Engine noise Forte EX...

🤖 AI Summary

📝 Summary:

A 2020 Kia Forte EX owner reports intermittent#1 valve train knocking at warm idle, distinct from injector noise. After switching to 10w-30 oil, engine noise reduced under load but idle knocking persisted#8. Debate ensues on oil viscosity: thicker oils e.g., 10w-30 are argued to reduce wear vs. 5w-20, which is criticized as government-mandated for minimal MPG gains 1-2%#4#6, though others cite modern engine designs and warranty safety#5. Suspected causes include timing chain tensioner or hydraulic lifters, with later users confirming similar issues#11#13#15. No resolution is confirmed, with monitoring advised under warranty.

TL;DR:
✅ Engine idle knock unresolved despite oil viscosity change to 10w-30.
✅ 5w-20 oil faces criticism for wear risks despite warranty backing.
✅ Timing chain tensioner suspected; others report identical 2020 Forte issues.

🔎 Key Insights:
Thicker oil reduced general noise but not intermittent idle knock#8.
Noise vanishes intermittently and above 1200 RPM, ruling out catastrophic failure#11.

🎯 Conclusion:
Intermittent valve train noise in newer Fortes remains undiagnosed, with timing components or lifters as likely culprits. Owners should utilize warranty inspections despite debates on oil viscosity.

🏷️ Tags:

Engine noise, Oil viscosity, Timing chain tensioner, Fuel economy, Warranty

📊 Data Source: Based on posts from page 1 to page 1 (total: 15 posts out of 15 total posts in thread) | ⏱️ Total Generation Time: 44s | 📅 Generation Date: 2025-08-27 18:37:30 | 🆕 New Posts after Generation: 0
A 2020 Kia Forte EX owner reports intermittent#1 valve train knocking at warm idle, distinct from injector noise. After switching to 10w-30 oil, engine noise reduced under load but idle knocking persisted#8. Debate ensues on oil viscosity: thicker oils e.g., 10w-30 are argued to reduce wear vs. 5w-20, which is criticized as government-mandated for minimal MPG gains 1-2%#4#6, though others cite modern engine designs and warranty safety#5. Suspected causes include timing chain tensioner or hydraulic lifters, with later users confirming similar issues#11#13#15. No resolution is confirmed, with monitoring advised under warranty.

TL;DR:
✅ Engine idle knock unresolved despite oil viscosity change to 10w-30.
✅ 5w-20 oil faces criticism for wear risks despite warranty backing.
✅ Timing chain tensioner suspected; others report identical 2020 Forte issues.

🔎 Key Insights:
Thicker oil reduced general noise but not intermittent idle knock#8.
Noise vanishes intermittently and above 1200 RPM, ruling out catastrophic failure#11.

🎯 Conclusion:
Intermittent valve train noise in newer Fortes remains undiagnosed, with timing components or lifters as likely culprits. Owners should utilize warranty inspections despite debates on oil viscosity.

🏷️ Tags:

Engine noise, Oil viscosity, Timing chain tensioner, Fuel economy, Warranty

📊 Data Source: Based on posts from page 1 to page 1 (total: 15 posts out of 15 total posts in thread) | ⏱️ Total Generation Time: 44s | 📅 Generation Date: 2025-08-27 18:37:30 | 🆕 New Posts after Generation: 0

Kia1109

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Hello,

I have a new Forte EX w/2.0 engine, and I have noticed a clattering noise while at idle with the engine warm. This noise is not the injector ticking noise, I know what that is and can hear it separately. It also should not be the AC idler, as my car is past the production date per the TSB.

The noise I'm talking about almost sounds like the valve lifters, an irregular clattering or slight knocking sound.

Is anybody else experiencing this in their new Forte? Responses would be greatly appreciated.
 
No one else with this kind of engine noise on a Forte EX? I find that difficult to believe. Better take a listen to your engine at idle while warm. And go to a heavier oil than 5w-20, such as 5w-30 or 10w-30. 5w-20 is too thin an oil under ANY conditions, IMO.

I'm doing an oil change at 800 miles and will be using 10w-30...hopefully that will quiet down the engine. It's definitely a valve train noise...I was able to trace it to there at warm idle with the hood up.
 
Have you taken your Forte in to have a technician listen to it? Before you change the oil and put in a different viscosity you might want to have them look at it. Lots of manufacturers have switched to the 5W-20 oil. It reduces friction for more mileage and the engines have been designed for it.
 
