Frmmli

The 2.5L engine is direct injection(DI) and all such DI engines of all makes cheap to luxury will inherently carbonize pretty fast starting at 30,000 miles per one service manager of Audi - fuel and oil molecules coke up behind the intake valve (the side inside the intake manifold) and the area of the intake valve close to the valve and hear. The fuel and oil coming inia little at aa time daily from the crankcase recirculation - the system is for anti--pollution. The enabler in DI of carbonizing is from locating their injector being not in the intake manifold any more but directly on top of the combustion chamber. Dealer service writer, particularly the less experienced in hands on ones and most of them are, will all start out claiming all engines will carbonize, skipping the details that yes but in non-DI engine, so little to be an issue in the life of the engine but DI will eventually within years affect valve proper closing and obstructing air flow to some extend. They sell you a non-Lexus cleaning service with an aftermarket chemical product/'kit' every 15k or whatever miles for $200 to 300. I never believe that will do a lot. Whatever is coked into carbon is insoluble and only mechanical means with manifold off the car can clean out( there are some in car alternative fixes also by special shops) and only the recent deposit yet to finish burning may be washed off.

My writing is to ask for your experience as to when you saw it on your engine and how was it repaired, for how much?

Littleguy

Does the 2AR-XFE not use the D4-S system?

jollick

I believe that issue was for early direct injection vehicles.I believe the addition of an injector in the port fixed this issue. I could be wrong but here is the wiki site for reference.
For the ES300h The 2AR-FSE [9] is a variant of the 2AR-FE equipped with D4-S direct-injection and port injection. https://en.wikipedia.org/wiki/Toyota_AR_engine#2AR-FXE
For the ES350 http://www.motorreviewer.com/engine.php?engine_id=129

Frmmli

Unfortunately the ES300H uses the 2AR-FXE not 2AR-FSE. No D4-S that I can tell; and not enough hint of a reason to verify on the actual car. Thanks.

john341

The engine(2AR-FXE) in es300h has port injection; which is not know for excessive carbon buildup like the cars with just Direct Injection. I have never agreed to use of cleaning agent as its a way for the Dealership to grab money and is utterly worthless. Our es300h is close to 75000 miles and has has been an excellent car, still getting 35-40 mpg's.

jollick

Ok, but doesn't the 2013 - 2015 use port injection and not direct injection?

Littleguy

I believe that is what he is saying. Come to think of it, I don't think Toyota/Lexus makes any direct injection cars without the D4-S system, which is probably why you never hear about carbon issues on any Lexus/Toyota vehicles.

Frmmli

Littleguy and the two other members, thanks. Would be nice if my 2014 ES300H's 2.5 has D4-S.

Jollick's answer may be correctly re-directing the conversion. The 2AR-FXE engine on my car has port injection and never a direct injection which a dealer may be wrongly informing me. So, it is also not having D4-S.

How did any of you confirm to yourself that 2AR-FXE only has port injection? Jollick, appreciate a confirmation and I have one less maintenance to worry about.

I have called one Lexus Parts just now. They find that car calls out 4 fuel injectors and not 4 of another kind. (i.e. not D4-S). The mechanic indirectly reply through the service writer that is has port injection. However, they are short of saying that that engine has port injection and no direct injection.

jollick

Here is an Australian web site that describes the engine. http://australiancar.reviews/2AR-FXE-engine.php Looks like only port injection to me.


