Parts for your 2004 Toyota Highlander-Oil pump

2004 Toyota Highlander oil pump — what it does and when to service it

Yes, the 2004 Toyota Highlander is fitted with an engine oil pump. Both engines offered that year — the 2.4‑litre 2AZ‑FE inline‑four and the 3.3‑litre 3MZ‑FE V6 — use a crankshaft‑driven trochoid (gerotor) oil pump. This is detailed in Toyota’s 2004 Highlander/Harrier Repair Manual under Engine Mechanical – Lubrication System, and illustrated in the Toyota Electronic Parts Catalog (EPC) for the 2AZ‑FE and 3MZ‑FE. On the 2AZ‑FE, the pump is integrated into the front timing chain cover and driven directly off the crank. On the 3MZ‑FE, it’s mounted at the front of the block and driven off the crankshaft behind the timing components.

This oil pump’s job is to push the right amount of oil, at the right pressure, through the engine. It feeds the crank and rod bearings, camshafts, and VVT‑i passages, helping to cool and clean as it goes. A healthy pump keeps the oil pressure light off at idle when hot and makes sure pressure builds quickly after start‑up, so the Highlander feels smooth and happy under the bonnet.

As a rule, the oil pump isn’t a routine replacement item on a 2004 Highlander. It usually lasts the life of the engine provided regular oil and filter changes are done using the correct viscosity specified by Toyota for local climate. If the oil light flickers, top‑end ticks on hot idle, or there’s a verified low reading on a mechanical gauge, then it’s time to investigate. Always confirm pressure with a gauge before blaming the pump, because a clogged pickup, tired bearings, or a dodgy pressure switch can mimic pump issues.

When a pump or its seals do need attention, it’s a bit of a spanner‑heavy job. On the 3MZ‑FE V6, consider inspecting or resealing the pump and replacing the front crank seal during a timing belt service, as access is already open. On the 2AZ‑FE, the timing chain cover must come off, so many techs pair the work with chain, guide, and tensioner checks. Priming is critical: pack the pump with assembly lube or clean engine oil, fill the filter, and crank with ignition/fuel disabled until the oil light goes out.

Good practice during any sump‑off or front cover work includes:

• Cleaning the pickup strainer and replacing the pickup O‑ring
• Using the correct sealant on the timing cover and torqueing bolts to spec
• Fitting a quality (OE or reputable brand) pump and a fresh front main seal

Popular questions about the 2004 Toyota Highlander oil pump

Does the 2004 Toyota Highlander actually have an oil pump?

It does. Both the 2AZ‑FE 2.4‑litre and 3MZ‑FE 3.3‑litre engines use a crank‑driven trochoid oil pump, as shown in Toyota’s factory repair manual and parts catalog. Without it, there’d be no oil pressure and the engine wouldn’t last long at all.

What are common signs the oil pump might be struggling?

Watch for a flickering oil pressure warning at hot idle, delayed pressure build after cold starts, rumbling or ticking noises when warm, and verified low readings on a mechanical gauge. Rule out a clogged pickup, thin/old oil, or a faulty pressure switch before calling the pump.

Should the oil pump be replaced during timing service?

On the V6 3MZ‑FE, it’s smart to inspect the pump, front main seal, and related gaskets when the timing belt is off, resealing or replacing if there’s wear or leakage. On the 2AZ‑FE chain engine, the job is more involved, plan it with timing chain and front cover work if evidence points to a pump or seal issue.