Mazda Premacy Overheating Issue and Check Engine Light - Suspected Faulty Engine Coolant Bypass Valve

Hey, sounds like a familiar scenario! I got my 2009 Mazda6 and around 250K km on the dial, I bumped into pretty much the same issue. Overheating, blinking check engine light, the whole package. After a bit of research and some prodding under the hood, I was on the same track as you, something off with the coolant bypass valve. So, I took my car to the shop, laid out my suspicions to the mechanic, expecting a thorough check-up. The inspection showed my hunch was bang on, the bypass valve connection was indeed faulty. The thing about this issue is it's less about the severity but rather the potential damage it can cause if left unchecked. Overheating can definitely result in big problems in the long run. The fix? Needed a valve replacement plus dealing with the cable connection. Trust me, you wouldn't want to let this slide. Because of the overheating aspect, it could start impacting other parts of the engine. So yeah, pop into a reliable garage, get that coolant bypass checked, it might simply be the cable connection. Anyway, hope that helps. Keep us posted. Cheers!

Hey, thanks for the solid advice! Good to know I'm not alone with this issue on my Mazda. This tip about the cable connection could be a real headache saver. I'm definitelyma planning on getting this checked ASAP - don't need any extra trouble out of the blue. Just curious, if you don't mind sharing, roughly how much did the repairs set you back? And has something similar crept up since? Cheers!

Glad to hear you found the advice helpful! You're definitely making the right call getting your Mazda checked out. In terms of the expenses, I ended up shelling out around 155.00 € to get that coolant bypass valve cable connection sorted. It might seem a bit pricey, but trust me, it was worth every penny. You're potentially saving a lot more down the line by avoiding damage from overheating. Since that trip to the mechanic, I've had no more bumps in the road related to this issue, or any overheating in general. That danged check engine light also finally decided to behave. So yeah, seems like the bypass valve was the main culprit here. Hope this helps you out a bit, keep us posted. Cheers!

Thanks a ton for the intel! 155.00 € sounds fair enough, given it avoids more havoc in the long run. I think it's time for me to bid adieu to that check engine light as well. Keeping my fingers crossed to have the same smooth ride as you post the fix. Really appreciate your time and help. Will sure keep you guys updated on how it goes. Cheers!

Hello, today I'm asking the question, we are in 2025, have you resolved your overheating problem with your Mazda Premacy? I own a 2004 Mazda Premacy - 2.0 DiTD100 GTX diesel, it overheats and then cools down, only one fan runs. What problems should I check? (radiator / thermostat / bleeding the cooling system) What is the connection of the coolant diverter valve cable for? Is it a connector that needs replacing? Thanks in advance for your answer.

(Translated from French)

Start by checking the radiator fan operation, as only one fan running could indicate a problem. Ensure both fans are functioning properly, as they are crucial for cooling. If one fan is not working, inspect the fan motor, relay, and wiring for any faults. If the fan issue is resolved and the problem persists, then proceed to check the thermostat and consider bleeding the cooling system. The coolant diverter valve cable connection is typically related to controlling the flow of coolant; if faulty, it might need replacement. Keep us updated on your progress, and let me know if you have further questions!