No need for any apology, Trinh. We are all on a learning journey with these cars, just look at my last post on wheel bearings !

 

It's been several days and my coolant level has not dropped, so I think I'm good for now. I'll add coolant instead of water next time.

Cheers,

 

+1 on that look at what I managed to do with my super charger swap.

 

Looks good.

 

What are the options for a "Low Coolant" warning with a "No Coolant Leak" situation?

 

If you are sure there is no coolant leak and the coolant is topped up then possibly the sensor in the coolant reservoir is not working.

If it is disconnected I am not sure what it would "read".

 

The coolant reservoir assy was replaced (new sensor) due to a cracked bleed-line nipple and "Low Coolant" msg. No traces of coolant leak and the reservoir is full. After the reservoir tank was replaced, the "Low Coolant" msg was out for about 10 seconds then returned and has stayed on.
I am getting close to bypassing the switch, tired of having the msg and red light on the dash.....

 

Did you replace the reservoir and sensor? Did you keep the old sensor?

 

Wanted to share my experience if it can help others.
I had recently a Low Coolant msg on my SV8 when getting out of the highway, temp gauge still normal.
When I immediately stopped the car and opened the bonnet, there were some fumes, probably the evaporation of coolant dripping on hot parts of the engine, and the blower was at full speed.
The level in the reservoir was however still full.
Looking under the engine though showed a substantial dripping of a pink liquid.

A Jaguar dealer being only a few miles away and because I was stuck with my family far from home on a Friday evening, I took my chance and decided to go there for a possible fix instead of calling the assistance.
I restarted the engine after having waited for some cooling down, and I drove very very slowly til there
A few times I had to stop when seeing the needle of the temp gauge departing from the middle (which never happens normally and indicates that there is a real high temp excursion) or if the red light of low coolant flashed again. I verified then that there was still coolant in the reservoir, and the leak underneath which looked intermittent. .
When I arrived, the engine was still running smoothly, there was still coolant in the reservoir, no fumes in the engine bay and the temp gauge looked "normal" but the blower was at full speed.
However, after having stopped the engine, the reservoir drained itself in a few minutes.

Outcome: The dreaded engine hose under the supercharger had failed. Still needs a check to see the nature of the failure, small hole or bigger crack.
I am lucky not to have blown my engine, because I guess that when this arises, the leak and loss of coolant pressure in the circuit produce air pockets in the liquid and local variations of pressure and flow, both worsening cooling and hindering a correct temp reading, with all catastrophic risks associated.

My advice: never take the risk to run the engine with a low coolant warning without being sure that the cooling efficiency is still there.

 

The coolant reservoir assy was replaced along with the sensor. The old sensor also had the "Low Coolant" msg displayed. I looked all over the engine compartment and found No traces of coolant leak and the reservoir is full and stays full. After the reservoir tank was replaced, the "Low Coolant" msg was out for about 10 seconds then returned and has stayed on.

As I mentioned previously, I am getting close to bypassing the switch, tired of having the msg and red light on the dash. I might install a separate coolant temperature gauge for actual coolant temp.
Also, I have been monitoring the temp gauge and it has held steady in the center.


Is there another coolant level sensor other then the one located in the reservoir?

 

I'd sooner find and fix the root cause rather than disable a warning system.

 

+1 on that.

 

I wouldn't bypass it. You sound to have a bad connection / chafed wire.

(BTW use OBD to check the actual ECT.)

 

Tried that, no codes or any indications displayed on the OBD scanner.

 

This has been going on for several months now, done everything I could short of removing the engine or radiator. Replacing the reservoir was supposedly my last step, but not...

At this point, since the sensor/wiring or something, is not functioning, it doesn't matter if I bypass the system (personal preference). I perform weekly under the hood/bonnet inspections on all my vehicles anyway so.....

The professional side of me wants to keep on searching for the cause since that is what I teach my Heavy Equipment Maintenance students, the other side of me wants to stop searching really bad. OK, done for today....

 

If you were not getting a low coolant message before the nipple was broken and now with a new reservoir and sensor the only thing that has "changed" is the new sensor.

I would strongly suspect the new sensor and or wiring. Can you see if the electrical connector is connected to the sensor? This could be a very easy fix.

 

I had the low coolant msg prior to replacing the reservoir, the nipple broke due to an error on my part while doing something else. I honestly believe the connector is at fault, but will need to test it after the holidays.


I intended to post photos of the sensor in my first post and forgot....I might cut open the old reservoir and post photos of the float and internal baffles.

 

I didn't mention codes. I said to check ECT using OBD.

 

As Mentioned: Tried that, no codes or any indications displayed on the OBD scanner. If there was a problem with the ECT circuit, P0115 - P0118, P00B1 - P00B7, P060F, P0A00 - P0A04, might has been displayed. Also, the engine might run rough till warmed to operating temp but the ECT circuit seems to be OK.

 

Here it is:

Cross section of the sensor mount and float.
Note: The float is soft and easily damaged, contains a magnetic ring that encircles the sensor.