed a 3/8" breaker bar to turn the spring loaded tensioner pulley counterclockwise (see fig. 1).

I used this video as my guide for removing the radiator. It is accurate with very good pointers. Here are some additional observations from my experience. All comments about assembly and disassembly are in reference to the video, so the assumption is that you have already watched it.

• If you are not able to identify the source of a coolant leak, start with using a coolant pressure tester. Very easy to use and can be borrowed from an auto parts store, such as Autozone, Oreilly and others. I use Autozone, as it is the closest to my house. Usually, you pay for the tool as a deposit, and when you return it you’ll get a full refund.
• If you still cannot identify the source of the leak with the pressure tester, then use a UV dye that you pour into the coolant reservoir. This is what I used. After you pour the full bottle of dye into the reservoir, use the coolant pressure tester or drive the car a little bit so the dye can leak out, then use a blue light or UV glasses to trace the dye. That’s how I found the source of the leak in my car. I was able to see where the leak started and where it ended by tracing the dye.
• The video shows all 3 fan connectors removed from their mounting plastic plate before disconnecting them. You should not have to do that, you should be able to disconnect them while they are still on their mounting plate. I was able to disconnect the top and the bottom connector, but the middle one I had to remove from the mounting plate before disconnecting it, but you may have stronger fingers and better luck than me.
• Once you get to the radiator removal part, it may look like it won’t come out without disconnecting the AC condenser, but it will, you just need to push the AC condenser aluminum pipe far enough to maneuver the radiator lower hose connector around it (fig. 2).
• The radiator has sharp edges, so make sure not to hit and damage the AC condenser while removing it. The chances of damaging the AC condenser (fig. 3) is greater when putting the new radiator in, so be even more careful during installation.
• The new radiator did not come with the 4 metal clips that go on the bottom that are used to hold the plastic shield in place, so remember to move them from the old to the new radiator.
• After the assembly, ensure that the hose that goes into the bottom of the coolant reservoir (fig. 4) is seated properly and the metal clip is properly in place. It is easy to miss this part and will make it harder to reach and adjust once all the parts have been assembled. I mention it because mine was not seated properly and it started leaking as I was still filling up the reservoir. .
• Remember to replace the O-rings on the transmission coolant lines and make sure the lines are fully tightened. I did not fully tighten the upper line and it caused a leak once the car was started. Easy to fix, but made a mess.

Fig. 1

Fig. 2

Fig. 3

Fig. 4