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The other day, the check engine light came on and I pulled code P026E. It’s now cleared on its own, but it only seems to pop up on days when it’s 95°F+ outside.
From what I’ve gathered, it might be related to the coolant pump, but I’m not 100% sure. Anyone here experienced this code before?
Here’s what’s odd:
When the car sat overnight, the coolant level was below MIN.
Drove to buy coolant, and suddenly the level read normal again.
I topped it off to MAX just in case.
A few hours later, the check engine light cleared on its own.
The car drives and runs perfectly—no noticeable performance issues. This just has me on edge because it feels like something is off, but no real symptoms yet.
For context, I just threw on a set of AMG 22” rims yesterday, swapped from the stock wheels. Not trying to fully G63-ify it (though I like a few things about the G63), but the ride on that was way too stiff for my wife.
Would appreciate any input or similar experiences. Pics attached! Stock AMG 22's - 7/25/25 - Bull Bar still makes it a G550 Car sitting for hours - coolant LOW AFter driving car to buy Coolant - Level was NORMAL ( no coolant added)
I think that's normal. I Googled it, and found this explanation:
The radiator fluid (coolant) level does change depending on engine temperature. When the engine is hot, the coolant expands, causing the level in the reservoir to rise. As the engine cools, the coolant contracts, and the level drops back down.
This change is normal and expected due to the thermal expansion of fluids. That’s why coolant reservoirs typically have separate "cold" and "hot" fill marks, indicating where the level should be when the engine is at different temperatures.
If you are checking the coolant level, it should be done when the engine is cold, as the "cold" mark reflects the proper level for a non-running engine
Could this potentially be covered under the 7yr/70K warranty?
Originally Posted by sweet63
Hi,
I think that's normal. I Googled it, and found this explanation:
The radiator fluid (coolant) level does change depending on engine temperature. When the engine is hot, the coolant expands, causing the level in the reservoir to rise. As the engine cools, the coolant contracts, and the level drops back down.
This change is normal and expected due to the thermal expansion of fluids. That’s why coolant reservoirs typically have separate "cold" and "hot" fill marks, indicating where the level should be when the engine is at different temperatures.
If you are checking the coolant level, it should be done when the engine is cold, as the "cold" mark reflects the proper level for a non-running engine
I don’t know what the code P026E means. 95 degrees is pretty hot, but a Mercedes G550 should be able to handle it without any problems. If it happens often, then I’d contact the dealer. I believe the radiator and cooling system are covered under the extended warranty.
I Googled this topic, and found:
Yes, a Mercedes-Benz Extended Limited Warranty generally covers the radiator and cooling system, along with other components like the engine, transmission, fuel injection system, and climate control system. However, specific coverage details can vary by plan, so it's essential to review the terms and conditions of your particular extended warranty.
What is typically covered within the cooling system:
Radiator: Including mounting brackets.
Water Pump:
Cooling Fan Motor:
Fan Clutch:
Thermostat:
Coolant Recovery Unit:
Engine and Transmission Oil Coolers:
Originally Posted by momo80
Could this potentially be covered under the 7yr/70K warranty?
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