Heater blowing cold air

AUBZ44

MEMBER
2001 VOLKSWAGEN GOLF
1.9L
TURBO
2WD
MANUAL
162,000 MILES

Hi, I have a mk4 golf GT tdi pd 130. The heaters are blowing cold air through. I changed the thermostat but not the sensor. I topped up with new coolant. Was just wondering if I do a full coolant system flush including the radiator if this will solve the problem?

Monday, December 7th, 2020 AT 1:06 AM

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

I suspect this is a blend door actuator issue and not necessarily a coolant issue. It could be a heater core but I would start with the actuator and make sure that is functioning properly first.

Here are guides that will help with this:

https://www.2carpros.com/articles/car-heater-not-working

https://www.2carpros.com/articles/replace-blend-door-motor

Then if the heater core is still an issue, you will not be able to flush it. These are called multipassage units which means if there is a restriction or a blockage it will just find another path and not remove the blockage. If that is the issue then you will have to replace it. However, I doubt that is the cause so let's check this first.

Let me know what questions you have. Thanks

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Monday, December 7th, 2020 AT 8:31 AM