A/C works off and on

JARHEAD47

MEMBER
2001 JAGUAR S-TYPE
4.2L
V8
AUTOMATIC
80,000 MILES

Hi,

Mi wife’s car engine works one day, then won’t work the next. If we let it sit for a few days it will work, but then might not work the next.
Where should I begin my search?

Thanks!

Monday, May 10th, 2021 AT 12:35 PM

11 Replies

KASEKENNY

MECHANIC
18,907 POSTS

I assume you mean the A/C works one day and not the next? You said engine but this sounds like a compressor issue or low pressure.

So we need to start with these guides and go from there:

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

https://www.2carpros.com/articles/air-conditioner-leak-detection

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

If you find that the system is low on freon then we can try and charge it using this guide:

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

Please run through this material and let us know what questions you have. Thanks

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Tuesday, May 11th, 2021 AT 5:11 PM

JARHEAD1947

MEMBER
6 POSTS

KASEKENNY1,

Thanks for replying. Yes it’s my wife’s A/C; bad proofreading on my part. Give me a few days to read through the material and I’ll get back to you.

Thanks again,

Hal

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Wednesday, May 12th, 2021 AT 12:09 PM

KASEKENNY

MECHANIC
18,907 POSTS

Sounds great. Please let us know if you have questions as you work through it. Thanks for the update. We will be here when you get back to us. Thanks

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Thursday, May 13th, 2021 AT 6:26 PM

JARHEAD1947

MEMBER
6 POSTS

Hi,

I could not find the low side service port, I looked in reference manuals, forums and I found places that told me where to find it, or that it was difficult to find, but no actual pictures.
I finally went to my local Auto Zone who showed me where it was. Attaching my gauge to it is another story, but my previous mechanic must have been able to do it.
I’ll put my Jag on ramps tomorrow and try to attach it.

Best

Hal Burke

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Wednesday, May 19th, 2021 AT 12:24 PM

KASEKENNY

MECHANIC
18,907 POSTS

Yeah. Unfortunately a lot of these high line cars get bury these types of components.

Please let us know how you make out with this. Thanks

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Wednesday, May 19th, 2021 AT 7:47 PM

JARHEAD1947

MEMBER
6 POSTS

Hi,

Well, I have gotten under the car twice now ti try to put the low side gauge over the nipple to check the pressure. I can't seem to get enough leverage to pull back the clause to snap the gauge on. Somebody has got to be doing it, but not me. I’m going to let my mind cogitate over it for a while and ask for Divine intervention.

Hal Burke

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Sunday, May 23rd, 2021 AT 3:17 PM

KASEKENNY

MECHANIC
18,907 POSTS

Totally understand. There are many things that I no longer do either and this sounds like one I would pass on as well.

Thanks for the update. Please let us know how it turns out. Thanks

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Sunday, May 23rd, 2021 AT 7:48 PM

JARHEAD1947

MEMBER
6 POSTS

Will do.

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Monday, May 24th, 2021 AT 3:34 AM

JARHEAD1947

MEMBER
6 POSTS

Well, I got under the Jag one more time and I was finally able to get the low side port gauge on. I then connected the high side connected and I got a reading of 150 on the low side and 125 on the high side.
How do we proceed from here?

Thanks again.

Hal Burke

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Sunday, June 20th, 2021 AT 5:51 PM

KASEKENNY

MECHANIC
18,907 POSTS

That is great. I assume this was with the engine on and A/C off? If it was then the system is most likely overcharged.

If the compressor was on then the compressor is not building pressure.

Take a look at this chart attached and that will show proper pressure based on ambient temp and then possible causes.

If the compressor was running then you need to look at the low side being high pressure and the high side is low. This indicates the compressor is the issue.

Please run through this and let us know what questions you have. Thanks

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