factory replaced 3.0

[newyotaowner]

Before i got my truck , the dealership put in a new " improved " 3.0 in it . All i know it was not supposed to build up as much sludge in the engine as the previous engine . My main question is . Is this engine designed like the 3.4 ? Do i change the timing belt at 50,000 miles or closer to 90 ? And is there anything i need to watch out for if I go and get parts from another 4runner or truck with the 3.0 in it ?

[DHC6twinotter]

Toyota did some changes to the motor around mid '92 or '93. Some changes I've noticed:

1) Older 3.0s have a spring type timing belt tensioner, while the newer engines have a hydraulic tensioner.

2) Because of the above, the fan pulley bracket (also known as fake water pump) and upper timing belt cover are different.

3) Valve covers are different on newer models. The tops are more horizontal instead of parallel to the head surface.

4) Older 3.0s have a coolant line that runs from the coolant neck on the front of the motor, under the plenum, and to the heater hoses in the firewall. Newer models don't have this pipe, and the heater line comes off somewhere at the back of the motor (coolant bypass manifold, I think). As a result, the upper water neck and I think the coolant bypass manifold are different. NOTE: I'm not talking about the coolant pipe under the intake manifold, but just the one under the plenum.

5) I think some of the AC and PS lines were rerouted at one point or another.

6) Some of the sensors may have changed. I know there are a few different TPS sensors.

Not sure what other changes there are, but I'm sure there are more. I don't have an answer to the sludge question, but maybe the different valve covers have something to do with this? I dunno.

The 3.0 and 3.4 are both from the VZ family of engines, so I suppose they share some in common. There is a lot of differences though.

What does the manual say about timing belt change intervals? I've never looked at my manual, but 50k seems pretty early. I've always assumed 90k. :headscratch: I've got about 217k on my 3.0, and I'm on my 4th belt. First one changed at 134k by the PO, then at 189k when the waterpump went out, and again at 216k (should have lasted way longer, but had to change due to my own negligence).

I can't remember if the stuff changed in mid '92 or '93, but I would just be a bit careful when finding parts.

[slosurfer]

I think timing belts used to be 60,000 miles, but I bet the newer ones are more like 90,000. FWIW, I changed my original one at 104,000 miles due to a leaky waterpump. :)

[Robinhood4x4]

I think I went well over 60k too for the first one, but that's the interval I would use.

As to what to watch out for, post specific things you'll need when the time comes and we'll help you out.