Fluctuating Car Temperature (Towards the H side)

[Mitevo7]

Dear All,

My 10 years old Lancer CY4A is giving me flucttouating temperature issue, the temperature gauge shows towards the high side and will return to normal at random timing. The engine still takes normal time to reach operating temperature, and fluctuations can start without any given symptoms. Here's what i have gathered so far:

1.) Head gasket - unlikely because my coolant in radiator is always full even early in the morning, no white exhausts smoke nor weird engine performance issue
2.) Water pump - mild chances that its faulty, because it was replaced 2 years ago with other pulleys as well. It does not leak any coolant and it's extremely rare that a water pump is damaged without leaking coolant
3.) Thermostat - Very high chances, the thermostat has never been replaced for the past 10 years, 230k KMs mileage. From my experience, thermostat can be either stuck open or stuck closed, intermittent issue is also possible but not very frequent.

Any other possible issues that i may missed out?

P/S: Last week has been very awesome, 2 of my main cars having same temperature issue, the other one has blown fan motor which is under repair. In this very hot weather, all of our cars' cooling systems are working overdrive, so please get your cooling systems checked and top up coolant, you don't want to end up like me. 2 cars in a row.

Thanks,
Ken

 

[vr2turbo]

Why not change the thermostat first and check from there.......

 

[alcyon]

Could be a bad water temp sensor. Just replace it , isnt very expensive.

 

[gunnerzz]

Happened to me on my waja (Renault F4P engine). Turns out just bad grounding. Temperature is normal all the time. Was scared at first thinking the worst...expensive repair bill.

 

[sanekit]

best to try get another external gauge and see if it fluctuates or not. if so, then your temp gauge problem.

 

[Izso]

One of the things also worth checking is the radiator cap. If it's not opening/closing properly it'll cause problems too. Cheap replacement

 

[Mitevo7]

Why not change the thermostat first and check from there.......

You are right, the 230k mileage thermostat has reached its limit, we tested my old one vs new one, the old is significant opens slower and lesser in gap, water pump has no physical symptoms (thank god !) and should not need replacement . We are replacing the thermostat first and monitor from there.

Happened to me on my waja (Renault F4P engine). Turns out just bad grounding. Temperature is normal all the time. Was scared at first thinking the worst...expensive repair bill.

Grounding is reworked for months and did not see any weird symptoms, so it should pass.

One of the things also worth checking is the radiator cap. If it's not opening/closing properly it'll cause problems too. Cheap replacement

Well said, however no physical damages or spilt from the radiator cap side so it should be safe, does it worth upgrading to hold more PSI ?

Thanks,
Ken

 

[Mitevo7]

Could be a bad water temp sensor. Just replace it , isnt very expensive.

No fault code detected, i heard from LGT club folks that it will should CEL if one of any sensors went wrong on the engine side.

Thanks,
Ken

 

[gunnerzz]

No fault code detected, i heard from LGT club folks that it will should CEL if one of any sensors went wrong on the engine side.

Thanks,
Ken

In general, For water temperature display purpose ecu will take whatever reading from the sensor as good. Error code will come out if the sensor is totally kaput or not detected.
Anyway, in cars with ecu any rise in temperature above the set limit will trigger the radiator fan ON. Does this happened when your temp rises?

 

[Mitevo7]

In general, For water temperature display purpose ecu will take whatever reading from the sensor as good. Error code will come out if the sensor is totally kaput or not detected.
Anyway, in cars with ecu any rise in temperature above the set limit will trigger the radiator fan ON. Does this happened when your temp rises?

Yes the fan is working very hard when the temp raises above normal temperature, which in long term is very unhealthy as it will shorten the lifespan of the fan motor, although the symptoms only show very short period of time, but i am still worried the fan motor might be affected.

Thanks,
Ken

 

[Izso]

Well said, however no physical damages or spilt from the radiator cap side so it should be safe, does it worth upgrading to hold more PSI ?

Nah, no point uprating the PSI. It just means it's holding in more heat - which is what you don't really want.

Yes the fan is working very hard when the temp raises above normal temperature, which in long term is very unhealthy as it will shorten the lifespan of the fan motor, although the symptoms only show very short period of time, but i am still worried the fan motor might be affected.

Thanks,
Ken

time for an upgrade of fans! SPAL!

 

[vr2turbo]

You are right, the 230k mileage thermostat has reached its limit, we tested my old one vs new one, the old is significant opens slower and lesser in gap, water pump has no physical symptoms (thank god !) and should not need replacement . We are replacing the thermostat first and monitor from there.
Thanks,
Ken

Hope is thermostat issue, the slower and lesser gap could be the problem. Hope all is well......

 

[Mitevo7]

Hope is thermostat issue, the slower and lesser gap could be the problem. Hope all is well......

Just got it changed, the temp seems stablized like before but i haven't have time to take it for a hardcore run. For now i will be hooning my 1J until i have time to retrieve the car

Thanks,
Ken

 

[Mitevo7]

Hi All,

I am replacing the radiator with a racing aluminium one due to the stock radiator finally clocked out itself. As we open up the inside, this is how it looks like in the images.

Is it consider very clogged ? My mechanic said its pointless to clean it anyway and there's broken pieces inside the radiator as well.

Thanks,
Ken

 

[gunnerzz]

Hi All,

I am replacing the radiator with a racing aluminium one due to the stock radiator finally clocked out itself. As we open up the inside, this is how it looks like in the images.

Is it consider very clogged ? My mechanic said its pointless to clean it anyway and there's broken pieces inside the radiator as well.

Thanks,
Ken

Can still be use, just require servicing.
What broken pieces is there? i can see only oxidation.

Radiator servicing shop will run through a long small piece of steel or coppler into the water line to clear the line, assemble, then test for leak.

 

[Mitevo7]

Can still be use, just require servicing.
What broken pieces is there? i can see only oxidation.

Radiator servicing shop will run through a long small piece of steel or coppler into the water line to clear the line, assemble, then test for leak.

The broken pieces are actually under neath the radiator, there's leak below and radiator servicing shop said eventhough they can fix it but it will not perform good.

What's the take for this?

Thanks,
Ken

 

[Mitevo7]

Just got it changed, the temp seems stablized like before but i haven't have time to take it for a hardcore run. For now i will be hooning my 1J until i have time to retrieve the car

Thanks,
Ken

On side note, after replacing Thermostat, within 30 minutes of driving, the temperature starts creeping to H, therefore we decided to open up the radiator and sees the inside are crappy. Replacing radiator to a racing aluminium one.

Thanks,
Ken

 

[vr2turbo]

The broken pieces are actually under neath the radiator, there's leak below and radiator servicing shop said eventhough they can fix it but it will not perform good.

What's the take for this?

Thanks,
Ken

Radiator shop say no good, then better change. Anyway, looking at the picture the top look ok......

 

[Izso]

On side note, after replacing Thermostat, within 30 minutes of driving, the temperature starts creeping to H, therefore we decided to open up the radiator and sees the inside are crappy. Replacing radiator to a racing aluminium one.

Thanks,
Ken

Do you have a water temp meter? Maybe would be good to have one

 

[^pomen_GTR^]

Hi All,

I am replacing the radiator with a racing aluminium one due to the stock radiator finally clocked out itself. As we open up the inside, this is how it looks like in the images.

Is it consider very clogged ? My mechanic said its pointless to clean it anyway and there's broken pieces inside the radiator as well.

Thanks,
Ken

yes very2 clogged radiator from the looks of it