2010 Hyundai Santa Fe 3.5L V6, loud startup rattle (with recording!) vvt phasers?

Your battery is probably on its way out. Change your battery and see if it fixes the issue. Had the same issue on my wife's 2017 SF 3.3L V6 and on my mother's (same make/model/year). Swapping the batteries for Die Hard AGM batteries fixed the issue. It's CVVT related, they actuators don't have enough voltage at startup to lock the pins so they rattle. Good luck!

Sorry, but this makes absolutely zero sense. They are mechanical, driven by oil pressure. The solenoids that control the oil flow to them are controlled by the ECM. You’d have to have a reference voltage issue to the VCT solenoids.
 
Sorry, but this makes absolutely zero sense. They are mechanical, driven by oil pressure. The solenoids that control the oil flow to them are controlled by the ECM. You’d have to have a reference voltage issue to the VCT solenoids.
That would be a huge coincidence since I fixed this issue in two Hyundais the same way. Actually it was because of my mother's Sanata de that i figured it out. Her battery was in worse shape, so it was rattling even if it was off for a couple of hours, then it went down to 30 minutes or so. Her battery finally died and we had to actually jump start it. So I replaced the battery and it never rattled again. My wife's battery was in better shape, so it rattled only every now and then. Before I got to this point I upped the oil viscosity to 0W-40 but it didn't make a difference. It's weird, but in our case it was battery related. Since I swapped batteries i have not heard either engine rattle at startup. Also, the batteries on these Santa Fes are really small, smaller than in the Sonata and even the 2.4 Santa Fe Sport, because they only had so much room to spare under the hood. Before I got to this point, my wife's car spent a week at the dealership, and they tested everything except the battery and couldn't figure it out. They were about to take the valve covers off and manually measure the oil pressure (instructed to do this by Hyundai Techline). Me and the technician working on our car agreed it was nonsense, so i just to look the vehicle home. I'm just trying to help others here.
 
That would be a huge coincidence since I fixed this issue in two Hyundais the same way. Actually it was because of my mother's Sanata de that i figured it out. Her battery was in worse shape, so it was rattling even if it was off for a couple of hours, then it went down to 30 minutes or so. Her battery finally died and we had to actually jump start it. So I replaced the battery and it never rattled again. My wife's battery was in better shape, so it rattled only every now and then. Before I got to this point I upped the oil viscosity to 0W-40 but it didn't make a difference. It's weird, but in our case it was battery related. Since I swapped batteries i have not heard either engine rattle at startup. Also, the batteries on these Santa Fes are really small, smaller than in the Sonata and even the 2.4 Santa Fe Sport, because they only had so much room to spare under the hood. Before I got to this point, my wife's car spent a week at the dealership, and they tested everything except the battery and couldn't figure it out. They were about to take the valve covers off and manually measure the oil pressure (instructed to do this by Hyundai Techline). Me and the technician working on our car agreed it was nonsense, so i just to look the vehicle home. I'm just trying to help others here.

VVT actuator drainback/wear has nothing to do with the battery.
 
VVT actuator drainback/wear has nothing to do with the battery.
And I believe you 100% and in fact I thought that that's what was going with our motors. Yet, since I swapped batteries, no more startup rattle. How do you explain that?
 
Interesting... like the radio that pauses or switches off when cranking, maybe cranking voltage is delaying VVT solenoid function or ECU signaling current on some engines. Or, maybe cranking speed gets oil primed and pumping quicker. Glad that none of my batteries makes it past 4 years in the southern heat.

If the engine is running fine, you live with it.

If there are VVT screens, you remove and clean or replace them.

Test VVT solenoid function on the bench, if equipped.

Biggest issue I've seen is partially clogged screens or varnished/crud'd solenoids.

Once the mechanical damage or wear is done, not much you can do but replace worn out or broken parts.

Mask the noise.

With my troubleshooting of VVT start up noise, I keep changing variables until I find a combo that works for the owner. Sure cheaper than thousands in repairs since it'll simple chug along with normal maintenance while substituting brands, grades, filters, additives.

Quicker oil flow... maybe skip the cellulose media and use full synthetic media. Alternate among filters and see if any make a difference.
Quicker oil flow... use a thinner full synthetic oil, if grade is recommended. For example, if it calls for 5w30, use a 0w30. If it calls for 5w20, use a 0w20.
Or, slower oil drain back.... the opposite.... use a thicker oil that drains back slower. If it calls for a US 5w30, use a Euro or high HTHS 5w30, or step up to a 0w40 or 5w40, weather permitting since I don't care what owners manuals recommend for grades anymore.

Additives.... some seem to keep things moving better than others. Add a bottle of Lubegard Biotech, STP synthetic gold bottle, Rislone Nano, BG MOA, or even Tufoil to an interval and see if it makes a difference. They might free something up with cleaning.

