Strange overheating problem

[Izso]

Guys,

Need to get feedback from anyone who cares to reply :

I just recently discovered a strange problem with my Myvi. Whenever it's a hot day and I get stuck in a jam or is parked with the engine on, the aircon will start to lose it's cold air and the water temp will start to go up.

If I start moving normally (>50km/h) the temp goes back to normal and aircon works again.

- Thermostat changed to a new one
- Changed to new coolant
- Radiator not blocked
- Hoses not leaking
- Radiator water level and overflow tank coolant level normal
- No obvious oil leaks from the head (head has never been removed before)
- Radiator and aircon fan moving and I think it's moving at full speed, not slower.

Car is almost 7 years old. Any ideas how to resolve this overheating problem? Or what might be causing it?

 

[huakenny]

-the fan motor is weak
-water level is insufficient
-radiator cap

these 3 normally cause the problem(either one)

 

[jerrysiow]

Hi, the water pump might weak or spoiled edi. Do you check you water pump?

 

[Izso]

-the fan motor is weak
-water level is insufficient
-radiator cap

these 3 normally cause the problem(either one)

1. Fan motor weak - how would I check if it is or not? Visual checks looks like the fan is working really well. Loud, fast and quite strong wind.

2. Water level as mentioned earlier - it's all normal

3. Radiator cap - I'll need to look into this. Forgot to replace this - thanks.

---------- Post added at 10:29 AM ---------- 6 hour anti-bump limit - Previous post was at 10:28 AM ----------

Hi, the water pump might weak or spoiled edi. Do you check you water pump?

How do check the water pump other than taking everything out? If it really is the water pump then I'm screwed. That's a lot of work to remove

 

[jerrysiow]

If technical I do not know how to check. I just know if the water pump spoiled, the water and coolant is not able to circulate the whole system like usual from radiator (cold water) go into engine and engine (hot water) go back to the radiator. Try to check thermostat, it's working fine?

 

[N/A secret]

Bro, adding a relay might solve your problem :)

 

[twistedichc]

how frequent do you service your air-cond coz 7 years of use for todays car is very2 long already coz moving parts must have wear @ tear, never service my a/c for 5 years now it cost me a lot especially for perodua cars,

 

[huakenny]

Bro, adding a relay might solve your problem :)

this is shortcut to fix problem, not a proper way.

it works too, but see owner wan proper way o short cut

 

[leynye yamin]

must be the radiator fan motor, compare your radiator fan motor spinning sound with your friend's myvi motor sound, optimum condition fan motor should be quite high pitch.

---------- Post added at 01:42 PM ---------- 6 hour anti-bump limit - Previous post was at 01:41 PM ----------

check your radiator fan fuse, might be weak and need replacement d.

 

[cvkit17]

Myvi uses ONE god damn fan only for both radiator and condenser. If there's a linkage of problem between AC and engine temp, i could only think of the fan. My wira had this problem before where the AC fan is moving, but not fast enough sometimes. Initially I thought it was functioning as it is spinning. But then the problem became worse and the fan sometimes stopped spinning. Only when the car is moving the air cond is cold.

You mentioned that it is alright when you are driving at 50kmh. Means at that speed and above only the heat passing through the radiator and condenser could dissipate through ram air. Maybe check with another myvi and see if the fan speed is actually correct?

 

[Izso]

If technical I do not know how to check. I just know if the water pump spoiled, the water and coolant is not able to circulate the whole system like usual from radiator (cold water) go into engine and engine (hot water) go back to the radiator. Try to check thermostat, it's working fine?

If the water pump is spoiled would it mean the temperature would be high all the time or only when hot? Mine is specifically only when ambient temperature is hot and only when the car is barely moving.

I've already changed the thermostat to a new one.

Bro, adding a relay might solve your problem :)

To permanantly leave the fan on? No thanks. I need some heat to warm up the engine when cold. 90% of engine wear occurs when the engine is cold, I don't want to wear it out that fast. Someone mentioned to me verbally to remove the thermostat - no thanks again.

how frequent do you service your air-cond coz 7 years of use for todays car is very2 long already coz moving parts must have wear @ tear, never service my a/c for 5 years now it cost me a lot especially for perodua cars,

Aircon serviced before. Condensor cleaned, compressor serviced (inside parts swapped out) and aircon gas refilled. Done it one time only. I normally don't touch the aircon parts unless there's a problem - learnt it the hard way when I over serviced my old car and the condensor actually broke down faster than normal. Bolts were loose and all that too.

must be the radiator fan motor, compare your radiator fan motor spinning sound with your friend's myvi motor sound, optimum condition fan motor should be quite high pitch.

check your radiator fan fuse, might be weak and need replacement d.

Side by side with my other myvi the fan sounds and looks the same. If I'm parked and idling and the temp goes up, opening the hood stops the temp from going up. I'm guessing the fan works then?

Not sure what you mean by a weak fan fuse? Or you mean weak fan? Fuse is ok since the fan is moving.

Myvi uses ONE god damn fan only for both radiator and condenser. If there's a linkage of problem between AC and engine temp, i could only think of the fan. My wira had this problem before where the AC fan is moving, but not fast enough sometimes. Initially I thought it was functioning as it is spinning. But then the problem became worse and the fan sometimes stopped spinning. Only when the car is moving the air cond is cold.

You mentioned that it is alright when you are driving at 50kmh. Means at that speed and above only the heat passing through the radiator and condenser could dissipate through ram air. Maybe check with another myvi and see if the fan speed is actually correct?

