Coolant Pressure Testing
07-06-07, 07:23 AM
#51
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Just curious if you've changed either of the caps (AST or filler neck) and if so when you pull them off have you found any black residue on the seal (black, oily, possible carbon grains) and is your recovery tank clean or dirty with any of the same residue in it. When you pulled the dip stick out of the recovery tank is it clean or any of the above mentioned residue. A friend of mine was having the same issues and found this stuff on the seals and once the car boiled over this stuff got trapped on the seal preventing it from building pressure and letting it boil over sooner. With you being in the mountains I would think straight water and just watter wetter wouldn't give you a very high boiling point.
07-06-07, 09:32 AM
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Just curious if you've changed either of the caps (AST or filler neck) and if so when you pull them off have you found any black residue on the seal (black, oily, possible carbon grains) and is your recovery tank clean or dirty with any of the same residue in it. When you pulled the dip stick out of the recovery tank is it clean or any of the above mentioned residue. A friend of mine was having the same issues and found this stuff on the seals and once the car boiled over this stuff got trapped on the seal preventing it from building pressure and letting it boil over sooner. With you being in the mountains I would think straight water and just watter wetter wouldn't give you a very high boiling point.
I haven't changed the cap since I installed the AST elimination filler neck. That was a cap off a 2nd gen if I'm right.
The cap and OF tank are clean, no build-up.
I'm still hoping there is just a leak somewhere that I can not find. I really don't feel like having to replace the engine.
07-06-07, 09:59 AM
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I only have one coolant cap. Which cap should I get?
I really appreciate all the help you guys are giving me.
I rented a car trailer and am taking it back up to North Dakota to my Dad's shop where I actually have some room to work. I am going to tear it down this weekend and look for any leaks that I can find.
- Josh
07-06-07, 10:02 AM
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07-06-07, 10:21 AM
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I just got off the phone with the shop where I did my pressure test. They don't have a hydrocarbon tester, but he said they do have a test procedure to where a clear tube is connected to the filler neck with some sort of liquid in it and if it detects hydrocarbons it changes color.
Has anybody ever heard of a test like this?
Will I be wasting my time doing this test?
Everybody with a hydrocarbon sniffer is backed up for a couple of days and I would like to get this done at noon.
Has anybody ever heard of a test like this?
Will I be wasting my time doing this test?
Everybody with a hydrocarbon sniffer is backed up for a couple of days and I would like to get this done at noon.
07-06-07, 11:21 AM
#60
jhammerrx7,
I have read your entire thread and viewed your videos. My car has been doing nearly the exact same thing the past 3 years. If the bubbles in your Lisle Yellow Funnel cease after the car runs for 10 minutes or more, I'd say that you just have air in your system. But looking at the video, those bubbles are huge and consistent, which leads me to believe that they're being caused by exhaust gas pulses and NOT just random air.
The other things you've mentioned, i.e., rough starting, sounding like it's running on 1 rotor, could be symptoms of too much fuel, but are more than likely symptoms of coolant in your rotor housing fouling out your plugs on startup. Mine will do the same thing and after 30 seconds to a minute after starting it begins to smooth out.
I guess the final thing you've said that solidifies my feelings is your descripton of the car getting hot up the hill, but then not recovering once you crested the grade (especially since your evening ambient temps were fairly cool). Runaway temps are yet another indicator of a breach in your coolant o-ring (i.e., air in the system). If you're running straight water wetter and water, the risk for runaway temps is even greater. I used to run a similar mix to what you've indicated, but switched back to 70/30 with water wetter based on warnings from several rotary engine builders about rust and galvanic corrosion from running that aggressive a mix (straight water and WW). Also, the 30 percent EG will give you 'some' protection from runaway temps.
The exhaust gas test may or may not tell you anything. I've spoken with more than one Mazda mechanic who feel that the test can give you inconsistent results.
I know that I've needed a rebuild for more than a couple of years, but since I only drive the car about every other weekend, I've just nursed it along. However, over the last 6 months my symptoms have gotten progressively worse. I'd like to be more positive, and it could be that you just have some freak leak somewhere that's hard to detect, but I fear that it's worse than that. Good luck with your diagnosis. I hope that you prove me wrong!!
I have read your entire thread and viewed your videos. My car has been doing nearly the exact same thing the past 3 years. If the bubbles in your Lisle Yellow Funnel cease after the car runs for 10 minutes or more, I'd say that you just have air in your system. But looking at the video, those bubbles are huge and consistent, which leads me to believe that they're being caused by exhaust gas pulses and NOT just random air.
