Overheating On 93 Es300 - What Not To Do...

[poneyboy]

ES300 Overheating Guide

OK all, this is an attempt to sum up several experiences I've had with my ES300 and it's overheating problems and hopefully decrease the pain that everyone is feeling when this happens:

What happened to me:

1) Had a leaky radiator a year ago that was letting air into the system but not leaking coolant when under pressure. So I had this intermittent boil over issue that would crop up from time to time. When it was finally obvious, I replaced the radiator and it ran great - for a while.

2) I had leaky radiator caps that were also letting air in. So if I topped off the system and drove around, everything was fine. After a day or two, air was getting in and I would have an intermittent boil over - but only so often. Replaced them and it did well for a while.

3) Recently, I had a more consistent elevated temp issue. This was happening after 15 minutes on the highway on hot humid days. When I pulled into my driveway, the temp would jump up slightly. Plus, there was a lot of bubbling into the resevoir, so I thought there was air getting blown into the system from a blown head gasket. Decided to find that damn petcock and completely drain the system and replace the thermostat before I went for a head gasket.

Low and behold, I found an old gasket that had been melted to the inside wall of the thermostat housing. It was dangling over the thermostat and possibly jamming it's operation. I removed this and replaced the theromstat thinking I was ok.

Well, it heated up again. This time it was in my parking lot at work the next day. Opened the hood and the heater hose had blown a pin hole. Hmmm - thought for sure I had a blown head gasket now. Replaced the hose and limped home.

Funny thing, the bugger behaves pefectly. Instead of stopping in the driveway and finding the temp goes up, it actually adjusts down slightly. This indicates that the flow is greatly improved. So I think that hose was balooning and messing with the ability to create enough pressure in the system. It may also have become gas permeable and been allowing air into the system as it cooled.

Now, with all this, it has become clear that the cooling system in this car is very delicate and requires that every element be working perfectly. It is also clear that it can take a tremendous amount of punishement before needing a new head gasket. Given all the stories of head gasket problems and hydraulic fans being replaced by electric ones (this NEVER solves the problem folks, it's just not a part that breaks), I can only conclude that there are a lot of rich mechanics out there who don't understand this thing or there are a lot of poor owners out there who have been duped.

I looked into this and here are several fixes that have been used (my own car history indicates that someone was throwing parts at the car).

What not to do:

1) :chairshot: Replace the hydraulic fan with electric ones. This fan doesn't break. This is not a solution and don't let any mechanic tell you otherwise. Again, this fan doesn't break. You may need to replace the filter and/or the fluid, but this thing is rock solid. Two electric motors will not be able to move as much air as that original fan, and they will never work right. It's a gerry rig at best and may only mask your real issues.

Why the hydraulic fans? To decrease fan noise. Why not replace it? Because it always looks bad and because it doesn't really solve the problem. Mechanics see it and think it is a design flaw. In reality, you may only need to replace a solenoid or something like that to improve it's operation.

2) :chairshot: Replace the whole hydraulic system. It's been done, but it doesn't help. Again, they are throwing parts at you. Only if the pump is making noise and obviously broken do you need this. The assumption is again related to the fan. Mechanics see that hydraulic fan and always assume it's the problem when in reality it's the one element in the system that is not likely to break.

3) Replace the water pump. This isn't a solution to the overheating. Don't do this unless you have a leak or you are replacing your timing belt. These water pumps don't last long enough to wear out impellors. If this is your mechanic's solution to the problem, he doesn't really know what's up. There is no good way to test flow in this system anyhow, so how could he know?

4) Replace a head gasket. This may be your problem - but if your trouble is intermittent, don't go for it unless you have irrefutable proof. These things are pretty solid and can take some serious punishment. I may still have to do this on mine, but every time I'm worried about it, something else manifests itself.

