Losing Coolant but not overheating

[Clincher610]

Hi to all,
I just purchased myself an F-Type V6S 2014, in black, collected it 2 days ago.
Drove it home from the dealer with no issues, other than a faint burnt oil smell (which i put down to them spilling a drop of oil during the service).
Having driven the 30 miles to get home, i left the car for 3 hours then went for a little drive, after less than a mile i got a low coolant warning, drove straight home. Let the car cool and checked the coolant level, it was showing below minimum. Topped up with some G12+.

Gave the dealer a call to explain my concern that it has lost coolant and they agreed for me to take the car back to them today for them to have a look over it. On the drive to the dealer this morning i again got the low coolant warning after maybe 25 miles.

At no point did the water temperature go above normal during any of this. No signs of leak under the bonnet.

Could the 3-Click closure method of the filler cap cause this?

I don't expect anyone to be able to give me an exact diagnosis from this description, just interested if anyone has experienced similar symptoms etc.

 

[Lunar]

The only symptom I ever had was the level always settling at just below the top of the full bar - never found out why and it was always stable there.

I experienced all of the below in my ownership...

Some of the caps / bottle necks were poorly moulded and a bit oval, which leads to loss of pressure and accompanied leaking - there is a JLR Bulletin about it.

As for a leaky Y pipe under the supercharger that is more likely to go altogether in a ball of under-bonnet steam - ditto for one of the electric coolant pumps.

Other possibilities could be one of the 3 pack radiators, which get silted up and rusty over time.

If it just below minimum then it might just have burped - you don’t say if the car had a recent service / coolant change.

I guess the level they found after it had cooled would give the best indicator as to what is happening.

A pressure test is certainly worth doing.

 

[RPSN]

The coolant leak could be caused by the thermostat?...

https://www.ftypeforums.co.uk/viewtopic.php?t=9061

 

[Panstee08]

Hi,
I had this exact issue with my F Type last month, took it back to Jaguar and turned out to be thermostat housing leaking.
All sorted under warranty.

Paul

 

[Clincher610]

Thanks for the responses everyone.

When I dropped it back at the dealer he said first thing they’d check is thermostat.

 

[RPSN]

As you couldn't see any signs of a coolant leak under the bonnet there's a good chance that the thermostat is the culprit!

 

[WhoKnows]

At no point did the water temperature go above normal during any of this.

Good luck on the garage fix, but don't rely on the dash to know if the temperature is getting hot as it dampens the actual reading.

Torque pro or things like that are better for getting actual oil temp

 

[CentaX]

Mine leaks slowly at the (already once replaced) heater pipe at the back of the engine, but not the amount you are are witnessing. I also rarely have coolant smell. I can see the dried coolant on top of the heater pipe in the rear, you could check this out. Never had a low coolant warning.

In any case, I expect the dealer has to fix this problem on your car?

 

[RPSN]

At no point did the water temperature go above normal during any of this.

Good luck on the garage fix, but don't rely on the dash to know if the temperature is getting hot as it dampens the actual reading.

Neither did the coolant temperature on the instrument panel go above normal when my car had the sudden coolant loss which was caused by the thermostat leaking.

From what I understand, the temp reading will sit mid-gauge for a while even if the engine is overheating. By the time it climbs to the top it maybe too late and critical damage is caused!

This is what TOPIx says about the engine coolant temperature (ECT) sensors...

The ECT sensors are NTC (negative temperature coefficient) thermistors that allow the ECM (engine control module) to monitor the engine coolant temperature.

There are two identical sensors installed which are identified as ECT 1 and 2. Each sensor is secured with a twist-lock and latch mechanism and is sealed with an O-ring. A two pin electrical connector provides the interface between the sensor and the engine harness.

ECT 1 is installed in the heater manifold, at the rear of the bank 1 cylinder head. The input from this sensor is used in calibration tables and by other systems.

If there is an ECT 1 fault, the ECM adopts an estimated coolant temperature. On the second consecutive trip with an ECT 1 fault the ECM illuminates the MIL (malfunction indicator lamp).

ECT 2 is installed in the lower hose connector which attaches to the bottom of the thermostat. The input from this sensor is used for OBD 2 diagnostics and, in conjunction with the input from ECT 1, to confirm that the thermostat is functional.

If there is an ECT 2 fault the ECM illuminates the MIL on the second consecutive trip.