Former 1999 ML-320 owner here.
Something went wrong with it every 8.5 weeks on average.

Back when I bought my GX I test-drove a diesel GLK-250. Which I liked a lot. But then I thought back to my experience with the ML, and kept looking.

Chip H.

 

It seems that I will be taking on this job soon. Local general mechanic seemed a little too high. Nearest Lexus dealer doesn't return emails or phone messages and I refuse to chase people with my money (next nearest dealer has the same name). Tried my local Toyota dealer which I expected to be easy but explaining that it has a 4.7L v8 wasn't enough for them, they required the VIN. After the VIN was provided, one of their tech's asked if we were sure it had a belt (why did I send you the VIN???). Once I finally convinced them that it had a belt, there price was higher than the general tech.

I have watch several videos and it doesn't look that scary, just a lot of parts/bolts to keep track of. Has the RockAuto Aisin kit been confirmed as legit/not "cloned"?

 

Rock Auto has always been legit with my parts purchases but I have not bought a timing belt or water pump from them.

I was going to do my timing belt and water pump but decided I did not want to give up a whole day. It was worth the $900 I was charged to do it at a local Lexus/Toyota independent shop I have had good experiences with.


It is wild to me that people are not changing their timing belts for over 100K miles. The interval is supposed to be 90k miles and I have been pretty religious about doing it then (two replacements so far being over 200K miles). I guess that 90K recommendation is being very conservative.

 

Hello y’all, if you wanna own/drive your GX470 for the longest time, what other parts would you want to be changed during a timing belt & water pump change? Would it be a good idea for the starter and all other ignition accessories( Spark plugs, high tension wires, battery, etc…) be changed as well during this time(TB & Water pump change)?
Would appreciate all your 2 cents about this curiosity. Thanks

 

Our Iridium spark plugs are due every 120k.

I would use the Aisin kit (or have shop use it). It comes with the belt tensioner, idler pulley, water pump and gasket. All parts from OEM suppliers.

On my last timing belt (at 180k), I went ahead and also had the serpentine belt, tensioner, and idler pulley done as well. The serpentine belt and tensioner come off anyway, so no extra labor involved there.

I actually also bought a fan bracket (bracket for fan clutch) and for some reason the mechanic forgot to replace that. Might’ve been overkill on my part to want that done.

 

When I did the TB for the second time I also had them replace some of the other parts that would be labor-expensive to do later.I'm still on the original starter. If it dies I'll use the opportunity to change the coolant crossover pipe seals and maybe replace the knock sensors.
If you have the secondary air injection system (I don't) that's a good time to refresh it (or disable it)

Chip H.

 

Well, I haven't actually driven it yet but it ran in the garage long enough for a full heat-soak while I refilled the radiator. I am 99% sure that I can call this timing belt swap finished. It was freshly washed before I started this job and it was raining when I finished.

The biggest challenges were removing the crank pulley and keeping track of all the bolts/nuts. The crank pulley cost me a day while I waited for the correct tool to arrive - even with the correct tool, it required a LOT of leverage. I started out bagging all my nuts and bolts and keeping those bags with the items that were removed. At some point, I abandoned that strategy but I would not do that again. Once I had most everything back together I realized that I had an extra bolt with no obvious home. I had to re-watch a step-by-step video to realize where it went. Luckily it was the bottom/hidden bolt on the belt tensioner and I didn't have to disassemble anything.

If you don't have a fully equipped tool box then I would let a pro do this. I am not an expert auto mechanic but I have spent the last 25 yrs working on CNC wood working machinery from Italy. So I am not lacking when it comes to metric tools.

All told, I probably have less that $400(Aisin kit, coolant, blue loctite, gasket material and a torque wrench) and about 6 hrs of my time invested in this job. Not bad compared to the best quote I got at $1300. In what could be considered my twisted logic, depending on who you ask, that is $900 I can spend on getting my suspension where I want it.

One last piece of advice for those considering this job: Make sure you save some patience for reinstalling the fan assembly. This was a PITA to remove and even worse going back on. Luckily, I had finished all the engine reassembly a day before finishing the radiator and "other" stuff.

