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ROBinGa
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I just changed out the valve cover gasket today on daughter's 2004 Highlander 2.4 inline four cylinder with 116,000 miles. There was not any oil leaking on outside of engine that I could see except just starting to see a little moist dark smudges on front right corner. We have not owned it long and have no idea if previous owner had changed it. So I bought the Felpro gasket and decided to change it today while she is in town for holidays. When I got the cover off the gasket stayed attached to the engine and not cover. I was shocked at how dry and brittle the old original gasket was. The inner part that seals spark plug wells was so brittle it crumbled as I took it off in tiny chunks. The band around edge of valve cover was no longer pliable and I had to pry it with a plastic scraper. It was still intact and not letting oil seep out but it was just a matter of time. I used brake cleaner to wash and get out lots of oily grime on the underside of valve cover, and overall I was ok with how the moving parts looked under the cover.

One tip I will give is to use a little silicone paste or something slightly tacky to put in channel where gasket goes to help keep it from falling down as you reposition the valve cover. It's fairly straightforward job except for the condition of the old gasket. If the old gasket were still pliable it would be a 30 minute or less job. I took my time tightening down the bolts and couple nuts that hold cover down. The cover did not readily want to seat as the gasket is nice and thick. It does come down as you tighten bolts and sealed very nicely. I ran the engine and went for a short drive and all is well and bone dry around the edges.
 

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I'm in the midst of changing knock sensors on a 2003 Highlander and noticed a ton of oil coming from the valve cover so figure I better do that too. How do you go about getting the small Torx-head bolts out on the front? Those things are in there good and I don't want to strip them! Or do they not come out?
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I'm in the midst of changing knock sensors on a 2003 Highlander and noticed a ton of oil coming from the valve cover so figure I better do that too. How do you go about getting the small Torx-head bolts out on the front? Those things are in there good and I don't want to strip them! Or do they not come out?
View attachment 289723
On my 3.3l for the front vc those 2 e8 bolts (if I remember the size) do not come out and are part of the valve cover. Keep in mind the tube seals can be a nightmare. They all break all over the place and are just as difficult to get back on. The best method I found after multiple tools was, I used a flat head bent out of shape by myself to fit it under the seal and pry out. Lube the area with some oil to make it easier. There are also 2 tabs which indent upwards to release seal and before inserting new one. Lube new one and jam it in there. Use a big socket, smaller size than seals ofcourse, with a rubber mallet hitting socket from top to knock into place. Use light force not to crack the vc. Also note the way the seal goes in. Good idea to lube seal where the plug tube meets seal so it doesnt crack up. I lube them all over anyways.

Someone also had a write up where he froze the seals for 30 mins and heated up the surface before inserting them. It did seem to help somewhat, but maybe I didnt heat it too well. Regardless it still went it with a few smack. Make sure to use a mechanic's mirror to check seal all around before torquing


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Wow, thanks very much for the quick response and helpful tips. I tried fitting an E6 Torx socket on there but it was just too sloppy of a fit for me to risk it. Glad I didn't! Everywhere else I've seen those style of bolts they've had nuts over them and seem to be used just as guides to line things up, so I was hoping that was the case. Knock sensors are out, manifold gaskets, spark plugs and valve cover are next!
 

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Now I've gone and done it...yesterday (before I saw your response) I tried removing the two E6 Torx bolts that hold that plastic bracket on top of the valve cover (as per the Autozone instructions), and with very gentle pressure immediately sheared the head off one (left).

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Unfortunately I don't see any other way to get this thing off there, and it sits directly over one of the bolts you need to take out to remove the valve cover.

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I just think it's weird out of all the tutorials/Youtube videos I've seen this is the one part they DON'T show. Argh. Now what?

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Like the ones on the front of the valve cover, they have the round "stoppers" around them instead of standard nuts, and aren't threaded all the way down anyway, so I don't see how you'd get them out.
 

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Now I've gone and done it...yesterday (before I saw your response) I tried removing the two E6 Torx bolts that hold that plastic bracket on top of the valve cover (as per the Autozone instructions), and with very gentle pressure immediately sheared the head off one (left).

View attachment 289789

Unfortunately I don't see any other way to get this thing off there, and it sits directly over one of the bolts you need to take out to remove the valve cover.

View attachment 289790

I just think it's weird out of all the tutorials/Youtube videos I've seen this is the one part they DON'T show. Argh. Now what?

