yoji6365

as for the todd332's comment about never understanding the bad radiator cap:
the cap can go bad in that the rubber ring underneath does not make a good seal.
The cap will not be able to maintain the pressure needed in the system to elevate the boiling point of the water/antifreeze liquid higher than the normal operating temperature of the engine. The coolant only elevates the boiling point a few degrees. The radiator cap creates a pressurized environment that creates a higher elevation of the boiling point than just the coolant.


Sounds like air in the system. Could be because coolant wasn't refilled properly (i.e. idling the car for 10 minutes with the heater turned on and radiator cap removed).

bad rad cap
no fluid movement= no cooling temp creeps up as it is hot soaking the engine and spews out the res

I put on new radiator caps and drove about 200 miles with the A/C on and turned the car off and no more spitting fluid..Been driving it the last few days and everything seems fine..

It seems the radiator cap isnt pressurizing the system. I would check the gasket on the rad cap to make sure its sealing properly.

Hope this helps

P_M_G

Have had zero issues with engine temp in the last week...taking her in for a coolant flush and will replace thermo and gasket as well.

Hoping this keeps the issue gone...will post if it does.

Thanks again to all for the suggestions/help!

P_M_G

OH GOD PLEASE HELP!!!!!!

Just had the thermo and gasket replaced, and when I go to leave from work today, a large puddle of coolant on the ground.

I slide underneath and it's leaking like a sieve from what I think is the bottom of the water pump housing. WTF??????????

Of course, the shop closed at 5 so I can't have them look at it...

Why suddenly would I get a coolant leak on the opposite side of the engine from where the dang thermostat is housed (driver's side on my '94...of course if it had been built 1 month later apparently it would have been on the passenger side like NORMAL).

Toyota svc telling me unless I'm changing timing belt as well its $135 for the pump and 7 HOURS labor? If I do it with timing belt change (due now anyway) it's only an extra $180 for labor. So with the 'coupon' on the timing belt repl (for $235) and this I'm up to like $450....

Can somebody tell me what would cause the leak from simply replacing a thermostat????

I'm dying and can't afford to be shelling out dough day after day after day.....

PERRYinLA

Diagnosing this over the internet is iffy at best, but the thermostat may never have had anything wrong with it, and the water pump was the culprit all the time. Or, running it over the past several days in an overheated / low coolant mode caused the water pump (which is lubed by additives in the coolant) to fail prematurely.

P_M_G

Perry,

When ur right....ur right.

Upon further reveiw, there is a reversal of the ruling of the forums! Turns out the water pump was indeed the culprit. Now, I don't know if, as you suggest, the added strain over the last week sent it over the edge, but I had it replaced when I did the timing belt yesterday.

Gotta love dealers....

Tustin Lexus - Timing belt and water pump - $1200
Mission Viejo Lexus - $1100
Irvine Toyota - $650 including replacing the drive belts.

When I asked the Lexus guys why so much more, they said "Toyota doesn't do anything BUT replace the timing belt - we TEST all the other components (idler, blah, blah, blah) and they don't" - but they actually did, so when I asked if they would need replacing, Lexus added even more to the estimate.

However, Toyota did pull the classic - "we recommend xxxx " including a new thermostat, so I know they didn't look to see it was brand new - "well, the service manager just recommended that based on the mileage." HA!!

Either way, she runs a lot smoother now, idles smoother and (fingers crossed) can make it a few months before I have to sink any more $$$$ into her!

Thanks again to everyone who replied to my predicament!

mike5.9

MY PROBLEM FIXED!

Radiator cap over radiator was not keeping pressure in the system.

Radiator cap was obviously deteriorated.

Pressure seal between radiator cap and top of radiator was also non existant because the radiator top portion that is designed to seal with the cap was "melted" on each side providing an inconsistant surface (not flat)

I replaced the cap and dremeled down the rad. top making it flush to allow the pressure seal.

No problems noted.

yoji6365

I hope you didnt get metal shavings in your radiator.

Tammy

I'm glad you had good luck with the cap... Thanks for the feedback.

gary64

I have a 93ES300. Replaced..psp, thermastat, o2 sensor, all hoses (power steering and radiator), radiator, fan. The temp gauge hangs out between the middle and 3/4 line. This is a used and my first lexus. I'm learning as replacing parts, however, is that normal for the temp?

CUMan

No, that is not a normal reading for the coolant temperature. On our 94 ES, the normal needle position is slightly below the middle mark.

You have added your post to a very old thread. There are many newer threads that discuss overheating problems in the early to mid-90's ES models. Search further and find one of these newer threads. As I recall, overheating problems were discussed within the past month or so.