My engine was already quiet but after all this work, the only noise I hear from the engine is the air moved by the fan and the injectors clicking. My belt appeared to be in pretty good shape so no bullet was dodged. But the only record I can find of this belt begin replaced happened at near 90K and it now has 240K. This job IS documented incase I don't own this after another 90K.

 

Hi All,

I searched the forum but couldn't find a post with the same circumstances. Bought my wife an 06 GX and wanted to do the timing belt since there was no previous service documentation for it. During the process, I bumped the starter to loosen the crankshaft pulley bolt. The next day, after buttoning everything back up, it wouldn't crank. Let me explain precisely:

I get in the vehicle and insert the key, and the red security light quits blinking and goes off. Everything works (battery is new and charged). All lights come on and stereo starts to come on. I turn the key. The stereo and clock dim, but there is no crank or sound from the starter (though I can hear the fuel pump).

Battery disconnected through the whole process. Fuses checked. Starter relay checked (and replaced just to be certain). I have jumped the relay terminals (battery to solenoid terminal) to check the starter, and when I do so the starter cranks (but engine does not start, even when key turned to "ON"). Terminals/wires going to relay look to be in good shape with no corrosion. Battery connections are nice and tight.

My primary concern now is whether my immobilizer is the issue. However, since the security light goes off and the lights come on it may be that the ECM is recognizing my key.

Any help is greatly appreciated!

 

Can you rotate the engine by hand?

Chip H.

 

Hi, Chip. Yes, can rotate by hand. I've run a few more tests. Jumping power between battery and solenoid terminals activates starter, which cranks but the engine does not start (key turned to "ON"). Control terminals do NOT receive power when key is turned to start; therefore, no power is being sent to starter relay. ALL fuses have been tested with test light, and the two fuses in small fuse box in cab labeled "STA" and "ST2" are NOT receiving power when key is turned to "ACC" or "ON".

I have a wiring diagram and am going to check NSS and ignition switch, though my gut is telling me that this is a computer/security issue. I know wiring can fail without warning, but failing between bumping the starter and finishing up the timing belt (that is, while immobile and not transferring current) just seems a bridge too far.

 

It sounds like something is not plugged in properly or the crank/cam sensors is somehow not getting data. Also FYI in any modern car, if you turn the key and it won't start, jumping the starter will never work because the ECU is smart enough to know that it did not command that and therefore will not fire the injectors and/or spark plugs. Not that helpful but I'd start there and also double check that there are no large vacuum leaks and the MAF is working properly. If you can get the engine to turn via the key, verify spark, then fuel, then timing.

 

Thanks, Captain. Yes, you're correct, I was just ruling out the starter/post-relay power and trying to describe in detail. Yep, getting the engine to turn via the key is definitely problem numero uno. Will verify again that all sensors are plugged in correctly. At this point, everything is fair game. Appreciate any and all help!

 

I am far from being an expert on cars that are covered in sensors but I wonder if the cam position sensor, crank sensor or anything else that had to be disconnected would keep the engine from turning over via the key.

I did see a video showing a ground strap on the alternator. My 08 didn't have this but maybe the 06 does?

The fact that you removed the crank pulley bolt with a starter bump makes me think that the starter does turn without a couple of sensors connected. The starter bump method was a little too scary for me, I waited for the special crank holding tool to arrive.

 

Hey, GSG. Yeah, you are exactly right that the bump method worked with all of the sensors required for the service disconnected. I've looked and looked thinking maybe something is still disconnected - but it all was when the starter was bumped (also, nothing is disconnected).

Man, I went back and forth over trying the bump method, but it was no big deal once I got it all set up. Bolt popped loose right away.

One thing I was able to do today while the kids were occupied is verify that the "STA" and "ST2" fuses DO receive current/go hot when the key is turned to crank. This makes me think that the ignition switch is not the problem. Looking over the wiring diagram, it looks like my next step is to test the NSS. My plan at this point is to see if I can trace the wire going from the ignition switch to the harness on the NSS to test whether it goes hot when the key is turned. Sigh...nuts and bolts are so much more my speed!

Thanks again for the replies.

 

How much should I pay to get my Timing Belt & Water Pump replaced? I know it’s an expensive job but not sure what’s the right number