The other things you've mentioned, i.e., rough starting, sounding like it's running on 1 rotor, could be symptoms of too much fuel, but are more than likely symptoms of coolant in your rotor housing fouling out your plugs on startup. Mine will do the same thing and after 30 seconds to a minute after starting it begins to smooth out.
I guess the final thing you've said that solidifies my feelings is your descripton of the car getting hot up the hill, but then not recovering once you crested the grade (especially since your evening ambient temps were fairly cool). Runaway temps are yet another indicator of a breach in your coolant o-ring (i.e., air in the system). If you're running straight water wetter and water, the risk for runaway temps is even greater. I used to run a similar mix to what you've indicated, but switched back to 70/30 with water wetter based on warnings from several rotary engine builders about rust and galvanic corrosion from running that aggressive a mix (straight water and WW). Also, the 30 percent EG will give you 'some' protection from runaway temps.
The exhaust gas test may or may not tell you anything. I've spoken with more than one Mazda mechanic who feel that the test can give you inconsistent results.
I know that I've needed a rebuild for more than a couple of years, but since I only drive the car about every other weekend, I've just nursed it along. However, over the last 6 months my symptoms have gotten progressively worse. I'd like to be more positive, and it could be that you just have some freak leak somewhere that's hard to detect, but I fear that it's worse than that. Good luck with your diagnosis. I hope that you prove me wrong!!
07-06-07, 11:28 AM
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jhammerrx7,
I have read your entire thread and viewed your videos. My car has been doing nearly the exact same thing the past 3 years. If the bubbles in your Lisle Yellow Funnel cease after the car runs for 10 minutes or more, I'd say that you just have air in your system. But looking at the video, those bubbles are huge and consistent, which leads me to believe that they're being caused by exhaust gas pulses and NOT just random air.
The other things you've mentioned, i.e., rough starting, sounding like it's running on 1 rotor, could be symptoms of too much fuel, but are more than likely symptoms of coolant in your rotor housing fouling out your plugs on startup. Mine will do the same thing and after 30 seconds to a minute after starting it begins to smooth out.
I guess the final thing you've said that solidifies my feelings is your descripton of the car getting hot up the hill, but then not recovering once you crested the grade (especially since your evening ambient temps were fairly cool). Runaway temps are yet another indicator of a breach in your coolant o-ring (i.e., air in the system). If you're running straight water wetter and water, the risk for runaway temps is even greater. I used to run a similar mix to what you've indicated, but switched back to 70/30 with water wetter based on warnings from several rotary engine builders about rust and galvanic corrosion from running that aggressive a mix (straight water and WW). Also, the 30 percent EG will give you 'some' protection from runaway temps.
The exhaust gas test may or may not tell you anything. I've spoken with more than one Mazda mechanic who feel that the test can give you inconsistent results.
I know that I've needed a rebuild for more than a couple of years, but since I only drive the car about every other weekend, I've just nursed it along. However, over the last 6 months my symptoms have gotten progressively worse. I'd like to be more positive, and it could be that you just have some freak leak somewhere that's hard to detect, but I fear that it's worse than that. Good luck with your diagnosis. I hope that you prove me wrong!!
I have read your entire thread and viewed your videos. My car has been doing nearly the exact same thing the past 3 years. If the bubbles in your Lisle Yellow Funnel cease after the car runs for 10 minutes or more, I'd say that you just have air in your system. But looking at the video, those bubbles are huge and consistent, which leads me to believe that they're being caused by exhaust gas pulses and NOT just random air.
The other things you've mentioned, i.e., rough starting, sounding like it's running on 1 rotor, could be symptoms of too much fuel, but are more than likely symptoms of coolant in your rotor housing fouling out your plugs on startup. Mine will do the same thing and after 30 seconds to a minute after starting it begins to smooth out.
I guess the final thing you've said that solidifies my feelings is your descripton of the car getting hot up the hill, but then not recovering once you crested the grade (especially since your evening ambient temps were fairly cool). Runaway temps are yet another indicator of a breach in your coolant o-ring (i.e., air in the system). If you're running straight water wetter and water, the risk for runaway temps is even greater. I used to run a similar mix to what you've indicated, but switched back to 70/30 with water wetter based on warnings from several rotary engine builders about rust and galvanic corrosion from running that aggressive a mix (straight water and WW). Also, the 30 percent EG will give you 'some' protection from runaway temps.
