Hi my name is Will. I have recently had problems starting the car. It has been fortunate to start everytime i tried this past week but it sounds like it is trying too hard. A couple of times when i started the car, there was a loud rattling sound coming from the engine. Last night it barely cranked. It all started about a week ago and about a week ago I helped my buddy jumpstart his LS400 with mine cause he left his radio on too long while he was talking to his GF. I am wondering if that has anything to do with it because there were no problems before I helped my friend. My battery is about a year old and there are no warning lights. Thank you.

 

Sounds like your battery is out of juice.
There is a procedure to be followed when jump starting other cars with your LS. It basically goes like this: Don’t F’N Do It! Why? When your friend cranked his engine, he overloaded your alternator and burned it out. Now you have to replace it for about $350!
I tried to jump start a tiny Nissan once and when he began cranking, I felt my motor slow down and smelled some fried wires. I disconnected the jumper cables immediately and saved my alternator just in time. Another second and I would’ve been in your shoes.
Hope this helps.
Good luck.

 

Thanks for the relpy Rice. It sounds like it is the problem cause last night the warning light turned on for a sec and the radio wouldnt stay on. I gave it a little revvin and it went away along with the problem. Things seem to be fine right now cause the last couple of starts, the car cranked fine. My only question is now, almost half a year ago, I had to help my dad jump start his big 454 V8 truck and no problems came out of that. Another thing is, if its not good to jump start other cars, why do they put directions in the owners manual?

 

If done correctly and if the wiring on both cars is not messed up, then jump-starting is not a problem.
I've jump-started lots of cars and only had trouble once or twice.
The problem may arise when the car that you are trying to jump start has a short or improper aftermarket wiring. That's when your system may overload and you will end up paying dearly for your good deed. How do you know if the wiring on the other car is OK? You don't. That's why I suggest to think twice before giving someone a boost.
If you really must give someone a boost, I suggest swapping his battery for yours and then swithcing them back once the car starts. It's a little more work, but it's worth it.

Here's a good link for jump-starting other cars. They even talk about the risk of frying your alternator.
How to jump-start a car.

 

Thanks for you help again Rice. So changing the alternator is 350? is that including labor? I want to change it as a precautionary, even if it MIGHT be ok. Hmm...maybe I should just reconsider helping my friends...hehe..