2003 Lexus IS 200 Loosening water overflow tank

MBARTIS200

MEMBER
2003 LEXUS IS 200
2.0L
6 CYL
RWD
MANUAL
90,000 MILES

Hi, I have a lexus is200. Aslong as the overflow tank is full it run fine and stays at temp, but when Check the overflow tank after going anywhere it's almost emty. I have plugged it in and it come up with "engine coolant temp malfunction" while plugged in I noticed that them temp sat at 70-80c but when ignition is off it drop to -50 any ideas where to start. Engine temp sensor, thermostat? Many thanks Matt.

5 Replies

JACOBANDNICKOLAS

MECHANIC
108,164 POSTS

Where is the coolant going? Is it leaking? Is there white smoke from the exhaust? Have you checked the engine oil to see if it is mixing with it?

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Wednesday, May 7th, 2014 AT 6:46 PM

MBARTIS200

MEMBER
3 POSTS

It's not mixing with oil I don't think no mayo on oil cap and water is clean in radiator. I can't see any leaks on pipes only small amounts off water under the overflow pipe, I did notice that the fan do kick in sometime even when not warm?

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Thursday, May 8th, 2014 AT 1:37 AM

JACOBANDNICKOLAS

MECHANIC
108,164 POSTS

How much coolant do you lose each time you drive it?

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Thursday, May 8th, 2014 AT 5:04 AM

MBARTIS200

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3 POSTS

Just over 500ml, I tried an airlock test this morning and seem to have help using little water after 10 mile run, Iv also replaced the pressure cap I the radiator as it didn't look great. Do you think a faulty pressure cap could push the pressure in expansion tank and down overflow pipe as the radiator always seem full. Thanks matt

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Thursday, May 8th, 2014 AT 5:34 AM

JACOBANDNICKOLAS