Engine or transmission getting much louder when hot

[Flyer]

I have about 112,000 on my T4R. Everything is good except for what is happening the past couple of months that we have noticed...maybe longer. After some stop-and-go on a hot day, the engine sounds much louder- still shifts okay and drives okay but just gets louder.

History- I bought it at 65,000 miles but the previous owner had towed with it...a trailer of some sort since it also had the brake controller. I had a dealer change the trans fluid fully at 75,000.

After it rests a while, the engine sounds go back to normal. It isn;t a clicking or anything...just the sound seems amplified. Could the transmission be going bad or could this be something else? It's freaking me out a bit.

 

[fdbyrne]

It's probably your fan kicking in to cool the engine.

 

[Flyer]

I thought about that but then it stayed on while I was on the highway too. That is very possible though. I did notice that a bunch of radiator fins are smashed from road debris impact. Maybe I should fix that somehow and help the radiator cool things.

 

[Flyer]

Oh, I then discounted that being fan noise because I did not think I could hear that fan that loudly over usual engine noise. Also, as the engine shifts into higher gears, the sound adjusts accordingly and goes down with the shift points.

 

[gm350reratliff]

How long does it take to start making this louder noise?

I'm Guessing the exhaust is expanding when heated and rubbing on something which is transmitting the noise inside.

 

[Flyer]

It was fine for maybe 30 minutes today, and then we stopped at a place for 30 minutes, and it started pretty soon after leaving and a few stop signs...maybe 10 mins into the second part of the drive. Air temp was probably 80 degrees at the time.

 

[RPS13]

Is it a whine, maybe differential?

If the cooling fan clutch is completely locked up you might need to replace it. You should be able to stop it with a stick or something and hold it while the engine is running and cold.

 

[Flyer]

Could be a whine-like sound but not too high-pitched. Would something be going on with the differential when it heats up? I'll drive around in stop-and-go tomorrow but will keep the AC off and see if I can recreate it.

 

[BlackWorksInc]

Is it a whining noise or a roaring noise? I'm thinking fan clutch (what I suggested in T120) but I'm not sure what exactly the noise is here.

 

[Flyer]

More like a roaring noise. Definitely not a high-pitched whine.

 

[Flyer]

So how do I eliminate (or confirm) the fan clutch as a suspect here? One thing to note is that when this roaring type noise starts up, it seems to decrease with each gear change and increase of speed. It increases on the way back down.

I could take it to a Toyota mechanic and may have to but it does not happen all the time. The mechanic is pretty far away and leaving it there is impractical but the other option is to take it to a closer dealership and have to deal with the associated high cost. Since it does not occur all the time, will a fan clutch issue (if this is the problem) be easy for them to identify?

If not too hard to replace, I could tackle it myself. I'd prefer to use OEM parts. Anyway, all this assume it is the fan clutch but I am starting to lean towards that at this point since it is a roaring sound and not much of a whining or squeaking sounds. Am I on the right track?

 

[ChaosStarter]

So how do I eliminate (or confirm) the fan clutch as a suspect here? One thing to note is that when this roaring type noise starts up, it seems to decrease with each gear change and increase of speed. It increases on the way back down.

I could take it to a Toyota mechanic and may have to but it does not happen all the time. The mechanic is pretty far away and leaving it there is impractical but the other option is to take it to a closer dealership and have to deal with the associated high cost. Since it does not occur all the time, will a fan clutch issue (if this is the problem) be easy for them to identify?

If not too hard to replace, I could tackle it myself. I'd prefer to use OEM parts. Anyway, all this assume it is the fan clutch but I am starting to lean towards that at this point since it is a roaring sound and not much of a whining or squeaking sounds. Am I on the right track?

This sounds like how the fan clutch should be operating. It's not being used at higher speeds because of airflow at higher speeds and engine RPM.

It's more noticable at lower speeds because there's less wind and road noise. It'll be even more noticable if you have the A/C on because even more heat is being pulled off the condesor and radiator.

I honestly don't think there's a problem. If you didn't hear the roaring at lower speeds with a hot outside temp, then I'd be concerned.

 

[Flyer]

Oh, I thought there was a problem but maybe not. Thanks for the info. What I may do is get those comb things to gently straighten out the radiator fins. Too many of them seem to be bent/smashed. That may be reducing the cooling.

 

[RPS13]

Yea, you can hear the clutch fan spin up, particularly if you've been idling at a stop light for a few minutes and getting things hot. It will gradually decouple some in the next couple of minutes as you get up to speed and the clutch cools down.

 

[Top Shelf Synthetics]

Could it possibly be your tires...tread wear, out of balance?

 

[ChaosStarter]

Could it possibly be your tires...tread wear, out of balance?

In my experience, tires that are cupped that make road noise, will increas in volume as your speed rises and decrease as you slow down. That's the opposite of what the OP was stating.

Balance issues will also show up at higher speeds (above 25-30) assuming the tread is worn evenly.

 

[Flyer]

Tires are perfect- pretty new DuraTracs with no issues I went for a drive today and did not run the AC. The fan never became loud and the 4R ran as quietly as usual. I came back home and looked at the radiator again. So many of the find are smashed so I took a toothpick and gently straightened out as many as I could. I would consider replacing it at some point, though I suspect the OEM radiator price is sky high. I am always leery of using aftermarket parts when it comes to critical things like this.

So I think everything is normal...just that the clutch fan kicks in on those hot AC days when in traffic or stop-and-go situations. I live and drive (normally) in areas with light traffic so the driving was unusual and I started to notice the noise.

 

[Top Shelf Synthetics]

In my experience, tires that are cupped that make road noise, will increas in volume as your speed rises and decrease as you slow down. That's the opposite of what the OP was stating.

Balance issues will also show up at higher speeds (above 25-30) assuming the tread is worn evenly.

Thank you, that is good info to share! Luckily I haven't had to deal with those issues, I thank firestone's lifetime alignment, balance & rotation for that.

 

[Top Shelf Synthetics]

Tires are perfect- pretty new DuraTracs with no issues I went for a drive today and did not run the AC. The fan never became loud and the 4R ran as quietly as usual. I came back home and looked at the radiator again. So many of the find are smashed so I took a toothpick and gently straightened out as many as I could. I would consider replacing it at some point, though I suspect the OEM radiator price is sky high. I am always leery of using aftermarket parts when it comes to critical things like this.

So I think everything is normal...just that the clutch fan kicks in on those hot AC days when in traffic or stop-and-go situations. I live and drive (normally) in areas with light traffic so the driving was unusual and I started to notice the noise.

Happy to hear its just normal operation....Definitely have had those "What is that" moments. Here in AZ, I get nervous if I don't hear the fan!

This post may help if you decide to change out the radiator
http://www.toyota-4runner.org/4th-gen-t4rs/186401-radiator-replacement-write-up.html