Help with CEL P2CEF code

[Rainier]

Got the word that "thermostat stuck" is the issue. Replacement is the fix. Seems they've had a few of these with this issue. ....

Same situation here (US I4). Any further updates from anyone?

I'm hoping this is a bad batch of thermostats (rather than sand in the coolant system ).

 

[gcmak]

Same situation here (US I4). Any further updates from anyone?

I'm hoping this is a bad batch of thermostats (rather than sand in the coolant system ).

how many miles did you have on the car when the error appeared?

 

[Rainier]

how many miles did you have on the car when the error appeared?

Approx 1400 miles, CEL on then automatically turned off after a few start - stop cycles, then fine for a bit and again on and auto cleared itself.

I'm not sure if it just needs to 'settle in' and wont happen again, however dealer will replace (2, upper and lower I think?) thermostats in a few days when parts arrive.

Lotus did not mention anything about sand in the coolant to my dealer.

I did see the video in this thread and find it hard to believe that AMG would still have a sand issue given that the video shows people complaining about it at least 2 years ago in Mercedes cars, but who knows...

 

[Ryan_929]

CEL came back this weekend. I’m taking it back to Lotus on Friday. So far it’s come on 4 times from 100 miles to current 550 miles. Cleared the first 3 and left this last one. I’ll let y'all know what the results are.

 

[yk793]

I read in the FB forum twice from two different I4 owners about the code. Hope it all gets sorted and everyone can enjoy this special car problem free..

 

[MajHall04]

Well add me to the thermostat issue! Car was purchased in December and has 1900 miles. I hope it’s not the sand issue but I suspect it is.

 

[ToonFan]

3 week update. Both thermostats are being replaced. Then another flush and then a "spirited" drive rest and repeat sequence to make sure everything is all good. It's taken a bit to get the parts and go through the process. Fortunately, i have other cars to play with. Note- if you get the check engine light; don't sit on it. Get it scheduled and fixed.

 

[MajHall04]

Well I’m looking at a couple weeks minimum to get my car back….

 

[Rainier]

An update from this owner on their similar/same issue.

Video seemed to refer to this: https://static.nhtsa.gov/odi/tsbs/2024/MC-11000622-0001.pdf

 

[Ryan_929]

Video seemed to refer to this: https://static.nhtsa.gov/odi/tsbs/2024/MC-11000622-0001.pdf

Dropped mine off yesterday for a fix. I shared that video with the service department at Lotus. Hopefully they will actually watch it. They said it should be ready by Monday. I’ll let y’all know the outcome.

 

[Rainier]

A song for the dealer

 

[Rainier]

(AI generated analysis)​

Casting Sand in Lotus Emira M139 Coolant: Potential Damage and Repair Considerations​

The presence of casting sand in the coolant of the Lotus Emira equipped with the Mercedes-AMG M139 engine is a known issue, mirroring concerns found in some Mercedes models. This leftover sand from the engine manufacturing process can circulate within the cooling system, acting as an abrasive and causing blockages, potentially leading to significant damage.

Potential Damage to Cooling System Components:

Several key components within the Emira's cooling system are at risk when casting sand is present:

• Water Pump: This is a primary concern. The water pump's impeller circulates coolant throughout the engine. Abrasive sand particles can wear down the impeller blades, reducing their efficiency. More critically, the sand can damage the water pump's seals, leading to coolant leaks and eventual pump failure.
• Radiator: The radiator consists of numerous small tubes and fins designed for heat dissipation. Casting sand can accumulate in these narrow passages, causing blockages. This restricts coolant flow, reduces cooling efficiency, and can lead to engine overheating.
• Heater Core: Similar to the radiator, the heater core (responsible for cabin heating) also has fine passages that can become clogged by sand. This typically results in a loss of heating performance inside the car and can be a difficult and costly component to access and replace.
• Thermostat: The thermostat regulates engine temperature by controlling coolant flow. Sand can interfere with its mechanical operation, causing it to stick open (leading to slow engine warm-up) or, more dangerously, stick closed (leading to rapid overheating).
• Coolant Hoses and Seals: While less likely to suffer immediate catastrophic failure, the abrasive nature of the sand can potentially contribute to accelerated wear on the internal surfaces of hoses and various seals throughout the cooling system over the long term.
• Engine Block and Cylinder Head Passages: In severe cases, significant accumulation of sand could theoretically impede flow within the intricate coolant passages of the engine block and cylinder head themselves, though this is less commonly reported than issues with ancillary components.

Is Multiple Flushes Enough?

Multiple coolant flushes are often the first line of defense employed by dealerships when addressing this issue. The goal is to suspend the sand particles in the coolant and then drain them out.

• Potential for Success: In some instances, particularly if the contamination is minor and caught early, several thorough flushes might remove a significant portion of the sand and alleviate immediate symptoms.
• Significant Risks and Limitations:
  • Incomplete Removal: It is very difficult to guarantee the complete removal of all sand, especially from complex areas like the radiator, heater core, and engine block. Sand can settle in low-flow areas and become dislodged later, causing problems to reappear.
  • Existing Damage: Flushing will not repair any abrasive damage that has already occurred. A worn water pump impeller or damaged seals will remain worn or damaged.
  • Persistent Clogging: Deeply embedded clogs in the radiator or heater core may not be fully cleared by flushing alone.
  • Risk of Further Damage: If not done correctly, an aggressive flush could potentially dislodge a large amount of debris at once, leading to a sudden blockage elsewhere.

The Possibility of Permanent Damage:

Yes, permanent damage can and does occur due to casting sand in the coolant.

