Ongoing 2015 Q50s overheating issues

[Pew]

Hi folks,

So my lady friend has a 2015 Q50s awd with the 3.7 V6. Her radiator got replaced by a shop because it developed a bad leak. They also did the thermostat and radiator caps at the same time.

Now her car still kind-of overheats. When she drives ~40min drive over, her fans will be on the max speed by the time she gets here and the coolant temp gauge will sometimes go past the halfway mark when she's down the street. The heat will be coming out the inside vents as well, even if it's set to a mild temp.

Coolant does disappear slowly, going from max to low requiring a top off once a month. I do not notice any odd smell or smoke pur the tailpipes.

The top radiator hose is hot and the lower hose is room temp at worst.

Am I missing anything?

 

[rijndael]

Check it for a head gasket leak. It may have overheaded and warped something.

I'd also check out the water pump.

 

[JavierH19]

Am I missing anything?

Yeah a stealership to dump it at.

 

[Pew]

Check it for a head gasket leak. It may have overheaded and warped something.

I'd also check out the water pump.

Those were the two that I thought of too, but no way to check without replacing the part. I'm thinking of doing the water pump next.

Yeah a stealership to dump it at.

That's what I said too!!! She just paid it off also and then the issues started up.

 

[Trav]

Did the engine ever overheat when it had the leaking radiator? I would do a pressure test on the radiator to see if it drops even slightly over 20 minutes, you can try a blue fluid test to check for hydrocarbons getting in the cooling system.
That car uses a very expensive OE radiator, I seriously doubt the shop used an OE ($600-800 online dealer price) but probably used a parts store cheap radiator and no OE thermostat which may be a problem. If no HG issues I would try a new OE thermostat and vacuum fill it to insure there is no air lock in the system.

This is fluid tester, it is not the be all and end all but if there is a combustion leak into cooling system it works okay, a pressure test will detect external weeping and leaks. Coolant dye can be a big help if it fails the pressure test.

https://www.harborfreight.com/combustion-leak-detector-64814.html

Big $$$ OE radiator.

https://www.infinitipartsdeal.com/parts/infiniti-radiator-asmy~21460-4gb0a.html

 

[dishdude]

Did the engine ever overheat when it had the leaking radiator?

We all know the answer to that

 

[Oliveoil2]

Sounds like there is air in the system and it just needs to be bled.

 

[ls1mike]

Is it just heating up at idle or running down the road?

 

[Pew]

I forgot to mention the car does have around 170k miles. The serpentine belt melted and ripped itself apart after an idler pulley seized up and the same shop was able to clean up the melted rubber off the pullies with no extra charge and install a new one. I give them big credit for this - I thought they were going to pass on it.

Did the engine ever overheat when it had the leaking radiator? I would do a pressure test on the radiator to see if it drops even slightly over 20 minutes, you can try a blue fluid test to check for hydrocarbons getting in the cooling system.
That car uses a very expensive OE radiator, I seriously doubt the shop used an OE ($600-800 online dealer price) but probably used a parts store cheap radiator and no OE thermostat which may be a problem. If no HG issues I would try a new OE thermostat and vacuum fill it to insure there is no air lock in the system.

This is fluid tester, it is not the be all and end all but if there is a combustion leak into cooling system it works okay, a pressure test will detect external weeping and leaks. Coolant dye can be a big help if it fails the pressure test.

https://www.harborfreight.com/combustion-leak-detector-64814.html

Big $$$ OE radiator.

https://www.infinitipartsdeal.com/parts/infiniti-radiator-asmy~21460-4gb0a.html

Thanks for the link, I'll try out that leak detector. It overheated pretty bad to limp mode several times. The shop did use a parts store radiator and thermostat. She brought her car back and they said they retested it and the thermostat was okay. She told me they also said they found a small coolant leak somewhere at the back of the engine bay but no more details on that - I have not found a leak myself nor have we seen a stain in the garage.

My plan is if the fluid test passes, to redo the thermostat, and then the water pump after.

Is it just heating up at idle or running down the road?

