Hi guys,
my 05 LR3 (78k) displayed check engine light. Checked fault code and it was P0128 (meaning from computer - coolant temp is always low). I checked the coolant level when engine was cold and it is almost empty. Checked for leaks and there is no leaks in any place. Checked thermostat housing and no leaks too.

1- I am hearing some water bubbling in passager side.. is this related to any coolant issues?
2- Why the coolant level low messages was not displayed? Maybe the coolant sensor went bad?
3- Where is the coolant if there is no leaks? Naive question. If the thermostat is bad or opened (not sure if this is possible) can be the coolant in the pipes and not returning to the reservoir?
4- Should I put more coolant to see if the check engine light turns off?

I found a very good DIY (Land Rover LR3 ? Thermostat Replacement DIY) .. should I check thermostat and see how it looks?

Thanks in advance, Roberto

 

4. Yes, fill to normal level with 50:50 premixed coolant.

3. No, the system is closed, so there is coolant flowing whenever engine is turning, and there should be no air bubbles travelling through or trapped in the system.

2. Don't know, that manual is not part of the RAVE, but perhaps one of our pro shop members will comment. You can down load a manual for a fee from Land Rover (TOPIx system).

1. Water bubbling sound is gas bubbles of some type in the coolant system. Most modern Rovers circulate coolant at all times thru the heater core, and use HVAC damper vents to shift the air mix from cold to warm. Old school was turn off water to the heater core, and it corroded by sitting for months during the summer. Usually the bubbles can be bled or purged when coolant is refilled. But it could be leaking from any hose of connection, O rings on pipes to heater core if equipped, etc. There is a coolant pressure tester you can rent/borrow from a parts store, pump up air to 15 PSI, leave for 30 minutes, leaks usually make themselves known. When coolant leaks out, air leaks in.

That's if you are lucky. Now if you happen to own the multi-volume set of Murphy's Law, those same bubbles could be exhaust gas in the coolant from a leaky head gasket. There is a $50 chemical test from the parts store that will confirm this (makes like 15 tests, so can use on other vehicles). Head gaskets $1500 - $1700 at a lot of indy shops. More at dealer.

The water sounds under dash is a built in Rover diagnostic feature, for cooling system leaks, head gaskets, cracked heads, cracked blocks, etc.

The P0128 code is also an indicator for a new thermostat being needed, the existing one is sticking open, and engine is not warming to above the stat operating temp. It is running "cold", will impact emmissions, mpg, and in the summer it won't cool as well, because water actually has to stay in radiator long enough to cool down. Please be sure to buy an OEM "real Rover" thermostat, aftermarket ones have been reported unreliable in other Rovers (D2). The D1 is a more basic stat, used by several thousand types of cars.

 

we see alot of issues with both the thermostat and the hose cap underneath engine cover and the egr valve cooler.

the cel light is the thermostat by the way.

 

When changing the thermostat you might want to plan on changing the plastic housing. They have a history of cracking and leaking. You may discover yours is cracked upon dis-assembly.

This is a fairly common situation, they part is made out of plastic.

 

Hi Guys,
thanks a lot for all your feedback and suggestions. I finally found the leak in one of the hoses in the thermostat housing and as already mentioned bu others the leak was being evaporated by the heat of the engine so I wasnt sure .. I replaced clamp and also checked the thermostat and found the gasket complete broken.. see attached picture.

As soon as I replaced thermostat and added coolant the check engine light went off and so far no leaks .. I have been checking it a couple of times per day.

https://plus.google.com/u/0/photos/1...99099571924354

Thanks again!