Fluctuating Car Temperature (Towards the H side)

Mitevo7

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Mitevo7

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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
 

gunnerzz

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gunnerzz

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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.
 

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Izso

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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
 
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Mitevo7

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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

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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

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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

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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
 

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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!
 

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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......:driver:
 
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Mitevo7

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

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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
 

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gunnerzz

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gunnerzz

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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

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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

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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
 
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vr2turbo

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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......
 

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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
 

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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
 

vr2turbo

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Do you have a water temp meter? Maybe would be good to have one
My wife's forester don't have as with newer cars, just the blue and red light....lol
Will try out water temp using OBD2 with phone app, done by some already.....:driver:
 

Mitevo7

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


time for an upgrade of fans! SPAL!
You think i print bank notes ah ?? :dontknow:

-Ken-
 

Mitevo7

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Do you have a water temp meter? Maybe would be good to have one
I am relying on the stock temp gauge, which is pretty good to tell me whether the engine cooling system is compromised. Would want to have one for the 31JZ though, that one is more crucial.

Thanks,
Ken
 

Mitevo7

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yes very2 clogged radiator from the looks of it
That's what i thought too, i have been draining coolant every 2 years and yet this still happened. I need to ensure my coolant is drained every year then to ensure my new radiator does not go bonkers.

Thanks,
Ken
 

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Not too sure about your car specifically, but generally Mitsubishi have a 2-wire temp sensor for the ecu, and the sensor for the meter is actualy a seperate 1-wire sensor, and the gauge is calibrated in such a way that it will show 'normal' over a wide range of temperatures, and will only shoot to H suddenly when it passes a certain temperature, and because the sensor is only 1 wire, the accuracy of the gauge also depends on the chassis and engine grounding. So basically, the stock temp gauge is generally a decent enough indication for overheat, but if you want to be really sure, it is best to install a seperate temperature gauge. Also usually the stock temp sensor detects the water temp at post radiator entering the engine, and not the temp of the water exiting the engine entering the radiator. If you install your own gauge, it will be on the top hose which means you will be reading the higher temperatures of the water exiting the engine entering the radiator.

But then again, looks like you had found your culprit, so just change the radiator and see how la, but if you still experience the same issue again, check your obd water temp see if it tallies up with the gauge reading.
 

Mitevo7

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Not too sure about your car specifically, but generally Mitsubishi have a 2-wire temp sensor for the ecu, and the sensor for the meter is actualy a seperate 1-wire sensor, and the gauge is calibrated in such a way that it will show 'normal' over a wide range of temperatures, and will only shoot to H suddenly when it passes a certain temperature, and because the sensor is only 1 wire, the accuracy of the gauge also depends on the chassis and engine grounding. So basically, the stock temp gauge is generally a decent enough indication for overheat, but if you want to be really sure, it is best to install a seperate temperature gauge. Also usually the stock temp sensor detects the water temp at post radiator entering the engine, and not the temp of the water exiting the engine entering the radiator. If you install your own gauge, it will be on the top hose which means you will be reading the higher temperatures of the water exiting the engine entering the radiator.

But then again, looks like you had found your culprit, so just change the radiator and see how la, but if you still experience the same issue again, check your obd water temp see if it tallies up with the gauge reading.
Changing to a new radiator solved the issue and A/C runs colder and cools faster. Engine also performs much optimum and easier to Rev. OBD engine temp sensor shows 87 degree as per the thermostat setting is. Looks like the temp issue is gone for now. Looking into more mods for this car now ? AMR500 supercharger :)

Thanks for all the supports here !

-Ken-
 

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that was an interestingly "easy" fix. What radiator did you opt for?
 

Mitevo7

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that was an interestingly "easy" fix. What radiator did you opt for?
It wasn't easy at all. I wasted RM150 bucks on coolant when changing thermostat, 50 bucks on water pump and other inspection services to finally track down to radiator. The symptoms were not showing when driving in town after thermostat change, until the day i collected the car and went on highways for 30 minutes driving home, the heat shoots up and it was determined that the radiator has to be open up.

I am using Synergy Radiator, Evo X size, need to modify the mount point and relocate the AC piping a little.

Thanks,
Ken
 

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Usually Synergy can custom build your radiator, probably since yours neither this nor that, so modify existing one......
 

Mitevo7

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Usually Synergy can custom build your radiator, probably since yours neither this nor that, so modify existing one......
Evo X size is good enough for N/A applications, even for forced induction. I am exploring small boost but reasonable prices for the Lancer. This radiator mod just came in time. If i ever get into that path, will update here again.

Thanks,
Ken
 

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Nice.. it's great we actually have a confirmed resolved issue shared by the TS. haha! Most just disappear after they post their questions
 

Mitevo7

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Nice.. it's great we actually have a confirmed resolved issue shared by the TS. haha! Most just disappear after they post their questions
Call it a habit of seeing things through. I also found it frustrated at times when i was reading through forums and information left hanging after a while due to TS MIA.

Thanks,
Ken
 

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Can transplant 1j must be rich ...:smirk:
Can do it cheaply if you know your ways around, i studied the process of it for 3 whole years before deciding to do it. So you won't waste too much unnecessary budget to get things right.

Thanks,
Ken
 

gunnerzz

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Can do it cheaply if you know your ways around, i studied the process of it for 3 whole years before deciding to do it. So you won't waste too much unnecessary budget to get things right.

Thanks,
Ken
That and for sure the money printing machine u got in your store...hahah.

Make me remember during my banking time..whenever we talk about spending money which we dont have on cars, the sentence 'kejap, aku amek duit lebih kat bawah (the strongroom downstairs), rim nk tuka?, body nak cat?, aku bleh standby lebih' will comes out which will end the conversation abruptly.
 
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Mitevo7

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That and for sure the money printing machine u got in your store...hahah.

Make me remember during my banking time..whenever we talk about spending money which we dont have on cars, the sentence 'kejap, aku amek duit lebih kat bawah (the strongroom downstairs), rim nk tuka?, body nak cat?, aku bleh standby lebih' will comes out which will end the conversation abruptly.
:deal: Mechanic's face be like when the project is done.

Fortunately my car's condition is pretty well kept, and i don't have to spend so much in painting, change rims, this and that, the only unexpected one is the oil sump modification which costs me 2k. Have to hope and pray i got bonus that time, luckily i got it hahaha.

Thanks,
Ken