Service Schedule on Serpentine Belt

Hi Charles,

Yes, it would be difficult to get the serpentine belt around the crankshaft pulley without being able to reach the pulley from below the car.

Thanks for your comments, Jay. Do you know the history of that particular Tacoma, regarding fuel brand used and the oil change frequency?

 

AFAIK the owner claims whatever was cheapest wrt fuel and oil. Oil changes usually every 6 months or 6,000-7,000 miles

NJ isn't Winnipeg, but in winter is cold enough to cause problems with condensation, causing oil breakdown. I have to admit I was surprised at the deposits on the piston, the intake valves also have deposits. I thought all gasolines were supposed to have additives to prevent that? See attached photos of the intake valves and head

You can tell it's an area with salt in winter. Check out the rust on the studs

The teardown convinced the Tacoma owner to change his ways. His project wasn't cheap, around $9,000 by the time the rebuild and performance upgrades were done. Would have been cheaper to just bolt on a TRD supercharger, at least until the motor finally went

 

Oops, no more attachments for me. I've just reached my 50 MB limit

 

Great phots and description! Thanks Pat.

 

What alloys are used for the block, head, and cams?

 

Hi Jay,

Your photos serve as good advertising for Shell, Chevron, and the other major gasoline brands that claim top-tier affiliation. The photos also should encourage owners in cold areas to change their engine oil frequently (or use synthetic oil). I've noticed a few recent posters reporting visible sludge at the bottom of the engine oil cap, which is not a happy sight.

Hi Richard,

The block and head are aluminum, while the camshafts, crankshaft and bearings are steel.

 

If you have visible "latte" underneath the oil filler cap, you have sludge buildup in the motor itself

Remember that bare minimum spec API oil dropped the requirement to prevent cold black sludge. I'm sure if you changed the oil often enough, you would be ok on cheap oil.

But how often is often enough? 5,000 miles? 3,000 miles?

An uncle of mine was a mechanic at the Alcoa plant in Port Lavaca, TX. He used to tell the family members living up here to never put more than two months or 2,000 miles on the oil and filter, in winter. That probably helped, the family members who listened to him got long life out of their cars

 

Jay, the cam follower buckets look buggered in your picture, are they that pitted really or is that something on the top? Those pistons look to how I would expect them to look in a car with 300,000km on it, at least like ones I have pulled apart.

I noticed in another post where you had a picture of the underside of a cylinder head, one cylinder looked washed like it had a head gasket leak while the other 2 had carbon build-up. I'd rather see a little carbon than none. Carbon is a byproduct of combustion and the cylinder head and piston crown are cooler than the combustion gases so there will be condensation of hot vapour on them.

 

The guy claims they really are that buggered. The motor wasn't running very well when he had the work done

Apparently, the compression was already below the bottom spec

Not sure, had to look at the photo again to determine what you saw. Sure looks like a coolant leak, doesn't it

 

I should note - again - this Tacoma received very indifferent maintenance from the owner. If it wasn't cheap, on sale, it didn't go in. Apparently he never changed the gear oil either

 

Can you delete some of the old ones? Is that possible?

 

I suppose I could do that. Not sure where to start though. I also have a large number of Adobe Acrobat files attached, some folks may miss them. I'd rather see my attachment limit increased

Nudge nudge wink wink hint hint

 

What gauge do you use for checking the belt tension? The most common one I see for sale is the OTC 6673. It reads from 30 inch pounds so that might not work well if you need 22 inch pounds for the 2004.

My belt started making a little noise when the engine starts and stops. It looked glazed on the outside so it was probably slipping. I changed the belt but I'm not confident in my uncalibrated thumb pressure. It's quiet now.
Thanks

 

As a DIYer I don't have a gauge. If you don't hear any noise then the belt should be tight enough. The concern is that if it is too tight then you may damage the water pump bearing or idler pulley bearing.

 

I have a warning for anyone doing this. The bolt that was coaxial to my idler pulley was really tight, to the point that I had to use a two foot cheater bar to loosen it and even then struggled a little. I thought it was way too tight, but I didn't trust my instincts, and when I went to tighten it back up it I tried to get it back to the same tightness and ended up snapping the bolt. So anyone doing this at home, the factory might have fastened it on insanely tight, and you should do what I didn't and use common sense when tightening it back up.

 

Thanks for relating your experience. I believe that you are referring to a nut, not a bolt? See the center of my first photo in post #18.

Did you have any trouble obtaining a replacement piece of hardware?

The specified tightening torque is 30 ft.-lb. I agree that the nut was fastened pretty tight and that use of a cheater bar will be very helpful to remove it. I've got a 2 ft piece of iron water pipe that fits over my 3/8" ratchet handle, and a 3 ft piece of steel TV antenna mast that I use over my 1/2" ratchet handle as needed.

 

You're right, I thought it was a bolt but it is a nut. I have to order a whole new idler pulley, which cost about $60 from the dealership and should get here tomorrow after placing the order today.

Also, I found that I did not have to remove the RH under cover to replace the belt, although it was a tight fit.

 

With this wonderful information in hand, I replaced my belt on my 2005 with 70K on it. I was able to easily do this without removing any plastic covers, plastic fasteners, etc. You can just push the plastic out of the way a little and slip on the belt. Also good to note at 70K my belt was very cracked on the inside of the belt. Well worth doing today rather than getting towed for $100 from the side of the road. All the thanks to Priuschat and the good people on here.

 

Here's an alternative approach to serpentine drive belt replacement that does not require removing the engine under cover.
http://priuschat.com/forums/knowled...87166-belt-change-how-photos.html#post1219273

 

I'm doing my serpentine this rainy weekend (Dec 2010) ... and always knew I'd resurect Patrick's helpfull guide here, when it finally became time for my own belt change. Time to change? Um, yea, how does 100K miles sound.

Yep, I'm bad. But it took that long to finally see cracks. As for belt tension, I have a 5-100 lb tensionometer I'll be using ... . but for super-duper accuracy, they DO make another cool device. I give you the -
Sonic tensionometer:

To detect tension, a sonic type hears the vibrations when you strum the belt (just like you might strum a banjo string). The unit has to know what type/size belt it's dealing with in order to match it's frequency/tension. Very slick, AND expensive. That's why the cheaper style ... like mine ... basically a fish scale is way more popular.