2AR-FXE Toyota engine
Introduction
Toyota's 2AR-FXE was a 2.5-litre inline four-cylinder petrol engine. Based on the 2AR-FE, the 2ARFXE differed in that it had:
Atkinson cycle operation; and,
A unique cylinder head, camshafts, pistons and fuel supply system.
To reduce fuel consumption, the 2AR-FXE used electric motors to power ancillaries such as the
water pump, variable air-conditioner compressor and electric power-assisted steering, thereby
removing the need for an accessories belt. The key difference between the 2AR-FXE and 2AR-FSE
engines was that the latter had direct fuel injection in addition to conventional port injection.
For Australia, the 2AR-FXE engine was used in the Toyota XV50 Camry Hybrid, Lexus XV60 ES 300h
and Lexus NX 300h.
2AR-FXE Toyota engine
Engine Trans. Peak power Peak torque
Toyota XV50
Camry Hybrid
2.5-litre petrol I4
(2AR-FXE) CVT 118kW at 5700rpm 213Nm at 4500rpm
Lexus XV60 ES
300h
2.5-litre petrol I4
(2AR-FXE) CVT 118kW at 5700rpm 213Nm at 4500rpm
Lexus NX 300h 2.5-litre petrol I4
(2AR-FXE) CVT 114kW at 5700rpm 210Nm at 4200-
4400rpm
4 of 6
2/7/2019 2AR-FXE Toyota engine
http://australiancar.reviews/2AR-FXE-engine.php 2/4
2AR-FXE block
The 2AR-FXE had an aluminium alloy cylinder block with 90.0 mm bores and a 98.0 mm stroke for
a capacity of 2494 cc. With the cylinder bores, the 2AR-FXE had ‘spiny-type’ liners which were
manufactured so that the casting exteriors of the liners had irregular surfaces for better adhesion
between the liners and the cylinder block.
The 2AR-FXE block also contained:
Oil jets for cooling and lubricating the pistons and bores;
Water passages between the cylinder bores so that coolant could flow and keep the
temperature of the cylinder walls uniform; and,
A shallow bottom water jacket used to reduce the volume of engine coolant for faster
warm-up. The water jacket included a water jacket spacer to suppress water flow in the
bottom of the water jackets and guide the coolant in the upper area of the water jacket for
uniform temperature distribution. As a result, the viscosity of the engine oil that acted as a
lubricant between the bore walls and the pistons was lowered.
Within the crankcase, the 2AR-FXE contained:
Two balance shafts to counteract the secondary inertial forces that were generated twice for
each rotation of the crankshaft. The crankshaft had a balance shaft drive gear that was used
to drive the no.1 balance shaft, while the no.2 balance shaft was gear-driven from the no. 1
balance shaft. To cancel secondary inertial forces, the balance shafts rotated twice for each
rotation of the crankshaft to generate inertial force in the opposite direction. To cancel the
inertial force generated by the balance shaft itself, the balance shaft consisted of two shafts
rotating in opposite directions;
Blowby gas passages with an oil separator that would separate oil from the blowby gas to
reduce oil degradation and consumption; and,
Oil drain passages to prevent the crankshaft from mixing the engine oil (reducing rotational
resistance).
Crankshaft, connecting rods and pistons
The crankshaft for the 2AR-FXE engine was made of micro-alloyed steel, had five journals and
eight balance weights. To reduce lateral forces to the cylinder wall, the crankshaft was ofFXEt to
move the bore centre 10 mm towards the exhaust side (relative to the crankshaft centre). Other
attributes of the crankshaft included:
A micro-grooved lining surface for an optimal amount of oil clearance; and,
Narrow crankshaft bearings with eccentric oil grooves to reduce the amount of oil leakage
from the bearing.
The connecting rods and caps were made of micro-alloyed steel; to reduce mass, the connecting
rods used plastic region tightening bolts. Like the crankshaft, the connecting rod bearings had
micro-grooved lining surfaces and a narrow width to reduce friction.
The 2AR-FXE engine had aluminium alloy pistons with resin coated skirts and low tension piston
rings.
Cylinder head
The 2AR-FXE engine had an aluminium cylinder head in which the camshaft housing (cam journal
portion) was separated from the cylinder head. The cylinder head was affixed to the block with a
triple-layer metal type cylinder head gasket the surface of which was coated with fluoro rubber.
2/7/2019 2AR-FXE Toyota engine
http://australiancar.reviews/2AR-FXE-engine.php 3/4
The 2AR-FXE engine had a magnesium alloy die-cast cylinder head cover which contained an oil
delivery pipe for lubrication of the sliding parts of the roller rocker arm.
Camshafts and roller rockers
The intake and exhaust camshafts for the 2AR-FXE engine were driven by a 9.525 mm roller chain.
The timing chain was lubricated by an oil jet, while the chain tensioner – a ratchet type with a
non-return mechanism – used a spring and oil pressure to maintain chain tension. The 2AR-FXE
engine had roller rocker arms with built-in needle bearings that reduced friction between the
cams and the roller rocker arms (which actuated the valves down).
Dual VVT-i
For the 2AR-FXE engine, the ‘dual variable valve timing with intelligence’ (Toyota’s ‘Dual VVT-i)
system controlled the intake and exhaust camshafts to vary valve timing according to operating
conditions.
Each VVT-i controller consisted of a housing that was driven by the timing chain and a vane that
was coupled with the intake or exhaust camshaft. Both the intake and exhaust sides had fourblade vane-type actuators. The camshaft timing oil control valve controlled the spool valve using
duty cycle control from the engine control module (ECM) – this allowed hydraulic pressure to be
applied to the advanced or retarded side of the VVT-i controller, causing rotation in the VVT-i
controller vane circumferential direction to vary intake and exhaust valve timing. Once target
timing was attained, valve timing was held by keeping the camshaft timing oil control valve in its
neutral position.
The 2AR-FXE engine had 36.5 mm diameter intake valves and 31 mm diameter exhaust valves.
Atkinson cycle
In a conventional (Otto) cycle engine, compression stroke volume and expansion stroke volume
are practically identical, such that the compression ratio and expansion ratio are also identical.
Hence, any attempt to increase the expansion ratio also increases the compression ratio, and
hence the likelihood of engine knock or pre-ignition. Please note that:
Expansion ratio = (expansion stroke volume + combustion chamber volume)/combustion
chamber volume; and,
Compression ratio = (compression stroke volume + combustion chamber
volume)/combustion chamber volume.
Toyota described the 2AR-FXE engine as having an ‘Atkinson cycle’ since the compression stroke
was shortened and the expansion stroke extended. This was achieved by keeping the intake valves
open during the initial stage of the compression stroke (when the piston was ascending) to allow
a reverse flow of intake air into the intake manifold – this allowed for an increase in throttle valve
opening in part load conditions, thereby reducing intake manifold vacuum and pumping losses.
Furthermore, closure of the intake valves was delayed until the end of the expansion stroke,
thereby increasing the expansion ratio.
Since this ‘Atkinson’ operation used a smaller portion of the compression stroke to compress the
intake air, it did not take in as much air as a comparable Otto cycle engine and had lower power
density, yet higher thermal efficiency.
2/7/2019 2AR-FXE Toyota engine
http://australiancar.reviews/2AR-FXE-engine.php 4/4
Toyota quoted the 2AR-FXE engine as having a compression ratio of 12.5:1.
Intake
Like the 2AR-FE, the 2AR-FXE engine had a long-port plastic intake manifold to reduce induction
noise and increase performance. The 2AR-FXE engine had a linkless-type throttle body and
Toyota’s ‘Electronic Throttle Control System – intelligent’ (ETCS-i) which controlled throttle valve
opening according to with the amount of accelerator pedal effort and the condition of the engine.
Injection and ignition
The 2AR-FXE engine had L-type sequential multiport fuel injection (SFI) system with a hot-wire
type mass air flow meter to measure intake air density. The 2AR-FXE engine used long nozzletype fuel injectors, each of which had twelve-holes. To reduce evaporative emissions, the 2AR-FXE
engine had a returnless fuel system used to reduce evaporative emissions.
The 2AR-FXE engine had a ‘Direct Ignition System’ (DIS) in which there was one ignition coil (with
igniter) for each cylinder. Furthermore, the 2AR-FXE engine had ‘Electronic Spark Advance’ (ESA)
which determined ignition timing according to inputs from sensors, including a wave-form
analysis type knock sensor.
Exhaust and emissions
The 2AR-FXE engine had a long branch, stainless steel exhaust manifold and a three-way catalytic
converter.
The 2AR-FXE engine had an exhaust gas recirculation (EGR) system which recirculated a portion of
the exhaust gas back into the intake air to slow down combustion in the cylinder and lower the
combustion temperature – this, in turn, reduced the amount of NOx emissions. For the 2AR-FXE
engine, the EGR system included a step-motor and a water cooler to reduce gas temperatures.
Article by Ian Lithgow

