'92 sc300 Overheating, need some advise, please.
#16
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Despite having replaced the thermostat a couple months ago I took it out this morning and filled the car with water. (no coolant) and then drove about 15 minutes to work.
The temp gauge never went above the normal halfway point and now both hoses are equally hot. However when I shut the car down the water in the overflow was boiling vigourously.
The temp gauge never went above the normal halfway point and now both hoses are equally hot. However when I shut the car down the water in the overflow was boiling vigourously.
First, you took the t-stat out, filled it with water, drove it for 15 min and no overheating. Then you added some coolant and drove it for 15 min again, but this time it overheated.
Is this correct? . . . and the t-stat was out both times??
Also, by "overheating" I'm assuming you're referring to the engine temp. and NOT just the boiling in the overflow bottle, correct?
#17
Lexus Champion
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Mine blew a HG as well, and its symptoms were needle hunting around and slowly losing coolant.
I drove it for about a month and a half with these symptoms. It eventually started to miss at idle and finally went out in a cloud of glory. Spewing out the rad, puffing white smoke, water in the oil, etc etc.
When its acting up, turn on the heat and see if its cool or hot like it should be. Cool indicates lost coolant resulting in air pockets.
I drove it for about a month and a half with these symptoms. It eventually started to miss at idle and finally went out in a cloud of glory. Spewing out the rad, puffing white smoke, water in the oil, etc etc.
When its acting up, turn on the heat and see if its cool or hot like it should be. Cool indicates lost coolant resulting in air pockets.
#18
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Wait, I'm trying to follow this sequence, so correct me if I'm wrong.
First, you took the t-stat out, filled it with water, drove it for 15 min and no overheating. Then you added some coolant and drove it for 15 min again, but this time it overheated.
Is this correct? . . . and the t-stat was out both times??
Also, by "overheating" I'm assuming you're referring to the engine temp. and NOT just the boiling in the overflow bottle, correct?
First, you took the t-stat out, filled it with water, drove it for 15 min and no overheating. Then you added some coolant and drove it for 15 min again, but this time it overheated.
Is this correct? . . . and the t-stat was out both times??
Also, by "overheating" I'm assuming you're referring to the engine temp. and NOT just the boiling in the overflow bottle, correct?
Another symptom pops up as I limp the car home. I ran the Heater on full blast and now 2 of my center vents aren't pumping any air hot, cold or otherwise... The other vents in the car still work fine.
I'm taking it in to have it diagnosed at the radiator shop this morning...before I make it worse.
#19
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Update!
Welll... Embarrassed to say... I took it in to the Radiator place... A few minutes later they called me back and said "Come Pick it Up" - I thought "Oh No, This is bad news for sure!"
I get there and the Old Guy tosses me my old radiator cap and said it was bad... He through a good one on there and sent me on my way. No Charge.
Cool Old Dude and I'm relieve to say my car is Back to Top Notch again.
Phew, I love my Lexi!
Thanks for all your help and advise everyone.
-Sarah
Welll... Embarrassed to say... I took it in to the Radiator place... A few minutes later they called me back and said "Come Pick it Up" - I thought "Oh No, This is bad news for sure!"
I get there and the Old Guy tosses me my old radiator cap and said it was bad... He through a good one on there and sent me on my way. No Charge.
Cool Old Dude and I'm relieve to say my car is Back to Top Notch again.
Phew, I love my Lexi!
Thanks for all your help and advise everyone.
-Sarah
#22
Yeah -the Radiator isn't a huge job. I replaced mine in my 93' SC400 around a year ago with an after market OEM replacement. Took about 3 hours I think total. Just go get a good picture and text based tutorial and you'll be fine if you have at least the proficiency to say replace spark plugs, or coil packs or something along those lines. Just be careful with your hoses and don't cut anything up - and have a workspace that you're ok with some coolant getting on - depending on how much you drain or don't drain.
#23
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Ok A rock or SOmething Must Have nailed us. I have No idea when this could have possibly happened. I haven't hit or been hit by anything. But the whole radiator is bent!!
Btw: The Photo is of the damage to the A/C Condenser.
Last edited by SmCross; 09-15-10 at 10:27 AM. Reason: additional Info
#24
Racer
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Funny. I had been dealing with the same thing over the last two weeks. After pulling the radiator & thermostat mine turned out to be the radiator cap. The radiator would not build and hold sufficient pressure so the coolant starts to boil off and back flows into the overflow bottle eventually loosing most of the coolant. Check your radiator caps people.
#25
#26
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Unless the car is leaking coolant your symptoms lead me to think your headgasket is blown. The reason your car is blowing hot air when it "seams" like it is overheating. Your blown headgasket is over putting excessive pressure into your coolant system overwelming your radiator cap. When this happends your coolant resivor will overflow and spill excessive coolant to the outside of the vehicle.
This will leave air pockets in your coolant system and once your coolant temp sensor gets some hot vapors passing by, it will automatically shoot up to full Hot. The reason is that your coolant temperature ( probably around 185-200 deg) is cooler than the hot steam passing by the sensor ( 250+deg). Your car is probably not really "overheating" rather than the steam passing by the sensor.
Ususally the temp guage will fluctuate when this happends. Like when you are on the freeway and it reads full hot and then you pull off and it starts to go down slightly. The pockets in your coolant system will leave your heater core without coolant thus it will stop blowing hot air.
Easiest way to check is to find a shop that does emission testing. They will put the emissions probe just above the radiator opening with the cap off. If the machine picks up any hydrocarbons your head gasket is blown. That is a 100% way to make sure its blown. I wouldnt have any work done untill you have it properly diagnosed. If that shop didnt catch it, please take it to another shop.
Lawrence
This will leave air pockets in your coolant system and once your coolant temp sensor gets some hot vapors passing by, it will automatically shoot up to full Hot. The reason is that your coolant temperature ( probably around 185-200 deg) is cooler than the hot steam passing by the sensor ( 250+deg). Your car is probably not really "overheating" rather than the steam passing by the sensor.
Ususally the temp guage will fluctuate when this happends. Like when you are on the freeway and it reads full hot and then you pull off and it starts to go down slightly. The pockets in your coolant system will leave your heater core without coolant thus it will stop blowing hot air.
Easiest way to check is to find a shop that does emission testing. They will put the emissions probe just above the radiator opening with the cap off. If the machine picks up any hydrocarbons your head gasket is blown. That is a 100% way to make sure its blown. I wouldnt have any work done untill you have it properly diagnosed. If that shop didnt catch it, please take it to another shop.
Lawrence
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