Coolant leak with A/C issue under high load - help appreciated

Technical Advice, Faults and How-To Information.
Richard_SVK
Posts: 5
Joined: Thu May 03, 2018 9:44 pm

Post by Richard_SVK »

Hello everyone,

First of all, apologies for the lengthy comment, but the issue has been dragging on for quite some time.

Anyways, I've had my 340 V6 Coupe for three years now. Last June on a road trip in Austrian alps the car suddenly switched the A/C off. A minute later a low coolant level warning appeared on the screen. As the car was leaking significant amounts of coolant it was towed to the nearest Jaguar dealer. Problem was initially diagnosed as a water pump issue. Pump replaced, two days later back on the road the minute I started to push the car in the mountains, same story, A/C switched off, coolant was leaking. Car was towed back to the dealer.
A week later a dealer found the source of the leak, car was back on the road. I drove back home 500km on motorway to Bratislava, Slovakia with no issues.
Few days later I went for a drive and the minute I started to push the car, same problem again... This time car was towed to my local dealer who found out the radiator was so full of gunk, and claimed it may have been the cause of the problem. It was cleaned out, car was back on the road.
As this was taking all summer long by the time it was finally fixed it was September. I went for one more drive for around an hour, the car seemed ok.
Winter passed, I drove the car many miles since then under normal city/motorway conditions, with no problems. However, two nights ago the temperatures here in Slovakia have risen above 30 centigrade. I was driving home from work in stop/go traffic. A/C switched off again briefly, then went back on. The next morning I checked the coolant levels, and I am suspecting I am loosing some once again (not as violently as before).

Both Austrian and Slovak dealers are perplexed by the issue, and it is getting really frustrating for me. It reached a point that I am finding it hard to use the car for what it was intended for. Anyone had similar problems, or could point me in a direction where the problem may lie?

Thanks a lot!!
2015 F-Type Coupe 340, Salsa Red

simpleR
Posts: 2447
Joined: Tue Oct 31, 2017 11:56 am

Post by simpleR »

I had a coolant leak on my last car (not a Jag) and they swapped the water pump, then some pipes, then cleaned the rad and it ended up being the reservoir leaking! (It was all under warranty).

I would of thought the AC and Coolant would be completely separate systems but I would guess the coolant radiator and AC rad/condenser are close so if the AC condenser got hot it might shut the AC off? The compressor would probably put extra load on the engine and make pressure rise so the leak gets worse.

All theory sorry but when reservoir was leaking on my last car, it only looked like a small splash on the reservoir it's self and sometimes a golf ball size blob of coolant on the floor but after a couple of days the level would drop from max to min.

You would hope that your dealer could run the car for a couple miles with AC on and then leave it ticking over in the sun for 10 minutes and then get it inside for a pressure test if that is possible?
400 Sport AWD - MY18 - Black, pano roof and thats about it 8-)
Richard_SVK
Posts: 5
Joined: Thu May 03, 2018 9:44 pm

Post by Richard_SVK »

Thanks a lot for your inputs.
I would imagine the reservoir should be fine, since it passed multiple pressure tests. The source of the leak was always in a different place and was always located.
The issue is the leak (up until now) appeared only during high loads, which dealership is not able to replicate during their test drives.
I initially thought the A/C shuts off when the cooling system senses they may be an overheating issue coming up, so it stops it to prevent the car getting even hotter from the A/C compressor. However now I am sceptical that this is the case.
Do you think it could be that there's an issue with failing A/C compressor, which puts extra load on the engine, thus increasing pressure in the cooling system (which then subsequently forms a crack in the weakest link of the system)?
2015 F-Type Coupe 340, Salsa Red
simpleR
Posts: 2447
Joined: Tue Oct 31, 2017 11:56 am

Post by simpleR »

When mine had the coolant loss it always passed the pressure test! It took weeks to find the cause and only after I noticed a small bit of coolant on the outside of the reservoir. The garage theory was that under the bonnet was so hot the very slow leaking coolant simply evaporated leaving no trace.

