[Carspotter]

Hi all,

I'm seeking some advice regarding a problem that has been plaguing my juke for some time. I'm pretty much out of options and want to know if anyone has experienced similar issues or knows of any possible solution, any help is greatly appreciated.

I own a 2011 Juke SV (CVT) with 190,000km on it and got into a collision a little over a year ago. It was low speed and into a ditch, I was able to drive out no problem but then realized the vehicle was overheating due to the radiator being punctured in the crash. The vehicle did overheat and went into limp mode, until I pulled over and cooled it down. Since then, the vehicle has been overheating constantly. After the collision I replaced the radiator and overflow tank, flushed the system completely then poured in a 50/50 mix of coolant and water to the brim of the coolant system. I assumed everything was fine and drove the car for around 30km before I saw the temperature rising once again. The coolant was boiling out of the overflow. After that I did some research and assumed that I likely did damage to the head gasket when the vehicle first overheated. I purchased some steal seal head gasket repair (not the best solution, I know) and followed the directions precisely but it did not solve the problem.

Since then the problem has been getting worse - I'm down to about 10km of range per drive and experiencing the same symptoms:

• The vehicle overheats after driving at highway speeds, low speeds seem okay for longer distances. The car has overheated several times and I am worried about the condition of the block and head gasket due to the amount of times it's shown the temperature at full bars, however I don't see or feel any performance decrease or other issues which would indicate a warped block or head gasket failure.
• When the vehicle overheats, coolant is running out of the overflow and the coolant in the overflow appears to be bubbling or boiling. There are no visible leaks elsewhere.
• The engine runs well. It is at times difficult to start in the cold which I think is typical of most vehicles, but otherwise I don't notice any issues at low or high RPMs while driving.

To provide some more context; my drive to work and back is a short distance on the highway. Every morning I top up the coolant (Usually > 1L is missing from the previous day's drive) and it lasts for the drive there and back. Since the highway goes up an escarpment on the return trip, I typically drive between 2500 to 5000 RPM for the 1km it takes to climb the hill. It's important to note that the only sign of head gasket failure the car shows is overheating and bubbling in the reservoir. There are no streaks of coolant in the oil, the pistons are not misfiring and the exhaust smoke isn't white.

What I have tried thus far:

• New radiator and coolant reservoir
• Steal Seal head gasket repair for 4 cylinder vehicles
• Several full coolant flushes
• Running the engine with one of the radiator tubes running into a bucket to verify the coolant pump and the thermostats are working, both are.
• Running the engine with a funnel at the top of the system to remove any air
• A bottle of seafoam into the gas tank (not in the hopes to fix anything, just in a small effort to keep it running smooth after 150,000km)

There are some other issues with the car that I should mention as well:

• The check engine light has just come on after about a year of driving without issues (other than the overheating). I'm going to scan the code sometime this week to see what the issue is.
• When the CVT upshifts under heavy throttle I notice there are two delays where power bogs out for about 1-2s while the gear ratio is changing (sorry this is probably not the correct terminology)
• When driving at high RPMs after the vehicle is warmed up to operating temperature, the turbocharger whines loudly when it spins, it sounds like a supercharger. I worry this may be something to do with the bearings but I'm not too sure. I can provide a video or audio recording upon request, it seems unsettling to me.

From here, I'm really not sure what the cause of the problem is or what else to try. I've been driving the car fine for about a year, filling up the radiator every day but I would really like to make a proper effort to revive the vehicle; it seems to do everything fine despite the overheating.

Thanks in advance for any help or insight you can provide

 

[Bargeld]

Not all coolants are the same. If I recall, the juke uses a specific type of coolant. What coolant have you been using?

Did any other small hard lines get bent anywhere? It sounds like a blockage somewhere. The turbo sound reinforces this as it shouldn't whine excessively, unless there is damage or oil/coolant issues.

I like to think I'm competent with troubleshooting, but there could be any number of things happening here. Personally, I would have taken it to a dealership immediately after the initial incident. Although engine and component system design is pretty standard across vehicles, actual physical implementation and locations can vary widely. Simply put, who knows what is busted if you aren't a trained or experienced tech for that specific vehicle.

I'm sure some others with more of that specific knowledge will be along to chime in. I would get that video posted just as additional info. Otherwise good descriptions and info so far!

 

[Carspotter]

Not all coolants are the same. If I recall, the juke uses a specific type of coolant. What coolant have you been using?

Did any other small hard lines get bent anywhere? It sounds like a blockage somewhere. The turbo sound reinforces this as it shouldn't whine excessively, unless there is damage or oil/coolant issues.

I like to think I'm competent with troubleshooting, but there could be any number of things happening here. Personally, I would have taken it to a dealership immediately after the initial incident. Although engine and component system design is pretty standard across vehicles, actual physical implementation and locations can vary widely. Simply put, who knows what is busted if you aren't a trained or experienced tech for that specific vehicle.

I'm sure some others with more of that specific knowledge will be along to chime in. I would get that video posted just as additional info. Otherwise good descriptions and info so far!

Thanks for the quick reply and the useful info. I've tried Prestone Concentrate and OEM Blue both at separate times after flushing the system through the radiator plug.

I have checked to make sure none of the lines are pinched or bent before but I will look again tomorrow with a diagram of the system to make 100% sure, that's really good advice.

I did in fact take it to a dealer, but they were less than helpful. They did not diagnose the cause of the issue, and instead quoted me $12,000 for a new engine and turbocharger with install and everything else they could think of. Nobody at the dealer wanted to spend the time to look into the issue although I would have paid the diagnostic fee had they given me the option for a proper diagnosis.

I'm pretty well a beginner's beginner at troubleshooting engines and I'm totally with you that a trained professional would be way more effective in getting to the root cause of the issue.

 

[SamusFarron]

Is it possible the sensor or thermostat was damaged either during the initial collision or during the subsequent overheat event?

Also are you sure it's pumping coolant still?

 

[Carspotter]

Is it possible the sensor or thermostat was damaged either during the initial collision or during the subsequent overheat event?

Also are you sure it's pumping coolant still?

Thanks for the reply,

I thought that initially, but I did a test after flushing the system a while ago while replacing the coolant. I took off one of the hoses going into the radiator and pointed it into a bucket. I then ran the car in the driveway at mid range RPMs until the engine reached operating temperature and the thermostats opened. The thermostat did definitely open and water did flow out of the tube at a relatively high velocity. Although now that I think of it, I did not test the lower thermostat so it could potentially be possible that the coolant is flowing into the radiator but not back into the system, I will look into this.