5) Remove the thermostat. This can help, or it can make things worse. I'm not sure if it's a bad thing to do when it makes the overheating stop. But it's only masking the real problem. In some cases, this actually increases your temperature by increasing the flow too much and not allowing enough heat exchange through the radiator. In other cases, it really stops the overheating. It could be a stop gap measure, so I wouldn't rule it out. Just realize it's only that.

So in case it's not been obious, here are the legitimate fixes:

What to do:

1) Make sure you have good caps. These are critical

2) Make sure you properly fill the system from the top fill point. Let out all air as you do. I have posted the proper procedure previously. Do not assume the air will find it's way out!

3) Make sure all your hoses are in johnny !Removed!&span condition. This includes your overflow hoses that run to the resevoir as well as your upper heater hose.

4) Make sure your thermostat is good. It's rarely the problem, but not expensive as a rule-out step.

5) When you bleed and re-fill the system, use the petcock on the back of the block to get it all out. And refill with Toyota long life. Your water pump will thank you for that.

6) Make sure your radiator is good. If it has any small cracks or signs of wear, it may be your problem.

7) Get really good advice and be very certain if you suspect a blown head gasket. It's risky to drive it if you do have one, but also very painful to replace it and find out it's not your problem! In many cases, the head gasket is impossible to diagnose if your problem is intermittent.

Sorry for the long post, but I was hoping this could help someone out there. The 93 and similar ES300s have very solid motors and are worth fixing. So be patient and don't let a mechanic quote you $2500 for a new head gasket set when you can buy a very nicely rebuilt motor for $1795 and pop it in yourself for nothing. Or better yet, do your own head gasket for under $400. And make sure that's your problem!

Ciao

Stevo

[Toysrme]

The cooling system is not delicate if the owner takes proper maintenance. The system is no worse than any other good cooling system.

Many times the problem happens from correction, and sludge buildup. Old fluid is bad to clog the radiator, and corrode the pump fins.

Youa re very correct that the hydraulic fan system doesn't wear out (itself) Typically the problems that arise with it are:

1) burned fuse

2) the connector from the Cooling fan ECU to the Cooling fan clutch (what controls it's high-low speed) is not plugged in.

3) something shorted and destroyed the cooling fan ECU ($5 part in a junkyard)

It can be checked by jumping E1 and OP1. If the fan does not go into high speed, there is a cooling fan problem.

The water pumps last a very long time, if you keep good fluid in them and skip their replacement every other timing belt change. Normally that is not worth it, they only cost $75 with no extra labor charge. You can also easily corrode the fins off one (loosing pressure) by having poor fluid in them.

If it occurs more than once, it is a great idea to have the pressure tested to make sure the pump is OK.

A common problem with fluid boiling over is worn pressure caps. That is common to all cars, not just that particular engine. Also the reason why you can't use a 1mz-fe radiator on a 3vz-fe. The 3vz-fe has the over-flow returns, and a pressure cap.

A pressure cap will raise the temperature before the coolant boils 40-70*F. If one is malfunctioning, or worn, it will cause many such problems.

You are correct that removing the thermostat is a bad idea. It only masks the real problem.

$2500 for a new head gasket!? That's a $1250-$1500 job.

[poneyboy]

The cooling system is not delicate if the owner takes proper maintenance. The system is no worse than any other good cooling system.

Many times the problem happens from correction, and sludge buildup. Old fluid is bad to clog the radiator, and corrode the pump fins.

I disagree. This is a very touchy system. I've owned cars that could go with only 60% of their coolant and corroded radiators and still run like a champ. Most cars are more forgiving than this one.

The pump fins will not corrode before the pump seal goes. You will see yourself replacing leaky pumps before you will see a corroded impeller. If you have a corrosion problem, the pump will leak first. Hence my point that it's not a solution to overheating. If your overheating is because you don't notice the water dripping from your pump, yes it is the fix. But when you have the symptoms that most of us have been scratching our heads over, then the pump won't fix it.

Youa re very correct that the hydraulic fan system doesn't wear out (itself) Typically the problems that arise with it are:

1) burned fuse

2) the connector from the Cooling fan ECU to the Cooling fan clutch (what controls it's high-low speed) is not plugged in.