Not yet, but I might if the noise persists or worstens. I'll see what effect 10w-30 has, it's listed in the Forte owners mnaual as an approved viscosity(per temp range chart) along with 5w-30. They only recommend 5w-20 for optimal MPG.

Did you know that 5w-20 is only recommended in the US and no car mfgrs recommend it in other regioins of the world, even for these cars? The US gov't, through their CAFE stds, are forcing the car mfgrs to recommend it here and the oil compnaies to formulate it for this market. I'd rather use a thicker oil that is better for the engine.

BTW, the engines have not been "designed for it". That is a myth. Think of how thin 20w is at 100 degrees on a hot summer day. Think of the volatility, the burn off, the varnish created and coating your engine parts as a result. This is typically not happening with thicker oils. Not too long agao the car mfgrs were recommending 10w-40 and even 20w-50, and they were the most popular viscosities selling off the shelf. So, 5w-30 and even 10w-30 should be fine.

If you lease your car, I wouldn't worry about it. But if you own your car and want to prolong engine life, go to a slightly thicker oil that still fits your area temp range.

Read up on this subject, you'll be surprised.
 
If you search the web you'll find lots of sites that are against the 5w-20 oil saying it increases wear...and, of course, they all have oils that are better and additives that can help too...what a surprize! Trying to get the most mileage to meet the Government requirements is a factor. BUT, changes in manufacturing has brought about some tighter tolerances in the engine as well as advances in metalurgy coupled with the fact that these engines do not run as hot as previous engines (notice the compression ratios of modern engines -- 10.0:1 to 12.0:1-- yet preignition isn't as much of a problem -- and yes, the computer controls help too). I have one website that's pretty good listed below -- it also states what was once 10w-30 is now 5w-30 in the new standards/testing. One other point to consider...Honda and Ford have been recommending 5w-20 (since 2001 I believe) yet there isn't a big problem in the longivity of their engines that has come about. I would imagine if 5w-20 truly caused 30% more wear there'd be some complaining going on...

If Kia warranties my engine for 10 years/100K miles and puts it in the manual to use 5W-20 I don't see a problem with running it that way. If you go to the slightly thicker oil let us know if it solves your clatter/noise.

http://www.machinerylubrication.com/article_detail.asp?articleid=518
 
Thanks for the info. You make some good points. I still think the heavier voscosity oils make for a quieter engine, and quiter means less wear interanlly. That's a given.

I'll let you know if going with 10w-30 has any effect on the valve noise...which is not really a clatter, but a light knocking. It's at the top of the engine, the valvetrain, so it's not a piston rod bearing or main bearing. Aslo, it's totally quiet at anything above 1200 rpm.

BTW, using a 5w-20 over a 5w-30, for example, only yields about a 2 gain in gas mileage. And there are SO many other factors affecting gas mileage, not the least of shich is driving style and/or driving conditions.

Sorry for all the typos: that should say 25 gain in gas mileage. Damn Microsoft software! How does 'the' become 'to'? Impossible by making a mistake on the keyboard. Not even close.

Unbelievable!!! 2% gain in gas mileage, not 2 and not 25.
 
here's some good reading about the 5w-20 and even 0w-20 oils. it's on the AMSoil site, so they are trying to sell their own stuff, but it seems to be the common opinion of this oil.

http://www.smartsynthetics.com/articles/5w20oil.htm

i'll be putting their oil(probably 5w-30) in at my first oil change, then going to a once a year schedule.

haha, here's another answer to the question that i liked:
SAE 5W-20 Motor Oil
Should you use it in your vehicle?

The answer is simple:
You get about 1% better fuel economy, but you get 30% shorter engine life !

source: http://www.synlube.com/sae5w-20.htm
 
Yes, the call for 5w-20 is definitely motivated by fuel economy.

I did an oil change at 800 miles to 10w-30 conventional oil and the engine is much quieter, especially under load, but I am still getting the light knocking at warm idle.

However, it's not there all the time. Sometimes it's totally silent, no knock. I can test this by idling the car when warm after drving it and listening both inside the car and outside near the engine.

I disconnected the Variable Intake Solenoid(vacuum line) and the Variable Valve Timing oil control valve(electrical connector) and no change. Both are right at the front of the engine and easily accessable. So I can rule those out, as one was a TSB and the other was what another owner found to be the problem through his dealer.

