Hey guys, I'm kind of at the end of my rope here.

A couple background details. I'm not a mechanic, but I've been wrenching on cars since I was a kid. I'm almost finished with a complete restoration of a 70s Ford, I went to college for mechanical engineering, and I've done a lot of construction over the years including flipping some houses on the side doing most of the work myself. So, not a mechanic, but a pretty capable guy.

I recently purchased a 2016 Land Rover LR4. I wasn't looking for a LR specifically, but just a decent larger family car for an extra winter vehicle for cash mainly. I was told at the Used Car Dealer they had replaced the thermostat while it was in their possession. On the drive home I threw a CEL. It was lean bank 1 & 2, and Low thermostat temp readings. After some research I replaced the PCV valve and the little elbow thing in the cooling system with the upgraded brass one because I found it leaking. Cleared the codes, drove it. Threw a CEL, just one of the banks was lean and a low thermostat temp. Decided to change the thermostat. When changing the thermostat I found a vacuum line on the drivers side (US) underside of the air box was not connected. Replaced the thermostat, which I think was never actually replaced by the dealer, replaced the hose that has the plastic press fit deal on the bottom of the thermostat. Put the whole thing back together. Vacuum filled the coolant and put all the vacuum lines on. I drove it on and off for a couple days (maybe 40 miles total) with no issues, no CEL, runs amazing with everything working properly. Take a trip to Cincinnati, OH about 300 miles round trip. Runs great, no CEL, zero problems at all. Slight coolant smell when we arrived in Cincinnati, which I expected because all the coolant I was able to coat the engine with while chaining the thermostat. After the trip and the drive home barely any smell at all which made sense. The whole time I hadn't seen a drop of coolant, no issues at all. Park in the garage all is good. The next day I go out, coolant under the car. The coolant level was at the max cold fill level when I closed the hood after the work I did, it's just below the low level line now. So I top it off again and decide to drive it short distances for a few days to try and find the leak. several trips, no leaks, on the 5th or 6th trip park it in the garage and the next day coolant on the floor. I decided to pressure test the coolant system even though it held a vacuum when I filled it I figure pressure is different than a vacuum so we'll see where the leak is. I pressure test it for 25 minutes and not a drip of coolant anywhere no loss in pressure.

I've thought about head gaskets, but that wouldn't really explain the coolant on the floor. I've though about an issue with the block, but that doesn't make sense when oil levels seems stable and the car runs like a dream. No oil on the floor. I do think it might be burning a little oil just from checking the oil level reading in the car, but it's always between full and half quart low and doesn't seem to change. I guess I'm assuming that at some point it was full and now it's down a little.

I know the front crossover has been replaced with an aluminum one somewhere along the way. I don't know what to do, but with the documented coolant system issues I'm not comfortable driving it much for fear of a major leak letting go and cooking the motor. I'm not the type of guy to fill it up, clean it up and sell it to leave the problem for someone else. I'm also more of a do it yourself guy but I'm not sure what to do.

Should I just replace everything from the head gaskets up and all the coolant lines and water pump? Maybe just the water pump, but I can't see any signs of that, but also can't rule it out I guess. Is there another test I could do to try and find the issue? I'm going to post this info on another forum too so if you use both sorry for the redundancy.

We really loved taking the LR to Cincinnati, it's great for our family, in great condition other than this weird issue, and we'd like to resolve this but I'm not sure what to do. Thoughts, opinions, and recommendations are welcome and would be very appreciated.

 

Have you pulled the engine skid plate, they tend to collect coolant. But before you go nuts UV coolant dye (dexacool safe stuff) helps a lot. Then start up and let the engine get to temp
In your case add a fair bit, then start shining the UV light around at night the dye glows bright green, it might take a couple of trips

 

I know the coolant issues can be a PITA. It's the same on all the supercharged land rovers. And based on my experience...which looks like your experience...they cause a waterfall effect. The entire plastic coolant system sucks and needs to be replaced. You fix one, and the next weak point in the system springs a leak. I was super pissed after I replaced my cross over pipes only to find another leak a few days later, but my mechanic explained it clearly: the original leak was allowing pressure to leak out of the system. As soon as you fix that, the next weakest point in the system starts to leak. Ive had:

- front and rear cross over pipes as well as water pump were first replaced
- then immediately after that my radiator sprung a leak (on the drive home). my mechanic said was there all along but was being masked by the cross over pipe leak. that was from a rock hitting it or something.
- then not long after that my thermostat starting leaking
- then the plastic fitting on the upper radiator hose started leaking a few months ago and I just replaced that.

So it's just a process of elimination until you get all the **** plastic bits replaced in the coolant system. Even though this car has been more a pain than my old LR3, I have come to understand it now and feel these coolant issues are "no biggie" once you know how to fix the parts. I would not be worried about head gaskets or anything like that - unless you suspect the prior owner did overheat it. But you would be smelling coolant in the exhaust I believe and you can check it by taking the coolant reservoir cap off when the engine is running and see if it's bubbling (but dont quote me on that). The people that cook these engines are usually the idiots that have been driving around with a low coolant light for weeks, or the ones who get an engine temp warning and think they can make it to the next gas station to check it. It's really only those cross over pipes that can cause a catastrophic coolant loss.

My last leak I couldnt find for a while. I could see stains on the driveway but I first thought it was oil. I finally found it and it took me 15 mins and $75 to fix. It was just the plastic fitting on the upper coolant hose and the seam started weeping when the engine was hot, but would evaporate pretty quickly.

I had my mechanic replace the cross overs before, but I feel I can do that myself now. Ive watched videos of people getting that supercharger off in 30 mins. Ive got 115k miles on my 2016 now and just about to give it to my son and hope it can be a car we can work on together for the next 85k miles. Im planning on buying an L405 next with the same engine, just because its the devil I now know

Dont stress about it too much. If you are mechanically inclined you can get it sorted with a little patience.

 

Coolant on the floor…
Was the pressure test done with the engine warm and cold?
Is the cap on the reservoir leaking?
Is the feed line nipple on the reservoir cracked?
Air lock in the system?
Did you follow the vacuum procedure, with heaters set to on, from the workshop manual, when filling?
…

 

Good info, I knew about the plastic pipes but not so much about the other plastic bits so I appreciate you sharing your experience. My 2016 LR4 SCV6 popped up with a low coolant warning light last weekend, I noted a small coolant puddle underneath the passenger side. Monday morning I immediately brought it into a shop which has been around a long time, this shop had what looked to be a decent reputation and with some Rover experience advertised etc this shop is within walking distance of my condo so I dropped it off to let them diagnose it. I have only owned the car since spring and put 4000 miles on it, the used car dealership I purchased it from is unfortunately 40 miles away though. Anyway this shop near me ran a pressure test for $100, they said it needed a new water pump and quoted me $1800. Luckily I have AAA premier, I had it towed out to the original dealership for a second opinion, I didn't want to risk driving it out there. They said a small plastic 'nipple' was replaced and the bill was $200 but they waived the bill and I could come pick it up. So that was lucky for me, it worked out in the end... but hopefully there aren't too many more pieces of plastic that are close to springing a leak soon. Next time I'm just going to have it towed all the way out to the dealership I bought it from... I feel like they can be trusted and that's rare these days.

 

Well done. I especially like how the shop with the "decent reputation" wanted to charge you for something you didn't need, to the tune of $1800! but the dealer was free.