3) something shorted and destroyed the cooling fan ECU ($5 part in a junkyard)

Cooling fan clutch? I think you mean a solenoid or better - butterfly valve. It is a continuously variable system with no real discreet speed settings.

It can be checked by jumping E1 and OP1. If the fan does not go into high speed, there is a cooling fan problem.

This is correct. My point here is that most mechanics may see that it's not cycling up and down and assume the fan is bad or a bad system. Jumpering the circuit will prove that your fan is fine.

The water pumps last a very long time, if you keep good fluid in them and skip their replacement every other timing belt change. Normally that is not worth it, they only cost $75 with no extra labor charge. You can also easily corrode the fins off one (loosing pressure) by having poor fluid in them.

Again, not at all very likely. You will have other more serious problems long before you corrode your impeller fins - like a leak.

A common problem with fluid boiling over is worn pressure caps. That is common to all cars, not just that particular engine. Also the reason why you can't use a 1mz-fe radiator on a 3vz-fe. The 3vz-fe has the over-flow returns, and a pressure cap.

A pressure cap will raise the temperature before the coolant boils 40-70*F. If one is malfunctioning, or worn, it will cause many such problems.

A slight correction here - the new radiator for this year car has no cap and no return hose. The reason is obvious - remove another relatively unnecessary point of failure. In fact, it's not common anymore as many many cars have gone away from caps altogether - all caps. It's much much more common in this car as there are two caps with return hoses as well as a petcock on the radiator. Hence their tendency to overheat more than other cars - many many points of failure.

Steve

[monarch]

Virtually all the overheating problems can be traced to owner refusal to keep the cooling system in factory original condition. Specifically:

1. Owners refuse to use only a 50/50 mix of Toyota Long Life Coolant and distilled water in the system. This prevent radiator leaks from cropping up and eliminates internal radiator clogging. Also greatly slows deterioration of the radiator hoses / heater hoses / radiator cap / thermostat / water pump / cylinder head gaskets.

2. Owners refuse to use a genuine Toyota radiator cap / thermostat / thermostat gasket / water pump / hoses / at replacement time.

Why do owners refuse to maintain the cooling system in factory original condition? Answer: They don't seem to appreciate the fact they own an ASIAN car and need to respect and follow the car care advice of the ASIAN car factory engineers (instead of American mechanics, American auto parts stores and American car care websites) if they want to realize the legendary http://www.saber.net/~monarch/463.jpg reliability and durability potential built into every Toyota. So they end up butchering up their cooling systems by using (or letting their mechanics use) non Toyota sourced parts, fluids and repair procedures.

I would imagine the same problem may occur in Japan. In other words the (obviously few) car owners in Japan who purchase a Ford or Chevy might fail to appreciate the fact they own an AMERICAN car and need to respect and follow the car care advice of the AMERICAN car factory engineers (instead of Japanese mechanics, Japanese auto parts stores and Japanese car care websites)

[Toysrme]

I thinks it's not very touchy system. Simply saying your previous engines will run with only 60% coolant and bad components doesn't say much for maintinance history.

The simple fact is that no Toyota v6 has overheating problems (Minus a non overheating related blown head gasket) are faults of the owners. Not the engines. If you maintain them, every aspect of them (minus the weak head gaskets during that time frame) will last indefiantely.

Fresh fluid every year and the cooling systems will last 200-300,000. You'll need a new thermostat along the way, but the pumps, radiators and hoses will survive fine on fresh fluid.

most mechanics may see that it's not cycling up and down and assume the fan is bad or a bad system.

I completely agree. The hydraulic system sucks because it takes power to drive. Most mechanics hate this style system.

They are so dumb, they will stick their hand IN THE FAN to see how strong the motor is. *Obviously* you can stop it with a single finger... That's ok, none of us are perfect, obviously mechanics are not! (Even Toyota ASE mechanics don't pick up on this. I had to demonstrate it to one a few weeks back)

They removed the radiator cap and overflow send->return on the 1mz-fe.

