Hi,

I recently posted on this forum complaining of climate control noise. My mechanic diagnosed this as being the heater control valve, so it was replaced with one off ebay. That had the same problem so it was replaced with another one off ebay.

It's still happening, so the boss mechanic had a listen and he said it sounds like an actuator flap, but he said he was just guessing and didn't know for sure.

The noise is intermittent, and seems to happen when the system changes temperatures ( either due to me turning on the car and the climate control going to 'auto' ), or seemingly randomly as I'm driving along. I'm guessing that the random occurrences correlate to when the car is adjusting the temperature of the air to compensate for the car getting cooler or warmer.

The noise sounds like load grinding and is loud enough to be heard from my living room if the car is running in the driveway. Sometimes it just makes the noise for a split second, other times it is constant.

It doesn't seem to discriminate between the AC or the heat being on full, so I wouldn't blame the AC compressor.

Does anybody have any ideas what this could be? I'm getting to the end of my tether with this now.

Seems similar to the noise the auxillary water pump makes she going bad. It is for the circulation of coolant through the heater core. Symptoms are similar to mine, but can't be sure unless you can post and audio clip. As mine became progressively more consistent, when I was actually making the noise I could turn off the climate control and it would stop immediately. This is how I confirmed it. It is tough to get to, sits just above the bell housing. You need to pull the resovior tank, throttle body, and a bunch of hoses. These hoses probably should be replaced at the same time, common.y referred to as the octopus hose.. The dealer did mine, cost me about $1000 for parts and labor, which is extensive due to location and the hoses. I know a few others here have done their own. Post an audio clip and I should be able to confirm it for you.

Steve may well be right. Try removing fuse 15 (10 amp) in the engine compartment fuse box - this ONLY feeds the auxiliary heater pump, so if the noise stops, you've almost certainly found the problem.

I haven't had time to try removing the fuse yet, as I only tend to remember when I'm in a rush, but here's a video of the noise.

https://www.youtube.com/watch?v=u_VR...ature=youtu.be

That momentary grinding noise just before th fan kicks on, is that what you are asking about? It is hard to tell in the video, possibly because the fan is on high and drowns out any noise, but I am guessing that by the time the fan comes on, that noise has stopped? I do think that what is heard is the auxillary coolant pump. To be sure, turn the fan all that way down to low, or just one level on, and the noise should be able to be heard better, and, the noise should be exactly the same, regardless of fan speed. If you hear a different tone noise depending on fan speed, consider the fan, but I think it is the aux pump. When I heard mine at first, I thought it was a transmission issue, as it sounds to me like it came from the bellhousing area, and indeed, that is where the aux pump is mounted. Gradually, my aux pump got worse, more frequently making the noise, and it lasted longer. It ALWAYS stopped when I shut off the climate control like you do in the video.

Yes, that's the noise ( just as I turn on the climate control ). Sometimes it stays on constantly until I switch it off.

It didn't occur to me at the time, but it's more frequent when the heat is on my normal setting of around 22c auto and is sometimes triggered by me slowing the car down ( something that runs on a belt ?? ), but I don't know if these things are in my head or not.

Next time I remember, I'll record another video - hopefully tomorrow, by my memory is awful.

Thanks. Finally seems like I might actually get this fixed.

Good luck if you chose to do this yourself. I had my car on a lift, and the pump looked accessible from underneath, if the left hand side exhaust, post the converter, was removed. That seems unconventional however, and the more correct way is from the top, as I said before. You pull the throttle body, overflow tank, and a bunch of hoses, and be prepared to replace the octopus hose while you are at it. There are posts on the forum about folks replacing the octopus hose, so you may have help with guidance from them. Let us know how you make out.

Here is a how to, https://www.jaguarforums.com/forum/x...val-how-96841/ I found it a hell of a job, no surprise someone above paid $1000 to have it done.

I've just got back from the garage ( new-to-me aux heater pump ) and it's fixed!

Thanks chaps.