93 Es 300 Overheating

[colloe3]

I have a 93 Lexus ES300 with 174 K on it. I think I have the highest mileage on this board :D

Anyway, I drive 80-90 miles to work and back everyday. In cold weather, under 60 degrees, the car does not overheat. However, recently due to the incoming summer and 65 -75 degree weather, I have noticed that after about 30 minutes/35 miles of driving the thermostat starts rising from the middle mark. Once the thermostat starts rising, it pretty much rises all the way to the top quickly unless I slow down and turn the heat and fan on at full blast.

I first noticed this after I had a transmission replacement at 162K. I also replaced the seal between the transmission and the engine.

I had a dealer check it a while back for $100 (ugh) but unfortunately we had a few cool days and they could not replicate the problem. At that time, I had not noticed the warm weather effect.

Any ideas on where to start to fix this? Thanks

Colloe3

[amf1932]

There's a good chance that a partially clogged radiator core is the source of this problem. There are many fine passages in the core and after so many miles on this car there could be a buildup of rust or other stuff that's not removed after a coolant flush. The fact that using the heater fan to help cool it down makes me think that the water pump is working properly. In my opinion I would have the radiator core replaced. ;)

Alan

[SKperformance]

what colour is your coolant red or green?

[colloe3]

I just went downstairs to check my coolant and it is a dirty green. That cannot be good. I thought about flushing the system a couple of months ago but I must have forgotten. Any suggestions?

Colloe

[amf1932]

Green colored coolant in your radiator is WRONG!!! You should have had the red coolant. As I said previously, you should take the car to a reliable radiator shop and have them test out the whole system.

Alan

[SKperformance]

thruthfully i can't remember if the older engine uses dex cool or ethyl-glycol

cheapest way to check it is buy a 5 dollar prestone flush kit

a jug of dex cool red coolant

( it can go in any system but the green can't)

flush the system and see how it is

i am not too sure if it also has the hydralic fan also

check the power steering fluid level also as it is the steering fluid runnig the fan which is tranny fluid

sorry i couldn't be much help as i have the newer engine 1mz-fe

[controlz5]

hey, im new to the club. but anyways i have a little over 230,000 miles on my 93 es. i had the same problem and what i did was changed the entire coolant system, thermostants coolants and upgraded to a thicker radiator. after that i didnt have any problems

[colloe3]

Thanks, ControlZ. I am having the cooling system flushed this morning and would have them check the radiator. What exactly do you mean by a thicker radiator? Is it a new one or from a later model ? Thanks

[Indiosix]

I may have a real simple fix for you, I have a 1992 ES with 180K on it. Back at about 158K, I had the same problem you have. I went to the Lexus dealer and they replaced the radiator cap, problem solved. From what I remember, they said this is a pressurized system and once the cap seal is compromised it causes overheating. You will want address this problem very soon with this being an aluminum engine. Hope this works for you.

[poneyboy]

Hi Colloe3,

I'm new to the group, but I have some points to answer your question and answer this cooling problem once for all. This car has a poorly matched set of components that spell overheating at some point in its life. There are three things that cause the 93 es300 to have overheating problems:

1) The original radiator is only about 12mm thick - way too thin to handle hellish heat like one would see in the Southeast in the summer. When everything else is perfect, you'll run fine. But if there is any clog, fan slowdown, or very high ambient temperature, you're going to overheat. This then sets off a whole series of nasty possibilities. The replacement radiator, (don't go to Lexus and pay the $600, get the SAME one from Advance for $229), is twice as thick at about 21-24 mm. This thing will drink the coolant and do a much much better job of sucking heat off your engine.

2) Hydraulic fan switch bad - not enough fan action. This has been blamed for overheating problems, and indeed, more fan action would help. But I really think (1) is the more significant problem. It's really a stroke of genius to make this hydraulic fan - in theory it should be more reliable. However, there is a switch that ports the fluid over to the fan from the power steering that can go bad. Your fan won't come on enough. Yes, this is better than an electric fan in that the fan itself really never wears out. As with the electric fans, switches are problematic at times. But electric fans just plain burn out. This thing will never break.

3) Cracked radiator - I don't know which comes first, but eventually your 93 ES300 will have a cracked radiator tank. On such a small and whimpy radiator as this, it doesn't take much. You will lose coolant over the course of minutes, hours, or days. As it boils off, you'll lose the ability to cool efficiently. Hopefully, you won't have a blown head gasket or any other heat related damage. The replacement radiator will not be as likely to do this as the whole system will work better. I replaced mine for $229 - no other parts are typically required.

And be sure to use the Dexron red coolant - it's silicate free and will be kinder to your water pump. If you don't, in a matter of months, your water pump will fail and that's a guaranteed $700 repair. I'm guessing that this coolant is not as efficient as the green stuff, but you really don't have a choice here. And the caps - they do need to be fresh, but in themselves aren't enough to cause problems. If you're having overheating and replacing the radiator caps helps, you have other potential monsters lurking under that hood. Having the thicker radiator covers a multitude of sins.