Littleguy

Agreed, looking at the diagram on this page, it looks like port only.

https://www.lexussouthatlantaparts.c...roduct=9914492

Frmmli

Thanks Jollick. It will be great if the ES does not need the de-carbonizing repair.

My car was back, Just to validate that is not Austrian specs, I took off the cosmetic engine top cover, and verified that all I saw on top of the cylinder head were 4 spark plug coils and no injectors. The injectors, I could not see them anywhere, and will assumed they are hidden behind plastic enclosure on the intake manifold side of the engine.

I therefore went back up and edited my original text a little to not start out declaring the engine is direct injection to benefit other members.

-------
In the process, I came across these:
- The gent 7 2019 ES has D4-S.
- Came across talk about Camry Hybrid being given 'injector cleaning'. Quick question without starting a new thread for now, Anysight as to whether Lexus factory has ever issued any recommendation or product(branded)?

I am of the understanding, that any of the major brand gas particularly Shell and forgot who is the other one, has more-than-adequate fuel detergent & additives to clean.
One dealer said their shop use Lexus BG fuel injector products, and I do not believe there is such a thing. Another will tell me they use the Toyota branded cleaner.

chromedome

I've used injector cleaner a few times when I was none the wiser. It's just a ploy from the stealership to make more money off servicing. The 6th Gen ES300h engine doesn't have direct injection so you don't need to bother with injector cleaners or throttle body cleaning, at least until you start hitting 10 years. Just use good clean petrol and you should be fine.