The exhaust gas test may or may not tell you anything. I've spoken with more than one Mazda mechanic who feel that the test can give you inconsistent results.
I know that I've needed a rebuild for more than a couple of years, but since I only drive the car about every other weekend, I've just nursed it along. However, over the last 6 months my symptoms have gotten progressively worse. I'd like to be more positive, and it could be that you just have some freak leak somewhere that's hard to detect, but I fear that it's worse than that. Good luck with your diagnosis. I hope that you prove me wrong!!
Thanks for your post. Everything you just listed is exactly what is happening to me.
07-06-07, 11:33 AM
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jhammerrx7,
I have read your entire thread and viewed your videos. My car has been doing nearly the exact same thing the past 3 years. If the bubbles in your Lisle Yellow Funnel cease after the car runs for 10 minutes or more, I'd say that you just have air in your system. But looking at the video, those bubbles are huge and consistent, which leads me to believe that they're being caused by exhaust gas pulses and NOT just random air.
I have read your entire thread and viewed your videos. My car has been doing nearly the exact same thing the past 3 years. If the bubbles in your Lisle Yellow Funnel cease after the car runs for 10 minutes or more, I'd say that you just have air in your system. But looking at the video, those bubbles are huge and consistent, which leads me to believe that they're being caused by exhaust gas pulses and NOT just random air.
Another thing I should mention is that since I recorded those videos I did a complete flush and did a couple more videos. Since the flush there wasn't any consistant bubbles. Just large "burps" every once in a while. But when the t-stat opened it had more large "burps". Then when the temp reached about 94C on my PFC the coolant started to "boil" or overflow from the Lisle funnel.
07-06-07, 11:37 AM
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[QUOTE=RCCAZ 1;7109531]
I guess the final thing you've said that solidifies my feelings is your descripton of the car getting hot up the hill, but then not recovering once you crested the grade (especially since your evening ambient temps were fairly cool). Runaway temps are yet another indicator of a breach in your coolant o-ring (i.e., air in the system). If you're running straight water wetter and water, the risk for runaway temps is even greater. I used to run a similar mix to what you've indicated, but switched back to 70/30 with water wetter based on warnings from several rotary engine builders about rust and galvanic corrosion from running that aggressive a mix (straight water and WW). Also, the 30 percent EG will give you 'some' protection from runaway temps.[QUOTE]
Do you think I should dump the coolant again? Do you think I should run a higher concentration of water wetter?
One thing that still baffles me is why doesn't the car overheat while driving in town? Only when it gets a steady load like climbing a hill does it really spike. This makes no sense to me. If it is an o-ring failure shouldn't it get hot no matter where you drive it?
I guess the final thing you've said that solidifies my feelings is your descripton of the car getting hot up the hill, but then not recovering once you crested the grade (especially since your evening ambient temps were fairly cool). Runaway temps are yet another indicator of a breach in your coolant o-ring (i.e., air in the system). If you're running straight water wetter and water, the risk for runaway temps is even greater. I used to run a similar mix to what you've indicated, but switched back to 70/30 with water wetter based on warnings from several rotary engine builders about rust and galvanic corrosion from running that aggressive a mix (straight water and WW). Also, the 30 percent EG will give you 'some' protection from runaway temps.[QUOTE]
Do you think I should dump the coolant again? Do you think I should run a higher concentration of water wetter?
One thing that still baffles me is why doesn't the car overheat while driving in town? Only when it gets a steady load like climbing a hill does it really spike. This makes no sense to me. If it is an o-ring failure shouldn't it get hot no matter where you drive it?
07-06-07, 11:43 AM
#67
Racecar - Formula 2000
Low boiling temperature of the coolant mixture (can you say pure water, or with just water-wetter?) can cause runaway coolant temps due to the localized boiling at engine hot spots (near exhaust port, for example). This causes the heat transfer to the coolant at those spots to become almost non-existant, making the problem self-sustaining. A higher proportion of A-F will raise the boiling temp and reduce this problem. Adding more watter-wetter will do nothing for that.
07-06-07, 11:47 AM
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Low boiling temperature of the coolant mixture (can you say pure water, or with just water-wetter?) can cause runaway coolant temps due to the localized boiling at engine hot spots (near exhaust port, for example). This causes the heat transfer to the coolant at those spots to become almost non-existant, making the problem self-sustaining. A higher proportion of A-F will raise the boiling temp and reduce this problem. Adding more watter-wetter will do nothing for that.
Thanks for the info Dave. If that's the case I don't know why I even tried the water wetter. I will dump the coolant again this weekend and do a 70/30 water/anti-freeze mix and see if it helps.
