V-belt replacement. Any tips on getting the right tension.

My tip is that you need to exert ~22 lbs pressure on the belt at the longest run between the crankshaft and idler pulleys, and strive for 0.4" displacement.

You may also want to replace the PCV valve while you are at it. With North American cars, the engine wiring harness that runs over the valve cover has to be removed for access, and the PCV valve is sticking out of the valve cover, nearest to the inverter. Please let us know if you can actually see the PCV valve on your engine without taking the wiring harness off.

If so, please take some photos of your engine compartment and post as I would like to see whether there are any other differences that become apparent.

 

Patrick. What exact belt tension checker tool did you use? I've looked on Amazon and can't find anything that resembles the recommended belt tension tools (Benso BTG-20 or Borroughs BT-33-73F).

Thanks.

 

I used a finger of my hand and estimated the required force to deflect the belt - not a belt tension tool.

 

What is the procedure for replacing the V-belt? My service adviser mentioned that there were some cracks starting to appear in it and I should replace it soon. Is this a difficult procedure or should I leave it to the pros.
Thanks, Hoss

 

1. Inspect the engine coolant pump for coolant seepage. If you see any pinkish deposits on the inside of the pump pulley or upon the air conditioner compressor, then plan to replace that pump.
2. To replace the serpentine drive belt, first disconnect the hose leading to the air cleaner housing, for access. Loosen the coaxial nut on the idler pulley. You will need a quality 14 mm 6-point socket, a cheater bar, and an extension for that bar to make loosening that nut effortless. Be careful - some posters have reported damaging that nut which makes it very difficult to remove. My belief is that improper/cheap tools were used. Do not use a cheap 12-point socket.
3. After that nut is loosened, then you can lower the idler pulley by turning the bolt that moves the pulley up and down.
4. Once the pulley is lowered, you can remove the serpentine drive belt. Before you do that though, look at the belt carefully so you can see how the outside surface contacts the engine coolant pump pulley.
5. It is possible to install the new belt from the top of the car. Use your fingers to feel around to make sure the belt is properly seated on the crankshaft pulley. Tighten the bolt to pull the idler pulley back up. Press on the longest length to gauge belt deflection. The idea is to exert 22 lbs force and have the belt deflect 0.4". Then tighten the coaxial nut on the idler pulley to lock it in place, the spec is 30 ft.-lb.
6. See my thread here: How to replace engine coolant pump and thermostat | PriusChat

 

uart -

How old was the belt in terms of year & km? Did you replace the idler-pulley too?

 

Yeah, the Prius ICE (Atkinson cycle) is definitely low-strung. My '05 has 10k more than yours so I'm thinking about replacing the factory issued plugs & PCV but the pix I've seen here show they have much less build-up than those from the Otto cycle engines. Current MPG is ~50 mpg and topping off engine oil is not necessary between changes.

 

Great guide - but, why are you even bothering with bolt B? - it would seem like you could just loosen bolt C enough to take the tension off and remove the belt - on all my other cars, I've never had to loosen a pulley belt unless I was changing the particular pulley (which isn't a bad idea, but I didn't think you were).

I can't post links - if you look on Amazon, the OTC 6673 should be roughly equivalent to the Burroughs BT-33-73F, but it's around $100 and might be tough to fit in the available space. I would recommend looking at a Kriket gauge (also on Amazon for around $15) - they make them for V-belts and ribbed belts, the Dayco V-belt is 93865, but Gates and other companies make them also. Get the correct style, although it probably isn't critical.

 

Makes sense looking at the pictures carefully - again, great job on the write-up and thanks!