Overheating ONLY when Lights are on? 11/94 V6 Astina

Zaggy · 04-07-2012, 12:13 AM

GDay guys,

I have a curly one here. I have a 11/94 V6 Astina which has this bizarre intermittent overheating issue. During the day, driving round without lights, the car is fine; the temperature gauge sits steady at about 25-33% its range. However, when driving with lights on, the car experiences noticable temperature fluctuations, suddenly increasing (to 66% or more) then dropping a little (to about 50%) and going a bit all over the place. At times acceleration, or sitting in 4th at about 3000RPM will help bring the temperature down (to about 40-50%), at other times nothing will help; and on occations, things will get to the point where I have had coolant coming out of the overflow when things have gotten too hot.

I beleive things are actually getting hot (as a result of the overflow when things got too hot).

Since the issue began, I have had my mechanic do all the radiator hoses (as one split when things got warm one night - and the insides didn't look great) and I've had a sparky look it over for obvious things (replacing a battery terminal and sorting out a few small ground issues); initially I thought this had sorted things out, but a bit over a week later and the issue has returned. Radiator fans are both switching on and off properly (or so it seems) as well.

Because it ONLY happens when the LIGHTS are on, logic would suggest some sort of electrical issue, but what exactly would cause this?? (My background is Air-cooled VW's, so obviously liquid cooling systems are something I have NEVER played with). In otherwords, what component/s of the cooling system regulate heat using an electrically driven sensor or something?

Do these things have some sort of electrical thermostat or switch somewhere, that if not functioning correctly, would cause things to heat up?

Any advice or suggestions or etc, would be welcomed. If ppl need more info, just ask

Cheers

Dan

04-07-2012, 12:13 AM	#1
Zaggy Junior Member Join Date: Jun 2012 Location: Newcastle, Au Car: Mazda Astina V6 Posts: 18	Overheating ONLY when Lights are on? 11/94 V6 Astina GDay guys, I have a curly one here. I have a 11/94 V6 Astina which has this bizarre intermittent overheating issue. During the day, driving round without lights, the car is fine; the temperature gauge sits steady at about 25-33% its range. However, when driving with lights on, the car experiences noticable temperature fluctuations, suddenly increasing (to 66% or more) then dropping a little (to about 50%) and going a bit all over the place. At times acceleration, or sitting in 4th at about 3000RPM will help bring the temperature down (to about 40-50%), at other times nothing will help; and on occations, things will get to the point where I have had coolant coming out of the overflow when things have gotten too hot. I beleive things are actually getting hot (as a result of the overflow when things got too hot). Since the issue began, I have had my mechanic do all the radiator hoses (as one split when things got warm one night - and the insides didn't look great) and I've had a sparky look it over for obvious things (replacing a battery terminal and sorting out a few small ground issues); initially I thought this had sorted things out, but a bit over a week later and the issue has returned. Radiator fans are both switching on and off properly (or so it seems) as well. Because it ONLY happens when the LIGHTS are on, logic would suggest some sort of electrical issue, but what exactly would cause this?? (My background is Air-cooled VW's, so obviously liquid cooling systems are something I have NEVER played with). In otherwords, what component/s of the cooling system regulate heat using an electrically driven sensor or something? Do these things have some sort of electrical thermostat or switch somewhere, that if not functioning correctly, would cause things to heat up? Any advice or suggestions or etc, would be welcomed. If ppl need more info, just ask Cheers Dan