View attachment 289791

Like the ones on the front of the valve cover, they have the round "stoppers" around them instead of standard nuts, and aren't threaded all the way down anyway, so I don't see how you'd get them out.
It seems like everyone does that at least once. I rounded one of those studs using a 1/4" ratchet. I felt more confident using an impact on those, as the 2nd one came off with an impact.

If its rounded, take some locking pliers and hit it with a rubber mallet the direction to loosen it up. That's how I got it off. Make the plier super tight. Good idea to spray some penetrating fluid before attempting


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Oh man, what a nightmare. I definitely did use some Bolt Breaker before attempting it. It seems like the metal is so soft on those things I would be nervous about just shearing it off in there. I guess I've got nothing to lose on the one that's already f$#@ed. My question is how did you get them back in? Or did you replace them with something else?
 

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Oh man, what a nightmare. I definitely did use some Bolt Breaker before attempting it. It seems like the metal is so soft on those things I would be nervous about just shearing it off in there. I guess I've got nothing to lose on the one that's already f$#@ed. My question is how did you get them back in? Or did you replace them with something else?
Get thinner vice grips and lock it at the lowest part of the stud, as not to break it off, making sure the valve cover wont block movement of the pliers. On my 3.3l those 2 studs dont get any nut on them so are useless. The front 2 are used by the engine cover. I took it to ace and got the same length/thread bolt instead.

Anyways, I refuse to put back the engine cover as I love to take a peek at things in my engine bay every few weeks or so.

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View attachment 289826

That sucker is NOT coming out. It was bending the vice grips! I'm about ready to snap that plastic bracket off and jury-rig something else on there instead.
All you need to do is loosen it up, once loose you can unthread by hand. A rubber mallet smacking on the vice grips worked well for me. Smacking it is better than apply force especially with stubborn bolts and studs

I see your locking the grips on the threads, try locking them on the rounded smooth surface just below the threads.

Dry the penetrating fluid first, then you can also try using a butane blow torch and heat the sucker up before attempting to use vice grips.

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289848


You were 100% right, that's all it took! A good dose of PB Blaster and a couple good smacks and it finally broke loose. Definitely more effective to smack it rather than applying constant pressure like I was.

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The same trick also worked for my knock sensors that were seized in there too. I had been using the 12-pt. box end and just rounding them off, turns out they just needed a good smack.
THANK YOU!!!
 

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When I first learned this, it didnt make logical sense, but I sure kept it in the back of my mind, and I'm sure you will too :)

Now I understand the logic behind it. After many years of a bolt not being removed it builds up rust and bonds to the surface that it becomes very difficult to remove with constant force, hence a couple good smacks breaks that bond. This is also why impacts are efficient. I do this with most bolts I remove and has avoided me big headaches.

I see you have the 6 cyl and have removed the intake plenum and manifold. Are you also replacing the bypass hose down there, and what about the water inlet plate that is prone to leaks?

If you end up replacing that rear vcg, it was a pain for me to remove and install it back due to those metal brackets close to the vc bolts and that huge wiring harness. I was actually able to move the right hand side mount (one that bolts to tb) back and forth so that helped get to the bolts close to that. For the middle bracket, I completely removed it and threw it in the bin (a headache less for next removal), but you can also loosen the bolt that holds it (easier to get to from under the car), and that will allow you to jiggle it back and forth. For the left side bracket, it is really close to that end bolt, I used a 1/4 torque wrench (you can also use a ratchet at first), with a long extension on a swivel socket to access that final bolt, 9 total on valve cover, you will have to force that harness out of your way while getting to that last bolt. You can also loosen that bracket as well to make life easier and move it out the way.

When installing the valve cover back use a mechanics mirror to make sure the gasket did not slip. I also used my fingers to feel gasket after having a mental idea of its passage. Those raised cams in the way took my gasket off and I had to remove it and reinstall into the groove. You can also use small amount of rtv sealant (give time to let dry) under the gasket so it doesnt move. Choice is yours, iI was able to get it in the 2nd time without using any rtv.

Be ready for some back ache and stiffness throughout your body. I used a 5 gallon bucket to step on and it helped a ton. Make sure it's on a non slip surface or have something behind it to block it from slipping.

My gosh, that 4cylinder must be a joy to work on

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Whew, got it done and everything seems good. I did not change out the bypass hose or plate, but they appeared fine. I didn't notice any recent coolant leakage so hopefully I'm okay. I also opted not to do the rear valve cover gasket once I saw what a major pain it was going to be. I checked with a mirror and didn't see signs of oil leaking, so I just re-torqued the bolts. Thanks again for all your help.
 
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