Car gurus, please help me before I get stranded on the road.

I traveled to Abia state today to drop my family for the Christmas holiday which is a journey of about 400km to and fro. I observed that on two occasions, my car temperature rose to about 3/4 of the guage. What I did was to switch off the a/c and immediately the temperature came down to normal which is about little less than half of the guage.

What could cause this temperature rise? For 4 years plus, I have always driven with a/c and haven't notice this before on the expressway. Please urgent solution needed because I plan traveling next two days to bring them back.

Yes I have scanned the car but its the oxygen sensor issue P0141 that it detected.

Siena, Gazzuzz, Ikenna351, Bossforever, Denn, luvinhubby, cardoctor, etc

Edited: I did Google search and they said the radiator fan may not be turning., which I checked and mine is turning. Also, there may be air in the system. Please how do I bleed the system?

Possibly car not breathing well. Where you in stand-still traffic when the temprature rise was observed ?

Lexusgs430:
Possibly car not breathing well. Where you in stand-still traffic when the temprature rise was observed ?

No. Cruising along. But it didn't happen always. Happened once when I was going and happened again when I was coming back. Just twice in total of about 400km.

Are you sure your thermostat is not going bad?

Remove your thermostat and test, check for failing fans. Check for a dirty condenser.


Below is a nairalanders condenser when it came in with complaints about the a.c

Next is after a wash.

Bumper had to be removed to access it properly.

Check all this. But before that does the water in the radiator dries up?

Check your fans if they arr working optimally. Check the speed at which they are moving

Check the cells on your radiator. Might be weak.

Is your thermostat working well

Also check your radiator cap. I have treated cases of over heating culminating to be radiator cap issue

In all carry out a cooling pressure test. That would reveal what is actually happening

GAZZUZZ:
Remove your thermostat and test, check for failing fans. Check for a dirty condenser.


Below is a nairalanders condenser when it came in with complaints about the a.c

Next is after a wash.

Bumper had to be removed to access it properly.

Thanks. My radiator is a little bit dirty but not like the one in the picture. Hope I don't need to remove the radiator before washing?

mayor2013:
Check all this. But before that does the water in the radiator dries up?

Check your fans if they arr working optimally. Check the speed at which they are moving

Check the cells on your radiator. Might be weak.

Is your thermostat working well

Also check your radiator cap. I have treated cases of over heating culminating to be radiator cap issue

In all carry out a cooling pressure test. That would reveal what is actually happening

The water in the radiator remains the same, I only top up the one in the reservoir after every 2 weeks.

lonelydora

Summary of the symptoms you mentioned :

Car overheats when ac on.

Does this occur during standstill or on motion?

Please confirm that your ac fan works when ac is on.

Have you been using the same coolant for 4 years? You might need to confirm that your thermostat opens when hot. You can confirm this with a simple pot and water on fire.

You also did not mention the car model, year, number of fans and if you have a mechanical fan.

All these are important in resolving your issue.

Denn:
lonelydora

Summary of the symptoms you mentioned :

Car overheats when ac on.

Does this occur during standstill or on motion?

Please confirm that your ac fan works when ac is on.

Have you been using the same coolant for 4 years? You might need to confirm that your thermostat opens when hot. You can confirm this with a simple pot and water on fire.

You also did not mention the car model, year, number of fans and if you have a mechanical fan.

All these are important in resolving your issue.

Car does not overheat when ac is on but a times the temperature rises above the middle mark. I don't allow it to get to the red zone. Once I switch off the ac, the temperature will come down to the normal spot, and when I switch on the ac again it won't rise again. Happened twice in a journey of 400km. When I checked both fans are on. It happens when in motion. I do normal change coolants. I have been using Total original coolant since 5 now.



Car is 2003 Honda EX-L 3.0 V6.

lonelydora:


Car does not overheat when ac is on but a times the temperature rises above the middle mark. I don't allow it to get to the red zone. Once I switch off the ac, the temperature will come down to the normal spot, and when I switch on the ac again it won't rise again. Happened twice in a journey of 400km. When I checked both fans are on. It happens when in motion. I do normal change coolants. I have been using Total original coolant since 5 now.

Thermostat seems not to open when it should.

Get it replaced. Availability in Nigeria is not sure. You might need to order it online then ship down.






Car is 2003 Honda EX-L 3.0 V6.