It'll heat up normally at idle. It seems like it wants to overheat after getting off the highway and not on local roads.

 

[ls1mike]

I forgot to mention the car does have around 170k miles. The serpentine belt melted and ripped itself apart after an idler pulley seized up and the same shop was able to clean up the melted rubber off the pullies with no extra charge and install a new one. I give them big credit for this - I thought they were going to pass on it.



Thanks for the link, I'll try out that leak detector. It overheated pretty bad to limp mode several times. The shop did use a parts store radiator and thermostat. She brought her car back and they said they retested it and the thermostat was okay. She told me they also said they found a small coolant leak somewhere at the back of the engine bay but no more details on that - I have not found a leak myself nor have we seen a stain in the garage.

My plan is if the fluid test passes, to redo the thermostat, and then the water pump after.



It'll heat up normally at idle. It seems like it wants to overheat after getting off the highway and not on local roads.

Man, that sounds water pumpish to me. Like it just isn't pushing enough fluid at idle.

 

[Pew]

Man, that sounds water pumpish to me. Like it just isn't pushing enough fluid at idle.

At 170k, it's probably a good idea to do it anyways. I need to find an under tray for her car to. The shop threw her previous one out and now the engine bay is filthy.

 

[97prizm]

Hi folks,

So my lady friend has a 2015 Q50s awd with the 3.7 V6. Her radiator got replaced by a shop because it developed a bad leak. They also did the thermostat and radiator caps at the same time.

Now her car still kind-of overheats. When she drives ~40min drive over, her fans will be on the max speed by the time she gets here and the coolant temp gauge will sometimes go past the halfway mark when she's down the street. The heat will be coming out the inside vents as well, even if it's set to a mild temp.

Coolant does disappear slowly, going from max to low requiring a top off once a month. I do not notice any odd smell or smoke pur the tailpipes.

The top radiator hose is hot and the lower hose is room temp at worst.

Am I missing anything?

Bad or swollen hose maybe? Much easier to repair than a water pump or head gasket.

 

[Pew]

Bad or swollen hose maybe? Much easier to repair than a water pump or head gasket.

I may replace the upper and lower hoses at the same time too while I'm down there.

 

[97prizm]

I may replace the upper and lower hoses at the same time too while I'm down there.

Check to see if it needs the system pressurized to bleed it. I know that EJ25 Subarus are a pain to bleed.

 

[Pew]

So another issue with her car, she now has a P2096. She said the code came up after I changed her spark plugs (denso, OEM) and had the driver's side catalytic converter changed after for an unrelated issue and I just changed the driver rear O2 sensor. Her car seems to be sucking up more gas than normal as well, down nearly 5mpg. Anything I should check? I don't have the ability to test voltages or do a leak down test either.

 

[Exhaustgases]

One guy claims air leakage around the airfilter box on a tube video, doesn't make sense but?
Fuel trim? O2 Sensor voltage conditions?

Check reported temp of the engine temp sensor with a real time scan tool.

 

[Pew]

So I figure I will update this; Today I changed the thermostat from a motorad that the shop put it to an oem one. I also found a small leak at the heater core inlet hose so I changed that as well. Once my friend got home, she said she noticed the fan isn't kicking in on high once she got to her neighborhood and the temp gauge didn't move at all. Finger's cross this is it.

 

[siriusc1024]

So I figure I will update this; Today I changed the thermostat from a motorad that the shop put it to an oem one. I also found a small leak at the heater core inlet hose so I changed that as well. Once my friend got home, she said she noticed the fan isn't kicking in on high once she got to her neighborhood and the temp gauge didn't move at all. Finger's cross this is it.

Well, I've had a similar problem happen. Changed coolant, thermostat, water pump. Wouldn't overheat parked and running, but after ~hr driving it would. Very confusing.

Turned out to be a bad torque converter.

Looks like the radiator for your vehicle might have an integral trans cooler. Maybe the shop did something wrong when a new one was installed or coincidence? Fluid level ok? Transmission problems can cause overheating.