Compair them, they're completely different.

I know, I just went throuh that problem with a habitually overheating 3vz-fe. Only to find out the original mechanic replaced the 3vz-fe radiator with an OEM '94 1mz-fe radiator. Lowering the boiling temperature 70*F, and not having an overflow return (If a 3vz-fe is overheating, it'll blow the pressure into the over-flow tank, and will suck coolant back into the radiator so there is no air trapped in the system, When 1mz-fe's overheat they blow the coolant out, but air is trapped in the system.)

I troubleshot a 1mz-fe last week who's waterpump was completely corroded off.

(Pay attention and you'll see why this is actually common by the end)

The guy had the radiator replaced when the plastic top sprang a pin-hole leak (high pressure + low flow + nasty corrotion from bad fluid = bad). The leaking coolant was fixed, but the car was still overheating. Normally you would ask why?

Because the water pump was corroded off! Most of the time, if you have left old fluid in long enough to blow the stock radiators, there will be some degree of pump damage. (Maybe that's why Toyota has always used plastic radiators.)

^ That's how the pumps get damaged. That is always why any *good* Toyota mechanic will tell you when the radiator is replaced, the pump may or may not be shot also.

For refferance, anytime any of your hear about a radiator blowing, or leaking. The entire system needs to be flushed for a long time to clear the corrotion & sludge, and the pressure needs to be tested when the enigne is warmed up to insure the pump is not damaged.

(VZ-FE owners don't fret because you're coolant is not comming clean... The blocks are iron, and the water will ALWAYS come out orange/rusty looking LoL!)

You're pretty much dead on tho. If people would replace the water pump on schedule, and keep fresh coolant in the system (drain the radiator every year, or flush the system every other) You'll simply never have a cooling problem.

I recommend to add in the perscribed amount of Redline's Water Wetter. Not just for the added cooling performance, but because it's inhibitor package is far superior to any type of anti-freeze, in both lifespan, and pure protection.

[monarch]

Here's what happens to a Toyota / Lexus cooling system after 17 years and 241,000 miles if the owner simply drains and refills the radiator every year or two with the factory original coolant mixture:

http://i5.photobucket.com/albums/y189/mastertech/89rad.jpg

http://i5.photobucket.com/albums/y189/mastertech/89hous.jpg

http://i5.photobucket.com/albums/y189/mast...h/89drained.jpg

[poneyboy]

I thinks it's not very touchy system. Simply saying your previous engines will run with only 60% coolant and bad components doesn't say much for maintinance history.

I think the changes made by Lexus after the '93 indicate continuous improvement. The fixes they implemented did make the system more robust and fault tolerant. And also, as I mention below, more "mechanic proof."

You miss my point. Like it or not, some cars are very tolerable of cooling system neglect. The 93 ES300 is not as much. This system has multiple points of failure - a point that can't be argued. The frequency of overheating problems when compared to even other Lexus cars indicates this to be so. The tendency for so many mechanics to provide weird fixes indicates the frequency of these events as well.

And yes, 60% coolant doesn't say much for maintenance history - but it also says a lot for the fault tolerance of that vehicle. And it wasn't I who did this to that car...it's the shape I found it in. But I also knew the car and it's record. Like it or not, Toyota has made some poor design decisions.

The simple fact is that no Toyota v6 has overheating problems (Minus a non overheating related blown head gasket) are faults of the owners. Not the engines. If you maintain them, every aspect of them (minus the weak head gaskets during that time frame) will last indefiantely.

You really can't say that. True, very few cars are built today with overheating problems but certain components start failing and the room for error becomes very clear. Now the Jag V12 - that's a car with overheating problems by design. But I agree that this car was not designed to overheat, but it was on the edge and had little room for error - unlike my truck with it's 22R.