Also, very unlikely that it's a serious engine problem, as it's entirely absent some of the time. The most likely culprit now is the timing chain tensioner. I'm going to monitor it and see if the noise eventually disappears or worstens. No trip to the dealer yet, I don't want to jump through all their hoops.
 
man, that would freak me out, it may not be a serious problem, but i would think that it would shorten your engine life. did you go to synthetic?
 
Kia1109 said:
Yes, the call for 5w-20 is definitely motivated by fuel economy.

I did an oil change at 800 miles to 10w-30 conventional oil and the engine is much quieter, especially under load, but I am still getting the light knocking at warm idle.

However, it's not there all the time. Sometimes it's totally silent, no knock. I can test this by idling the car when warm after drving it and listening both inside the car and outside near the engine.

I disconnected the Variable Intake Solenoid(vacuum line) and the Variable Valve Timing oil control valve(electrical connector) and no change. Both are right at the front of the engine and easily accessable. So I can rule those out, as one was a TSB and the other was what another owner found to be the problem through his dealer.

Also, very unlikely that it's a serious engine problem, as it's entirely absent some of the time. The most likely culprit now is the timing chain tensioner. I'm going to monitor it and see if the noise eventually disappears or worstens. No trip to the dealer yet, I don't want to jump through all their hoops.

Are you sure it's not a hydraulic lifter? A sound at the top of the engine that comes and goes is often a hydraulic lifter -- could have a piece of debris/dirt in it causing it to "knock" intermittantly.
 
vizunary said:
man, that would freak me out, it may not be a serious problem, but i would think that it would shorten your engine life. did you go to synthetic?

No, conventional 10w-30. Yeh, I'm not too thrilled about this kind of noise from day one on a brand new car, but since it's only at idle, and only when warmed up, I'm less worried. If I rev it to 1000 rpm at idle the noise is not there. Likewise higher and while driving. And, like I said, it's not there all the time.

KoupCoupe said:
Kia1109 said:
Yes, the call for 5w-20 is definitely motivated by fuel economy.

I did an oil change at 800 miles to 10w-30 conventional oil and the engine is much quieter, especially under load, but I am still getting the light knocking at warm idle.

However, it's not there all the time. Sometimes it's totally silent, no knock. I can test this by idling the car when warm after drving it and listening both inside the car and outside near the engine.

I disconnected the Variable Intake Solenoid(vacuum line) and the Variable Valve Timing oil control valve(electrical connector) and no change. Both are right at the front of the engine and easily accessable. So I can rule those out, as one was a TSB and the other was what another owner found to be the problem through his dealer.

Also, very unlikely that it's a serious engine problem, as it's entirely absent some of the time. The most likely culprit now is the timing chain tensioner. I'm going to monitor it and see if the noise eventually disappears or worstens. No trip to the dealer yet, I don't want to jump through all their hoops.

Are you sure it's not a hydraulic lifter? A sound at the top of the engine that comes and goes is often a hydraulic lifter -- could have a piece of debris/dirt in it causing it to "knock" intermittantly.

I don't think they use hydraulic lifters in the 2.0 Theta II engine. It could be an erratic lifter or valve though, as it's intermittent. My guess at this point is the timing chain tensioner, but I'm not willing to let the dealer tear into that yet.

I'm going to monitor it and see if the noise subsides over time. Only 800 miles and it's under warranty, obviously.
 
I'll be watching this closely - I noticed the same noise in mine last night. I've had one oil change and nearing the next scheduled change.
 
I BELIEVE MY KOUP IS IN THE SHOP FOR ITS TIMING TENSIONER. HOW DID YOUR'S TURN OUT ?
 
No one else with this kind of engine noise on a Forte EX? I find that difficult to believe. Better take a listen to your engine at idle while warm. And go to a heavier oil than 5w-20, such as 5w-30 or 10w-30. 5w-20 is too thin an oil under ANY conditions, IMO.

I'm doing an oil change at 800 miles and will be using 10w-30...hopefully that will quiet down the engine. It's definitely a valve train noise...I was able to trace it to there at warm idle with the hood up.
I just came a cross your post, my car is an 2020 Kia forte EX, with only 11,000km, I m experiencing that issue, it started right after I got it serviced. I’m looking into that, but not have to any conclusions yet as I just contacted the dealership.
 
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