rb2010

Hi everyone,

A quick electrical test at O'Reilly revealed that the voltage regulator in my alternator is failing. I found a replacement regulator for ~$55 delivered, original DENSO/TRANSPO unit. I am pretty sure it won't be a problem to replace the regulator once I have the alternator out but pulling it out doesn't seem to be so easy, not as easy as it would on a Ford, Hyundai or other vehicles that we owned. I am mainly concerned about losing the grip of the serpentine belt and then not being able to put it back together since the access is so inconvenient.

I have searched everywhere for a guide on removal the alternator from an 07 ES350 but only found one for GS350 which seems to be different. Does anybody know where to find one? Thank you!

nevernu

maybe this will help and see my post on the rib belt here
https://www.clublexus.com/forums/es3...procedure.html

rb2010

Thank you for the attached PDFs as well as the PDFs in the referenced thread. Do I understand it right that you can replace the serpentine belt by removing the RH wheel + fender apron but for the alternator you have to really undo the whole front end including draining the coolant and removing the radiator? Thank you!

chuyrobles

This may be too late to help out the OP but I will add my experience for others. I just replaced a busted alternator this weekend. The easiest way to remove the alternator is by moving the radiator. You don't need to remove it completely, but you have to remove the electric fans, hoses, and top radiator support bracket. Once that stuff is removed, you can leave the condenser bolted to the radiator and use a stick to push the radiator away from the engine about six inches. You don't need to remove the grill or bumper, not even the hood release mechanism - that stays bolted to the top rad support bracket and you move it out of the way and set it on the engine. You also need to disconnect the horn electrical connectors and some sensor above the passenger side horn. As for the alternator itself, there are two easy-to-see, and remove, 14mm bolts that attach the alt to the engine block. What is tricky to remove is the low and inside bracket attached to the alt and engine block. There are two 12mm bolts to remove the bracket. The tricky part is detaching the electrical wire that connects to that bracket. I ended up cutting off the connector and then using a zip tie to re-attach it.

BTW, our alternator had a decoupler pulley failure. I will post a separate thread to bring attention to their maintenance. It's essentially a clutch inside the pulley; it can lock up or free-spin. Mine went the free-spin route and stopped charging the battery. The free-spin generated enough heat to fry the alternator. Got a replacement one at O'Reilly's for $149. So far, so good.

rb2010

chuyrobles, thanks for posting that info! Did you have to drain the coolant fluid or did that stay in the system?

Also, your post reminded me that I didn't post back with what I ended up doing. In one nothing, nothing. I went to the Lexus dealer and they said that auto parts stores' testers are very generic and I should test it at a Lexus dealer (any dealer, not the one I was calling). So that's what I did and the results came out just fine, they said that the alternator is in a great shape and there should be at least another 70k miles on it left. The service advisor also added that he hasn't seen more than a handful ES350s that needed an alternator changed before 120k miles.

How many miles does yours have?

Thank you!

chuyrobles

We have 155k miles. It was the ADP pulley that went bad, which then fried the alt. Gates sells the unit for about $35 and recommends replacement every 100k. You will need to purchase new tools to remove the pulley.

Yes, drained the antiifreeze as I removed the hoses. You might get away with not removing lower hose but it does get in the way when removing the alt. plus, I added fresh antifreeze.

rb2010

Thanks for the info! Do you know if that was your original alternator? It seems like it failed because of the pulley though.

mlacomb

Does it seem like there is enough room in the engine bay to actually get the decoupler pulley off without pulling the alternator? Gates' website states this item is a wear item and should be replaced every time the belt is changed.... yet another thing to worry about (on a fairly worry-free vehicle!)

chuyrobles

Yes, we had the OEM alternator and there is no doubt in my mind the pulley led to the alternator break-down. I think I still have a pic of the pulley with the cap removed. It had about two tablespoons of rust dust inside. BTW the cover pops out by using a sharp pick on the edges. Then, it presses back in easily by hand. If I recall, there is enough room to service the pulley; you just have to remove the belt and use the special tool to remove it.

collinpyle

Hello all,

I just did this job a few days ago using the help of this post. Thanks to chuyrobles for input.