• Abrasive wear on the water pump is permanent and necessitates replacement.
• Severe blockages in the radiator or heater core often require these components to be replaced, as flushing cannot fully restore their function.
• In a worst-case scenario, persistent overheating caused by sand-related cooling system failures could lead to severe engine damage, such as a warped cylinder head or head gasket failure.

Recommendations for Owners:

If you suspect casting sand in your Lotus Emira's cooling system (symptoms include coolant discoloration/sludge, overheating, poor cabin heating, or coolant leaks), it is crucial to:

1. Contact an authorized Lotus dealership immediately. Document your concerns and any symptoms.
2. Inquire about known issues and technical service bulletins related to casting sand in the M139.
3. Discuss the diagnostic and repair plan thoroughly. Understand what steps they will take, including whether they recommend flushing, component inspection, or replacement.
4. Be cautious about accepting multiple flushes as a definitive fix without a thorough inspection of key components, especially the water pump. Consider requesting an inspection or replacement of vulnerable parts, particularly if the vehicle has experienced overheating or if significant amounts of sand are found.
5. Keep detailed records of all service visits and repairs related to this issue.

While multiple flushes can be a part of the solution, they are often insufficient on their own when significant casting sand is present. Due to the potential for abrasive wear and stubborn blockages, component replacement is frequently necessary to ensure the long-term health and reliability of the cooling system.

Casting Sand in Lotus Emira M139 Coolant: Potential Damage and Repair Considerations​

The presence of casting sand in the coolant of a Lotus Emira equipped with the Mercedes-AMG M139 engine poses a significant risk to various components within the cooling system. While multiple coolant flushes are often the first line of defense, they may not always be sufficient, and permanent damage can indeed occur.

Potential Damage and Systems Affected:

Casting sand, primarily composed of silica, is abrasive and can cause damage through both wear and clogging. The components most at risk in the Emira's cooling system include:

• Water Pump: This is a critical component with moving parts (impeller and bearings) that are highly susceptible to abrasive wear from sand particles. This can lead to reduced coolant circulation, seal failure, and eventual pump seizure.
• Radiator: The radiator consists of numerous small tubes and fins. Sand can easily become lodged in these narrow passages, causing blockages. This restricts coolant flow, reduces cooling efficiency, and can lead to engine overheating. Over time, the abrasive action can also weaken the radiator's internal structures.
• Heater Core: Similar to the radiator but located within the vehicle's dashboard for cabin heating, the heater core also has very fine passages. These are prone to clogging by sand, which can result in a loss of heating performance inside the car. Due to its location, replacing a heater core is often a labor-intensive and costly repair.
• Thermostat:The thermostat is a valve that regulates coolant flow based on temperature. Sand particles can interfere with its operation, causing it to stick open (leading to slow engine warm-up) or, more critically, stick closed (leading to rapid overheating). Abrasive wear can also damage its sealing surfaces.
  
  
• Coolant Hoses and Seals: While less likely to be immediately damaged, the constant circulation of abrasive sand can potentially accelerate the wear and tear on rubber hoses and various seals throughout the cooling system, increasing the risk of leaks over time.
• Engine Block and Cylinder Head Coolant Passages: While the sand originates here, residual particles can continue to cause issues by creating hot spots if they settle and obstruct flow in critical areas, even after initial flushing.

Sufficiency of Multiple Flushes vs. Permanent Damage:

Whether multiple coolant flushes are an adequate solution depends on the amount of sand present and whether it has already caused significant wear or become deeply embedded in components.

• Multiple Flushes:This is the standard initial procedure aimed at removing as much of the contaminant as possible. Using specialized flushing equipment and potentially back-flushing components can sometimes be effective, especially if the issue is caught early. However:
  • It can be very difficult to remove all sand particles, especially those lodged in the intricate passages of the radiator and heater core.
  • Flushing does not repair any damage that has already occurred.
• Permanent Damage:If the sand has been circulating for an extended period, or if a significant amount was present initially, permanent damage is a real possibility.
  • Abrasive wear on the water pump impeller or seals is irreversible and necessitates replacement.
  • Radiators and heater cores that are significantly clogged may be impossible to clear completely and will require replacement to restore proper cooling and heating.
  • Damage to the thermostat usually requires its replacement.

Recommendations for Emira Owners:

If casting sand is suspected or confirmed in the coolant of a Lotus Emira M139:

1. Seek Professional Diagnosis: Contact an authorized Lotus service center immediately. They should be aware of potential issues with the M139 engine and have access to any technical service bulletins or recommended procedures.
2. Document Everything: Keep records of any overheating incidents, loss of heating, check engine lights, and all service visits and communications.
3. Insist on Thorough Inspection: Beyond flushing, request an inspection of key components. This might involve checking coolant flow rates, inspecting the water pump (if accessible), and potentially using a borescope to examine the radiator and heater core internals.
4. Consider Component Replacement: If significant sand is found, or if flushing does not resolve symptoms, be prepared for the possibility that key components like the radiator, heater core, water pump, and thermostat may need replacement to ensure long-term reliability.
5. Oil System Check: While less likely, as a precaution, consider requesting an oil analysis to check for any signs of cross-contamination or unusual wear, although the primary issue is typically confined to the coolant.

In conclusion, while multiple flushes are a necessary step, they are not a guaranteed fix for casting sand in the M139's coolant. Permanent damage to various cooling system components is a distinct possibility, and owners should be prepared for potential replacement of affected parts to ensure the engine's health and longevity.