Possibilities include:

Radiator and/or block internally clogged with rust, scale, silt, gel, or externally blocked with road debris
Bad radiator cap
Bad thermostat
Radiator fins corroded and falling off
Water pump impeller corroded
Lower radiator hose collapsing

Radiator or block internally clogged with rust, scale, silt, gel, or externally blocked with road debris


The radiator is the engine's main heat exchanger. Unless coolant can pass freely through it at the speed the water pump and thermostat want to push it, it can't get rid of the heat it needs to get rid of, and deposits prevent fluid movement.

Any deposits at all in the radiator are bad and are caused by one of more of the following:

Incorrect coolant
Mixing incompatible coolants
Old, corrosive coolant
Use of tap water to mix with aftermarket coolants

When you pull the rad cap off and shine a flashlight inside, the coolant should be transparent (plus whatever color it was when put in), and the fins should be clearly visible.

If the fluid is murky, brown, smells like rubber, goopy, or if the fins have white, crusty deposits on them, you've got circulation problems, and likely corrosion problems inside the engine.

Old coolant gets acidic and corrosive, and will eat all sorts of internal parts, from your head gasket to the water pump impeller. It also cannot carry heat as effectively as fresh coolant.

Inexpensive silicated coolants (the cloudy stuff) can cause silt to build up in the engine's water jacket as well as the rad, providing an impediment to free flow of coolant. Honda emphatically recommends that you use their coolant and no other in their cars.

Coolant should be changed every two years with a non-silicate, non-borate type. Long-Life coolant is supposed to be good for five years, but I've never personally been comfortable with that. I change mine every two years or less.

Bad radiator cap

The radiator cap does several things. It

seals the system against the outside world (main seal function)
keeps the system pressurized when needed, so as to raise the boiling point of the coolant
allows excess pressure and coolant expansion to vent to the expansion reservoir (pressure seal function)
allows coolant to return to the radiator when the engine cools down (return seal function)

As you may have gathered from the above section, the radiator cap has three seals, any of which may fail independently of the others:

The main seal is the one that seals the cap against the top of the filler neck. Just a rubber gasket that operates just like one on the lid of a pickle jar. Simple and reliable.

A failed pressure seal will allow the coolant to boil at a lower temperature, and coolant will be able to travel freely and foamily to the expansion reservoir. This will cause localized hot-spots inside the engine, which can lead to premature head warpage, and may hasten head gasket failure. It will also cause the rad coolant level to be low, just like a failed head gasket.

A failed return seal will prevent the coolant from returning to the radiator as the rad cools off, causing a vacuum that can collapse the radiator's hoses. This will prevent the coolant from circulating if the hoses don't re-expand as the engine warms up.

A bad rad cap can cause similar symptoms to a failed head gasket, so it's a cheap first step to try before bringing it in. If you replace the rad cap and you still have bubbles in the coolant (or foam in the reservoir), then suspect the head gasket.

If the engine starts to overheat at idle, or in heavy traffic, and the gauge goes down when you rev it, the coolant is probably low.

Moreover, a neglected cooling system can load up the cap with crud and corrosion, preventing proper coolant flow in and out through it. Peel the seals back with your fingernail to check for goop. If you find any, a blast with a garden hose and probing with a toothpick should clear most of it out.

But anyway, a new rad cap is less than $20. Make a habit to change it every 5 years, just in case. It's pretty important.

Bad thermostat

This part is the traffic cop that controls when the coolant is allowed to circulate and when it isn't. It's the device that's meant to quickly allow the engine to warm up to its design temperature, but no hotter than that.

Thermostats can stick shut or open, get lazy, or fail to open at the correct temperature. Depending on how and when they fail, they will cause either overheating or underheating. Overheating usually happens when the thermostat fails to open, or fails to open enough. If it fails to close, the engine will run too cool, causing all sorts of other problems.

A cooling system full of rust, scale, silt, or gel will interfere with the thermostat's operation, causing even more cooling problems. Gunk can plug up the thermostat, causing overheating, or make it stick open, causing underheating. Incorrect installation of the thermostat (can be done, even by professionals!) will also interfere with thermostat operation.

Normally mounted in the top of the lower rad hose in modern Hondas, the thermostat senses engine heat in the coolant. It is supposed to open up when the coolant in the block has warmed up enough, allow the cooled coolant in the rad to flow into the block, pushing the hot coolant from the block into the rad.

