Ok my s type 2.7 D 2005 arrived without functioning aircon. I have checked hoses - no leaks in bay or signs there of, replaced heater control valve and also aircon head unit for one i know works . Sensors have been cleaned. Basically the air warms but wont cool. Even distribution across vents. Given the constant uk drizzle the aircon button needs to be depressed and fans buzzing away all the time to keep the screen clear. I note burbling from top left outside of dash. O rings checked and fine. Engine running perfectly no water in oil. During the attempt to fix it ive replaced the relay for the auxiliary coolant pump as the one on there was cracked and nasty. Blowers were all working fine other than no cold. Running about seemed ok.

Forward to a week ago when i started up, let it idle for a while to start clearing screen then did a short 5 min drive. As I swung around to park the cabin filled superfast with a thick plasticky smoke - like evaporated coolant. Car stopped - it was also eminating from grill mainly near side. (uk)
I immediately stopped and was forced out of car. Started making some calls then returned to vehicle wondering if id been mistaken and it was water and wax pool trapped during the car wash previous day that had splashed over manifold and caused smoke.

Vehicle driven short 5-10 minute journeys x 20 over next week until friday pm which was cool. Got into car, idle to clear screen 5 min drive then massive clouds of plastic ( not oil) / coolant smelling smoke. Forced out of car. I did a couple of short journeys today attempting to reproduce issue with no joy BUT the head unit display started flashing and did so with either AC button depressed or in other blower modes.

I have attempted to search but am frustrated by the ammount of " its the o ring " type posts when the smoke i get is clearly not oil.

A heater core search produces loads for other models but cant see a clear one on S type with this issue.

I will be taking this to the garage again tomorrow but dont have cash to keep throwing at the issue. The rest of the car is a mint and fantastic XS and i want to keep the faith but cant afford to keep having it off the road.

If anyone of skill and knowledge says the smoke is definitely caused by the auxiliary cooling pump kicking in, can they also tell me if taking out the relay or fuse and deactivating it until i find some money in a few months is a good or bad idea please? Ie- will it cause further damage?

Yours - LOST!

Smoke or steam? Big difference in how to proceed, so I want to be sure.

I think you mean steam, as in a moist vapor. Steam will typically leave condensation inside the windows. If you were getting steam from the heating/cooling ducts, you're probably looking at a leak from the heater core. Use a cooling system pressure tester, the type that connects in place of the cap on the cooling system reservoir. With the engine off, pump it up to the pressure listed on the cap and make sure it holds for at least 15 minutes. If not, you've got a leak.

More details here:

https://www.jaguarforums.com/forum/s...ol-how-185002/

​​​​​Hmmmm, it's fairly acrid but could be steam. Its not oil smoke and doesn't smell like fire smoke. I've read the post - I'll link it to my mechanic tomorrow. If possible can you give a layman's input on why it's only occasional and such a thick sudden spewing if it's the heater core please? Its not misting the screen and the flashing air con display isn't mentioned either I don't think?

HiThank you for your time.
can you give a short layman's input on why the thick discharge of " smoke" is very ocasional if it's the heater core and an idea for me on its its function
The cloud is very quick and acrid but smells more like coolant than oil or fire smokeAlso I cannot see anything about further steps to take of it is the core or its removal /fitting.
Finally no notes.on flashing display on AC control panel.
I will link the test procedure to mechanic tomorrow.
Is it categorically the heater core if the test is done on the expansion tank as described and we.get a leak?

Nope, sorry, I've got nothing to explain why the discharge (vapor, not smoke?) comes and goes. My best guess is the leak is only active at higher pressure. Once a leak occurs and hot coolant escapes, system pressure drops just enough and the leak closes up until pressure builds back up. Strictly a guess, though.

The guide was intended primarily for troubleshooting. I didn't go into much detail for component replacement.

He may hurt himself laughing. At minimum, he may charge you an hour just to read it. The intended audience was the typical shadetree mechanic, not the professional. Most of it was designed so we mere mortals could reach an accurate diagnosis with only minimal experience and no expensive tools. Our time is more or less free. It may not be very cost effective to pay a professional to run these tests when anybody with a pulse could do them.

No, not at all. Not by a long shot. If the pressure test fails, more detailed troubleshooting is warranted to determine exactly where the leak is located.

The car is a diesel, which was never imported to North America, I believe. One other possibility is that these cars have a diesel fueled Webasto auxiliary heater, the exhaust plumbing from which can cause smoke intrusion into the cabin when the piping fails.

It's the devil's device.