For filters, don't get hung up on an OE filter. Most are nothing special. Use a full synthetic media oil filter from Amsoil, RoyalPurple, NapaPlatinum, WixXP, Purolator Boss, or the Fram Ultra/Titanium. Maybe one will reduce the startup rattle. Maybe the unrestricted flow of a stainless mesh filter, like gopurepower or hubb, will let the oil move more quickly thru the engine.

When its an intermittent issue, then there is a variable that is not accounted for. It doesn't automatically mean that its a drain back issue, a solenoid/battery issue, oil or filter flow issue, or crud/debris/varnish, or a non-parking VVT issue, or wear. And, I wouldn't blindly trust a dealer or mechanic that wants to spend more on parts/labor than what the engine is worth, only to have the issue repeat 30k miles later.

Things to help the engine run better..... new pcv valve, FI PEA based cleaner with toptier fuel, new spark plugs, new airfilter, cleaned throttlebody, fresh ATF/PSF, new coolant/thermostat/radiator cap..... This should help in keep moisture/fuel out of the oil, getting engine up to temp quickly, keeping all running good, and hopefully not add impurities to the sump.
 
It does sound like cam phasers not locking. Very similar to the noise my Honda 2.4 will make on occasion (rarely) that IS the VTC actuator. I know for the Honda K24 it seems to be a non issue for most owners. Many have the rattle for years with zero issue. Mine is more pronounced in the winter, and only lasts for a split second.

I don’t know enough about Hyundai’s V6 to really add anything of value, but it seems unlikely to me that the timing chain or tensioner would be the culprit as such low miles.

I thought it stretches the timing chain in the long term.

I also have same noise occasionally, especially when the weather is cold, but it's not loud. ('14 CR-V)

I was planning to change it when doing valve adjustment. I think I should keep it the way it is, if it doesn't stretch the chain or cause any other mechanical problems.
 
Interesting... like the radio that pauses or switches off when cranking, maybe cranking voltage is delaying VVT solenoid function or ECU signaling current on some engines. Or, maybe cranking speed gets oil primed and pumping quicker. Glad that none of my batteries makes it past 4 years in the southern heat.

If the engine is running fine, you live with it.

If there are VVT screens, you remove and clean or replace them.

Test VVT solenoid function on the bench, if equipped.

Biggest issue I've seen is partially clogged screens or varnished/crud'd solenoids.

Once the mechanical damage or wear is done, not much you can do but replace worn out or broken parts.

Mask the noise.

With my troubleshooting of VVT start up noise, I keep changing variables until I find a combo that works for the owner. Sure cheaper than thousands in repairs since it'll simple chug along with normal maintenance while substituting brands, grades, filters, additives.

Quicker oil flow... maybe skip the cellulose media and use full synthetic media. Alternate among filters and see if any make a difference.
Quicker oil flow... use a thinner full synthetic oil, if grade is recommended. For example, if it calls for 5w30, use a 0w30. If it calls for 5w20, use a 0w20.
Or, slower oil drain back.... the opposite.... use a thicker oil that drains back slower. If it calls for a US 5w30, use a Euro or high HTHS 5w30, or step up to a 0w40 or 5w40, weather permitting since I don't care what owners manuals recommend for grades anymore.

Additives.... some seem to keep things moving better than others. Add a bottle of Lubegard Biotech, STP synthetic gold bottle, Rislone Nano, BG MOA, or even Tufoil to an interval and see if it makes a difference. They might free something up with cleaning.

For filters, don't get hung up on an OE filter. Most are nothing special. Use a full synthetic media oil filter from Amsoil, RoyalPurple, NapaPlatinum, WixXP, Purolator Boss, or the Fram Ultra/Titanium. Maybe one will reduce the startup rattle. Maybe the unrestricted flow of a stainless mesh filter, like gopurepower or hubb, will let the oil move more quickly thru the engine.

When its an intermittent issue, then there is a variable that is not accounted for. It doesn't automatically mean that its a drain back issue, a solenoid/battery issue, oil or filter flow issue, or crud/debris/varnish, or a non-parking VVT issue, or wear. And, I wouldn't blindly trust a dealer or mechanic that wants to spend more on parts/labor than what the engine is worth, only to have the issue repeat 30k miles later.

Things to help the engine run better..... new pcv valve, FI PEA based cleaner with toptier fuel, new spark plugs, new airfilter, cleaned throttlebody, fresh ATF/PSF, new coolant/thermostat/radiator cap..... This should help in keep moisture/fuel out of the oil, getting engine up to temp quickly, keeping all running good, and hopefully not add impurities to the sump.
Nice thoughtful post with some viable suggestions. As an owner with the rattle I will try some of your ideas! THANK YOU!
 
