Low Coolant Light

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

M32H32IS

Full Access Member
Joined
Feb 8, 2022
Posts
173
Reaction score
60
Location
Texas
My LR4 began displaying a low coolant light recently. I added about 1/2 a cup of coolant and it has been fine for a few weeks.

Well, today the light popped up after an hour of driving.

I popped the hood and low & behold the coolant was low. I slowly released pressure in the overflow instead of opening it and getting scalded. As I relieved the pressure, coolant filled the overflow reservoir.

Now the light went away & it’s fine.

I’m really scratching my head
 

mm3846

Full Access Member
Joined
Feb 11, 2021
Posts
355
Reaction score
177
Location
LI, NY
Have you ever replaced the water pump or crossover pipes? How many miles?

Check the level cold. My truck was 1/2" low when I bought it two years ago, I added some coolant and it hasn't dipped below that level.
 

txfromwi

Full Access Member
Joined
Dec 18, 2013
Posts
494
Reaction score
248
Location
2013 & 2015 Houston TX. 2016 Rochester NY
So you de-pressurized the system when it was HOT ??
Did you drive it after that?

DO NOT DRIVE IT!

By relieving the pressure when it was hot you boiled off coolant inside the system. There are now air pockets in the system.

When we work on these vehicles there are specific bleed protocols to be followed because air in the system does not (unless it's a very small amount) circulate out to the reservoir.

If you drove it, it is very possible that you have just toasted the engine, that's about $18K or so to replace.

Have it towed to a repair shop, one that actually knows specifically about these specific LR4's and explain to them exactly what you did.

Worst case is you toasted the engine. Best case is you need the "crossover pipe project".

Plenty of other threads about that project, but I would suggest you just have the repair shop take care of that.
 

greiswig

Full Access Member
Joined
Mar 1, 2021
Posts
548
Reaction score
213
Location
Oregon
Hmmm...I'm actually not sure what happens to a steam-generated bubble, @txfromwi . Here are my hopefully-less-panic-inducing thoughts:

1. Let's assume that he DID boil the coolant by relieving pressure. If he let it cool after that, I think steam bubbles tend to collapse once the temperature goes down.
2. Small localized bubbles are less of a problem than are larger ones that make the pump not pump.
3. Unless the engine is really hot, or the coolant mix low, he may not have really boiled very much anyway. Pressure forms in the system below the boiling point, so he may have just released that and the expanded fluid went into the reservoir.
4. There is always going to be some air in the system. These rigs run with small leaks for fairly long periods of time, which probably suck air into the system as they cool. Truly catastrophic failures don't seem associated with that so much as with sudden, drastic coolant loss from the crossovers failing.

That said, the above advice to the OP to look for a leak, and in particular to learn about the crossover pipes and their tendency to fail and cost you an engine...all sound advice. As stated above, the safest approach not to drive it until you know, or at least until you get a vacuum bleed of the coolant system. But if my reasoning is correct, it seems unlikely to me that you ruined your engine because of this.
 

M32H32IS

Full Access Member
Joined
Feb 8, 2022
Posts
173
Reaction score
60
Location
Texas
Have you ever replaced the water pump or crossover pipes? How many miles?

Check the level cold. My truck was 1/2" low when I bought it two years ago, I added some coolant and it hasn't dipped below that level.
New water pump, coolant crossovers & radiator last May (+/- 12k miles ago)

They’re all under warranty so I’m having the shop who did the work take a look at them Monday.
 
Last edited:

djkaosone

'11 LR4 HSE LUX 5.0L V8
Joined
Oct 26, 2015
Posts
1,004
Reaction score
674
Location
SoCal
Did you do the work yourself? What year is your LR4?

There might be air pockets in the engine. You need to monitor the engine temps, if you have the gap iid tool, you can watch the live values. There are 2 sets of Engine Coolant Temperature values, 1 before and 1 after the thermostat. If the overheat warning lights pop up, turn it off immediately. Carry some coolant as a precaution for the next 30 days of driving.
 

M32H32IS

Full Access Member
Joined
Feb 8, 2022
Posts
173
Reaction score
60
Location
Texas
Did you do the work yourself? What year is your LR4?

There might be air pockets in the engine. You need to monitor the engine temps, if you have the gap iid tool, you can watch the live values. There are 2 sets of Engine Coolant Temperature values, 1 before and 1 after the thermostat. If the overheat warning lights pop up, turn it off immediately. Carry some coolant as a precaution for the next 30 days of driving.
How would I go about removing the air pockets? I’m guessing the bleed procedure which has been posted, but I can’t find the bleeder valve on the front crossover.

I don’t have a pressure system so I’ll have to do it the old school way.
 

txfromwi

Full Access Member
Joined
Dec 18, 2013
Posts
494
Reaction score
248
Location
2013 & 2015 Houston TX. 2016 Rochester NY
Sorry if that original response sounded reactionary - it was not meant that way at all, but I see how it could be interpreted that way....
My apologies...

I would highly recommend getting a vacuum system and using that - keep in mind that if you vacuum a system that is nominally full of coolant the procedure is slightly different than using it on an empty system. If you are going to work on any modern engine you will end up using it.

I would not remove that bleeder port without a new one in hand, it's just a bit of plastic and could be easily damaged. But because your system was serviced in May it should only be a few months old and therefore not too brittle so you might be able to get away with it.

Here is a photo of the port on the 2015 V6. Of course you need to remove the appearance cover first...
For orientation, this is pretty much dead center on the engine and as you can see it's right on top, pointing forward to vehicle front.
If you have the V8, I can get a quick photo of that as well....

The bit of plastic in the photo bottom, i.e. towards the front of the vehicle is the air intake plenum, that's a 2 minute project to remove, but you might be able to get that port on and off without removing the plenum - it's tight but there might just be enough space.





IMG_3723.jpg

I
 

M32H32IS

Full Access Member
Joined
Feb 8, 2022
Posts
173
Reaction score
60
Location
Texas
Update:

When cold, coolant is extremely low -almost none in the expansion tank.

When I open the cap to fill, it releases an air lock and coolant seeps back into the expansion tank.

Almost enough to reach the cold fill line.
 

Latest posts

Members online

Forum statistics

Threads
36,183
Posts
217,036
Members
30,444
Latest member
LR4TAZZ
Top