Ford Mustang: Cracked plastic intake manifold coolant crossover (4.6 2V V8 GT)
Cracked plastic intake manifold coolant crossover (4.6 2V V8 GT) is a very common cooling fault on the Ford Mustang on the 1996–2001 cars, and we rate it major. Putting it right costs $1,200 to $2,400 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 21 documented faults on the Ford Mustang.
- Vehicle
- Ford Mustang
- Engine
- 4.6L
- Years
- 1996–2001
- Fuel
- petrol
- System
- Cooling
What you are looking at
No photograph available
What goes wrong
The 4.6 2V V8 in the Mustang GT uses an all-plastic (nylon composite) intake manifold with the coolant crossover moulded into the front of it, next to the thermostat housing. With age and heat cycles the plastic crossover cracks and suddenly dumps coolant, which can cook the engine if the driver does not stop. Ford issued TSBs 97M91, 99M01 and 01M02 and settled a class action in 2005 covering 1996-2001 4.6 2V vehicles (reimbursement and a 7-year extended warranty); that programme has expired. The fix is a later-design manifold with an aluminium coolant crossover, which Ford introduced for 2002-on cars.
What you would notice
- Coolant leak or crust at the front top of the engine near the thermostat housing
- Sweet coolant smell after a drive
- Sudden loss of coolant and overheating
- Coolant puddle under the front of the engine
How to check it
Where to look. Top front of the engine, where the thermostat housing and upper radiator hose join the plastic intake manifold
With the bonnet up and the engine cold, use a phone torch to look at the front of the intake manifold where the top radiator hose and thermostat housing meet it.
Look for white or green crusty residue, damp patches or hairline cracks in the black plastic.
Check whether the manifold crossover at the front is aluminium (the fixed design) or all black plastic (the original).
Check the coolant reservoir level before and after the test drive and look under the front of the car for drips afterwards.
Ask whether the intake manifold has been replaced and with which part.
If a workshop inspection is possible: have the cooling system pressure-tested and inspected for seepage at the crossover.
What it costs to put right
$1,200 to $2,400 at New Zealand independent workshop rates. That is for this job on its own, not for the car.
Ask the seller
- “Has the intake manifold been replaced, and does the new one have an aluminium coolant crossover?”
- “Has the car ever lost coolant suddenly or overheated?”
- “Do you have receipts for any cooling system work?”
Now check the Ford Mustang 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.
Where this comes from
- FordMuscle: 'Ford settles manifold lawsuit' (Dec 2005, 1996-2001 4.6L 2V, TSBs 97M91, 99M01, 01M02)
- StangNet forums: 'PI manifold cracked around water housing' thread
- StangNet forums: 'Cracked intake' thread
- 8020 Automotive: Ford 4.6 intake manifold guide, problems, recalls and upgrades
Ford Mustang buyer questions
Is cracked plastic intake manifold coolant crossover (4.6 2v v8 gt) serious on a Ford Mustang?
We rate it major and very common on the Ford Mustang. The 4.6 2V V8 in the Mustang GT uses an all-plastic (nylon composite) intake manifold with the coolant crossover moulded into the front of it, next to the thermostat housing. With age and heat cycles the plastic crossover cracks and suddenly dumps coolant, which can cook the engine if the driver does not stop. Ford issued TSBs 97M91, 99M01 and 01M02 and settled a class action in 2005 covering 1996-2001 4.6 2V vehicles (reimbursement and a 7-year extended warranty); that programme has expired. The fix is a later-design manifold with an aluminium coolant crossover, which Ford introduced for 2002-on cars.
How much does it cost to fix on a Ford Mustang?
$1,200 to $2,400 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 Mustang years are affected?
Our research records this fault on the 1996–2001 Ford Mustang. 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.
How do I check for it before I buy?
With the bonnet up and the engine cold, use a phone torch to look at the front of the intake manifold where the top radiator hose and thermostat housing meet it. Look for white or green crusty residue, damp patches or hairline cracks in the black plastic. Check whether the manifold crossover at the front is aluminium (the fixed design) or all black plastic (the original). Check the coolant reservoir level before and after the test drive and look under the front of the car for drips afterwards. Ask whether the intake manifold has been replaced and with which part. If a workshop inspection is possible: have the cooling system pressure-tested and inspected for seepage at the crossover. Look here: Top front of the engine, where the thermostat housing and upper radiator hose join the plastic intake manifold