Suddenly overheating
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From: Woodstock, GA
Suddenly overheating 4 days ago, after a 40 mile drive I'm pulling into work and my water temp jumps to 280. I shut it off, go about my business and figured I must be low on coolant - but I've not seen any leaks. I topped it off with water and it didn't even take a gallon. So I've been keeping my eye on leaks ...etc. Today I'm driving home and same deal. I had a couple of gallons of water and after opening the radiator cap, it was bubbling and gurgling like crazy. It's as though it has air in the system ... or I guess it could be a stuck thermostat.
Any ideas?
Any ideas?
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
Perhaps I'm misunderstanding but...
...it shouldn't have needed any at all. If it was down a quart, half gallon, whatever, this indicates that coolant is leaving the system (leaking internally or externally, and/or it's burning). Have you checked the oil for cross-contamination? It's also possible that the missing coolant was pushed out the expansion tank during an overheating event (such as what you've been seeing lately), but then you should have seen steam from this happening. Was it low on coolant again after the most recent overheating event?
...it shouldn't have needed any at all. If it was down a quart, half gallon, whatever, this indicates that coolant is leaving the system (leaking internally or externally, and/or it's burning). Have you checked the oil for cross-contamination? It's also possible that the missing coolant was pushed out the expansion tank during an overheating event (such as what you've been seeing lately), but then you should have seen steam from this happening. Was it low on coolant again after the most recent overheating event?
Thread Starter
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Joined: Nov 2011
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From: Woodstock, GA
Perhaps I'm misunderstanding but...
...it shouldn't have needed any at all. If it was down a quart, half gallon, whatever, this indicates that coolant is leaving the system (leaking internally or externally, and/or it's burning). Have you checked the oil for cross-contamination? It's also possible that the missing coolant was pushed out the expansion tank during an overheating event (such as what you've been seeing lately), but then you should have seen steam from this happening. Was it low on coolant again after the most recent overheating event?
...it shouldn't have needed any at all. If it was down a quart, half gallon, whatever, this indicates that coolant is leaving the system (leaking internally or externally, and/or it's burning). Have you checked the oil for cross-contamination? It's also possible that the missing coolant was pushed out the expansion tank during an overheating event (such as what you've been seeing lately), but then you should have seen steam from this happening. Was it low on coolant again after the most recent overheating event?
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Could be a thermostat. Could be a head gasket introducing pressure and air into the system. Or a long list of other small things. Drain your oil and check it for water contamination.
If it is a thermostat you can usually get it to over heat just idling in the driveway.
Do you have access to a vacuum filler? You can rent them from some most of the parts stores. That's how I usually find leaks, vac the system and listen for the hissing sound or pressurize it watch for the leak or sound if the leak is higher than the coolant level.
You can put a valve stem through the vacuum sealing thing and put a couple psi to it through a hand pump or regulate it down to like 5psi on the air compressor.
If it is a thermostat you can usually get it to over heat just idling in the driveway.
Do you have access to a vacuum filler? You can rent them from some most of the parts stores. That's how I usually find leaks, vac the system and listen for the hissing sound or pressurize it watch for the leak or sound if the leak is higher than the coolant level.
You can put a valve stem through the vacuum sealing thing and put a couple psi to it through a hand pump or regulate it down to like 5psi on the air compressor.
Thread Starter
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Joined: Nov 2011
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From: Woodstock, GA
Could be a thermostat. Could be a head gasket introducing pressure and air into the system. Or a long list of other small things. Drain your oil and check it for water contamination.
If it is a thermostat you can usually get it to over heat just idling in the driveway.
Do you have access to a vacuum filler? You can rent them from some most of the parts stores. That's how I usually find leaks, vac the system and listen for the hissing sound or pressurize it watch for the leak or sound if the leak is higher than the coolant level.
You can put a valve stem through the vacuum sealing thing and put a couple psi to it through a hand pump or regulate it down to like 5psi on the air compressor.
If it is a thermostat you can usually get it to over heat just idling in the driveway.
Do you have access to a vacuum filler? You can rent them from some most of the parts stores. That's how I usually find leaks, vac the system and listen for the hissing sound or pressurize it watch for the leak or sound if the leak is higher than the coolant level.
You can put a valve stem through the vacuum sealing thing and put a couple psi to it through a hand pump or regulate it down to like 5psi on the air compressor.
Thread Starter
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From: Woodstock, GA
The level of the expansion tank, after it cooled down was slightly higher than the full mark.
I think my next move is to flush it, replace my thermostat and vacuum fill it.
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From: Woodstock, GA
BTW - You don't just have an overheating problem. You have a gas problem. (There shouldn't be air space in the radiator when you take the radiator cap off.) There could be a number of sources of this. (Bad head gasket, bad radiator cap, bad water pump, bad vent line, small leak in system, etc.)
