Lexus GS450h Engine overheating

alexchrisro · June 29, 2017

Hello guys, i need some help with my car... again :)) So the story goes something like this. Today i was on the highway cruising at about 80 mph. In my country today was extremly hot. On the highway the outside temperature was about 40C (104F). As i was driving, behind me a Volvo was tailgating me so i wanted to have some fun and i floored it from 80 to 120 mph for a couple of times(it was some traffic in front of me). At about the fourth time when i was flooring it from 80 i noticed a hesitation of the engine and the power was going down and car did not accelerate, i saw that i drained the Battery completely and i thought that's why i do not have power, but when i looked at the engine temperature gauge it was almost near the H sign. Instantly i let the accelerator off, the speed dropped to 80 again and in a couple of seconds the needle dropped at the middle between C and H where it sits normally.

Then i drove it a couple of miles at 80, floored it again to 120 to see if the temperature rises again and the needle moved very very little up to the H (one square).

After many miles, i was curious to see again if the engine temp rises if i floor it so this time i flored it from 40 mph to 120mph, everything was perfect the temperature did not rise at all.

So my question is... what is rong with my engine? No check engine or anything on the dash, it is the first time i encounter such a problem with the car. The coolant is at top level and it is perfectly clean. Oil same... (i thought of the worst, head gasket ex.)

Is this relatively normal because of the extreme heat outside? It was my fault for pushing the car hard or my engine has problems? I don't really know what to say, i thought this cars can live with such extreme temperatures, i don't think it is normal. I am a little worried.

Please help and thank you for your answers.

Britprius · June 29, 2017

It is possible that the engine coolant thermostat is sticking, and that would be the first thing I would change.

This may seem a strange question, but has the front of the car been damaged at any time?

John.

alexchrisro · June 29, 2017

Nope. I bought the car from a friend and i know all the history. The car has never been damaged.

Next week i will change the thermostat. Thank you very much John.

Upex · June 30, 2017

To jump up and return to normal so fast sounds like sensor or gague issue to me, or stat as John says. No way the volume of fluid can gain that much heat and more so lose it again and be back to normal within a few seconds, that's a lot of energy and dispersing that with the rad can't be done so quickly. Especially when it's already 40deg outside - perhaps in the south pole lol.

Hangie · June 30, 2017

Eventually water pump is dying and coolant is not circulating as it should.

Britprius · June 30, 2017

22 hours ago, alexchrisro said:

Nope. I bought the car from a friend and i know all the history. The car has never been damaged.

Next week i will change the thermostat. Thank you very much John.

The reason I asked the question is because Toyota/Lexus use two electric fans for cooling.

These fans rotate in opposite directions. The fans have a different number of blades, and are designed to run in one direction only pushing air into the engine compartment. If the blades get replaced because of damage it is not unknown for them to get put in the wrong position the drive motors turning them backwards.

This makes the draw air from the engine compartment blowing it forwards against the airflow at the front of the car as it moves forwards. At higher speeds the air comes to a standstill, and the car overheats. Leaving the motors where they are and swapping the fan blades cures the problem.

John.

alexchrisro · July 3, 2017

First of all, thank you all for all your answers. After the heating problem i added some distilled water to dilute the antifreze. Coming back home i pushed the car pretty hard to see if it happens again. This time the temperature gauge did not move an inch but the temperature outside was 70f (21c).

Strange thing was... after the heating problem i did have a p0430 code but it was in pending. After i started the car to come back home after about 10 minutes the CEL light up and the code p0430 was permanent. This was the first time i got this code, could it be somehow this was related to the heating issue?

Hangie · July 4, 2017

Why you wanted to dilute the antifreeze ?

you should use premixed one and keep the ratio as it is.

alexchrisro · July 4, 2017

Because it was never changed and from what i know it is possible that in time the antifreze gets thicker and does not cool down as it should.

Hangie · July 4, 2017

Shouldn't you just change it then ? As far I remember it is every 100k m / 160k km or 10 years ?

dont forget you got 2 cooling systems with separate coolant.

Britprius · July 4, 2017

Code PO430 Catalyst system below threshold bank 2.

John

alexchrisro · July 11, 2017

OK, after some time the problem with the overheating did not come back, i suspected bad fuel was the problem and the enginer was runing poor but now there is a new problem. The p0430 keeps coming, not permanent to light the check engine up but in pending. Funny thing is that i started to see that my idle is pretty rough. When i put the car in N the car shakes and underneath i can hear some strange knocks... What the hell is going on with my car, should i prepare for the worst? A lambda sensor or my cats ar starting to fail :))

Also is it normal, first morning start (after the car was sitting by night for about 20 hours) the engine starts, runs for about 1 minute then shuts off and it goes into EV mode? This thing started happening when the summer and hot days came (95F/35C).

110.000 miles on the clock

Thank you all for the help.

Hangie · July 11, 2017

For the roughness. I wasn't very happy about my idle too. It wasn't shaking a lot but I could fill it on red light.

also driving around 20mph wasn't 100% smooth. I blamed both for slowly dying spark plugs or air filter.

case is I was right. I just done my 120k service with new plugs and filters - all the roughness is gone :)

as you are also in my area mileage area you may want to look at spark plugs and filters.

if plugs are really bad you may not burn all the fuel in cylinders and killing cat.

Farqui · July 11, 2017

Flipping to EV mode quickly in hotter temps soon after starting (from cold) is normal provided the traction Battery has a good reserve.

