03 Camry engine runs cold - problem persits after thermostat (3 times) and waterpump replacement as well

Tiny
M_KAR
  • MEMBER
  • 2003 TOYOTA CAMRY
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 65,000 MILES
Hi

My car is acting weird - the temperature gauge drops down gradually when I turn the heater on in cold weather (summers are OK). This problem has been nagging me for the last 3 winters! The car never overheats and also blows good heat when it's warmed up! The thermostat and water pump were replaced last winter. In fact, I replaced the thermostat 3 times in the last 3 years! It's getting cold in here and I've to wait until the temperature needle hits the right temperature before I turn the heat on. This takes a good 5 minutes! Also, the coolant seems to be reducing slowly. I've already spent close to $1000 on this problem. Greatly appreciate your response.
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Thursday, December 9th, 2010 AT 2:54 AM

7 Replies

Tiny
KHLOW2008
  • EXPERT
When coolant is depleting from the radiator, there must be a minor leak somewhere. A pressure test should indicate where the leak is coming from. Visually, look out for signs of oxidation, especially around hose joints.

As to the heating problem, it could be due to partially clogged coolant passages. Have you tried to back flush the heater core?

Actually 5 minutes is the minimum time required for the coolant to get up to operating temperature when starting from cold. If heater runs well after 5 mins and do not have any other issues, I don't think there is anything you can do about it, except maybe to install a heater plug for winter use.
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Thursday, December 9th, 2010 AT 2:12 PM
Tiny
M_KAR
  • MEMBER
Thanks much for your reply. What is back flush? Will the technician understand the term? Please also let me know how much would it cost (just a ball park). Actually, the car taking 5 mins is not a problem - my concern is about the drop in temperature when I turn the heater on in the first 5 mins. My brother has a 99 camry with close to 200k miles and never had this problem.
Thanks again for your reply.
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Thursday, December 9th, 2010 AT 2:32 PM
Tiny
KHLOW2008
  • EXPERT
Back flush means to disconnect the heater hoses and using a low pressure hose to reverse the flow to flush out whatever that may be clogging that heater core. The technician should understand if you tell him to back fluch the heater core.

If the heater core is partially clogged, the heating efficient would be affected.
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Thursday, December 9th, 2010 AT 2:52 PM
Tiny
M_KAR
  • MEMBER
I took my car to an auto repair shop. They checked and didn't find any leaks. They think it could be the temperature sensor - they are not sure. They didn't have the part in hand, so I'll have to get it changed next week. Do you think the temperature sensor might be causing this problem?
Thanks.
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Saturday, December 11th, 2010 AT 7:15 PM
Tiny
KHLOW2008
  • EXPERT
Which sensor are they talking about?

After reviewing your question, I realised I had missed out on one point.

You mentioned the temperature gauge dropping when the heater is turned on and that means the heating efficiency is reduced. This occurs only when operating temperature is not achieved.

After engine has reached running temperature, does the problem occurs?

When thermostat was replaced, were they OEM and of the correct type and specifications?

The symptoms indicates an overcooling condition when the heater is turned on and this should not be the heater core problem.

Is your vehicle with automatic climate control or manual A/C control?
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Sunday, December 12th, 2010 AT 2:30 AM
Tiny
M_KAR
  • MEMBER
Thanks much for understanding my problem, KHLow2008. Every time I take my car to a dealer and explain this problem, they would never believe me. They keep repeating that it's ok for the engine to run a little cold or change something like thermostate/water pump!

No, once the engine reaches the running temperature, the problem goes away. Yes, the thermostat are OEM (toyota). Vehicle has manual A/C control. Please help me out. Thanks again.
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Sunday, December 12th, 2010 AT 2:47 AM
Tiny
KHLOW2008
  • EXPERT
As the heating efficiency is normalised after the operating temperature is achieved, the system seems to be working correctly.

When the heater is not used, the coolant in heater core is not circulating due to the heater valve being closed. The volume of coolant that needs to be heated up is lower and this would shorten the heating up time. When heater is used, the additional coolant from the heater core has to be heated up as well and that is the reason you are noticing the drop in engine temperature when heater is turned on.

The system seems to be working correctly and unless the heating efficiency is below expectations at normal engine operating temperature, I don't think any repairs is going to help.

The only thing you can do to get the heat working under extreme cold weathers is to run the engine for a few minutes before turning the heater on.
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Sunday, December 12th, 2010 AT 5:30 AM

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