Sorry if this is really long.

I was given a 2000 ES 300 with 240K miles recently. The previous owner owned the car since it was new and only had the car serviced by a Lexus dealer. They purchased a new Lexus and subsequently gave me the old car.
About a week before I was given the car it over heated for them on a hot day (80s). This is the first time in 12 years the car ever overheated. Upon inspecting the car, he found car had almost no coolant in it. He added almost 2 gallons of coolant and the car. Then, after allowing the car to cool down for a while he said it ran very rough initially but then started to run fine. This was about 500 miles ago. The car worked fine until it was given to me. The day I got the car I drove it a short distance (it was driven about 40 miles to me so the car was running at temp and it was a hotter day) and again it started to over heat. It never get into the red, more like 3/4 of the way. After I let it cool down, it ran rough, almost like in a limp mode (low RPMS, struggling). Again, almost immediately it started running fine again.
I took the car home, let it cool down, and saw that it needed some coolant in the reservoir. I added coolant and then for the last few days I have driven the car about 20 miles a day and I have had no problems. Coolant levels are solid in the resevior and under the cap.
I looked over the engine bay I can't find any evidence of a coolant leak. I haven't seen any on the ground after I drive it and let it sit either. The car runs smooth and I am not seeing any white exhaust either.
To further complicate things, around a month ago the car was involved in a fender bender involving the right front. It was fixed by a body shop.

So, my most pressing question is, where could the coolant have gone? If it was a slow leak, I am guessing the service guys at lexus would have caught it during oil changes. Is is possible the body shop removed coolant to fix the fender bender and forgot to put it back? They installed a new bumber cover and right finder and turn signal. I am not sure if they removed the bumber itself. I called the shop and they said they didn't remove coolant, but I didn't get to talk to the actual mechanic who did the job.
If it was the body shop, could the car run fine on 1/2 gallon of coolant until a hot day?

Any input it appreciated.

 

so your losing antifreeze but cant see where it's coming from. check your plugs and see if its going there if it is your head gasket is blown. i would say the water pump but you would see a ton on the ground when you turned off the car.

 

If I was burning it wouldn't the car show other symptoms? The ground is clean. So is the engine bay. And I never see any smoke from under the hood that is consistent with a leak in a host or radiator cap.

 

well if its getting on the plugs the car is gonna ride sluggish, and you wont see antifreeze cause its burning off into the motor. the best bet is to pull a plug or 2 and see if they are fouled with oil and antifreeze, if not we can go on to something else, it could be a few things if the gasket is good. i had a bad head gasket but the car ran fine and no smoke but would overheat if i drove it too hard. the problem is the lack of identifying where the antifreeze is going,

 

I'm not sure where your coolant is going, but I have a theory that when the guy added two gallons of coolant, he didn't purge the air out of the system. Also, when you refill a cooling system, the coolant level tends to go down a little bit over a week.

So maybe the shop did drain your coolant and forgot to refill it. Then the PO filled it up but didn't get rid of air bubbles. The car overheated. You topped it off, and the air bubbles went away.

 

Get your system pressurize to find your leak. Hope you dont have a head gasket problem

 

feels like ur coolant system was never bled properly thats all

 

+1

Try driving your car around with the heat turn to MAX HOT. Then check the reservoir level.
Make sure you don't open the radiator cap when the engine is warm/hot. You can open the reservoir cap.

 

Lots of good input here. Thanks everyone. A few followup questions:

BDSL: What does driving the car around with the heat to max do?

Is there a writeup on the forum on doing a coolant flush and fill that would have the bleed procedure?

If it was the body shop, does anyone know if the radiator would need to be removed to replace a fender? It looks like the radiator needs to come out to remove the bumper, but I can't figure out if the bumper needs to come off before a fender. The work order doesn't say if the bumper was removed, but I think they did need to touch up the paint on it.

 

Since the coolant line provides heat to the cabin air, there is a possibility that some air might be trapped in the line in that section. Setting the heat to MAX allows coolant to run through that line...perhaps freeing the trapped air.

 

Thanks BDSL, I'll give it a try.

 

Easiest way to bleed the air out is to buy a Spill Free Funnel on Amazon. It's a special funnel that mounts to your filler neck and lets you see the air bubbles come out.

 

im not sure if these cars have a bleeder valve but if it does, you have to open it while its running. or the old school way open your radiator cap and let run for a while with it open. also if there is bubbles coming out of you reservoir that can means theres a head leak. do not open the cap while its hot though onlty when cooled down.

 

So, I left the car with my wife today and she had problems with it overheating almost immediately. When I was driving it the last few days I was using it in the morning when it was aroun 65 degrees out. She took it out when it was about 80 degrees. She got about 2 miles and the temp guage started going above half so she turned around and brought it home. When she got home, the temp guage was about three ticks away from the red. When I got home from work I ran the car idle for around 10 minutes with the radiator cap off and the heat blowing on high. Temp stayed normal (just below middle) and I did see some small champagne size bubbles bubbling up from the radiator cap. When the bubbles stopped I took the car for a 5 mile drive, this time with the AC on full, and sure enough the temp started climbing above the middle. I was fine until I hit stop and go traffic.

Also, the coolant levels have been rock solid over the last 100 miles and I haven't observed any bubbling in the reservoir tank.

So, does this still sound like the car still needs to be bled? Or should I start thinking about other problems

thanks

I have attached a picture of the temp guage so people know exactly how hot it is getting.
https://plus.google.com/photos/11751...10447954226961

 

When the temperature rises, do your Fans turn on? Do your fans turn on when you turn on the A/C?

If they don't turn on under both conditions, than you found the problem, If they do turn on under both the above conditions, than other possibilities in order of probability include:

a) Defective Thermostat
b) Blocked, or partially blocked radiator,
c) Defective or Wrong Radiator Cap
d) Defective Water Pump
e) Coolant Mixture not to Spec. Example being antifreeze concentration is too high
e) Blown Head Gasket


All of the above assumes that you got all of the air out of the system.


Phil