Recently purchased vehicle. 247k miles. The coolant has been replaced at the recommended intervals. Has original thermostat, but the radiator and Honda blue coolant were replaced a year ago. Figure I'll wait a couple years and replace the original thermostat when I replace the coolant. In my experience 247k miles/18 years is beyond average for a thermostat. Noticed that the thermostat housing that the plastic thermostat assembly bolts onto is also plastic. Anyone know if there have been failures (cracks, etc) in these housings or have they hold up over the years? In other words should the housing be replaced along with the thermostat assembly due to age and miles?

Never had a vehicle with a plastic thermostat housing before, I've heard that the plastic ones in Ford Mustangs (for example) have a high failure rate. Maybe Honda utilizes a higher quality plastic.

Thank you

 

Also, does a Honda thermostat usually fail in the open or closed position? Have replaced a number of bad thermostats over the years, mainly failed in the open position.

 

This goes back to your previous thread, where if it ain't broke, don't fix it. I never had a Honda OEM thermostat fail in my vehicle. If you decide to replace, get the Honda thermostat. I haven't read of any thermostat housing failures, but it wouldn't hurt to replace it.

I think the thermostat can fail open or closed, but failing open is most likely.

 

Thanks again. I'm probably stuck "back in the old days" during which these components failed often and left people stranded....50 years of driving does that. Just a few years ago I switched to driving old Hondas and Toyotas. Should have done it decades ago. I've always driven cars 10-25 years old with my typical purchase at 15 years old. Then I baseline the car, changing fluids as necessary and other wear components. By doing this I've never been stranded in my old cars....with one exception, a 94 Jaguar that left me stranded not long after I purchased it. Should have known, Brit cars are/were always headache cars. Sold it shortly thereafter.

Another question. How long do the radiator hoses, heater hoses, and other coolant hoses last in a mid 2000s Honda??? All hoses in my vehicle are original 247k miles and 18 years old. Back in the day I had a top radiator hose fail in my 75 Gremlin when it was 2 years old and had maybe 16k miles. Stuff like that happened all the time on American vehicles. The Japanese forced us to up the quality control game.

 

The coolant hoses aren't a maintenance items where you need to replace every X number of years or miles. Definitely inspect them, I use a rag and wipe them off to identify an oil leak that will cause them to degrade. Squeeze them to ensure they are still pliable and aren't showing signs of small cracks/dry rotting. I also pay attention to the ends near the clamps to see if the rubber is cracking/degrading. Usually this isn't too bad and haven't had to cut back on the ends.

The radiator is also a component to replace only when you identify a problem. I'd say pressure test the coolant system and the radiator cap with the loaner tool you can get at most part stores. I replaced my radiator at 7 years because the crimp seal between the aluminum and plastic reservoir on top had a very slight leak where I was topping off the overflow reservoir every few months. There was also a faint smell of coolant in the engine bay at that time. The Denso replacement has lasted for 10+ years. With that leak the cooling system held at ~15 psi for a long time, so it wasn't a major leak.

 

Thanks, I agree. I edited my previous post to read "radiator hoses" instead of "radiator" for clarification. I meant to ask about the hoses. My experience with "plastic" radiators is that they fail at the crimp seal you mention, but usually give plenty of advance warning before major leaks occur.

Appreciate your insight.