Fresh fluid every year and the cooling systems will last 200-300,000. You'll need a new thermostat along the way, but the pumps, radiators and hoses will survive fine on fresh fluid.

You're making this stuff up for the sake of argument. Pumps, radiators and hoses will not survive 300,000 on fresh fluid every year. It's just not in them. Radiators sometimes go that far, but only if you're lucky. Iv'e never had a pump in any car that lasted that long. I've had two Toyotas now and the water pumps went out after about 150,000. It's not an indication of poor maintenance, but an indication of the lifespan of the mechanical seal. That's a proven documented fact - mechanical seals have a finite lifespan.

most mechanics may see that it's not cycling up and down and assume the fan is bad or a bad system.

I completely agree. The hydraulic system sucks because it takes power to drive. Most mechanics hate this style system.

Every system takes power. The fact that you drive an electric fan doesn't indicate that your not using power or that the engine isn't taxed. You're driving a generator/alternator aren't you? Putting a greater load on it will tax the engine more. The hydraulic fan system is great - designed for smooth and quiet operation and a very reliable component. Mechanics see it and don't understand. They don't hear a lot of noise. They think it has to have two speeds. That's why it went away I suspect - dumb mechanics at Lexus. Or perhaps cost. Two electric motors are probably very cheap as opposed to a hydraulic component like that one. The fact is that you can't do better with electric motors. They can't cover as much of the radiator and therefore don't induce as even a flow.

They removed the radiator cap and overflow send->return on the 1mz-fe.

Compair them, they're completely different.

This is a good fix. I agree with Lexus on this one. See the bulletin on the 93 ES300 - they initiated this change.

I know, I just went throuh that problem with a habitually overheating 3vz-fe. Only to find out the original mechanic replaced the 3vz-fe radiator with an OEM '94 1mz-fe radiator. Lowering the boiling temperature 70*F, and not having an overflow return (If a 3vz-fe is overheating, it'll blow the pressure into the over-flow tank, and will suck coolant back into the radiator so there is no air trapped in the system, When 1mz-fe's overheat they blow the coolant out, but air is trapped in the system.)

Again, the replacement radiator for this year ('93) car from Lexus is without a return hose and cap. You don't need that radiator cap or return hose. The air that gets into the system will find its way to the top and can be bled out through the engine cap/return hose. You don't need the radiator return hose/cap - it's just another point of failure - Lexus knew this and changed it. (However, I went out and bought an aftermarket radiator that does have the return hose. No, sorry, can't justify the $699 they quoted me for a plastic Lexus radiator. I like my aftermarket model better. )

I troubleshot a 1mz-fe last week who's waterpump was completely corroded off.

(Pay attention and you'll see why this is actually common by the end)

The guy had the radiator replaced when the plastic top sprang a pin-hole leak (high pressure + low flow + nasty corrotion from bad fluid = bad). The leaking coolant was fixed, but the car was still overheating. Normally you would ask why?

Because the water pump was corroded off! Most of the time, if you have left old fluid in long enough to blow the stock radiators, there will be some degree of pump damage. (Maybe that's why Toyota has always used plastic radiators.)

^ That's how the pumps get damaged. That is always why any *good* Toyota mechanic will tell you when the radiator is replaced, the pump may or may not be shot also.

Corroded where? You mean the impellor? That's just bad maintenance. Worn water pumps are not typical with this car or most other Toyotas. If they are abused as you indicate, then that can happen - with any car. I typically see the water pump lose it's mechanical seal before it corrodes. This is typical Toyota behaviour that I've noticed over the past 20 years. In fact, I've never personally seen a worn pump impellor on any of my cars - only heard about them! Long Life coolant is supposed increase the lifespan of the pump seals. Perhaps this is true, but not on my '93.

For refferance, anytime any of your hear about a radiator blowing, or leaking. The entire system needs to be flushed for a long time to clear the corrotion & sludge, and the pressure needs to be tested when the enigne is warmed up to insure the pump is not damaged.

