Valve Clearance Maintenance Check

I've been planning to due my 60K mile factory recommended service. One thing that has slowed me down is trying to get some information on a requirement to inspect the valve clearance on the V6. I have searched this and other forums trying to find a procedure or more importantly, how and what exactly is being inspected.

The dealer says the procedure includes removal of the valve covers which is a nut and bolt job but in terms of time is not trivial. What I haven't been able to get a straight answer on is what do they do once they have the valve covers off? I'm assuming this DOHC engine cams push on hydraulic lifters. Is there a lifter to cam clearance that must be checked? What is the reason that valve clearances must be checked as part of 60K mile maintenance intervals and literly how and what is it done?

Also, it seems the World Standard (WS) ATF fluid in no longer being talked about as being good for the life of the transmission. While I never bought into this concept I find it interesting the dealer is now recommending it be flushed as part of the 60K mile service. The problem is the WS ATF is still twice the cost of normal transimission fluid. Is everyone putting the recommended WS ATF fluid back in?

Thanks.

 

Don't think there is hydraulic lifters in our 4.0L V6. Valve clearances are checked because the clearances tighten over time/usage. If the measured clearance is outside of tolerances, they will be adjusted, shims added, etc - depending on the method of adjustment our engines utilizes. According to Toyota, the 60K miles valve check was simply an "audible" one - for what that's worth...

As for the WS fluid specs, it was always stated in the Canadian version of the owners manual to change the fluid at 96,000 kms or 60,000 miles. Toyota USA beats around the bush and states to change the WS fluid if towing, but then again they state the same with the transfer case oil, front diff oil, and the non lsd rear diff oil - so take their info for what its worth once again (little).

Check out the maintenance link for Toyota Canada:

http://xws.xtime.com/xmmmenu/?varia...tomatic&mileage=96000&units=km&estimate=false

 

ive never checked valve clearances on a 4.0l?????????????

 

so......you a toyota tech?

 

Here's how it's done.

 

Basically, if it's out of spec, you buy a new lifter to make it right.

The one thing I miss on my Honda. I could experiment with clearance as much as I wanted with the screw-on-rocker adjustment. Made a big difference in mileage too, more than you'd think.

 

Thanks 08TacoTrD. So this is the procedure the tech performing the 60K mile maintenance is supposed to perform? If so, I would think he records the clearance readings between the valve lifter and camshaft and should be able to provide them.

Thanks again. This is exactly what I was looking for. I'm going to follow up with the dealer. I'll let you know what they say.

 

No need to do that check unless you have a problem with your engine. If it is running rough and you've gone through all the other steps to remedy a rough running engine, then do the check.

 

I have done valve checks and shim replacement on my Honda VFR motorcycle. It is done the same way, by removing the cams but in the bikes engine, the cams are gear driven and can be taken out without removal of a chain drive like on the truck.

Now, if you guys think a transmission fluid flush and change is expensive, can you imagine what a shim change on a Tacoma would cost. You could probably buy a late model used truck for what they would charge.

I have always considered the possibility that the dreaded "tick" these engines have could be a result of the valves set to the loose end of spec at manufacture (the tick does sound like valve lash noise to me) knowing full well that the valves tighten as mileage increases and just about no one will go for the cost of a valve adjustment with shim replacement on a higher mileage truck.

 

I'm curious what a survey would reveal in terms of how many trucks checked at 60K actually needed an adjustment.

 

thank u for this. exactly why i, or any of us have never needed to it to a 1gr

 

After weeks of getting the run around, I finally got the name of the guy who worked on my truck and walked down into the service bay area (like I owned the place), found the technician and asked him what he did.

There is a VERY intrusive and extensive procedure for adjust valve clearance if it is needed. All that is done for the 60K mile maintence, with regards for the valve clearance inspection, is check for codes and listen to the engine. If the top end isn't tapping they don't do anything.

For what it's worth, no one at the dealership intentionally gave me the run around. They found a/the procedure but just didn't know what the technician is actually supposed to do.

 

I've down quite a bit of checking around about this and can't find anyone who has actually found a problem when doing the full inspection. That includes a guy who works at an independent Toyota shop. I have also heard the requirement was deleted from the service schedule from 2010 on. Can anyone look in their service/maintenance booklet and verify that?

Valve seat wear will tend to tighten the clearance, but cam wear will tend to loosen it. I've got a hunch the two basically cancel each other for the most part. I passed on checking mine.

 

I told you that in the first reply to your post. As for the codes, there isn't a sensor to measure valve clearance in the engine so you can rule that one out as likely being BS.