When the thermostat is closed, a small bypass hose allows coolant to circulate through the engine block, around the business end of the thermostat, through the water pump, and back around again. This keeps block temperature even, and helps the thermostat warm up as well. Once the thermostat opens, the bypass is closed off by means of a special extension on the bottom of the thermostat.

Aftermarket thermostats are highly associated with overheating and underheating. Most Hondas require 78C (172F) thermostats (that's the opening temperature). Too many aftermarket thermostats are wrongly rated for your car and are poorly made. Your emissions system may not work correctly with a different rating installed. In addition, some aftermarket units lack a bleed hole, the absence of which can trap air and lead to overheating.

A new genuine Honda thermostat is about $30 and is guaranteed to work properly in your Honda. In my mind, it's foolish to trust such an important job to an aftermarket part. Changing it every 5 years is excellent preventative maintenance.

Denn:

Thermostat seems not to open when it should.

Get it replaced. Availability in Nigeria is not sure. You might need to order it online then ship down.

Everything is pointing towards bad thermostat.

Thanks to everyone for the response. MY QUESTION IS, IF THE PROBLEM IS THE THERMOSTAT; WHY WILL IT MALFUNCTION ONLY WHEN THE AC IS ON? WHY NOT EVERYTIME THE ENGINE IS ON?



I went to my mechanic this morning, after much, he said I might need to change the thermostat. But the truth is I don't have 8k now (which he said is the price of tokunbo one).

After much I decided to steam wash the radiator, which was somehow dirty. I will manage it to Abia State and see how it turns out. Maybe by January I will order a new one because I don't fancy tokunbo things.

For now, I drove to Onne (a journey of about 64km total) and back and the temperature for now is behaving himself.

I will let you guys know how my journey was by tomorrow.

Luvinhubby, I guess you have the new thermostat?

Radiator fins corroded and falling off

A radiator problem peculiar to Northern regions is external corrosion of the fins. This is caused by winter and road salt, and reduces the fins to a white powder. The fins then crumble and fall off, and once they do, that section of the radiator cannot exchange heat with the outside air. Run your hand gently over the fins at the middle of the rad's core, at the very bottom, under the bumper. If they're crumbly, you'll know.

Warmer areas may suffer from sand, pine needles and other debris embedded in the lower half of the rad, which prevent air movement through the rad and thus impair heat exchanging.

Water pump impeller corroded

The only time you'll ever see this is if

you're using a low-quality aftermarket water pump, or
you've mixed incompatible coolants, or
the coolant has never, ever been changed.

If the impeller is gone or much reduced in size, coolant can't be pumped into and out of the rad, so it will boil and overheat

Lower radiator hose collapsed

If you're using genuine Honda hoses, you'll never see this problem unless your rad cap has gone bad and won't allow coolant back into the engine.

When the water pump is turning, it's sucking water through the thermostat and the lower rad hose. That suction can cause the same sort of hose collapse as you get in a drinking straw when you try to suck a thick milkshake through it. If the hose is insufficiently reinforced on the inside, it can get sucked flat and coolant flow will stop. When you let off the pedal or shut the car off, the hose pops back to normal. If you use aftermarket hoses, not all of them will be of high quality, and may be prone to this phenomenon.

To check for this, rev the car hard with your hand on the throttle in the engine compartment, and watch the lower hose. If it doesn't collapse, it's probably fine.

This can also happen as the car cools off, if the rad cap return seal has gone bad.


All the credit goes to: 'Honda overheating Symptoms and most likely causes' by www.tegger.com

lonelydora:
Thanks to everyone for the response. MY QUESTION IS, IF THE PROBLEM IS THE THERMOSTAT; WHY WILL IT MALFUNCTION ONLY WHEN THE AC IS ON? WHY NOT EVERYTIME THE ENGINE IS ON?



I went to my mechanic this morning, after much, he said I might need to change the thermostat. But the truth is I don't have 8k now (which he said is the price of tokunbo one).

After much I decided to steam wash the radiator, which was somehow dirty. I will manage it to Abia State and see how it turns out. Maybe by January I will order a new one because I don't fancy tokunbo things.

For now, I drove to Onne (a journey of about 64km total) and back and the temperature for now is behaving himself.

I will let you guys know how my journey was by tomorrow.

Luvinhubby, I guess you have the new thermostat?

You should be fine that is probably all you needed to do