little coolant there

Greetings everyone,

So i recently went under my 2001 S-Type to change my oxygen sensors and noticed coolant fluid (not a lot of it) draining down my passenger side CAT converter. I thought this was kinda odd because i had just filled my coolant reservoir up not to long ago with some fluid when it had gone missing.. I couldn't see any spots on my drive way and It never leaked before hand. After i changed my O2 sensors i started driving around and saw that my engine temperature was rising past the halfway mark and i immediately stopped. I look at my reservoir and its bone dry. Hmm, ok it must be a leak somewhere. So i fill it up with premixed coolant (as it was the only thing i had on me at that time) and slowly started driving around my neighborhood to get the fluid moving through the system. I stop the car and nothing was dripping, fluid was still there. I leave for a few hours and then i look under and it seems like I'm leaking fluid from the back of the engine somewhere?

I have changed my coolant pump some time ago, and i made sure i changed it with a model that had metal blades inside so that it would last longer. The reservoir itself isn't that new but the last time i had my reservoir leak, the spot under the car was more in line with its position on the drivers side. This seems to be dripping somewhere in the middle of the car, more like under the center console.

After having topped up again, i still see a drip but the coolant reservoir is full. Granted the drip isn't a large amount, but it still is something that bothers me.

I have also seen a very little bit of fresh coolant fluid pool towards the top of my engine ... maybe just a little help to figure out where i should start looking before i take everything apart would be helpful. This car is super old and i assume things are brittle hah... 220k miles on it and i refuse to give up on it.

I have searched the forums and saw some users talking about a valley pipe, but on the v8 non-supercharge the valley bar is in the front and not in the back.

 

ptec 4.0 has coolant stuff routed differently. just do everything, thermostat housing crossover pipe, intake reseal and the valley.

on an na 4.2 the valley pipe runs under and to the side and back around it’s not a straight shot from the back like the supercharged cars

 

Save yourself some aggravation and beg, borrow, or steal a cooling system pressure tester. Some auto parts stores have free loaner tools, so cost shouldn’t be an issue.

The tester looks like a bicycle pump with an gauge and connects to the expansion tank, in place of the cap. Pump up the system to the value marked on the cap and let it sit for at least 30 minutes. If the gauge drops more than a needle’s width, you’ve got a leak somewhere.

The beauty of such a test is it applies full pressure to the system. You can safely look over everything with no danger from hot parts and spinning pulleys. If you try looking with the engine idling, not much pressure is present so most minor leaks are not apparent.

One caveat: If the leak is up high on the engine, only air might escape. You’d still know you’ve got a leak due to the pressure drop, but you may not always see evidence of coolant.

 

The heater return hose is under the inlet manifold on the 4.0 litre unit and is a common failure point.

Use Karl's suggestion and pressure test the system to determine the source of the leak(s).

DO NOT use the temperature gauge on the instrument cluster to monitor engine coolant temperature. The gauge does not usually indicate a difference from 96 C to 128 C, which is excessively hot. Use the Torque app with a smart phone to monitor coolant temperature with a Bluetooth interface through the OBD port.

 

Here is a photo and listing for the heater return hose:

 

so i just finished replacing that pipe.. what a workout that was.. i did unfortunatly break a hose that comes out of the throttle body... would anyone be able to help me identify it ?

i tried using duct tape to seal it but thats not working hahaha

 

Could you please circle in the part/hose, which you are wondering about?

1. I noticed that the "connector" on the left of the picture (centre) is broken - this is probably a vacuum hose connector. Holding this in place with duct tape might work.
2. And I noticed that the hose just right of it in the picture is duct-taped - so that one? This is probably also a vacuum hose, and if so, duct tape would not help...
3. The ""pipe"" under the "connector", which has black tape, is just conduit, which contains electric wires, which it protects - but I guess that was obvious.

I guess I just try to clarify so that others with 2001 S-Type knowledge understand the question - my S-Types are X204s.

 

Take a look here:

https://parts.jaguarlandroverclassic...-s-type-parts/

You may have to dig a little bit. The hose could be under cooling system, engine, air/fuel, or who knows where they hid it.

Once you find it, if listed as not available, don’t despair. Search online with the Jaguar part number and you may find other vendors have it.

 

so it doesnt have any wires in it, it seems like a vacuum line.

 

First choice would obviously be to find a replacement part. If that is impossible, I'd suggest the following:

Remove the tube. If there is a trick regarding removing it, maybe someone here knows....?
Some of those tubes are stuck into something, which at first glance seems to be a seal ring - but it is a cunning locking system - one needs to press into that "ring", while carefully pulling on the tube - I do not know, if your tube falls into that category. Another system is like the broken connector on the left of your picture: This is a "squeeze and pull connector". Once removed, "repair" the damage on the hose (assuming it is cracked somewhere) with black roof and gutter silicone. let it dry a short while and then wrap it in duct tape, preferably black for the looks.

PS: when you have finished applying that silicone all around the damaged section, put a bit of dish-washing-liquid onto your finger and glide over the outer surface with the silicone. That makes it really smooth. Before wrapping duct tape around that section (which is actually optional), the dish washing liquid needs to be washed off, or the tape will not stick... I suggest a drying time of 24 hours before use.

 

If a new hose is not available, I’d suggest splicing in a new section of hose with barbed fittings and constant tension hose clamps. I’ve done this on my ‘02 V6 (and other vehicles) and fully expect such repairs to outlast me.

 

...or as Karl says... - sounds good.

 

The small hose in question is part of the breather system from the Bank 1 cam cover to the throttle body.

 

Is that one of those brittle rigid plastic tubes? If so, skip the barbed fittings and find some flexible hose (fuel line?) that will fit snugly over the plastic tube. Add a constant tension hose clamp at each end and you’re back in business.