MajorCommonEngine

Ford Explorer: 4.0 SOHC V6 timing chain cassette & tensioner rattle

4.0 SOHC V6 timing chain cassette & tensioner rattle is a common engine fault on the Ford Explorer on the 1996–2001 cars, and we rate it major. Putting it right costs $2,500 to $6,000 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 11 documented faults on the Ford Explorer.

Vehicle: Ford Explorer
Engine: 4.0L
Years: 1996–2001
Fuel: petrol
Gearbox: auto
System: Engine

This page covers the Ford Explorer as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Ford Explorer faults11 documented faults on this model

What you are looking at

What goes wrong

The 4.0-litre SOHC V6 fitted to the Australian-delivered US-series Explorer drives its camshafts through long chains running in plastic guide cassettes with hydraulic tensioners. The tensioners bleed down and the plastic cassettes/guides embrittle and shatter, producing a loud chain rattle (a spark-knock-like clatter on cold start-up and under acceleration around 2400-2500 rpm). The front-left cassette can be done with the engine in the car, but a failed rear chain or guide requires the engine to be pulled, and shattered guide debris can circulate through the oil. On these now-elderly cars the noise commonly appears once past roughly 150,000-200,000 km, and earlier where oil changes were stretched.

What you would notice

Rattling/clattering from the front of the engine on cold start that quietens as revs rise
Metallic knock or rattle under light acceleration around 2400-2500 rpm
Chain rattle that returns and worsens over time
Check-engine light for camshaft/crankshaft correlation in advanced cases

How to check it

Where to look. Front of engine, timing chain cover (front-left cassette) and rear cylinder-head chain

Cold-start the engine and listen at the front timing cover for a chain rattle in the first few seconds and again on a light throttle blip; ask for service history showing tensioner/cassette work and regular oil changes. A rattle that persists warm is a strong warning.

Parts involved: Timing chain.

What it costs to put right

$2,500 to $6,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the timing chain, tensioners or guide cassettes ever been replaced, and was it the front only or the rear as well?”
“Does it rattle on cold start-up, and can I hear it now?”
“How often has the oil been changed and with what grade?”

Now check the Ford Explorer you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

Ford TSB 02-7-6 (4.0L SOHC timing chain rattle) as referenced on explorerforum.com Serious Explorations thread 'TSB 02-7-6 4.0L SOHC Timing Chain Rattle'
underhoodservice.com - 'Exploring the Service Needs of the Ford 4.0L V6 Engine' (broken tensioners, plastic guide/cassette failure)
carsguide.com.au used-car review 'Ford Explorer 1996-2002' (broken tensioners, plastic timing chain guides and cassettes)

Ford Explorer buyer questions

Is 4.0 sohc v6 timing chain cassette & tensioner rattle serious on a Ford Explorer?

We rate it major and common on the Ford Explorer. The 4.0-litre SOHC V6 fitted to the Australian-delivered US-series Explorer drives its camshafts through long chains running in plastic guide cassettes with hydraulic tensioners. The tensioners bleed down and the plastic cassettes/guides embrittle and shatter, producing a loud chain rattle (a spark-knock-like clatter on cold start-up and under acceleration around 2400-2500 rpm). The front-left cassette can be done with the engine in the car, but a failed rear chain or guide requires the engine to be pulled, and shattered guide debris can circulate through the oil. On these now-elderly cars the noise commonly appears once past roughly 150,000-200,000 km, and earlier where oil changes were stretched.

How much does it cost to fix on a Ford Explorer?

$2,500 to $6,000 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Ford Explorer years are affected?

Our research records this fault on the 1996–2001 Ford Explorer. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.