I just also called the local Napa store and they have a cap for an 86 RX7 with the 16 psi spring. So I will pick that up at lunch.
07-06-07, 11:59 AM
#69
Racecar - Formula 2000
Thanks for the info Dave. If that's the case I don't know why I even tried the water wetter. I will dump the coolant again this weekend and do a 70/30 water/anti-freeze mix and see if it helps.
I just also called the local Napa store and they have a cap for an 86 RX7 with the 16 psi spring. So I will pick that up at lunch.
I just also called the local Napa store and they have a cap for an 86 RX7 with the 16 psi spring. So I will pick that up at lunch.
The 16-psi cap is better (than the 13-psi cap) to prevent boiling, but puts more stress on the hoses, seals, etc.
In the FD, I run 50/50 A-F & distilled water. In my racecar, I run 10% Valvoline super-coolant, 90% distilled water to prevent corrosion.
Dave
Last edited by DaveW; 07-06-07 at 12:04 PM.
07-06-07, 12:06 PM
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Yeah, I have a 16psi cap on it now.
Like many of you guys said I also have a feeling that it is in fact an o-ring, but before throwing in the towel I want to try everything else before a submit to a rebuild.
With my luck I would send the short block off for a rebuild and everything be mechanically fine. There goes some time and money.
I will post up again after lunch and let you guys know what I find out from the hydrocarbon test. Even though I think we all know what I will find.
Like many of you guys said I also have a feeling that it is in fact an o-ring, but before throwing in the towel I want to try everything else before a submit to a rebuild.
With my luck I would send the short block off for a rebuild and everything be mechanically fine. There goes some time and money.
I will post up again after lunch and let you guys know what I find out from the hydrocarbon test. Even though I think we all know what I will find.
07-06-07, 12:10 PM
#71
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Yup. I hear you. Definitely want to confirm the problem before throwing money at it!
Dave
Dave
07-06-07, 12:17 PM
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I am also going to try and locate a pressure tester again.
I would like to do my own testing with it and get under it and watch for leaks.
When I had it tested at the shop they only took it up to about 14 psi and its very difficult to locate a leak in one hour.
I hope its something stupid like a hose with a pinhole in it. But.............. who the hell knows.
I would like to do my own testing with it and get under it and watch for leaks.
When I had it tested at the shop they only took it up to about 14 psi and its very difficult to locate a leak in one hour.
I hope its something stupid like a hose with a pinhole in it. But.............. who the hell knows.
07-06-07, 02:10 PM
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I just got back from the garage that did the pressure testing for me.
While he didn't have a hydrocarbon sniffer, he did have a block tester (more or less a tube that inserts into the filler neck and has a liquid inside it. If the liquid detects hydrocarbons it is supposed to turn yellow. The liquid is originally blue.)
After letting the car idle for about 5 minutes the liquid didn't change and there weren't any bubbles present. But the overfill tank started to overfill and leak. It dumped probably about 1/2 gallon of coolant.
The temps driving over to the garage were fine considering that its 94F out right now. They held at about 91C.
But when we let the car idle they stayed around the 100 - 103C mark. I'm guessing because of a little heat soak.
So now I'm totally losing it. I don't know what to do next!?
Any thoughts?
While he didn't have a hydrocarbon sniffer, he did have a block tester (more or less a tube that inserts into the filler neck and has a liquid inside it. If the liquid detects hydrocarbons it is supposed to turn yellow. The liquid is originally blue.)
After letting the car idle for about 5 minutes the liquid didn't change and there weren't any bubbles present. But the overfill tank started to overfill and leak. It dumped probably about 1/2 gallon of coolant.
The temps driving over to the garage were fine considering that its 94F out right now. They held at about 91C.
But when we let the car idle they stayed around the 100 - 103C mark. I'm guessing because of a little heat soak.
So now I'm totally losing it. I don't know what to do next!?
Any thoughts?
07-06-07, 02:12 PM
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I think I may have a problem with the system holding pressure. While I can't find any leaks, it seems like the overfill is not working correctly. It seems like the coolant never returns back to the engine when it cools. It seems like the overfill tank is always getting fuller.
What could be causing this?
What could be causing this?
07-06-07, 02:17 PM
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I should also mention, I stopped at Napa to pick up the radiator cap and the only one they had was a 13psi cap. I have a 16psi cap on it now. Will it hurt anything to use the 13psi cap and test the system in case the 16psi cap is damaged?