Topic: Valve adjustment : Toyota engine

[duck]

Ok  so my  1998  Toyota  Sienna, 3.0 L, V 6 engine,  has a knocking noise when the engine is  warmed up and  idling.  I was wondering if it is the valves.  Toyota recommends the first Audible  valve inspection around the 96,000 km mark and the 192,000km mark.  I bought the vehicle with 123,000  km on it last year and I don't know if any inspection was done. It currently has 136,000 km.


The previous owner became ill and his son sold me the vehicle.  He did not have any previous bills.


(Message edited by duck on November 15, 2004)

[Driver]

Maybe switching to synthetic oil could help remove the sound.  As you are aware, it's getting cold already and normally engines would emit clatter sounds on cold start.

[johngenx]

When you bought the van, you had a PPI done, right?  And your mechanic talked about the lack of service records and came up with a plan to address that, right?  He/she talked about mileage related jobs like timing belts and valve adjustments, right?

If you have no idea of the service history of this vehicle, then you'll have to get it up to snuff, and start looking after it from this point.  If you don't know if the valves have been adjusted, have them done, or do them.  If you're not sure about a timing belt (some Toyotas have chains) then have it done.  Better to be out a couple hundred bucks than sorry.

Is the oil level proper?  Do you have the right weight of oil?  Is the oil clean and the filter new?

[mark]

Given Duck's previous posts, I will assume he already uses synthetic oil.  However, those 123,000kms before you acquired the car are a mystery.  Toyota's 3.0 L V6 became known as a sludge monster, but I'm not sure which production years it applied to.  The engine was designed in such as way as to run very hot, resulting in some oil coking.  If oil changes were not done in a timely way, you could have a very sludgy engine.  This can definitely cause sticky (noisy) valves.  
With no history, you are completely in the dark, unless you've had a thorough inspection and have started doing some of the unknown work.  As already suggested, get going on those maintenance items.  

[articsteve]

I think Mark is right on the track with this.

Go here:

http://yotarepair.com/Sludge_Zone.html

Check your date of manufacture.

Lots of info on this problem.

However, you may not have this problem because sludge motors tend to burn a lot of oil.

The other problem is Toyota requires proof of oil changes.

I'd flush the engine oil with a good product like recommended on the site I listed.  Fill with synthetic and get the valves adjusted. As mentioned, if it has a timing belt get that done too asap along with a new water pump.

[articsteve]

Here is a bit more detail.

What I can ascertain so far is that the problem was a result of toyota messing with the original design to meet emission standards.

Below is a good detail of the situation.  Seems noisey valves when running at normal temps is a bad sign;

You have to remember the real problem are the valve cover(s,) they will become clogged and can't breathe. I still recommend replacement in the most severe cases. Using Kleenz-it wand to inject the fluid into the engine does help clean the valve cover baffles, but it's still the weak link in the process.

Visit their internet site and learn more. If you are facing a major repair due to sludge and the engine is still running and quiet then you don't have much to loose.

[johngenx]

I wonder if Toyota Canada is offering the same extended warranty coverage that they had to provide to US customers as per the US class action lawsuit concerning sludging engines?  Mercedes lost in the US, and did not provide one cent of assistance to Canadians.  Just plain 'ol gave us the middle finger about it.

The push to extend oil change intervals has resulted in a few makes with sludging engines, including the V-6 Mercedes, 3.0 V-6 Toyota and 2.2 I-4 Toyota engines.  All these engines have close tolerances and minimal exposed to atmosphere venting to reduce emissions.

[duck]

OK,  I swithced to Mobil 1 5W-30 after I bought the vehicle and I use Mobil 1  5W-30 year round.  I change  the oil and filter every four months.   I use a Toyota oil filter each time.

According to the owners manual the timing belt should be replaced at 150,000 km.  Yep,  they last longer these days.


Okay, so I have a Toyota shop manual and this engine may require "shims" to be placed somewheres when the valves are adjusted.  I have done valve adjustments before but never using shims.   Any ideas???

Thanks  

duckie

[tpl]

I don't know about Toyotas but some engines  use valve adjustment shims as follows.
With the engine hot carefully measure the clearance between the lifter and the cam/cam follower for each and every valve..requires lots of turning the engine over a few degrees at a time, Measure to .001 inches tolerance.
Disassemble the valve train and measure the thickness of the shims that will be there already.
From your box of shims ( bought or borrowed from the dealer(!)) select new shims for each valve to get to the correct value for the lift... if you measured 0.015 " and it should be 0.012" then you need to adjust the total shim thickness by 0.003"
At these tolerances obviously everything has to be spotlessly clean as a tiny piece of grit or smear of thick grease can alter the measurement
Ideally you do this with a minimum number of shims per valve.

Reassemble the whole thing, warm up the engine and repeat the measurments.  It is not impossible that the job needs to be repeated!

If there is anyone on this forum who owns a 1960's Jaguar straight six they may please correct my description!

One hopes that Toyota have a better way that does not require a full disassembly each time..I'd bet that they do.

[johngenx]

My Honda CBX had buckets and shims (as do many motorcycles) and it was a PITA to do.  24 valves meant having a pretty good selection of shims, and I don't know what Toyota shims cost, but those Honda ones were about $3.00 each.

Six pots also means extra engine turning to get the right piston to TDC.  I would ask the mechanic what the labour charge is and I'd be tempted to have this job done.  Shims means investment in parts, many shim/bucket set ups are easier with a special tool, and so on.

[duck]

Yea,  this sounds like a trip to  the dealer.  I will keep you guys posted on my decision.

[duck]

So the other day I took my van to the dealer and inquired about the knocking noise.  They listened to it and said it is normal.

Well,  I hope they are correct.