Overheating

KHA325

MEMBER
2013 VOLKSWAGEN PASSAT
2.5L
5 CYL
2WD
MANUAL
127,000 MILES

So this has been ongoing. First, about seven months ago, started blowing cool air on the passenger side. According to what I have read, this is a partial heater core blockage. Regardless, the car was running fine no problems. About five months ago it started heating up after getting off the highway. Needle would go past halfway but still not bad. Dealer recommended a coolant flush. Sadly that did not help. Testing shows it getting up to 225-230 Fahrenheit. Changed out the thermostat, no difference. Fans kick on so I do not think that is the issue. Not throwing any codes and not loosing coolant or oil. Only thing I can think of is the water pump or temperature sensor. Would a partially blocked heater core cause this? Any suggestions?

Thursday, February 8th, 2018 AT 12:05 PM

3 Replies

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

There is only one heater core, so the loss of heat to one side of the vehicle is not a plugged heater core. Now, if it does not overheat at highway speeds, that tells me (if the fans are turning on in traffic or stopped) a higher engine RPM is allowing enough coolant to flow.

I need you to review the 2CarPros' article below. It walks you through all the possible problems. Keep in mind, you have already done a lot. However, I think if you start at #5, it will be helpful. Review it and let me know what you find.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

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Thursday, February 8th, 2018 AT 7:02 PM

JIS001

MECHANIC
3,412 POSTS

I would say the radiator could be clogged since you are not overheating when cruising at high speeds.

VW uses a plastic propeller on there water pumps that do fail but the symptoms it will be is like having a thermostat closed shut and the fans will not kick on. So a flush would not do you any good.

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Thursday, February 8th, 2018 AT 10:49 PM

JACOBANDNICKOLAS