It's a bit spooky but you soon get used to it. My wife hasn't driven my Hybrid much (yet) and gets totally flummoxed by the EV switching.

doro708 · July 11, 2017

For that code you could check the gaskets between the Y-pipe in the exhaust , from the engine just before the cats . I had the same error on mine as it was blowing air from there just before the cats and post 1 set of lambda so the 2nd set of lambda was seeing abnormal readings . Just put it on a ramp and if you see black soot around that area just change the gaskets .

alexchrisro · July 11, 2017

First of all thank you all for your answers. Today I put the car on the ramp and I discover something which is very weird the driveshaft is moving very little left right when the car is in neutral. It's kind of shakes and I don't think this is normal. The knocking sounds from underneath the car are coming from the driveshaft because it's shaking when the car is Neutral but not when in park. I suspect the rough idle is coming from the driveshaft too it's weird because it is like the gearbox wants to move the wheels a little. Can anyone tell me if this is normal? To be Honest I'm little worried at this point.

Thank you all for all your help

Britprius · July 11, 2017

The shaft movement you are talking about in neutral is normal if the engine is misfiring. In park the shaft is locked, but in neutral it still has a small amount of drive as the engine runs erratically. With a hybrid gearbox the gears are never out of mesh they are always engaged.

Your problem is with the engine misfiring or running rough.

John.

alexchrisro · July 11, 2017

Thank you John for replying. the strange thing is that i have no errors on the engine. No misfires. I am guessing it is bad gasoline. In my country we do not really have very good gasoline

Upex · July 12, 2017

20 hours ago, alexchrisro said:

Thank you John for replying. the strange thing is that i have no errors on the engine. No misfires. I am guessing it is bad gasoline. In my country we do not really have very good gasoline

Your details say your in Newport Alex, is fuel in Wales that bad? Seriously though, have you serviced her of late? Air filter, plugs and oil service, check of the crank breathers etc. as sound like it's due to me.

alexchrisro · July 12, 2017

Well... when i register i could not put my country. I am from Romania, Bucharest(that is why sometimes my english is crap, btw nice to mee yout guys, you helped me allot :) ) and here the fuel sometimes is crap all do i fill her up with the best possible fuel that exists here. The car is been very well serviced, oil and filter changed every 3000 miles, new spark plugs, everything and every sensor that can be cleaned, was cleaned (throttle body, MAF(new), vvti filters, etc) did an engine oil flush.

However... crank breathers... i don't know anything about this, can you help me with more detalis, where they are, how can i clean them, etc?

Thank you.

alexchrisro · August 11, 2017

Guys i need your help... again :) now i do not know if this is normal i will try to explain the best i can.

A couple days back i discovered a very strange sound. I will try to explain the best i can how this sound appears.

I am starting the car, engine runs for two minutes then it shuts down and then i am starting the ac. The ac drains all the Battery and then the engine kicks in to recharge the Battery. Now when the engine does this if i very gentle touch the acceleracion then lift of the foot and let the car rolling at the tranny speed there is a very werid sound coming from the engine. It is like a vibration and it is feeling weird inside the cabin to. I tried to film but i do not know if my phone recorder the sound. Is this normal? Is it something that the tranny does not like when it is recharging the Battery and moves the car at idle? If i very gentle touch the acceleration the sound goes away but if a lift the foot when the speed reaches the transmision idle(by this i am refering at putting the car in "drive" lift of the brake and let the car roll without acceleration) the sound reapears and this only happens when the Battery is been recharged by the engine.

Again thank you all for your help and answers.

alexchrisro · August 11, 2017

Another info. If a put the car in maintenance mode and drive like i posted above there is no weird sound. Except for a nasty clunk when i stop but i think this is normal since the car is not made to be driven in maintenance mode.

Again thanks for the help.

alexchrisro · August 24, 2017

On 6/30/2017 at 10:10 PM, Britprius said:

The reason I asked the question is because Toyota/Lexus use two electric fans for cooling.

These fans rotate in opposite directions. The fans have a different number of blades, and are designed to run in one direction only pushing air into the engine compartment. If the blades get replaced because of damage it is not unknown for them to get put in the wrong position the drive motors turning them backwards.

This makes the draw air from the engine compartment blowing it forwards against the airflow at the front of the car as it moves forwards. At higher speeds the air comes to a standstill, and the car overheats. Leaving the motors where they are and swapping the fan blades cures the problem.

John.

John thanks a million for your post. Since then I did not have problems with overheatig... however i do not know how but today when i was cleaning the engine bay i saw the two electric fans spin in the same direction. That is why my car overheated. The car did not have any accident i do not know how this was possible, maybe when the valve recall was done the fans where not mounted corectly.

Can you please tell me what is the direction of the blades rotating? Towords the exterior of the car? (One spining to the left and one to the right looking from the front of the car?)

thank you very much!

alexchrisro · August 25, 2017

After i studied a little it seems that my fans are in the corect place. the 7 blade is on the left and the 5 blade fan is on the right (looking from the front of the car) but... they both spin clokwise.

Britprius · August 25, 2017

9 hours ago, alexchrisro said:

After i studied a little it seems that my fans are in the corect place. the 7 blade is on the left and the 5 blade fan is on the right (looking from the front of the car) but... they both spin clokwise.

Alex. The first thing to do is to find which way the fans are blowing air. Hanging a piece of tissue or wool by the fans when they are running will tell you the direction of the airflow. It should be from the front of the car into the engine compartment. If this is the case nothing is wrong.

If one or both fans are blowing out through the front grill the fans or motors have been changed.

John.