Is anyone familiar with the substance Liqui Moly 3339?
XJ8 4.2 2004 drips a little coolant and sometimes the warning text "Coolant low" comes on.
You only need to add 0.5dl and it will go on for many days. A few drops have fallen on the cardboard on the garage floor. But you should find out where the leak is. You could start by removing the bottom plate, but it looks so tight, at least from the top of the roof, that you can't see where the leak is, so it occurred to me that there was some substance that could be detected with UV light that you could put in the expansion tank and then cover it with UV / UV glasses to see if you could see the leak.
It seems that at least Fixus has a small bottle for about €44, but googling it turned up the Liqui Moly 3339 from Autodoc and I even saw a YouTube video on the subject. But is anyone familiar with such a substance and is it worth trying to find a leak with that product or what do you recommend?

 

I had to Google it, because I did not even know that something like this exists for the cooling system. I only knew something similar for A/C systems.

On one hand it seems like a good idea, but the problem with our cars is that you cannot see all of the hoses and thus I think that you will not be very succesful with it.

You mention drops on the cardboard on the garage floor. Where are they? More to the front of the engine, or more towards the back? If they are more to the back, it's probably the so called valley hose, and I would not wait too long to replace it. Unfortunately, it is one of those hoses that cannot be seen without dismantling the aspiration part of the engine and is the reason for my comment above about the success of using the fluorescent liquid.
Also, the valley hose is quite a big job, there are various threads about it here in the forum
(For example this one: https://www.jaguarforums.com/forum/x...y-hose-282393/)

Good luck and best regards,

Thomas

 

Any auto store should be able to sell you some UV dye for cooling systems. In the states its about 10 dollars or so. Also, yes I have used it. It works well. Make sure to wear eye protection. The UV light is very bright. Before using it I would just spray off the engine bay and from the underside if you can reach it.

 

I think coolant drops are visible near the front and on the right side.

 

Over the years the special crimp fittings used on the coolant lines can start to leak either from the bands starting to loosen up or the lines themselves start to deteriorate. In some instances, you can swap the special fitting for traditional clamps. Other times you may need to replace it.

If you are losing enough to frequently trigger the low coolant light it shouldn't be too hard to find. I would consider taking off the front pan under the engine, putting it on some jack stands, and having a good look. Coolant will leave some residue as it leaks and dries. UV dye just makes it much quicker for the auto tech to find.

 

Ok. Thanks for the info.
I found Liqui Moly 3339 on autodoc.com when I googled, coolant leak search etc.
That's how Liqui Moly 3339 came up and it's a completely unknown substance to me. I asked a local auto parts store and they also didn't know the product, but suggested a substance they had for sale that was about 5 times more expensive.

 

Drips on the floor do not position the leaks, they position where the coolant runs off of the under-engine aero panel. You can remove that panel and then get a better idea, but it will be VERY difficult to locate a leak visually. The UV dye will certainly help.

My own experience started with a crack in the side tank of the radiator, and when that was replaced, the expansion tank cracked, and then the water pump leaked, pretty much a daisy-chain of the next weakest component failing, until I ended up with a fairly complete overhaul of the hoses after replacing the water pump. Until stuff comes out of the car, you can't even see most of the cooling system, the front of the engine bay is so densely packed. See my experience in the link in my signature lines. I hope you don't need all of that, but keep in mind this stuff has some age on it now, and the occasional bad hose is more than expected. The valley hose is by far the worst, because the intake manifold has to come off to even check it. and after all that effort, you'd better replace it while you're there; That hose is not something you check, it's something you fix.

 

Thanks for the reply.
I'll start by removing the base plate under the engine and the plastic piece on top of the radiator in the engine room.

But did I understand correctly that none of you are familiar with Liqui Moly 3339?
When I look at its product description, it says that the substance can be used to check for leaks, but on the other hand it also says that it would block leaks.
That's not what I want, I want to use the substance to find the leak.
The price of that substance is really attractive (€8.33), while when I inquired at the spare parts store, they suggested a substance that was the same size for €45.

I'll take a look at the link you sent next. THANK YOU.

 

I agree with you, I would also not use a substance that is adveertised as to block leaks, as I fear that it would block the coolant flow where it should not, as well...

Best regards,

Thomas