engine temp goes up when running air conditioning

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ghadley_00@yahoo.com - 01 Jul 2006 03:09 GMT

Hi,

I have a 2000 Mazda 626 which recently began overheating when I run the
air condition. Without running the AC the car has been able to tolerate
2+ hours of stop and go traffic while maintaining the engine temp at
near mid gauge *around 3.5 the temp start goign up near top gauge, but
then came down running hor air into the cabin). The coolant levels
seems ok at present as well. Any suggestions on what could be wrong /
things I could do? Would degreasing the engine possibly help? Any
particular parts of the engine I should look for debris?

Thanks,

George

ghadley_00@yahoo.com

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Don - 01 Jul 2006 15:15 GMT

>Hi,
>
>I have a 2000 Mazda 626 which recently began overheating when I run the
>air condition.

If this happens at low speed check the fans under the hood.

> Without running the AC the car has been able to tolerate
>2+ hours of stop and go traffic while maintaining the engine temp at
>near mid gauge *around 3.5 the temp start goign up near top gauge, but
>then came down running hor air into the cabin). The coolant levels
>seems ok at present as well. Any suggestions on what could be wrong /
>things I could do? Would degreasing the engine possibly help?

Highly unlikely.

Don
www.donsautomotive.com

>Any particular parts of the engine I should look for debris?
>
[quoted text clipped - 3 lines]
>
>ghadley_00@yahoo.com

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Kevin Bottorff - 01 Jul 2006 16:33 GMT

>>Hi,
>>
[quoted text clipped - 22 lines]
>>
>>ghadley_00@yahoo.com

If the eng fans are working ok then a new rad or flush or rod out is in
order. KB

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Thunder Snake #9
"Protect" your rights or "lose" them.

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Scott Dorsey - 03 Jul 2006 15:18 GMT

>I have a 2000 Mazda 626 which recently began overheating when I run the
>air condition. Without running the AC the car has been able to tolerate
[quoted text clipped - 4 lines]
>things I could do? Would degreasing the engine possibly help? Any
>particular parts of the engine I should look for debris?

The engine temperature is always going to rise when you turn the AC on.
Your problem is that it's rising too much, because the cooling system
is already marginal.

First thing I'd do is look inside and see what the inside of the radiator
is like. Is it nice and clean, or is it plugged with all kinds of white
deposits?

Second thing is I'd pull the thermostat and make sure it's not damaged.
Might as well just replace it whether or not it's good, while you have
the cover off. You'll have to replace the thermostat gasket anyway.
It's only a couple bucks.

If it looks clean inside and the thermostat is good, odds are you are
having a water pump issue. But I'll make a bet that you have some clogging
somewhere as well and that it doesn't look so clean.

There are various chemical flushes that will remove deposits from the
cooling system. If you try one, you should realize that some radiators
are held together only by the deposits and they may start leaking like
mad after they have been flushed out. But this is a sign they should
probably have been replaced years ago anyway.

Have you been changing your coolant every year like the manual suggests?
--scott

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"C'est un Nagra. C'est suisse, et tres, tres precis."

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ghadley_00@yahoo.com - 04 Jul 2006 07:59 GMT

> >I have a 2000 Mazda 626 which recently began overheating when I run the
> >air condition. Without running the AC the car has been able to tolerate
[quoted text clipped - 12 lines]
> is like. Is it nice and clean, or is it plugged with all kinds of white
> deposits?

I am not sure where you are suggesting I look - from what I can see by
looking down at the radiator while standing in front of the car with
the hood open I don't see any obvious deposits.

> Second thing is I'd pull the thermostat and make sure it's not damaged.
> Might as well just replace it whether or not it's good, while you have
> the cover off. You'll have to replace the thermostat gasket anyway.
> It's only a couple bucks.

Had the thermostat replaced twice in the last 6 months.

> If it looks clean inside and the thermostat is good, odds are you are
> having a water pump issue. But I'll make a bet that you have some clogging
[quoted text clipped - 7 lines]
>
> Have you been changing your coolant every year like the manual suggests?

Have been having the coolant changed at my local oil change location
once per season as they had recommended (so about 1-2 times per year).
Is the coolant flush they do at placeslike valvoline/ lube express the
same as the chemical flush you are referring to, or is there something
else I should try?

Thanks for the recommendations.

Best wishes,

George

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ray - 18 Jul 2006 03:04 GMT

> Hi,
>
[quoted text clipped - 12 lines]
>
> ghadley_00@yahoo.com

are your fans working? Not sure about Mazdas, but it seems common that
once you turn the AC on, the electric fan comes on.

Why does it do this? The condensor is mounted in front of the radiator,
and when you turn on the A/C, it dumps the heat out... right in front of
the radiator, and if your cooling system is marginal (and it sounds like
yours might be) it can't hack the extra load and starts overheating.

Ray

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