Hi guys, need your expertise!
I've had to replace the thermostat on my 2002 Accord FOUR times now over the past 5 years, and I have no idea why this is happening so frequently.

All four times, the same exact thing happened: While driving, the temperature gauge would bounce from its normal position all the down to 'C' and would go back and forth constantly. Sometimes it would stay at 'C' for long periods of time.

And all four times I took it to the shop, they said that the thermostat was stuck open and needed to be replaced. No biggie (especially since a stuck thermostat matched up with everything I read online), but why would this keep happening over & over & over again? That's what's confusing me.

I asked the technician, and he said that my new water pump might have something to do with it but couldn't say for sure. Does this sound like a reasonable explanation though?

Here's all the work I've done on the timing belt/water pump and the thermostat:

• 2015: Bought car from previous owner
• 2016: Replaced timing belt & water pump
• 2018: Replaced thermostat the 1st time because it was stuck open
• 2018: Thermostat was stuck open again (5 months later), so it had to get replaced a 2nd time (thank goodness the warranty covered it)
• 2021: Thermostat was stuck open a 3rd time, so I had to get it replaced once more
• 2023: Replaced timing belt & water pump again
• 2023: Thermostat was stuck open again and had to get replaced a 4th time

Any idea why I keep having all these thermostat issues?
Thanks in advance!

 

Very unusual, ive never had one fail open, but i have had them fail closed a few times over the years.

What brand thermostat have you been using? Are you running coolant/antifreeze or just water?

 

Hey, thanks for the reply man. I'm not exactly sure of the brand, BUT I got the thermostat replaced at the Honda dealership all 4 times, so I assume they were all Honda parts? Also, been running coolant the whole time.

I'm just totally confused as to why each new thermostat keeps getting stuck open. I'm wondering if it's a sensor or computer issue? I'm just completely baffled.....

 

The thermostat is completely mechanical, no sensor or computer control in that honestly.

Are you sure your thermostat was bad and you don't just have an intermittent issue with your temperature gauge and or gauge cluster?

I think it highly unlikely you would have so many thermostat failures. Are you sure the car was overheating?

 

There are causes for overheating in addition to a stuck thermostat, and a $30 investment in can display real data. The '99 V6 in my sig reguarly shifts from mid-to-upper 180s to lower 200s in plenty of stop and go traffic (via a garden variety Scangauge). In that car at least, the installed temp 'gauge' is a glorified idiot light.

 

Nope, the car wasn't overheating. Per the original post: "All four times, the same exact thing happened: While driving, the temperature gauge would bounce from its normal position all the down to 'C' and would go back and forth constantly. Sometimes it would stay at 'C' for long periods of time."

It's so weird because I took it to a Honda dealer the first 2 times, and each time they said the thermostat was stuck open (and each time it got replaced). But then I took my car to another dealer after that (because I moved), and each time they said that thermostat #3 and #4 also got stuck open.

I put nothing past anybody though. Do you think it was just a gauge problem and that either (or both) of the dealers did unnecessary repairs? Because like you said, it seems highly unlikely that 4 thermostats would fail so fast like that!

 

Honest im inclined to think you have a gauge cluster or temperature sensor issue, I really really dont see it failing so often. Just so I know, did they show you the changed part each time they replaced it? Did they show you it being stuck open, because the thermo is supposed to be CLOSED and room temperature.

 

That's a really good point. They didn't show me any of the parts they replaced.
I think I'm gonna ask them to save the thermostat if this happens again because (like you said) it doesn't make sense why it would supposedly "fail" so often.

 

Or you know, you could change it yourself. Takes $10 worth of tools and about 15 mins to change a thermostat. The part also costs like $8 for a good aftermarket one

Im getting the distinct vibe that someone been making A LOT of money off of you... Have you tested your temperature sensor to see if that is the problem etc?

How much does a dealer charge to change a thermostat anyway

 

In 2021, they charged me about $320 to replace the thermostat. But when it got replaced again last week, the price was $465. (Even though the price of pretty much everything has gone up recently, that seems like a pretty hefty increase to me.)

I think I might take your advice and change it myself next time. I don't know how to test the temperature sensor, but I'm going to look into that too, since that could very well be the issue. Thanks so much for your help man!

 

Are you trolling or something?

$465 for a thermostat? You sure? Seriously speaking a thermostat change on these is SO easy. Its literally one of the first mechanical things i learned to do.

I am in shock

 

Nope, I wish I was trolling. Sadly, that's what they charged me for parts/labor.
But I'm glad you told me how easy it is to replace.......because I think I'll just do it myself next time!!

 

I think you need to go back and talk to the service manager and discuss how you've being taken advantage of.

 

Im with Chris above. If what you are saying is correct you paid enough to literally buy another CD accord

 

Thanks guys...really appreciate your help & I'm gonna follow your advice!