22 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHHow the coolant bleeder valve works
Leading reported evidence
Replace water pump
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Performed · outcome unconfirmed
I recently changed the water pump on my 996, and I think there still may be an air bubble trapped in the system.
The car runs at ~200'F in the hottest conditions (the needle is around the '0' of the '180' on the coolant temperature gauge at its highest point), and it hasn't overheated yet (~30'C at least on the hottest days), but when I check the bleeder valve, I notice it's always open when the coolant is hot, and maybe I just wasn't as attentive to it before changing the water pump, but now I notice it's open when hot, and wondering if it should always be like that, or if there's an air bubble in there.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
The car runs at ~200'F in the hottest conditions (the needle is around the '0' of the '180' on the coolant temperature gauge at its highest point), and it hasn't overheated yet (~30'C at least on the hottest days), but when I check the bleeder valve, I notice it's always open when the coolant is hot, and maybe I just wasn't as attentive to it before changing the water pump, but now I notice it's open when hot, and wondering if it should always be like that, or if there's an air bubble in there.
Leading evidence: 'Replace water pump' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check bleeder valve, i notice it's always open' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
Everytime I use my heater in the winter, when the engine and coolant reach a certaion temp or pressure, my cabin fills with the smell of coolant and steam comes out from under the hood where the exlpansion tank/bleeder is located.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
I used the uview vacuum tool so I didn't need to do any manual bleeding.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
The car runs at ~200'F in the hottest conditions (the needle is around the '0' of the '180' on the coolant temperature gauge at its highest point), and it hasn't overheated yet (~30'C at least on the hottest days), but when I check the bleeder valve, I notice it's always open when the coolant is hot, and maybe I just wasn't as attentive to it before changing the water pump, but now I notice it's open when hot, and wondering if it should always be like that, or if there's an air bubble in there.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Check bleeder valve, i notice it's always open
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
The car runs at ~200'F in the hottest conditions (the needle is around the '0' of the '180' on the coolant temperature gauge at its highest point), and it hasn't overheated yet (~30'C at least on the hottest days), but when I check the bleeder valve, I notice it's always open when the coolant is hot, and maybe I just wasn't as attentive to it before changing the water pump, but now I notice it's open when hot, and wondering if it should always be like that, or if there's an air bubble in there.
The car runs at ~200'F in the hottest conditions (the needle is around the '0' of the '180' on the coolant temperature gauge at its highest point), and it hasn't overheated yet (~30'C at least on the hottest days), but when I check the bleeder valve, I notice it's always open when the coolant is hot, and maybe I just wasn't as attentive to it before changing the water pump, but now I notice it's open when hot, and wondering if it should always be like that, or if there's an air bubble in there.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
Everytime I use my heater in the winter, when the engine and coolant reach a certaion temp or pressure, my cabin fills with the smell of coolant and steam comes out from under the hood where the exlpansion tank/bleeder is located.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
22 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
I have had it in 6 times to the dealer and they have never fixed it.
Just thought this is interesting and wanted to share with you some pics. I took an "x-ray" view of the reservoir with the valve removed. What's below the valve is an inner opening and a chamber surrounding it.
Bleeder-valve.jpg
The vent lines from the radiators and the oil/coolant heat exchanger are connected to the inner opening only. These are the two highest points in the cooling system where any trapped air will naturally migrate to. The outer chamber is connected to the reservoir via that bright vertical slit. The valve is made up of a spring loaded rubber diaphragm that normally presses down and closes the inner opening, preventing any vent air to flow into the reservoir. When the coolant warms up, the pressure pushes up on the diaphragm so any air from the vent line can escape into the reservoir. Any excessive air in the reservoir can then escape via the CAP, which opens at about 18 PSI. The bleeder valve itself starts to open at ~8PSI.
When the coolant cools down, the valve closes to prevent air being sucked back into the vent lines. The system is designed to do one-way bleeding.
After a coolant drain, air is introduced into the system so we need to manually raise the valve to let air burp out of the system when cold. That's why the manual bleeding method works as well, albeit more hassle.
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This is amazing, just what I needed, because I have always had coolant stains around my bleeder cap. So I went and bought both o-rings. Only to discover upon removal that the large one was not there (!) and began to doubt whether it is necessary / where it goes. This clears things up nicely.
Some bozo must have assyd without the large o-ring. Result, my coolant only ever saw (say) 8 psi of pressure, what the bleeder valve builds up, as after it opens there is a direct vent to atmosphere.
Guess that was enough, thankfully.
how do you bleed the system? when I changed the heater core, I filled up and ran the car with the valve up until I could hear the fans turn on. let it run for 10 minutes revving and holding to 2k rpm every once in a while. seemed to work as I never had over heating issues and that coolant smell finally disappeared
I used the uview vacuum tool so I didn't need to do any manual bleeding. My understanding of manaul bleeding is, you pop up the bleeder valve (so air could escape to the reservoir
even before
the coolant gets hot) and do what you described. Then keep the bleeder valve open when driving the car for a few days. Keep in mind the bleeder valve doesn't vent to the atmosphere so you won't loose any coolant via it.
Also, you can jack up the rear of the car to encourage the trapped air to migrate toward the reservoir when you rev the engine.
I recently changed the water pump on my 996, and I think there still may be an air bubble trapped in the system. The car runs at ~200'F in the hottest conditions (the needle is around the '0' of the '180' on the coolant temperature gauge at its highest point), and it hasn't overheated yet (~30'C at least on the hottest days), but when I check the bleeder valve, I notice it's always open when the coolant is hot, and maybe I just wasn't as attentive to it before changing the water pump, but now I notice it's open when hot, and wondering if it should always be like that, or if there's an air bubble in there. Any input and help would be greatly appreciated!
Do you mean the bleeder valve is popping up by itself? It should only be in the up position when you place it in the open (up) position. Temps sound normal with standard thermostat.
Thanks for the help, everyone! I didn't vacuum bleed the system; I made some custom clamps to minimize the coolant lost during the whole procedure. The coolant level in the overflow tank seems fine, so I guess it's operating as it should.
Can a bad bleeder valve cause symptoms of coolant leak only when the engine is cold and the heater is turned on? Everytime I use my heater in the winter, when the engine and coolant reach a certaion temp or pressure, my cabin fills with the smell of coolant and steam comes out from under the hood where the exlpansion tank/bleeder is located. There is sometimes a small puddle of coolant under the car. I have had it in 6 times to the dealer and they have never fixed it. Now it is out of warrenty.
This is a source reference. Confirm exact model applicability in the original material.
