Air in coolant that just won't go away

[turkeyjerky]

Feeling a bit at a loss
Curious if anybody has ran into a similar issue?

Finally got my LR4 5.0 running after swapping the engine and wouldn’t have imagined I’d be subdued by the cooling system.
I vacuum filled it but thermostat won’t open(at least correctly).
I have tried several bleed methods e.g bleeder screws, workshop manual procedure, inclined etc and can’t seems to get it to open correctly.

The only way I start seeing it work is when the vehicle starts seeing a decent uphill grade then values(temp sensor by thermostat) jump immediately to what are expected 120-130 f
Could it just be a faulty OEM thermostat?
Took it to a specialist to confirm that this wasn’t normal but they weren’t much help after they quoted me for a $2,000 job that wasn’t guaranteed to work

Note: Engine does not overheat. Heater works(some times hotter than others)
As temps get to 195 I see the 2nd temp(thermostat) reading drop from ambient e.g ambient air is 60 the coolant sensor starts dropping to 56.

Additionally, when I hold rpm’s at 2k and release throttle the temps spike to no more than 199 before going back to 195.8 and 2nd temp sensor(thermostat) reading also goes down.

What are your temp values like? When do you see your 2nd temp sensor readings start creeping up?
Would sincerely appreciate your insight and guidance

TIA


tl;dr Temp sensor before thermostat only reads when car is on an incline, suspecting air pocket that has made a comfy home in my cooling system.

 

[powershift]

Yes, it sounds that simple. They are electronic and can go bad. Buy the Land Rover brand from the dealer. I had it replaced proactively when I bought my rig at 97k mi.

 

[turkeyjerky]

I wish this was the case for the 5.0 but mine isn't an electronic thermostat. I appreciate the response

 

[powershift]

Whatever mechanism it sounds broken lol.

 

[Pagoda]

Feeling a bit at a loss
Curious if anybody has ran into a similar issue?

Finally got my LR4 5.0 running after swapping the engine and wouldn’t have imagined I’d be subdued by the cooling system.
I vacuum filled it but thermostat won’t open(at least correctly).
I have tried several bleed methods e.g bleeder screws, workshop manual procedure, inclined etc and can’t seems to get it to open correctly.

The only way I start seeing it work is when the vehicle starts seeing a decent uphill grade then values(temp sensor by thermostat) jump immediately to what are expected 120-130 f
Could it just be a faulty OEM thermostat?
Took it to a specialist to confirm that this wasn’t normal but they weren’t much help after they quoted me for a $2,000 job that wasn’t guaranteed to work

Note: Engine does not overheat. Heater works(some times hotter than others)
As temps get to 195 I see the 2nd temp(thermostat) reading drop from ambient e.g ambient air is 60 the coolant sensor starts dropping to 56.

Additionally, when I hold rpm’s at 2k and release throttle the temps spike to no more than 199 before going back to 195.8 and 2nd temp sensor(thermostat) reading also goes down.

What are your temp values like? When do you see your 2nd temp sensor readings start creeping up?
Would sincerely appreciate your insight and guidance

TIA


tl;dr Temp sensor before thermostat only reads when car is on an incline, suspecting air pocket that has made a comfy home in my cooling system.

Do you have rear AC?

 

[jlglr4]

Not clear from your post why you think there is air in the system, but I’ll offer this info in case it helps you make sense of the situation: One temp sensor is on the hot side of the coolant system (located on the heater manifold/rear cross over) and one temp sensor is on the cool side of the coolant system (leaving the radiator, located near the T-stat). I believe the hot side temp should stay roughly around 190-195F, and the cool side temp will stay pretty cool (maybe somewhere around 75-95) until the engine needs that extra cooling capacity. I think the v8 t-stat starts to open around 180F or 190F and is not fully open until about 203F. These t-stats are electrically assisted. They have a wax element with a heater that the engine can control to make the t-stat open faster if necessary. So, still a mechanical t-stat, but they do have an electrical connection (although it’s possible some of the early v8’s maybe didn’t have that).

 

[Rover Range]

What is the actual concern with the vehicle?
May not be anything wrong.