Advice appreciated please. My car has only done 50,000 miles, serviced by Jag every year, but has recent cooling fan issue.

Even in moderate temperatures 20 degrees C, 70 degrees F, the cooling fan is running for 10 mins or so after switch off.

This is after a short 5 mile journey at low speeds.

I note that whereas the temp gauge was always normally just below half way, it now shows slightly more than half way.

I have checked coolant level, and it "appears" to be between the max/min indicator. There are no warning lights!

Could I have misread the level indicator?

Is there a possible air lock?

I have checked for faults with Gendan Engine Check, but no faults are shown.

Your advice would be appreciated please.

D

 

What is the actual coolant temp while running? There are two hints in your post that it's too high.

 

Thanks for quick reply. The car does not show the actual temperature, just a needle.

On a scale of 1-100, historically the temperature needle would always show 45 when warm and driving. (the red-shaded high temp area is a- 90-100

Recently, on arrival home after 5 miles it was showing 55. i.e. certainly elevated over normal

D

 

Doesn't your Gendan unit show the coolant temperature?

 

Norri - I just looked for faults, I will check tomorrow it's 6pm here in France

Thanks - D

 

Cocktail hour? :-)

 

Perhaps I did not leave system running for long enough. It did not show any freeze frame data. Probably my inexperience showing
Tomorrow ...

 

You have a coolant leak somewhere as with the fans running after shut down is a tell tale sign. Please investigate, identity and fix the issue before causing damage.

A coolant system pressure test is in order.

 

Normally my cocktails start at 5pm when I pursuade myself that the sun has dropped "below the yard arm"
But Madame, la Patronne, boss, has put us on a diet and I have to wait till Saturday for a drink
D

 

Thanks Abonano! Please excuse long post below.

Here is the conundrum:-
Firstly, the coolant header tank is full, and has not dropped below normal. No ovrtemp llight on dashboard.

BUT - some months ago - over some weeks, I did have a fluid loss - a drip drip on the garage floor from under front right side! - It was colourless, not aircon water, and not (I believe) coolant. Seemed light oil, but oil level was OK.

Perversely, and stupidly, it was there before I had a Jag Service last November (forced early due to rear suspension repair needed)!

BUT i forgot to mention the leak - and they did not highlight anything or spot a problem!

Leak continued for some time, then stopped.

I checked all levels - all OK! NO panel warnings.

So what was the fluid? Could it only be from the gearbox which is not (I believe easily checkable?) - and could low gearbox oil causing overheat cause my higher temp and fan run problem?

I will put on the Gendan tester later and recheck for anomalies.
D

 

two seperate problems .

as stated you need to monitor your temps via obd2 or laser gun .
your water pump may have lost a fin or fins possably .
thermostat may be sticking .
or a sensor going out .
lots to rule out

 

it might also pay to check the charge cooler circuit is full from the fill bung right up on top of the engine . and bleed the coolers as that circuit could have been your fluid loss .

 

Thanks for your advice guys.

I took the car to Jaguar this morning. As usual the temp gauge showed slighty warmer than normal - at about 55% (as opposed to 45-50%)

The cooling fan was running.

Service manager looked at car - opened radiator cap (seemingly no excess pressure, but I'm not sure) - and said "the radiator is too full of coolant"!

For me, when checking cold, it had been at the level specified in the manual.

He said he would take the car into the workshop to "remove some coolant"

After he came out with the car, he checked the temp - and fan was still running.

He then said it needed urgent inspection, since "it may be an engine seal (or gasket) he was French, my French is good, but not so good technically!

He also mentioned possible bubbles in the system!

??? I seem to have read on the Forum that mechanics often say the problem is engine gasket related, but this may not be the case??

I have the car booked in for next Friday.

BUT - on the 5 mile drive home, the temp gauge started to show high - 90%, just under the red mark (was never higher that 55% before!)

So I will not be driving the car except to the Service!

I ran the Gendan when I got home. Was showing NO faults, but 109° C temp (228°F)

D

 

109 is abnormally high when running at constant vehicle speed.

1)Stop driving the car until this is fixed. I'd go after the thermostat and maybe the water pump first.

2) Keep the car away from that dealer and his team of ex-spurts for now, seems they're full of (excuse my french) merde.

 

Have you checked the oil filler cap for signs of coolant mixing with the engine oil? If it is, the cap will have a milky coffee coloured oil on it.
If indeed it is going that way, could be a blown gasket blowing straight into and out of the exhaust.
To reiterate abonano, a coolant pressure test might helpdiagnose the problem.
A compression leak down test might also be useful.
I've never heard of a radiator being "too full of coolant".
Does the cabin temperature get hot or stay cold?

 

...
Thanks Steve
no milky colour I can see - orange liquid.
Will ask Jag dealer to do pressure check - than check/replace thermostatat, and let me know if pump a possible issue

Cabin temp OK with aircon

Car is 15 years old almost, Jag serviced each year, only 50,000 miles, but one cannot keep annual big spends going (was 5000 Euros/55500 USD) last year for rear suspension
D

 

I'm guessing that you don't do your own spannering then if you paid someone to do the rear suspension.
There are some good guides on here that can walk you through changing and testing the thermostat yourself if you think you're up to it.
Just a small amount of time, small amount of money.
And the water pump. Both pretty easy to do the DIY way.

However, before letting the dealers have your money, there may be some members on here that can point you in the direction of a good independant mech in your area.

 

+1 on both

Your car is in HUGE distress. It must be close to wrecking the engine so avoid causing such heat.

 

So let me make sure I follow the chain of events. The temp gauge has normally shown about 45%, or slightly left of center. Recently, for reasons unknown, it started showing about 55%, or slightly right of center. No actual steam venting or other indications of an actual overheat condition.

You take the car to the dealer, they proceed to drain some coolant (and possibly take some other actions) and suddenly the gauge is way near the top of the band! Oy vey!

The very first thing I'd do is reverse whatever action(s) the dealership did. Could be as simple as topping off the coolant and making sure the system is properly bled. Sounds like the dealer turned a minor issue, which may have only been an indication fault, into a major near overheat situation.

After that, I'll second the previous recommendations to take a temperature reading with a laser gun. Your previous shift from 45% to 55% may have been nothing more than an indication problem. Keep in mind that same temp sensor also feeds the computer, so a temperature reading from your scanner may not reflect the true coolant temperature.

In case you hadn't seen this, be aware the dash temperature gauge is deliberately misleading. This is from another forum, but the principles are the same:

https://www.jaguarforums.com/forum/x...e-gauge-62813/

 

SNG Barratt - The Ultimate Jaguar Parts Specialist

So A 2004 V8 4.2.

I would check the thermostat housing, is holding the thermostat in place ,correctly, and not recirculating the CW. by passing the rad.

This would lead to overheating, would it not, ho hum...............