Just from Friday, my car is giving out smoke from under the hood some times. Likely after a quick acceleration, or after running 70+ miles for a while, but not sure when exactly the smoke starts and stops. Idling for 5 minutes, no smoke.

There is no warning on the dash. Oil temp is steady at the middle. Oil level is ok. But checking the coolant tank, the liquid level is half a inch below the min mark when car is cold.

I can smell something when seeing the smoke, but can't tell if it is the coolant since this is my first time seeing the problem.

Is that a sign of leaking coolant? And if yes, where likely the leak is?

If do a full flush of coolant, how much i need to purchase? Prestone AF888 is the correct one to buy?

Thanks.

 

If it was smoke - something burning - it would probably already have come to a very dramatic end.

Steam from leaking coolant is the most likely explanation. Check the level in the Expansion Tank to ensure there isn't a significant loss which could easily lead to overheating and engine damage.

A common cause on other Jaguar models is tiny amounts of coolant dripping onto a hot exhaust manifold or front pipe and immediately flashing off as steam. Notoriously difficult to find the source but pinholes or tiny splits in an Expansion Tank which only open up under heat and pressure are a known cause.

A Pressure Test Kit could help you identify the source of a leak.

The coolant specification is WSS M97B44 (colored orange) Extended Life Coolant. Many brands meet this specification and it will be on the container label. It is used at 50/50 mix with water and the total capacity will be in the technical specification of your Owner's Handbook.

Graham

 

Yes you probably have a coolant leak. The 5.0L engines are very sensitive to that I would guess the 3.0L is the same, you could end up with a ruined engine if you keep driving it. The owners manual will tell you what antifreeze to use. This is a very expensive car to practice on, I would take it to a shop if I wasn't sure what I was doing. The coolant system has a very unreliable water pump and plastic coolant lines. It's likely one or both has gone bad. On my other cars, I would just add antifreeze until I could get around to fixing it but the water pumps are so poor and the consequences so drastic I'd stop driving it right now and hope I haven't ruined the engine. My advice would be to get it on a flatbed to a shop as soon as you can. You can read all the threads about blown engines, just look for them. Of course they are mostly 5.0L like mine, I assume the 3.0L has similar problems. Good luck with it.

 

Thank you for the advice.

I read the manual, and found the capacity table on page 171, but it does not have V6 Supercharged, only V6 Normally Aspirated. But that should be good enough to get an estimate for the amount of coolant to buy.

I have read quite a lot about the water pump issue and am worried about that. As the car is 50K miles and 5 years, i don't think it is covered by warranty now. Before heading to the dealer who can make wild charges, I'd like to have more understanding of the problem. Should the water pump failing showing more obvious trace of leaking and obvious dropping of coolant level?

 

I have to say I would have expected a low coolant warning by now.Have you looked in the header tank to assess the coolant level ? As others here have said, it is fatal to just ignore this, and carry on. The problem will not get better on its own, and you could risk losing the engine if a small leak becomes a large one, and you're doing a speed on the freeway. By the time you have managed to stop the engine could be scrap metal.

 

Thanks for the warning. I am taking this serious and have avoided drive the car as much as possible. Having the post here is to knowledge myself more before start talking with the dealer, and help others if they run into the same situation.

I am too puzzled that no warning has been thrown so far. I checked the coolant tank, as shown in the picture. Liquid level is below minimum required, but not too low. And the sensor seems to be installed at the bottom of the tank and it should not be able to detect this difference. Over the course of 2 days, no dripping noticed under the car and no obvious change in the coolant.

 

Definitely low coolant looking at your photo. In fact I'm surprised you haven't yet had a 'low coolant' message. When I got mine on my previous X350 it only took a small amount of coolant to top it up. Later in the day I looked around the engine compartment in the dark with a torch to see if any globules of coolant glinted back at me. You can't see them in daylight, and it gave me a clue as to where the coolant was leaking. It was a very small leak, but when the shop saw it they told me to leave the car with them as they had to order the part in. I protested that I had to get home, but they said the leak (at a nipple where a pipe connected to a water rail), could let go at any time and I could end up with no coolant and a scrap engine. So it was home on the bus for me !!

My car was the 3 litre V6. I understand the water pumps failing and leaking is a common syndrome on the 5 litre V8s, so this could well be your problem.

Hope you get it fixed without too much expenditure.

 

My early warning system - the smell test - worked!

My water pump was replaced under warranty at 30K miles after I noticed the tell-tale aroma of anti-freeze coming from the front of my XJ after I parked. Before going to my dealer, I checked the expansion tank and it was almost full, and there were no puddles, steam, warning lights or messages for either low coolant level or overheating. I also looked around the engine compartment for any signs of leaks and didn't see any. And the upper radiator hose and radiator appeared to be OK.

When it was up on the lift, the tech found dried anti-freeze on the water pump and confirmed a slow leak. It wasn't visible from the top.

I use an old Samsung cellphone to monitor water temperature while driving using the free Torque app connected to an inexpensive Bluetooth Elm 327 OBDII reader. Cheap insurance.

 

 

Got more DIY diagnose result.

I rented the radiator and cap test kit from OReilly (it is free, big thumbup) and start the testing. I connected the pressure tool on the tank and pumped some air in, at around 19 to 20 psi, suddenly a hissing sound started from around the front of the engine. The pressure in the tank is slowly dropping. No obvious splashing or spitting from visible angle and the pump seems not the problem. The hissing sound is gone at 5 psi, and then I heard slow gushing sound at around the same area, like excessive water coming over an edge and dropping down onto a pool. Best guess, the hose that deliver the coolant for throttle is having a leak.

After that, I poured coolant into the tank trying to bring back the liquid level to normal range. To my surprise, it took much more than I thought to bring it up one inch.

So my theory is: the leak on the hose drained out a lot of coolant, bring the liquid level down. But the leak is not at the bottom so there are still coolant in the system, which is shown as the coolant tank is not completely empty. Then, not all the hot coolant was returned to the tank due to the air in the system, the temperature around the sensor is not that hot to trigger alarm. The engine is working in a hotter environment and can gone wrong without the coolant alarm.

One ask: can anyone share the repair page for coolant system in the service manual? With that, i can probably do a bit more diagnostic to find out the exact problem, and have a better situation talking to dealer