Yeah.. already checked. Side by side with a 2008 Myvi. 2004 vs 2008 side by side and fan seems to be running the same.



Like I said folks - this is a very strange problem. But I will try changing the radiator cap first, that might be stuck so pressure buildup when hot. That's actually a good idea actually - didn't think of replacing that.

 

[leynye yamin]

btw, sometimes atf cooler in front of condensor also can cause this problem, check check.

 

[Izso]

btw, sometimes atf cooler in front of condensor also can cause this problem, check check.

Yeah thought of that too. My DIY ATF cooler has already been taken out sometime ago. So now the car is pretty much stock lock and barrel.

 

[^pomen_GTR^]

u've mentioned changed coolant previously...

errr how about the inner side of radiator look a like??? full of rust or clean like new??

if full of rust might be a good reason to get the radiator flushed/cuci by the radiator shop.....

 

[LesleyAprotto]

Could be one or combinations of these problems....

1) Excessive dirt built up on your aircond condenser, next to your radiator

Can be solved by using chemical wash and rinse properly.

2) Inadequate aircond gas, shortage of gas may trigger the fan from not running in full capacity.

Can be solved by topping up some aircond gas.

3) Fan motor needs to be replaced or change new carbon, though its running but not at original speed

Can be solved by changing the carbon in the fan motor or totally replaced a new one.

Hope my suggestions helps..

 

[YYC]

If the water pump is spoiled would it mean the temperature would be high all the time or only when hot? Mine is specifically only when ambient temperature is hot and only when the car is barely moving.

I had my water pump problem with the impellers rusted away causing erratic water temperature during car at stationary and running. Regardless, it is wise to open up your water pump to check its condition since your car is 7 years old which is equal to 60 human age. My 2002 car's water pump impellers were fully rusted away when I opened it in 2011.

 

[Izso]

u've mentioned changed coolant previously...

errr how about the inner side of radiator look a like??? full of rust or clean like new??

if full of rust might be a good reason to get the radiator flushed/cuci by the radiator shop.....

The radiator doesn't have gunk or whatever, it's clean. I flush it whenever I change it and I take out the thermostat too to flush out whatever is in the block. The shops just use a high pressure water gun to flush the thing, I don't do that mainly because I don't want to break anything. If the amount of water flowing out is as much as the water flowing in, then I'm fine.

Could be one or combinations of these problems....

1) Excessive dirt built up on your aircond condenser, next to your radiator

Can be solved by using chemical wash and rinse properly.

2) Inadequate aircond gas, shortage of gas may trigger the fan from not running in full capacity.

Can be solved by topping up some aircond gas.

3) Fan motor needs to be replaced or change new carbon, though its running but not at original speed

Can be solved by changing the carbon in the fan motor or totally replaced a new one.

Hope my suggestions helps..

1. No. As mentioned only serviced once and I keep everything clean
2. No. See #1.
3. Possible but not obvious since side by side with another Myvi the fan appears to be running equally fast.

---------- Post added at 08:17 AM ---------- 6 hour anti-bump limit - Previous post was at 08:15 AM ----------

I had my water pump problem with the impellers rusted away causing erratic water temperature during car at stationary and running. Regardless, it is wise to open up your water pump to check its condition since your car is 7 years old which is equal to 60 human age. My 2002 car's water pump impellers were fully rusted away when I opened it in 2011.

Sigh. This was what I was hoping to avoid. It's a b*tch to remove the water pump in a Myvi. I'll try the radiator cap suggestion first then swap out the water pump as a last resort. My temp is constant throughout the day and these last few days it's been cold and wet so the temp has been been fantastic too. The problem only occurs on hot days and when the car is close to idle and/or moving very slowly.

 

[arturo]

during idle...try getting the temperature of the AC condensor...if its super hot, means its not dissipating heat enough before recirculating the gas back to the cooling coil. reasons? could be compressor dying since u said yr rad n condensor's fins are both clean. simply check ac gas pressure to know how healthy the compressor is. if compressor is healthy, then it could mean that heat excessive heat from the rad is getting transmitted to the ac condensor which could mean the rad/ac condensor fan not working up to par.

for the rad, is there a big temp difference between the inlet hose vs outlet hose? the outlet hose is supposed to be only warm and u are supposed to be able to hold onto the hose without any pain...like warm bath water...but the inlet hose is supposed to be close to boiling...if both hoses feel about the same (really hot), then either water pump not pumping water thru the rad fast enuff or rad no dissipating heat fast enuff....

also...did u check yr ac/alternator/water pump belt? any slippage? i know a guy who drove his myvi with a broken belt for a full day without knowing it...he only found out when his battery died haha

i had the same problem with my ac not being cold during idle...my mech kept telling me that the condensor fan is not working up to par...but i kept arguing that it was still strong as the wind is strong and no difference to "feel" compared to other same car with cold AC. one day...i made a bet with him and said change la..if still not cold then he need to belanja me lunch...if it works, then i belanja him lunch. i ended up paying for his lunch.

 

[DanzEterna]

agree with arturo, could be the aircond fan.....

---------- Post added at 10:59 AM ---------- 6 hour anti-bump limit - Previous post was at 10:57 AM ----------

get your wife or someone to sit inside the car, with the engine running & aircond on,
once it gets hot & temp increases, spray water on the condensor...if the aircond feels cooler & temp decreases, confirm its the fan.

 

[vr2turbo]

Bro. Izso,
You can open radiator cap when cold, then start engine and bring up to operating temperature. That is when thermostat open and you can see the water movement from radiator cap hole to see if water pump is working...

But usually when idling heat up, is mostly fan problem....