 

If you do the valve clearance check yourself mic your feeler gauges first. I bought a set of go-nogo gauges at NAPA and after using them for a few years on my Honda CRF 250 X I decided to mic them one day and lo every one in the set was .002" over!!! No wonder I went through two titanium intake valves at $130 a piece.

 

first off its a yota.... 200k miles and i doubt valves will be out of spec.


BUT that stated, listening for valves is not a great way to see if they are adjusted properly... to be honest a loose valve (one that you can hear) is not really a problem... its the tight valves... the ones that are zero'd out that do not shut all the way... that make no extra noise that are the problem as you will burn valves..

But i doubt you will ever find a story of someone with burnt valves on a yota motor who hasnt completely abused it.

 

I'm 58 years old and I've been driving Toyotas since I was 20. Hundreds of Thousands of miles. I have never touched the valves or needed to get the valves adjusted.

 

There are varying opinions being expressed here on checking valve clearances. Since I have experience with a 1991 V6 SR5 that I sold to a friend after putting 230,000 miles on it, a 2001 V6 4Runner that got totaled with 150K miles on the odometer, and now 5K miles on a 2012 Taco with those new fangled don't worry about clearances until it runs rough motors, I thought I would offer mine. I do all of my own engine maintenance and rebuild work (including the heads), because it is fun to do (and when I strip one of my own threads I at least know about it).

On the 91, at 60K miles, all of the valve clearances measured to specification. Since the "take apart" to measure clearances on that motor was a real pain, even for someone who enjoys such work, I skipped the check at 120K miles. At 150K miles the clearances on three exhaust valves closed. I was lucky in that I noticed the poor running, what the tech will look for on the new motors, on the way to work and checked compression when I got home to find three bad cylinders. The motor only develops a tick when clearances open up and this generally does not happen unless there is a really bad wear problem where your problems are usually much bigger than exhaust valves burning. Clearances on exhaust valves close when the valve stems stretch (due to heat) and the seat wears (less likely, but it does happen). I pulled the heads off the motor and rebuilt them, replacing all 6 exhaust valves but just cleaning up the intakes. All the seats were ground properly. The valve guides and piston cylinders were in great shape so the work stopped there.

After another 60K miles, now 210K miles on the motor, I had the religion now and checked the clearances. They were within spec. The truck was sold to a friend with complete records on the shims and valve clearances. He had to fix a water pump leak this weekend, the toyota seal packing is not all that good for water pump sealing, and needed to change the idler pulley because I had given him a new one with the sale of the truck, so he decided he would check clearances while the intake plenum was off. Three exhaust valves had hit the minimum clearance, still within spec, but he decided to open them back up to the maximum with the bag of shims I had given him with the truck (borrowing my tools for changing shims). The clearances on these three valves had moved one thousandth. My guess is that by 150K miles after the head rebuild clearances would close on some valves, repeating the past.

My experience with the 4Runner, now with four smaller valves per cylinder, is that no movement of clearances was seen between 60K and 120K miles. Given this evidence of stability the motor might have run to the 180K mile check with the valves clearances still within specification.

Now, on the new motors which are all 4 valves per cylinder, if the clearances are staying just fine to 180K miles or more unless there is a severe wear problem that would have to be addressed anyway, what do you think the dealer policy on checking clearance will be? You got it, the tech will listen to the motor to see if it is running rough, and that is it. It is a lot of work to check clearances, and a whole lot more work to change them on the new motors without shims.

So, will I be checking clearances at 60K, 120K, 160K miles and beyond on my 2012 Taco? You bet I will. If you check the clearances you know what is going on with those pesky exhaust valves and the valve covers appear much easier to get to on the 2012 motor. Adjusting the clearances will be a real PITA because there are no shims, but clearances out of spec will get adjusted on my motor. Life is a bitch when you burn a valve thousands of miles from home, instead of the more friendly situation of noticing rough running on the 3 mile trip to work.

Take this opinion for what you will. I am just a nut who is crazy enough to put a magnetic drain plug in the engine oil pan,
and change the oil in all of the gear boxes every 30K miles, checking their magnetic drain plugs for evidence of unusual wear.

 

If there are no shims, for information purposes, please give a brief description to what does make the adjustment.

 

As there are no shims to change, the valve clearances on the 1GR-FE V6 motor are adjusted by changing the lifters themselves. You check and record valve clearances in the usual way with feeler gauges. If there are any that need adjustment you remove the camshafts to get at the lifters, measure the existing lifters with a micrometer, and then replace the lifters with numbered lifters bought from the dealer that restore the clearance back to spec. It would pay to check the replacement lifter with a micrometer because you don't want to pull it apart again. A lot of work that clearly requires some skill, and perhaps more tools than you might have, but worth it if valve clearances are not the problem that forces a motor rebuild.