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From: Woodstock, GA
This is telling. Was the engine running, or was it off?
BTW - You don't just have an overheating problem. You have a gas problem. (There shouldn't be air space in the radiator when you take the radiator cap off.) There could be a number of sources of this. (Bad head gasket, bad radiator cap, bad water pump, bad vent line, small leak in system, etc.)
BTW - You don't just have an overheating problem. You have a gas problem. (There shouldn't be air space in the radiator when you take the radiator cap off.) There could be a number of sources of this. (Bad head gasket, bad radiator cap, bad water pump, bad vent line, small leak in system, etc.)
Thread Starter
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From: Woodstock, GA
Also yesterday before I left for work, I made sure that the radiator was full. I managed to drive 45 miles to work without any problems. I didn't see any leaks when I arrived at work. When I drove home, I was a few miles from home when the temps started to skyrocket. To me that rules out the thermostat as well as the water pump; that's only about a year old with maybe 15,000 miles on it.
Then you were witnessing boiling. This shouldn't happen. Check the basics first - you could have a bad radiator cap, which isn't keeping the pressure.
If you aren't running the stock radiator cap, that could also be a problem. If you changed it when you did your thermostat and didn't go to a GM style cap - I'd go back and do that. Aftermarket caps are notorious for being problematic.
If you aren't running the stock radiator cap, that could also be a problem. If you changed it when you did your thermostat and didn't go to a GM style cap - I'd go back and do that. Aftermarket caps are notorious for being problematic.
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From: Woodstock, GA
After leaving the vehicle sitting, I see a small puddle under the left side of the radiator at the bottom. As for the cap, I do have an after market cap, although I have had it for a while. Just to cover all of my bases, I've got a radiator, thermostat, cap and vacuum filler coming in. I don't usually throw parts at a problem, I'm usually more methodical but with the high mileage, I'd rather cover all my bases.
To replace the radiator, the manual says to capture the AC refrigerant. Really? I have to pull the condenser with the radiator?
To replace the radiator, the manual says to capture the AC refrigerant. Really? I have to pull the condenser with the radiator?
I'd go a little slower before replacing all those parts. That puddle and your problem could be a bad water pump, for instance.
Even if you want to replace some old parts, I'd drill down on either what is causing you to loose pressure or what is introducing gas into the system first. (Go part by part, if you need to.) To start, you may be able to rent a radiator and cap testing kit from a local parts store to make sure the radiator and neck holds pressure. (There should be a separate cap tester in the kit, if they have it.)
Even if you want to replace some old parts, I'd drill down on either what is causing you to loose pressure or what is introducing gas into the system first. (Go part by part, if you need to.) To start, you may be able to rent a radiator and cap testing kit from a local parts store to make sure the radiator and neck holds pressure. (There should be a separate cap tester in the kit, if they have it.)
I was noticing a coolant leak up by the top hose and it was the original one so I replaced it and the GM clamp for a real hose clamp thinking that solved my problem but later found that the radiator did have a leak. My car is an M6 car and I didn't have to mess with the AC lines at all and the radiator I have to replace it was the same one for automatic trans cars.
While I was at it I had one of my fan motors that was squealing real bad so I replaced both fan motors while I was replacing the radiator. Be sure to elevate the front of the car when you adding new coolant and be sure to add it slowly as you will have trapped air in the system and the engine will want to overheat until its purged of air.
Thread Starter
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Joined: Nov 2011
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From: Woodstock, GA
I'd go a little slower before replacing all those parts. That puddle and your problem could be a bad water pump, for instance.
Even if you want to replace some old parts, I'd drill down on either what is causing you to loose pressure or what is introducing gas into the system first. (Go part by part, if you need to.) To start, you may be able to rent a radiator and cap testing kit from a local parts store to make sure the radiator and neck holds pressure. (There should be a separate cap tester in the kit, if they have it.)
Even if you want to replace some old parts, I'd drill down on either what is causing you to loose pressure or what is introducing gas into the system first. (Go part by part, if you need to.) To start, you may be able to rent a radiator and cap testing kit from a local parts store to make sure the radiator and neck holds pressure. (There should be a separate cap tester in the kit, if they have it.)
Thread Starter
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From: Woodstock, GA
While I was at it I had one of my fan motors that was squealing real bad so I replaced both fan motors while I was replacing the radiator. Be sure to elevate the front of the car when you adding new coolant and be sure to add it slowly as you will have trapped air in the system and the engine will want to overheat until its purged of air.
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From: Schiller Park, ILL Member: #317
Based on the posts above, I get the feeling that the radiator is still original. If so, at 365k that is shocking. They are quite prone to cracking (usually at the tank, but sometimes the neck as well) usually any time after ~100k miles or so (sometimes sooner). I would not be surprised at all to discover a leak in the radiator at this point.