Let me start by saying DO NOT FEAR THIS JOB.

Removal of the radiator, as well as draining of the cooling system is not necessary. Do not waste time or money following this part of the recommended repair instructions. (Unless your working under a shop maybe).

1. Remove all the plastic covers over the engine.

2. Disconnect the battery.

3. Disconnect all the electrical connections from the alternator.

4. Disconnect the bracket holding electrical connection on top of the valve cover.

5. Disconnect the bracket holding the oil dipstick.

NOTE: I would recommend putting all the bolts back into these brackets as to note lose them later in the process.

6. Remove the front bolt in the alternator. It's pretty tight, you may need kroil or liquid wrench to aid in the process.

7. Remove the out hose from the water pump. Fluid will come out so you can try catching it someway.

8. Remove the metal hose outlet from the water pump by remove the two screws holding it in.

9. Remove the right front tire and the splash shield to gain access to the tensioner on the belt.

10. Untighten the belt and pull it off the alternator pulley. You do not need to remove the belt out of the pulleys.

11. Remove the idler pulley to help gain better access to the rear bolt to the alternator.

12. Remove the rear bolt in the alternator.

13. Now move to the front of the engine, remove the bolts on the front frame holding the airbox. As well as the black ones to the left and right of it. This will aid in moving the radiator to give enough room for the alternator to be removed.

14. Look down the radiator and between the front bumper. Disconnect the electric connections to the horns and the other electrical component in the front. (If you cannot get the electrical connections just disconnect the bolts that mount the horns and electrical component.

15. Still looking in the area described before, unscrew the bolt on the bottom of the large black metal piece.

NOTE: This should free the whole front mount to be removed. If it does not, remove other bolts/fittings as required. You might need to remove the radiator out hose. to free the radiator. I personally did.

16. There is one more bolt towards to bottom of the alternator that needs to be removed. This a somewhat hard one to see. I'm sure others will agree.

a. looking at the alternator from the front of the car this smaller bolt is at the bottom right of the alternator. You will need a long extension to get this final bolt out.

17. The alternator should be free now! Pull the radiator forward towards you while weaving the alternator through the front of the motor. It should go eventually.

I'm sorry I could not provide pictures, bolt sizes, or more explicit information.

If you have any questions, please feel free to ask.

Best

chuyrobles

My Oreilly's replacement alternator acted up two weeks ago. The battery light came on. Using two voltmeters, I measured 11.6 volts at the alternator lead (with engine running it should be 13.5+). Took the alt to Oreilly's and it passed the bench test - twice! OTC dude said to put it back on and bring the car in for a test with alt on the car and if it fails then, I'll get a new alt. Put the alt back on and what do you know, output now read 14 volts. The only explanation that makes sense is that an alt brush got stuck; and then unstuck with the banging around it went through when removing it.

This time around, I did not have to remove the pass tire or side cover. I was able to access everything from the top. It helps to have the right length extensions and sockets. #8 above is not necessary - that's the thermostat cover, right? I've never had to remove that to remove or install the alt.

chuyrobles

The Oreilly alternator acted up again; this time, Oreilly witnessed the problem and I got a new alt on the lifetime warranty. Turned out to be a faulty voltage regulator.

Note, if you are going to replace alt, consider installing a new thermostat if the mileage supports it. With the alt off, it's quite easy to access the thermostat and housing. You're likely to have to drain half the radiator anyways; so, take the extra 20 minutes or so to change to replace the thermostat.

p_bplayer

Just found out I need to replace my alternator due to a faulty regulator. I'm also at the point that I need to flush and refill the radiator fluid as well so I might as well also replace the thermostat, correct? Since everything will be exposed, Is there anything else I need to look at doing while I've got it all apart at this point? Got 118,00 miles on it.

chuyrobles

Serpentine belt hoses and idler pulleys. The upper idler pulley, especially, is easy to access with the alternator removed.

jkayca

You may want to take a look at the water pump too to see if it's leaking. A known issue with this car and others that use the same drive train.