Howto: DIY LR4 Alternator replacement

[mbw]

So, this entire thread very well could be just a (stupid on my part) crazy learning experience. The charging profile may have just changed due to cold weather and I just never noticed how low the car lets the battery get. I did jump start someone with a very low battery and it drained me down lower than it usually gets. The alternator in general wont quickly charge my dual battery setup because I haven't done many long trips. So what I saw and am seeing could be completely normal.

I am going to continue to keep an eye on the charge profile and see what happens when I just live with it in the cold (will be -15F before windchill here today, was -11F when i just ran out to get some breakfast) and not use my CTEK to keep the voltage up. I usually do use my CTEK to maintain this setup.

Worst case I have a spare alternator and main battery. I can use the battery on my boat, which is a huge upgrade. It already had dual batteries also.

I should chill out though.. the car has still never thrown a code or even a low battery warning. The only reason I noticed all this was because I am a data nerd and have the national luna dual battery monitor and IID tool and whatnot.

I hope that all my drama ends up being useful to the community however. May as well get some education and entertainment at my expense (literally).

 

[jlach993]

So, this entire thread very well could be just a (stupid on my part) crazy learning experience. The charging profile may have just changed due to cold weather and I just never noticed how low the car lets the battery get. I did jump start someone with a very low battery and it drained me down lower than it usually gets. The alternator in general wont quickly charge my dual battery setup because I haven't done many long trips. So what I saw and am seeing could be completely normal.

I am going to continue to keep an eye on the charge profile and see what happens when I just live with it in the cold (will be -15F before windchill here today, was -11F when i just ran out to get some breakfast) and not use my CTEK to keep the voltage up. I usually do use my CTEK to maintain this setup.

Worst case I have a spare alternator and main battery. I can use the battery on my boat, which is a huge upgrade. It already had dual batteries also.

I should chill out though.. the car has still never thrown a code or even a low battery warning. The only reason I noticed all this was because I am a data nerd and have the national luna dual battery monitor and IID tool and whatnot.

I hope that all my drama ends up being useful to the community however. May as well get some education and entertainment at my expense (literally).

Hey i’m just digging up an old thread here!! So i have the same exact issue with my truck..what happened in your situation? Did the charging profile ever normalize or did you need a new alternator? My battery died and i installed a new one. Upon firing up the motor i get 14.7ish volts. Shortly like 30 seconds after it goes down to 11.8-12.2ish. I’ve been driving it around for days. Sometimes it goes to 13ish, but mostly it’s 11.8-12.2. The battery was super fresh when i installed it. It was charged 100% on a battery tender after it was bought from the store. Let me know buddy! Thanks.

 

[PaulLR3]

Is your passenger side valve cover leaking? Mine was and the oil was dripping into the alternator. My alternator was still working but the mechanic said he had seen this before and the oil would eventually cause the alternator to fail. This happened around 105K miles so I was fine with putting in a new alternator along with the new valve cover gasket.

 

[mbw]

Hey i’m just digging up an old thread here!! So i have the same exact issue with my truck..what happened in your situation? Did the charging profile ever normalize or did you need a new alternator? My battery died and i installed a new one. Upon firing up the motor i get 14.7ish volts. Shortly like 30 seconds after it goes down to 11.8-12.2ish. I’ve been driving it around for days. Sometimes it goes to 13ish, but mostly it’s 11.8-12.2. The battery was super fresh when i installed it. It was charged 100% on a battery tender after it was bought from the store. Let me know buddy! Thanks.

Back when this happened, now that I reflect on it more. I do think something was wrong with that alternator. I replaced it.

I do notice though, if I leave my truck parked for a long time (like a week) and put the CTEK charger on its charge mode (rather than just the 12v supply mode) The batteries are really really charged and if you start the vehicle after just having it charged up, the charging system just kinda shuts off. It will stay around 12v for a long damn time. If you reset the system (pull the negative battery terminal for a few minutes) and try again.. boom 14v.

So to make sure its not the charging system trying to be smart on a fully charged battery, just reset it and check again. My primary suspect for how I fried my alternator is that I had just jump started some ladies minivan a day or two before all this. Ever since I carry a Antigravity Batteries AG-XP-10 Multi-Function Power Supply and Jump Starter.

 

[jlach993]

So i did have an oil leak and oil did get onto everything below the oil filter housing which included the alternator. My brother had one too many beers and cross threaded the oil filter cap and it was spewing some oil for a few hundred miles before i realized. However that was roughly 10k miles ago. I did spray everything down with brake cleaner to clean everything up, including the alternator. Maybe all of that combined with 89k on the clock fried my alternator....

Hey i’m just digging up an old thread here!! So i have the same exact issue with my truck..what happened in your situation? Did the charging profile ever normalize or did you need a new alternator? My battery died and i installed a new one. Upon firing up the motor i get 14.7ish volts. Shortly like 30 seconds after it goes down to 11.8-12.2ish. I’ve been driving it around for days. Sometimes it goes to 13ish, but mostly it’s 11.8-12.2. The battery was super fresh when i installed it. It was charged 100% on a battery tender after it was bought from the store. Let me know buddy! Thanks.

 

[jlach993]

Back when this happened, now that I reflect on it more. I do think something was wrong with that alternator. I replaced it.

I do notice though, if I leave my truck parked for a long time (like a week) and put the CTEK charger on its charge mode (rather than just the 12v supply mode) The batteries are really really charged and if you start the vehicle after just having it charged up, the charging system just kinda shuts off. It will stay around 12v for a long damn time. If you reset the system (pull the negative battery terminal for a few minutes) and try again.. boom 14v.

So to make sure its not the charging system trying to be smart on a fully charged battery, just reset it and check again. My primary suspect for how I fried my alternator is that I had just jump started some ladies minivan a day or two before all this. Ever since I carry a Antigravity Batteries AG-XP-10 Multi-Function Power Supply and Jump Starter.

Hey thanks for the reply and insight. What alternator did you go with? Oem new or reman? Also what brand if not oem. I’m thinking about going with a new Denso unit.

 

[mbw]

Hey thanks for the reply and insight. What alternator did you go with? Oem new or reman? Also what brand if not oem. I’m thinking about going with a new Denso unit.

I went with a new Denso which is also OEM. Alternators are a weird parts segment. Lots of junk out there. reminded me of the damn wheel bearings market. Fakes and trash everywhere.

 

[ktm525]

I went with a new Denso which is also OEM. Alternators are a weird parts segment. Lots of junk out there. reminded me of the damn wheel bearings market. Fakes and trash everywhere.

If you can afford the downtime having your original alternator rebuilt can be a good alternative.

 

[mbw]

If you can afford the downtime having your original alternator rebuilt can be a good alternative.

I guess it depends on what is wrong with it, but ya.. I still have the other alternator. I should get it fixed up

 

[Quijote]

I guess it depends on what is wrong with it, but ya.. I still have the other alternator. I should get it fixed up

Definitely.