jcomrx350

I have a 2011 rx350. About 2 weeks ago, I turned off my car to pump gas and when I got back in, it wouldn't start. I had to be jumped off. I drove it home and to work the next day, but at lunch it wouldn't start again and I had to be jumped off again. We put in a new battery (gold) and it cranks but one day, it kept turning over. I immediately turned it off. When I tried again, it cranks but not immediately. It is a weak, struggling, long sounding crank. The only other thing I can assume it is is the alternator, but this is not suppose to happen with a lexus! any suggestions?

SteveCraig

With the engine running, assuming you can get it going again, check DC volts across the battery terminals.
Any type meter will work as long as it has a DC volts range.
You should see +/- 13.8 - 14.2 V for a properly charging alternator. Anything less you have a problem.
Could be a loose battery cable/connection, alternator diodes etc..

Yes, this will happen to a Lexus just as fast as my old Buick. Common to a point. Warranty still on the car ?
I always coat battery terminals with a thin layer of Vaseline. Inhibits any corrosion & ensures a good solid mating surface.
The old battery may have been fine. Get it load tested ( recharge it first). If good you now have a good spare.

Gene01

Two suggestions if you don't already have a voltmeter:
1. Get a really cheap (sometimes free) digital voltmeter from Harbor Freight when on sale.
2. Google for a voltmeter that plugs into the cigarette lighter (cost about $3 and free shipping) and leave it in the car. You can even leave it plugged in since the Lexus sockets are unpowered with the ignition off.
This will show you the state of the charging system with the engine running (as SteveCraig noted above) and the state of the battery with the ignition on ACC or ON. Could save you from being stranded away from home some day by warning you that something is going wrong.

RX330inFL

It is very possible you received a bad battery. Not unheard of. Best to take your vehicle back to where you got the battery to have it checked along with your charging system.

jcomrx350

Thanks for the the help. Just a little extra info, yes we still have a warranty but the closest dealership would cost us in gas what a new alternator would. It is cranking now and I am driving it. It just sounds different when it cranks. We checked the first battery and it was fine. They checked the alternator and said it was fine too. I am not sure what the readings were exactly. We ordered a new alternator so we will see if this works. Will let you know. thanks again.

raylor4

I am very interested in the cost of your alternator, parts and labor, because when we were offered the extended warranty for our CPO '11 RX, the salesman said a new alternator is $1,100 installed. You can buy a great deal of gas for $1,100. I think he was blowing smoke to sell the warranty. We declined the extended warranty.
BTW, why are you ordering an alternator when the tech said it was good?
My experience with a dead alternator on a Honda, many years ago, is that the engine dies and won't start, but cranks ok.
Ray A.

raylor4

If jumping the battery starts the engine, and it continues to run, and cranking sounds odd, my money's on the starter, or a starting relay.
Ray A.

SteveCraig

Pick-up a low cost volt-ohm meter. Diagnose at least a part of the issue yourself. Electrical parts can be spendy on modern cars & usually offer no returns/no exceptions.
Starter cranking makes a different noise ?
Might pay to get it to the dealer, possibly a Toyota dealer can help ?

raylor4

I Googled Lexus RX starting problems and got this:
https://www.clublexus.com/forums/rx-...-problems.html
Most surprising was having the key fob and a smart phone in the same pocket causes starting problems.
Steve: Toyota dealer is excellent idea. Same engine. No freebee warranty work, though.
Ray A.

raylor4

Just curious. What was the source of your problem?
Ray A.