See ya...

[steviej]

It stands to reason the 1993 car has green coolant.

The red ethylene glycol based coolant, (aka: Dexcool or Long Life) wasn't introduced to the consumer market until about 1996, so lets not start this crap about green vs red, AGAIN.

I think if he had the red, it would still give him the temp readings that were described. This problem is a mechanical one, not a coolant color one.

There is not sufficient transfer of heat from the coolant in the radiator when summer/warm air is flowing through the radiator. The heater trick helps to take heat out of the coolant from the other end.

We can rule out the waterpump, cause if it were bad even the heater trick would not help (regardless of the coolant color) and the car would overheat immediately.

Colloe3, you fail to mention if you are using the AC during the first 30 miles, minutes of you travel. Is the AC on before you have to switch to high heat?

I think some good points have been mentioned.

1. Either the radiator is paritally clogged and a thin pasasge radiator is now thinner.

2. The fan is not running at full capacity if it is running at all.

3. There could be alot of fins on the outside of the radiator and AC condensor that are bent and not allowing sufficient air flow throught the both of them.

4. There could also be a ton of leaves and debris between the condensor and the radiator.

Observe the fan or have a shop test to see if the fan is working properly. I would then try a new cap and a total flush (not just the radiator). Do them one at a time (the cap is the cheaper of the two) to isolate the problem for future benefit.

If neither of them work, then I would start thinking of new radiator as poneyboy suggested.

good luck and post what you do to solve your heated situation.

steviej

[poneyboy]

I seem to remember that Toyota/Lexus was selling the red coolant for some time before it went "consumer". I've seen many an older Lexus and Camry (early 90's) with the red stuff and I don't assume that many people were changing out their coolants. I could be wrong.

For the record, I replaced my radiator only when I had to - the crack was big enough to let out coolant. But clearly the newer/thicker one is a much better design. If you factor in the cost of taking it to a radiator shop and getting all this checking done, you might have replaced your radiator and cured the problem - weigh your options before going to repair shops.

[H8R Proof]

Uh oh.

I don't know if the coolant in my 98 ES is red or green.

Which one is it supposed to be? If it 's filled with the wrong one, should I have it emptied and re-filled with the right one?

This makes me nervous... !

[poneyboy]

Which one and how long have you had it in there? There is no harm to using the green other than using a silicate-based anti-freeze will wear out your water pump sooner. Lexus sells the non-silicate based coolant exclusively here in Atlanta under the Lexus name. (That is the red stuff.)

My Ford Windstar however CANNOT take the red according to the users manual. I wouldn't know why...I thought the red superceded all the others. There is the claim that changing coolant from green to red can make matters worse as a result of mixing, but I think a good flush should be all you need to get enough of the green's inhibitors out. If you take your Lexus to a dealership here in Atlanta, the first thing they'll do is yell at you for using the green stuff.

For the RECORD - both colours are ethelyne-glycol. It's the inhibitors that are different. The green stuff contains silicates while the red has some other stuff. It was designed to be longer life and cause less wear on pump seals. Which one is "right"? I'd say the red is "best", not "right". Best in this case means not having to replace your water pump at 95,000 miles.

STEVIEJ - there is no reason for the radiator to be so inadequate at transfering heat in the summer other than a fault or poor design from what I can tell. I've spent some time playing with this thing, and I've concluded that this cooling system was designed with no margin for error. Small faults that wouldn't bother another cooling system will put this one over the top. If one can get away with the original thin radiator, by all means use it. Just be aware that there is an alternative that can cure its ills.

[Lex3486]

so, for a 93, would y'all recommend red or green??? there's an awful lot of arguing about this, but lemme interject that yes; they are both ethelyne glycol, and what came out of mine did appear to be red, although I suppose that it is a possibility that it is really dirty green; I don't know the vehicles' complete service record, so...has it been swapped over, or ever changed at all? I don't know, but I do happen to know that it has undergone the 1000, 3750 and 7500 mile services, so....

[steviej]

poneyboy: I agree.

steviej

[poneyboy]

If you have red in it now - and you'll know if it's dirty red or brown - i'd stick with it. The green would never look like this. My dealership insists on this for my 93. Flush it good too.

By the way - anyone know where the engine block drain plug is? I've heard it's up there somewhere, but I can't find it.

[SKperformance]

not sure what you mean by consumer market in 96 gm used it since 89 in some cars

i belive red has a higher temp rating

most cars with green can go to red, but not vice versa

because of a problem with seals not being compatibale

i am only going by a data sheet i saw on the gm computer when i worked there which is where i first learned of the extended life coolant

[poneyboy]

Ford claims that some of it's seals on certain motors will go bad from the Red but not the green. Rather strange given what's in the green stuff...