[PainlessDeath09]

Hello Bhpians!

I recently got my 2003 Honda Accord 2.4AT. It’s been absolutely blissful so far up until today. Got the regular service and everything done. During the general service, there was a coolant leak which was from a pipe that was fixed.

Today, after about a 20 min drive, I stopped my car to find coolant all over my front bumper. Opening the hood, I see this:




The radiator neck had sheered off with the pressure. I have no idea why this could happen. I immediately had the car towed to my FNG. They had suggested a thermostat stuck open or a water pump failure.

Something to note, when I drive my car, the temperature gauge was never in the middle, it’s always been slightly cooler than the middle. Not sure if that’s relevant but yeah.

Any ideas/theories/personal experiences as to why this could’ve happened?

[dhanushs]

Originally Posted by PainlessDeath09

Hello Bhpians!
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Any ideas/theories/personal experiences as to why this could’ve happened?

I initially would've thought overtightening of the hose clamp would've done it, but looking at the photo seems like thats not the reason.
If your radiator mount/engine mount is weak and the radiator to engine hose moves a lot, that will also induce a failure over time.

but, looking at the bigger picture, the car is 21 year old. Think of it as a wear and tear failure.

[NomadSK]

Originally Posted by PainlessDeath09

During the general service, there was a coolant leak which was from a pipe that was fixed.

I would be more interested to know what kind of fix was done to the hose ? A new hose or the neck was just tightened to arrest the minor leakage. Rubber tends to loose its elastic properties over a period of time and if only tightening was done then that points to the mechanical damage to the radiator, in addition, due to the ageing of the vehicle the plastic component would have weakened by time.

They had suggested a thermostat stuck open or a water pump failure.

Sorry, but I guess that doesn’t adds up for the failure. Open Thermostat failure will run your engine cooler and closed thermostat will not let the coolant circulate and will overheat the engine you will get this warning on the dash, in both cases nothing to with the radiator assembly. And water pump failure would simply give you first warning for engine overheating on your dash.

In my opinion this is a mechanical damage (a brittle failure) and nothing to do with temperature/pressure of the coolant. And if I match the clamp location, it almost matches to the location where failure occurred. So it could be a weak plastic component, due to aging, which got damaged during the clamping of the hose.

[PainlessDeath09]

Originally Posted by NomadSK

I would be more interested to know what kind of fix was done to the hose ? A new hose or the neck was just tightened to arrest the minor leakage.

The coolant pipe clamp where it connected to the engine was leaking. So they just tightened that. I believe the fix was unrelated to the pipe breaking the neck on the other end. Rather, do you suppose perhaps the leak was caused by the system being over pressurised?

Originally Posted by NomadSK

Sorry, but I guess that doesn’t adds up for the failure. Open Thermostat failure will run your engine cooler and closed thermostat will not let the coolant circulate and will overheat the engine you will get this warning on the dash, in both cases nothing to with the radiator assembly.

Hmm. I do have a question though. If the thermostat was indeed stuck open, wouldn’t that result in excess pressure in the cooling system because it’s continuously working causing this?

Originally Posted by NomadSK

In my opinion this is a mechanical damage (a brittle failure) and nothing to do with temperature/pressure of the coolant. And if I match the clamp location, it almost matches to the location where failure occurred. So it could be a weak plastic component, due to aging, which got damaged during the clamping of the hose.

Hmm fair enough. Maybe I’m overthinking this. Perhaps it’s just the age. I’m just worried that I am treating just the symptom and not find the cause if I just replace the radiator top and not doing anything else.

[NomadSK]

Originally Posted by PainlessDeath09

I do have a question though. If the thermostat was indeed stuck open, wouldn’t that result in excess pressure in the cooling system because it’s continuously working causing this?

No, the thermostat works on the temperature of the coolant. It’s kind of temp related valve, Opens when the coolant temperature is elevated and closes when coolant temp is lowered, in order to have uniform temp around the engine block.

When pressure of the closed loop cooling circuit is increased due to increase in temperature of the coolant, there’s a pressure release valve near/on the radiator cap which releases this pressure through the overflow pipe and that’s why you see coolant flowing in the overflowing tank.

Hope that is clear

[arjab]

This looks to be a case of mechanical ageing. Can happen with any "teenage-d" automobile
Don't lose sleep over it. Yes, a replacement radiator for a Accord will be pricey but you do not have any option but to change the whole radiator assembly. Avoid getting talked into "plastic welding" and "changing the top tank and sealing it" kind of stuff. In aluminium radiators these "jugaad" fixes do not last long.

Also since your vehicle is a couple of decades old, if you haven't already, maybe it is a good idea to have certain main components checked for mechanical integrity & fitness.

[pranavt]

The previous owner had their mechanic glue the broken plastic so that they could sell the car. You found out the issue a few days later. As the poster above me has advised, best to change the radiator; who knows what sort of gunk has collected inside it over the past 20 years.

[PainlessDeath09]

Originally Posted by NomadSK

When pressure of the closed loop cooling circuit is increased due to increase in temperature of the coolant, there’s a pressure release valve near/on the radiator cap which releases this pressure through the overflow pipe and that’s why you see coolant flowing in the overflowing tank.

Hope that is clear

Ah thanks a ton, you’ve made it quite clear to me. Appreciate it

[PainlessDeath09]

Welp, after seeing the replies here, I’ll successfully conclude that it’s just wear and tear due to age. I’ve sent the car for replacement of the top part of the radiator. The radiator itself was inspected and found to have no issues and was cleaned and the FNG says just the top part can be replaced as it is removable.

Thanks a ton guys!