(VZ-FE owners don't fret because you're coolant is not comming clean... The blocks are iron, and the water will ALWAYS come out orange/rusty looking LoL!)

This is a little odd. I don't see how a pure and clean flush can't come clean in the end - mine does and I have the iron block. Maybe you need to find that petcock. However, I disagree somewhat on the radiator always indicating a bad pump. My radiator was very thin and quite frankly a very weak link. The later one was much thicker and heftier. I believe this was a mistake on Lexus' part and one of the many reasons this car ran into so many overheating problems. It couldn't take the heat very well so developed hairline cracks, and it was simply too small. Poor choice by Lexus. Good choice to come up with a new one...

You're pretty much dead on tho. If people would replace the water pump on schedule, and keep fresh coolant in the system (drain the radiator every year, or flush the system every other) You'll simply never have a cooling problem.

I have to add - keep those hoses and caps inspected.

[poneyboy]

Virtually all the overheating problems can be traced to owner refusal to keep the cooling system in factory original condition.  Specifically:

1. Owners refuse to use only a 50/50 mix of Toyota Long Life Coolant and distilled water in the system. This prevent radiator leaks from cropping up and eliminates  internal radiator clogging. Also greatly slows deterioration of the radiator hoses / heater hoses / radiator cap / thermostat / water pump / cylinder head gaskets.

Long Life is silicate free - I believe that's it's main claim to fame.  I use 60/50 because it's recommended in hotter climates.  Again, I lost a radiator at 110,000 or whatever it was, not because there wasn't Long Life in it, but because Lexus screwed up a bit on the sizing/manufacturing procedures on my radiator.  There were several of these on the 93.  I always used the "red stuff" and changed it out on a regular basis.  But I lost a pump and radiator.  So what, it's part of the wear and tear.  It's part of living in a hot as hell climate with 90% humidity in the summer that really wears on an engine.  That climate can reduce the cooling system's effeciency a good bit.

2. Owners refuse to use a genuine Toyota radiator cap / thermostat / thermostat gasket / water pump /  hoses / at replacement time.

This is a silly statement.  Genuine or not, replace your caps once a year and inspect hoses.  There is no magic to Toyota hoses - and probably not to their caps either.  Not using genuine parts on every place isn't an issue.  Not keeping up with them is.

Why do owners refuse to maintain the cooling system in factory original condition?  Answer: They don't seem to appreciate the fact they own an ASIAN car and  need to respect and follow the car care advice of the ASIAN car factory engineers (instead of American mechanics, American auto parts stores and American car care websites) if they want  to realize the legendary http://www.saber.net/~monarch/463.jpg reliability and durability potential built into every Toyota.  So they end up butchering up their cooling systems by using (or letting their mechanics use) non Toyota sourced parts, fluids and repair procedures.

This is ludicrous.  Toyota parts are sometimes better, but sometimes just more expensive.  I usually evaluate parts when I buy them and if the Toyota parts look better made, then I buy them.  If not, then I don't.  It's quite simple - there is no magic in it.  What you see is what you get.  And good procedures are not exclusive to Japanese cars.  You state it as if there is some kind of magic Asian formula that will keep a Toyota running longer.  The fact is that Toyotas are built to last and built to take neglect.  Not that you should neglect them, but time and again, treat the two the same way and your Toyota will outlast the American car.  Not only that, the damage you typically see won't be as devastating. 

I would imagine the same problem may occur in Japan. In other words the (obviously few) car owners in Japan who purchase a Ford or Chevy might fail to appreciate the fact they own an AMERICAN car and  need to respect and follow the car care advice of the AMERICAN car factory engineers (instead of Japanese mechanics, Japanese auto parts stores and Japanese car care websites)

←

Where do you have a Japanese car parts store? I've never seen one. This is again ludicrous. Good procedures have been established for most vehicles. American makers are adopting some of Toyota, Honda and Nissan's procedures and designs because they are universally good. The big three have made legendary strides in design and engineering and the world recognizes it.

S