MajorCommonCooling

Lexus RX: Radiator Plastic End Tank Cracking and Coolant Leak

Radiator Plastic End Tank Cracking and Coolant Leak is a common cooling fault on the Lexus RX on the 2008–2015 cars, and we rate it major. Putting it right costs $700 to $2,200 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 Lexus RX.

Vehicle: Lexus RX
Years: 2008–2015
System: Cooling

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

All Lexus RX faults21 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Radiator yet. We would rather show none than show a picture of a different part.

What goes wrong

The AL10-generation RX uses an aluminium-core radiator with crimped plastic end tanks. These tanks develop hairline cracks at the crimp seam after sustained thermal cycling, particularly on vehicles operated in regions with large temperature swings. The failure results in a slow coolant weep that progresses to an outright leak, and the engine can overheat if the loss is not detected early. The plastic also becomes brittle with age, making the tanks susceptible to cracking from even minor pressure spikes.

What you would notice

Sweet antifreeze smell from engine bay
Coolant reservoir level dropping between inspections
White or orange staining on or below the radiator
Temperature gauge rising above normal operating range
Coolant puddle visible under the vehicle after parking

How to check it

Where to look. Front of engine bay — radiator upper and lower plastic end tanks at crimped aluminium core junction

With the engine cold, inspect both plastic end tanks of the radiator carefully for discolouration, white mineral deposits, or dried coolant residue around the crimp seam.
Check the coolant reservoir level and look for a sweet smell under the bonnet.
Run the engine to operating temperature and recheck for any seeping.

Parts involved: Radiator.

What it costs to put right

$700 to $2,200 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 radiator ever been replaced or repaired, or has the vehicle had any coolant leaks?”
“Has the temperature gauge ever gone above normal, or has the engine overheated?”
“When was the coolant last changed and has the reservoir needed topping up?”

Now check the Lexus RX 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 published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Lexus RX buyer questions

Is radiator plastic end tank cracking and coolant leak serious on a Lexus RX?

We rate it major and common on the Lexus RX. The AL10-generation RX uses an aluminium-core radiator with crimped plastic end tanks. These tanks develop hairline cracks at the crimp seam after sustained thermal cycling, particularly on vehicles operated in regions with large temperature swings. The failure results in a slow coolant weep that progresses to an outright leak, and the engine can overheat if the loss is not detected early. The plastic also becomes brittle with age, making the tanks susceptible to cracking from even minor pressure spikes.

How much does it cost to fix on a Lexus RX?

$700 to $2,200 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 Lexus RX years are affected?

Our research records this fault on the 2008–2015 Lexus RX. 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 engine cold, inspect both plastic end tanks of the radiator carefully for discolouration, white mineral deposits, or dried coolant residue around the crimp seam. Check the coolant reservoir level and look for a sweet smell under the bonnet. Run the engine to operating temperature and recheck for any seeping. Look here: Front of engine bay — radiator upper and lower plastic end tanks at crimped aluminium core junction