My 98 sienna engine makes noise like the valves are loose. Now this has overhead cam and I have no clue how to check whether the valve or valves are actually loose. Anyone who has an idea, it will be appreciated. This is A 98 sienna with 243K miles on it. I had hoped to ride it out for at least 4 more years but it looks like it's quitting on me.
The sound is a rattling one and happens when I let go of the gas pedal after revving it up. When its idling there's also a wierd noise that seems to come from the back side of the motor on the left lower side when facing it from the front.
Been out of job now for 8 months and was hoping it would carry me thru until I can buy a new one. Boy! it never rains but it pours.
Last edited by zazman; 12-04-2011 at 05:09 PM.
Reason: adding more info.
The factory repair manual gives a detailed process on how to adjust the valve lash.
The specifications for my 2003 may be different than for your '98 as mine has VVT (Variable Valve Timing).
I gave the procedure a glance.....and it is more than I am comfortable with doing myself....a job that I would have a shop do if it needed done.
In short....there are shims that are used to "adjust" the valve lash.......
If they are off.....you use a different size shim to make the adjustment.
You may have more experience and tools and feel confident with doing it yourself.
As a point of reference.....I had a shop (dealership, as they were actually cheapest at around $450) do my 90K timing belt/water pump replacement because I do not feel confident doing it myself.
I only have 1 vehicle, so that changes things as I don't have another vehicle to drive while this one is apart.
I have a problem in tracking down underhood noises.
1 Noise that is right there is the tapping sound of the fuel injectors.
Also, you might want to make sure that your oil flow is OK..
A clogged pickup screen on the oil pump pickup tube (in the oil pan), "gell" (sludge) in the motor can also cause things to be noisy due to lack of oil at certain locations in the motor.
One would need to remove the front valve cover as a minimum to check for sludge.
The front will be cleaner than the back because the front is where the fresh air comes in through the breather tube and the dirty air is pulled out the rear valve cover through the PCV valve.
However, if the front is clean, then the rear is almost certain to be clean.
It is SUPER CRITICAL to check the PCV periodicaly to make SURE that it is not clogged or restricted with crud.
They tend to build up deposits over time....and if the PCV valve is not flowing correctly, you WILL develop sludge in the motor.
Checking the PCV valve is not so hard....and is a CHEAP way to avoid EXPENSIVE problems.
Thanks Wiswind,
After a thorough invetigation I conlcuded that the noise is not from the valves (I used a long screw driver and an empty beer can for my stethoscope) and found out the sound does not come from inside the engine. It is most likely some loose part vibrating against some thing in the engine compartment. This was confirmed by the fact that the rattling sound is not continuous when you rev up the engine and only comes at low idle speeds.
My job now is to find out what it is that could be loose in there and fix it. Might as well have the timing belt changed at the same time.
Did you figure out the source of the noise? Don't despair, our '98 Sienna now has over 304,000 miles on it and still going strong. It, too, has a noise similar to what you've described and I'm almost certain it's coming from an idler or tensioner on the timing belt. I'll find out soon because our timing belt replacement is due soon and I'm going to replace everything. Only the belt itself has been changed previously. The water pump, idler and tensioner are all original.
On our van, the noise is only heard after the engine has been running a few minutes, and then is heard only when the RPMs are between 1800 and 2400 (approximate). It sounds a little bit like spark knock / pinging but it's not. Pinging goes away when the accelerator is released but this noise only stops when the RPMs leave the range described above.
Finally made it back again.
I had just had a mechanic change my timeng belt since it was due and when I picked it up from his shop, the tapping sound was even louder. He said he had checked everything but could not figure out what it was. I went to another shop (midas I think) to have them check it out and give me a quotation on how much it would cost to fix. Lo and behold the manager tells me the engine has seen its days and that I should consider installing another one. I never imagined anybody could just blow smoke up my rear end like that, but anyway I knew the engine was ok and finally decided to have another opinion from a friend's mechanic. The minute I started the engine and told him I had just changed the timing belt, he told me to change the belt tensioner just from that sound. Indeed the belt tensioner was kaput and after replacing it my sienna is its old self again at 243K.
Which mechanic you go to makes a very big difference.
The Following User Says Thank You to zazman For This Useful Post:
Zazman, this is a great report! I had long suspected the noise I'm hearing on our van is coming from a timing belt component, and your report confirms that this is a good possibility. Congrats on finding the right mechanic, and avoid that one guy like the plague (the one who told you your engine is worn out). There's a good chance you've got several years of life left in your engine.
I'm trying to make up my mind whether to keep it or not. This baby took care of me for over ten years despite the beating I took it thru. I got all I asked out of it but I need to move on now knowing I'll look back and regret this decision. This is a good car to have. Kids are all grown up and hate being lugged around in a van and want their own cars.
Anyone need a 98 sienna ecm? I have two that I bought by mistake thinking mine was dead only to find that I had a short somewhere to a sensor.
Still haven't sold my sienna. callers want to steal it and I won't let them, it is too good to give away for less than $2500.
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