I recently plugged in my code reader to a family member's LR4 for an unrelated issue. I noticed that it was idling around 226F after a 30 minute stop-go drive, which struck me as a bit high. Coming from the D2, temps that high would be cause for alarm. With the LR4 though, I was wondering if this is normal for them? It's a 2016 with the 3.0 supercharged engine.

 

I have looked through some LR4 documentation and apparently on the 3.0 supercharged engine, the thermostat begins to open at around 204-207 degrees and is fully open at 228 degrees. Therefore, it appears that this is operating within spec I guess. It appears there is not a lot of margin for error in these engines between running temp and overheating to me given this info.

 

I just got done with an engine swap on a LR4 due to a blown engine from overheating. I got it after it was blown.

So, I wanted to incorporate some preventative measures during the rebuild. New radiator, res, and replace complex coolant lines/thermostat.

After a full bleed I am getting temps around 185 driving around and I have yet to see it go over 194. During bleed, when it had air pockets, it was getting 215 and I had to cut it when it hit 230.

 

I was just looking over your thread. Very nice work replacing the engine - nice to know that it can be done! A coolant change was completed by the dealer a few weeks ago. They are saying that generally normal operation is within 180-220 and this one is probably "within tolerance". Hearing what you're saying now, I’m not sure I like that response from the dealer. After warming up, the truck runs between 214-226, most of the time its between 221-224 even going down the highway. Given that it is winter, that seems warm. I am wondering if something (water pump, thermostat?) is on its way out. Or maybe the dealer did not bleed correctly?

 

It took nearly an hour to get all the air out running it up in the garage for the first time. At one point I must have suddenly pushed out an air pocket as it went from 221 down to 180 in about 10 seconds. It was smooth sailing from there.

Now, when I bled most of the air out and let the car just idle, after about 15minutes it got down to 160 sitting in the garage. So, the engine can run pretty cool. Keeping in mind a new t-stat, new radiator, coolant, and running heat on max with rear heat was all in play here.

That being said, it was running 185-190 when driving around for 2 hours(had to get 100 miles it for emissions) and it was 50 degrees out. When GA summer rolls around, I doubt it'll be sitting at 185.

 

It’s my understanding that the V8 uses a colder thermostat than the SCV6, and the SCV6 runs hotter. I believe my SCV6 runs right around 218-221 - probably gets hotter at times. I saw the same documentation re: thermostat temps on the SCV6 that CaptainAaron pointed out, and I’ve seen different (lower temp) specs in a manual for the V8 models.

 

Interesting. Anyone make a lower temp thermostat or know if a lower one from the v8's would fit?

 

That's very interesting info. I ended up getting more info from another dealer and Atlantic British. Atlantic British mentioned that they thought the temps were warmer than normal, especially given that we are in the middle of winter. The other dealer said that 225 was the top end of what they considered normal and not to let it get over 230. Both seemed to convey that they thought something might be amiss in the cooling system, but hard to say since it otherwise is operating normally. Warmer weather will tell for sure.

I would be interested as well. Given that these blocks are basically the same as the V8 with two cylinders blocked off and the V8s don't tolerate overheating well, I'd like some wiggle room.

Atlantic British lists this thermostat for the LR4 SCV6 LR035124G: https://www.roverparts.com/engine-co...ats/LR035124G/

And then this one for the LR4 V8 LR032135G: https://www.roverparts.com/engine-co...ats/LR032135G/

Looks like they made a switch in MY13/14 to the new stat for most V8/SCV6 models. I wonder what the differences are. They look interchangeable otherwise.

 

I’m pretty sure you could get the V8 thermostat on the V6. At the very least, you could use an adaptor. But if the V6 is designed to run at a higher temp, not sure it would be a good idea to run at a lower temp all the time. I think the entire fuel and emissions monitoring system is designed with the optimum engine temp in mind.

I’ve heard people mention 230F as the critical zone before heat damage, but I’m not sure where it comes from. It doesn’t seem like that would be hot enough to start warping heads, particularly if the OE thermostat is not even fully open until 228F. The only damage reports I’ve seen have been from episodes of coolant loss, and those temps would be shooting way above 230F. Using a different thermostat is not going to change that situation.

I would be curious to see other temp data on the SCV6 models. I know when mine was showing 220F or so, the dash gauge was dead center.

 

High coolant temp is about emissions compliance and not usually about performance or longevity. While 230 on coolant temp isn't high enough to cause damage, its what it represents as the temperature inside the combustion chamber and the block/heads. What will happen is as the coolant reaches the boiling point, in certain sections of the water jacket the water will turn to gas, the gas will then no longer be 'cooling' that section of metal and the temp will quickly spike in that region and cause the damage.

Long term the high temp could also reduce the longevity of the plastic components in the cooling system.

I just got the LR4 a week ago, don't have a new IID tool to see what my temps are sitting at - hopefully someone else can help answer that.