Valve cover gaskets

My 2001 3.4L has a burned oil smell , I’m guessing it’s the valve covers are leaking . Truck has 190k miles, never been changed. If you have changed the valve cover gaskets, how many miles did you have ?

 

Also interested in this. Mine leaks and is at 225,000 miles. I just bought it though so I don't know how long it has been like this. Previous owner said he tightened the bolts down some and that helped stop or slow the leak. He only owned it for a year.

 

https://www.yotatech.com/forums/f2/5vzfe-leaky-valve-covers-fixed-56k-beware-149594/

 

My 97 was changed around 250k by the previous owner but he cracked one of the valve covers and JB Welded it. So I changed them at 350k and tried to fix the valve cover but without much success. So then I changed them again at roughly 420k and put different covers on them. My 03 DC 3.4 has 376k miles and they are starting to leak but as far as I know they have never been changed by the looks of it.

 

Do some research before starting this work. There are some things you need to know.

 

Review here -
https://www.tacomaworld.com/threads...ping-out-valve-cover-gaskets-pictures.469596/

and then kick the feet up and watch -

https://youtu.be/N5fAXAuGozI

 

I second this. There are a lot of things that you need more than just the valve cover gasket. Also, there are a few "while you're in there" items to take care of like the PVC check valve.

 

235k when i changed it but it's been leaking for about 30k miles

 

I just did this work over the holidays, valve cover gasket and other items following the video shared above. It takes a bit of time, but it's all pretty standard maintenance for the 5ZE-FE engine and well worth it.

I recommend cleaning (wiping and degreasing) anywhere near where the oil may have leaked to get ride of the burnt oil smell, especially near and beneath the half moons on the back of the engine. The stubborn odor on my rig went away completely once I did all this.

It was also helpful to me to take lots of pictures of the engine and hose connections *before* I started so I could correctly reassemble everything.

 

You might want to try re-torquing the value cover bolts before you tear into it. I experienced a burning oil smell at 200k miles and I found several of mine loose. After tightening them up I haven’t smelled burning oil, or seen any oil leaking from around the valve covers after adding ~20k miles to the odometer.

 

They are "loose" because the valve cover gasket and the bolt washer rubber are failing.

This is, at best, only putting off the maintenance, and you'll also run the risk of over tightening or stripping one of the bolts, or cracking the valve cover. Roll the dice if you must, but at least understand the consequences.

 

I think it's because the rubber part of those washers slowly start to lose elasticity over time and that creates less holding power which then causes the leaks. I'm wondering why Toyota designed it this way since I have never seen another valve cover that uses washers like this. All of them have bolts directly through the cover holding it down and they never leak unless the valve cover gasket itself is worn.

 

Had my '03 done at 203,000, sold it about 8,000 later

 

This was my original plan until I realized that with the 5ZE-FE, it's very difficult to properly access all the VC bolts without removing the intake and lower plenum. By the time you've done all that, you may as well do the complete version of the job (all gaskets, half moons, etc.).

 

I agree 100% that retightening the valve cover bolts is prolonging the inevitable. In my case, I only tightened the bolts that were easily accessible while I was replacing my spark plugs. I’ve put ~20k miles on my truck and still haven’t seen or smelled any oil leaks. Just wanted to share my experience with the OP.

 

Did you consider what uneven torque might do to the heads when you did that?

Most people would evenly apply torque to the bolts in a pattern, slowly bringing them up to spec, so as not to distort anything.

Just a thought.

 

no, I did not consider what unevenly torqued valve cover bolts tightened to ~50 inch pounds might do to the cylinder heads.

 

thanks for the recommendations, we’ll definitely clean it up . Don’t want the smell to stay

 

Just did mine at ~160k

 

How important is it to reseal the half moons during this gasket change? Anyone have info on them being the source of leaking as mentioned by Timmy?