I would suggest the AC stops as the car is getting hot and therefore switches the compressor off either because the condenser is getting hot or the car stops the compressor to reduce engine load.

Either way you have a coolant leak. You seem to have covered the pump, rad and pipes which only leaves the reservoir which is why I posted back. (Presume your oil looks OK and no smoke).
400 Sport AWD - MY18 - Black, pano roof and thats about it 8-)
Richard_SVK
Posts: 5
Joined: Thu May 03, 2018 9:44 pm

Post by Richard_SVK »

Thanks a lot for the reply mate.
Oil is fine, car is not smoking, so I'm positive it's not a head gasket.

By the logic you are right, even the reservoir cap has been replaced already so the only place remaining is the reservoir itself. It is a plastic container worth a few quid, so it's not a big deal to replace it straight away, try the car out and see if it helped.

Thanks! Will report back :)
2015 F-Type Coupe 340, Salsa Red
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PussCat
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Joined: Fri Jan 05, 2018 6:20 pm

Post by PussCat »

Do you notice your engine temp before, during and after the A/C shutting itself off?

When I'm not in dynamic mode, I can see the temp gauge and it resolutely sticks to the middle of the range.
VROOOOM! (Pockle Pockle Pockle) MY17 V6S coupe in BRG.
simpleR
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Joined: Tue Oct 31, 2017 11:56 am

Post by simpleR »

Hi Richard_SVK, just found the pics of mine I sent to the garage when I was monitoring the situation.

After a spirited run and parked on a steep (ish) down hill slope you would get a few blobs after a couple of hours as it cooled down.

Coolant on Drive 1.jpg


And then I noticed coolant on the reservoir and sent the garage this picture noting where tiny pink blobs were noted. After a new reservoir the problem never came back.

Coolant Leaks when hot.jpg

Best of luck.
400 Sport AWD - MY18 - Black, pano roof and thats about it 8-)
Richard_SVK
Posts: 5
Joined: Thu May 03, 2018 9:44 pm

Post by Richard_SVK »

PussCat wrote: Fri May 04, 2018 3:40 pm Do you notice your engine temp before, during and after the A/C shutting itself off?

When I'm not in dynamic mode, I can see the temp gauge and it resolutely sticks to the middle of the range.
Temp always stayed bang in the middle (it was the 1st thing I checked) but that was presumably because I just never let it reach a point that it overheated. It always occurred quite fast. A/C stopped, a coolant warning and/or orange smoke from the engine started, I stopped on the side of the road - a matter of 20 secs.

As far as yesterday incident is concerned, temp. stayed normal, I turned the A/C off and on and everything went back to normal.
I scheduled a service appointment for the 21st of May so in the meantime I am going to top up the reservoir to max and monitor everyday how much (if anything) I'm loosing.

simpleR thanks for photos, I will monitor the reservoir before the replacement (however I will get it replaced as a precaution I think).
2015 F-Type Coupe 340, Salsa Red
m_101
Posts: 137
Joined: Tue May 31, 2016 12:01 am

Post by m_101 »

I think there is a technical service bulletin about this but can't remember the number - so think it might be a known issue.
16MY V8R, Ammonite Grey with full red leather interior, carbon roof, 770w stereo, few other bits.
Richard_SVK
Posts: 5
Joined: Thu May 03, 2018 9:44 pm

Post by Richard_SVK »

m_101 wrote: Sat May 05, 2018 11:24 pm I think there is a technical service bulletin about this but can't remember the number - so think it might be a known issue.
Good idea, I haven't thought of searching for a TSB since I haven't found a similar issue anywhere on forums. There seems to be something related to a coolant leak under a number JTB00566NAS3 - An 'engine overheat' message may be displayed on the instrument cluster and that coolant may be leaking from engine compartment area.

Any chance anyone from here can access it?
2015 F-Type Coupe 340, Salsa Red
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