Maximum heater temperature too low

1996 CHRYSLER NEW YORKER
95,000 MILES • 3.5L • 6 CYL • 2WD • AUTOMATIC
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CNYGERMANY
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Hello,

my HVAC is working fine so far but the maximum heater temperature is too low. Depending on the outdoor temperature the heater gives not more than approximately 15° Celsius. Temperature control works fine from hot to cold and reverse, A/C works too.

Ran the auto diagnostic procedure as explained here by KHLOW2008. Error code is 34 - Engine Temperature Message Not Received.

How to proceed?

Thanks!
May 9, 2021 at 2:28 AM
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ASEMASTER6371
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Good morning,

This sounds like it could be a thermostat stuck open not allowing the engine to heat up to the proper temperature. That will give you reduced heat from the system.

The other possibility is the heater core. It may be clogged with debris. You would need to remove both hoses from the firewall and use a garden hose to flush the core back and forth. Then hook the hoses back up and fill the coolant and retest.

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

The intake manifold needs to be removed to access the thermostat. I attached the procedure for you below.

https://www.2carpros.com/articles/replace-intake-manifold-gasket

Roy
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May 9, 2021 at 8:06 AM
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CNYGERMANY
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Thank you for your suggestions! Thermostat is right, engine temperature is proper. Checked it using OBDII diagnostic device. Next step seems to be flushing the core as you suggested. I will report. Regards!
May 11, 2021 at 1:13 AM
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ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
May 11, 2021 at 3:10 AM