Hey Everyone,

Was not going to post anything here because I had pretty much figured I had a leaky valley hose and then a bad coolant sensor.

My coolant was needing about 10 ounces daily after my drive to and from work which is about 10 miles. Very steady and consistent loss of coolant and since the expansion tank always had a little coolant in it I kicked the can down the road for a few weeks and continued to use the car while I ordered all of the hoses and gaskets necessary for the repair. Then the low coolant sensor went on and stayed on permanently. Very frustrating as I was relying on that to let me know if a major problem was about to happen. Tried moving the sensor around and "freeing it up" to no avail. Figured we certainly needed a new expansion tank.

The crazy thing, and reason for this post, is that on Monday the low coolant sensor actually went off. On top of that, the car lost maybe one ounce of coolant for the entire day! Now I know that the leak is going to need to be repaired but I am dumbfounded as to how the coolant sensor can magically get better after a month of being out but more surprised by the sudden recovery in the loss of coolant. It has now been 2.5 days and the light has stayed off most of the time, came on here and there and then went out, and the coolant level over the last 2.5 days has declined by maybe 2 or 3 ounces. Consistently, every day before now, I have had to nearly completely fill the expansion tank every day I used the car for work.

Has anyone ever seen something like this happen? Do you think that there is some other issue which has arisen that is causing this temporary reprieve from coolant loss and a bad sensor? Would you still replace the expansion tank when replacing the valley hoses?

Any thoughts would be greatly appreciated because I am at a loss here!

Thanke,

Corey

 

Corey,
You clearly have a leak!. For sure, the rubber hoses are the weakest link in the system. They are a natural compound that degrade and perish. As you point out, the valley hose is particularly vulnerable because it receives the most heat radiation. I haven’t experienced this failure, yet!, but I suppose a small weeping quantity of coolant will simply evaporate without notice? I would certainly expect this to get worse, not better.

There are other culprits for coolant leak like the Radiator, Pump, Seals & Joints, Head Gasket etc but these can be observed with signs like steam, smell, drips, crack, or white exhaust smoke.

I think you should run the engine to temp and inspect it to try and better determine the cause before changing anything.

 

Use a tester to put the system under pressure when it's cool. You can rent the testing pump with different caps at most of the auto stores. Use the green cap on the Jaguar, it has the right reach to get below the overflow pipe.
Being cool you can use your fingers in little holes, don't pump it over the normal cap pressure by much, read instructions.

 

Corey,

You seem on the way on fixing the coolant leak, and there’s good advice above for a pressure test.....but have you checked the octopus by the bulk head.

When I initially got my car, years ago, I had an intermittent leak from bad Norma connector on the Octopus. Later found out, years later, that my heater core was blocked, so probably that’s why I somedays I originally had a worst coolant leak.




My personal experience is that coolant leaks are generally at the pipe ends/ near clamps. Thankfully these are generally visible.

 

Thank you all for the comments and suggestions! I actually took it in to my mechanic and they let me know it was the valley hoses with a pressure test. I decided I would try to tackle it myself since I am fairly handy, the cost to replace with these guys was very high, and it would be one of the more complex jobs I have done hence a wonderful feeling if I am successful.

The main thing that I found odd was that after months of a steady and large leak rate, the leak seemingly stopped for a couple of days. I had figured the leak would only get worse over time. Anyways, we are going to try to tackle it this weekend or next. Hoping that I have managed to get all of the gaskets. It took a lot of reading up on old posts to try to piece everything together. Another quick question, do you guys know if there is a special gasket sealant needed or if I need to replace all clamps that are removed?

Thanks!

Corey

 

Corey, you will certainly have some clamps that have seen their time come, so a few of each would be a good idea. Be mindful of any pipe going on a plastic connection, the screw clamps can crush that old plastic in a heart beat.
Good luck and keep us informed.

 

I had a similar experience.
The Water Pump was the first thing I changed, and it had indeed been leaking. But my leak continued. I changed the tank, which made no difference. Then I looked at the plastic norma connector at the back of the engine on the RHS, as sitting in the car, just above the O2 sensor. The plastic had cracked underneath, and was dripping onto the hot exhaust and so therefore it evaporated.
I removed the plastic and replaced it with a new insert and some straight pipe and c clips.
My leak has been stopped finally, and now lose no coolant at all.