How long ago was the battery replaced?
In my mother's 2017 Santa Fe SE it was replaced in October 2020, and my wife's (same make/model/year) was replaced at the beginning of this month. So I had some time to compare the two. The engine in my mother's car stopped rattling immediately after the battery was replaced, my wife's continued until I replaced it. Both got Die Hard AGM batteries, size 124R. Also, the rattling happened right after the engine started. The Hyundai tech noticed this as well. I let the tech know that the battery made the rattle go away, and he said that it's very much possible because he's seen other issues with these engines that are caused by a weak battery or one that's on its way out, namely injector issues. I hope this helps.
 
Granted it’s easy for ME to say this, but if it doesn’t happen all the time and it’s not a major problem (I hear cam phasers rattling upon startup on a lot of cars), then I’d let it go and just enjoy the car until it really becomes a major problem, and it probably never will.

But if you’re just looking to try something to free up a pin, you could try draining a quart of oil out and adding a quart of mystery oil and running for a little bit. Sometimes mystery oil will free things up, sometimes it won’t. Change the oil after obviously. It’s worth a $10 dollar shot. My own car once in a blue moon will give me a cam phaser tattle upon startup, at first I worried about it, but it’s so infrequent now that I don’t even think about it.
 
I just wanted to add a tiny update to this thread. With me putting so few miles on the car these days, the startup rattle hasn't had much priority.

I had mentioned before that it seemed to no longer happen on the first start of the day, and only on starts that occurred an hour or two after it had been run. Well, I think maybe I was correct about that being temperature related. The temperatures have been slightly higher over the past month here and it is doing it on the first start of the day again. It seems when it has sat for a day at less than 20F it doesn't rattle on startup, yet it starts and runs fine. Any warmer than that and it does it any time it has sat for half an hour or more. Very strange! :p

Just to cover all of the possibilities, some time in the next couple days I will try hooking it up to my old '06 Sonata with jumper cables to see if it makes the startup noise after sitting a while. This will hopefully shed some light on whether there is anything battery related going on here. As an electronics person I would *love* for it to be a battery issue, because I can somewhat understand that.

However... I have been considering using a chunk of the incoming stimulus money to have this taken care of if I do need to replace the VVT actuators. I have read in a few places that the updated Lambda II parts (newly designed actuators, cams, etc.) are actually not something that a lot of shops\dealers can get anymore, and I've seen some say that it can be a $4000 job if they can. This is... a little more than I'd like to spend on the vehicle I paid $8000 for.

I have read some comments\reviews of aftermarket steel actuators where people either just replaced the actuators or even just replaced the internals of them (presumably not even having to remove the gear and chain) and the noise was gone. Has anyone here done this? Read the reviews on these:



I bought this for a 2011 santa Fe 3.5.
It had a bad phaser rattle on cold start up.
I only used the actuator part because the pulley was different on my car.
This piece was steel rather than the factory aluminum. But it fixed the problem . It was a big job but it was worth it.

Good product. But it does not fit a kia Sorento 2011. I had to disassemble the gear wheel and use the old gear wheel to make it fit.

$200 in parts for both actuators, with the possibility of only having to replace the part of them that actually wears out, leaving the gear, chain and cams untouched... that sounds great. I would love to be able to talk to these people to find out what has become of their vehicles or if they've had any engine related issues since doing this.

I highly doubt my Santa Fe has the updated actuators since Hyundai apparently only acknowledged the issue formally with the Veracruz, so these original style parts should fit. I have actually seen plenty of listings for aftermarket replacements of the REVISED actuators, so I'm not sure that it's worth spending thousands to update them if people are still having issues with them.
 
I just tried jump starting my Santa Fe to rule out a battery problem and it made no difference that I could tell. The rattle was just as loud as ever after sitting for about an hour and a half.

I'm planning to try it again after the car has sat for a while, and this time I'll measure the voltage at the battery terminals with the other car running just to be 100% sure the connection is good (I should have tested this before, since I've never jumped a car before). At this point I'm leaning toward it not being related to the battery. I have no explanation for why a battery replacement fixed the problem for YogiTheCat on two different cars.

I am thinking of doing other cheaper maintenance items though, as recommended, like the PCV Valve. Looks like it's a pain in the butt to replace that on this engine though sadly. I see that on some vehicles it is right out in the open and is a less than one minute replacement... on this, it looks you have to get behind the engine, which is super lame since this is something that people seem to recommend replacing every 30k miles or so.

I'm still not sure where exactly it is though, as there is only one video with instructions on PCV replacement for this specific engine, and it's still hard to decipher what he's doing.
 
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