During a cold start, the car remains in the warm-up routine with a slightly increased engine speed. It is advisable to wait with driving the car until the speed drops leaves the warm-up programm.
I do not know whether it is essential to wait for this drop in the 765LT.
What I can say is that my Ferrari Scuderia has ‘stuck’ in the warm-up phase when I didn't wait for the warm-up programme to finish. This meant that the I couldn't accelerate the car and remained stuck in the warm-up programme. The Scud had to be completely switched off and restarted.

 

Solid question, and not a dumb one at all — it comes up more often than people admit.
For McLarens, especially dry-sump cars like the 765LT, the main reasons long idling isn’t great come down to oil management and combustion efficiency at low load:
1. Dry sump scavenging is less efficient at idle.
The oil can pool slightly in the crankcase if the engine idles too long, which can lead to increased oil consumption or eventually throw level warnings.
2. Fuel doesn’t burn cleanly during extended idle.
These engines are calibrated for performance load, not prolonged stationary burn. Incomplete combustion leads to carbon deposits on injectors and valves, especially with short drives or cold starts.
3. Turbos stay hotter longer than you'd think.
Idling after a hard drive is good for turbo cooling — but casual idling (like 10+ mins in traffic) just prolongs heat soak and adds thermal stress to oil in the lines.
We’ve used DiagCode on a few cars to pull combustion data, idle time logs, and crankcase pressure behavior — and the pattern is clear: McLaren ECUs tolerate short idles fine, but extended idle time with short trip cycles often shows up later as carbon buildup or minor misfire correction.
TL;DR:
Let the car idle 30–60 seconds after cold start
Always idle for 60–90 seconds after spirited driving
DON'T routinely idle for long periods in neutral or park
Drive gently to warm up the drivetrain, not just the oil
And yep — always check oil warm, on level ground, and after shutdown with the official method. No dipsticks makes things... more fun.

 

Solid question, and not a dumb one at all — it comes up more often than people admit.
For McLarens, especially dry-sump cars like the 765LT, the main reasons long idling isn’t great come down to oil management and combustion efficiency at low load:
1. Dry sump scavenging is less efficient at idle.
The oil can pool slightly in the crankcase if the engine idles too long, which can lead to increased oil consumption or eventually throw level warnings.
2. Fuel doesn’t burn cleanly during extended idle.
These engines are calibrated for performance load, not prolonged stationary burn. Incomplete combustion leads to carbon deposits on injectors and valves, especially with short drives or cold starts.
3. Turbos stay hotter longer than you'd think.
Idling after a hard drive is good for turbo cooling — but casual idling (like 10+ mins in traffic) just prolongs heat soak and adds thermal stress to oil in the lines.
We’ve used DiagCode on a few cars to pull combustion data, idle time logs, and crankcase pressure behavior — and the pattern is clear: McLaren ECUs tolerate short idles fine, but extended idle time with short trip cycles often shows up later as carbon buildup or minor misfire correction.
TL;DR:
Let the car idle 30–60 seconds after cold start
Always idle for 60–90 seconds after spirited driving
DON'T routinely idle for long periods in neutral or park
Drive gently to warm up the drivetrain, not just the oil
And yep — always check oil warm, on level ground, and after shutdown with the official method. No dipsticks makes things... more fun.

Outstanding and informative reply - and pretty much why I asked the question! Thank you!

 

And checking the oil can be a little challenging. It's not like we have dip-sticks. Oil is worthwhile to check before and after a drive.

 

just make sure you have the right amount of oil in the car always.

 

Yes idling these engines is not recommended because the dry sump scavenging performance is pretty poor at idle speeds. This leads to a build up of oil in the crankcase and then increased oil consumption.

 

You can avoid this by installing the rear main seal incorrectly so it leaks away that build up of oil for you.

 

I know it’s an honest question…but the whole thing is silly. Idling til the revs drop and engine gets up to temp is normal…BUT let’s be real here, 99% of Mac owners don’t drive their cars that much anyway, so who cares. Modern engines are nearly bullet proof these days. People worry about too much stuff. Do an annual service and just drive the shit out of it rain or shine…If you track a lot then shorten the service interval but otherwise…this is just ridiculous. Worried about idling…jeepers…These are not F1 engines…not a Solus either…

 

Yup

 

Honestly the only dumb thing here was someone copy/pasting a ChatGPT answer.

Idling is fine. Idling to warm up won't warm up the transmission / differential, so they'll still be cold. And… the manual dissuades you from prolonged idling. From the 765 manual, page 2.47:
"Avoid idling the engine for more than 10 minutes."

Although that's not unique to the 765, I think they have that copy on all of them (Artura is the same).

 

as soon as the rpm’s drop after a cold start i start drivingi won’t get on it until engines up to temp.don’t know how close people live to the highway but just driving the car at a normal speed will be enough for the oil temp to drop so it won’t coke in the turbos.

 

Gosh, sorry if it's a dumb question. I let my Jeep warm up by idling for a few minutes when it's cold out. I would think idling for a few minutes for most engines would get things warmed up before driving but apparently it's best to just start driving in these things. Again, sorry for being a dumb-ass!

 

Every day, the dumbest thing I read is on this forum.

God forbid a guy asks a question on the forums you may know the answer to. He probably knows the answer to something you don’t.

Yeah, he could have googled it, but considering he’s asking about his new 765LT, he wanted a little reassurance from the McLaren forum to see if there were any specific hard rules. Nothing to go after the guy over.

 

Every day, the dumbest thing I read is on this forum.

 

lmao

 

From Chat GPT:


Idling a sports car occasionally and for short durations is not inherently harmful, but prolonged or frequent idling can have negative effects, especially on high-performance engines. Here's what you need to know:

---

### 🔧 Why Idling Isn’t Great for a Sports Car:

1. Carbon Buildup

* High-performance engines are designed to run hot and hard. Long periods of idling can lead to carbon deposits on valves, spark plugs, and injectors, especially in direct-injection engines.

2. Fuel Dilution

* In cold starts, unburned fuel can wash into the oil, especially if you idle for long before the engine warms up. This dilutes the oil and reduces its lubricating ability.

3. Incomplete Combustion

* Idling, especially at low temperatures, means incomplete combustion. This can produce more soot and clog up the exhaust system over time—bad news for turbos and catalytic converters.

4. Excessive Engine Wear at Cold Temps

* Modern engines warm up faster when driving, not idling. Letting it idle cold for 10+ minutes wears the engine more than just driving gently right away.

5. Turbos Don’t Like It

* If your sports car is turbocharged, long idling after hard driving is helpful to cool the turbo. But idling for no reason can keep the turbo hot unnecessarily and degrade oil.

---

### ✅ When Idling is Actually Helpful:

* Turbo Cool-Down (After Aggressive Driving)
Letting the car idle for 1–2 minutes after hard use gives the turbo time to cool, preventing oil coking.

* Cold Start in Frigid Weather
In very cold climates, idling for 30–60 seconds before driving helps get oil circulating and avoids a shock-load to a dry engine.

---

### 🚫 What You Should Avoid:

• Idling for more than 5 minutes routinely
• Letting the car warm up only by idling (better to drive gently)
• Revving the engine while cold or during idle
• Using remote start for long periods daily

---

### 👨‍🔧 Bottom Line:

A high-performance sports car is meant to be driven, not left idling.
Short, occasional idles are fine—especially after spirited driving—but avoid making it a habit. Drive it often, keep the oil fresh, and let it warm up with light load, not in park.

 

Starting the engine at all isn't good for it.