RX 350 cranks slow in the morning but fine after driving
Posté: Mar Aoû 18, 2026 4:02 pmRX 350 cranks slow in the morning but fine after driving - battery or alternator?
I'm hoping someone here can help me figure this out because I'm getting conflicting advice from different people. My 2017 RX 350 has been starting really sluggishly in the mornings lately, like it takes a good two or three seconds of cranking before it fires up. But once I've driven it and it's warmed up, it starts perfectly fine for the rest of the day, even after sitting for a few hours. A friend of mine who's a mechanic said it's probably the battery on its way out because the cold cranking amps drop overnight, but another guy told me it could be the alternator not charging properly. I took it to a local shop and they tested the battery and said it was showing 12.4 volts which they said is "borderline" but not terrible. The thing is, I don't want to just replace the battery and find out it was something else, but I also don't want to ignore it and end up stranded somewhere. The car has about 120,000 kilometers on it and I think this is still the original battery from when the car was new, so it's had a good run honestly. I've been looking around Sharjah for a place that actually knows these cars because Lexus batteries aren't just generic ones, they have specific specs and I've heard you need to reset the battery management system afterwards. I was thinking about getting a Genuine Lexus battery replacement in Sharjah from a proper specialist rather than going to a general workshop that might just throw in any battery that fits. Has anyone had this slow crank issue and did a new battery fix it completely? I just want to make sure I'm not throwing money at the wrong thing.
I'm hoping someone here can help me figure this out because I'm getting conflicting advice from different people. My 2017 RX 350 has been starting really sluggishly in the mornings lately, like it takes a good two or three seconds of cranking before it fires up. But once I've driven it and it's warmed up, it starts perfectly fine for the rest of the day, even after sitting for a few hours. A friend of mine who's a mechanic said it's probably the battery on its way out because the cold cranking amps drop overnight, but another guy told me it could be the alternator not charging properly. I took it to a local shop and they tested the battery and said it was showing 12.4 volts which they said is "borderline" but not terrible. The thing is, I don't want to just replace the battery and find out it was something else, but I also don't want to ignore it and end up stranded somewhere. The car has about 120,000 kilometers on it and I think this is still the original battery from when the car was new, so it's had a good run honestly. I've been looking around Sharjah for a place that actually knows these cars because Lexus batteries aren't just generic ones, they have specific specs and I've heard you need to reset the battery management system afterwards. I was thinking about getting a Genuine Lexus battery replacement in Sharjah from a proper specialist rather than going to a general workshop that might just throw in any battery that fits. Has anyone had this slow crank issue and did a new battery fix it completely? I just want to make sure I'm not throwing money at the wrong thing.