Coolant Pressure Testing
07-06-07, 02:27 PM
#78
Check your overflow tank and make sure that its filled NO HIGHER then the "F" mark on your dipstick. If you've been "topping off" at the fill neck and it hasn't been siphoning back into your engine your overflow will gradually fill up.
Even with a weak or slightly failing O-ring, my car seems to do pretty well as long as I make sure the overflow level stays at or near "Full" and the level in my coolant neck stays above my low level coolant sensor. If you reservoir is over full, you need to siphon some coolant out of it to get it back to the "F" mark.
Even with a weak or slightly failing O-ring, my car seems to do pretty well as long as I make sure the overflow level stays at or near "Full" and the level in my coolant neck stays above my low level coolant sensor. If you reservoir is over full, you need to siphon some coolant out of it to get it back to the "F" mark.
07-06-07, 02:34 PM
#79
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Check your overflow tank and make sure that its filled NO HIGHER then the "F" mark on your dipstick. If you've been "topping off" at the fill neck and it hasn't been siphoning back into your engine your overflow will gradually fill up.
Even with a weak or slightly failing O-ring, my car seems to do pretty well as long as I make sure the overflow level stays at or near "Full" and the level in my coolant neck stays above my low level coolant sensor. If you reservoir is over full, you need to siphon some coolant out of it to get it back to the "F" mark.
Even with a weak or slightly failing O-ring, my car seems to do pretty well as long as I make sure the overflow level stays at or near "Full" and the level in my coolant neck stays above my low level coolant sensor. If you reservoir is over full, you need to siphon some coolant out of it to get it back to the "F" mark.
When I did the coolant flush I siphoned all of the coolant out of the overfill and then added it on a cold engine til it was up to the "F" mark. And as of last night's overheating session the coolant is now up to the brim to where it comes out of the overfill hole. For some reason it will not discharge back into the engine.
I suppose that if there is an o-ring leak the pressure from the exhaust gases could be pushing the coolant into the overfill tank and not letting it come back when it cools down. But then why is the filler neck always low?
Correct me if I'm wrong, but the overfill tank is just an expansion tank so when the car is warm expanding coolant flows into the tank. Then when the engine cools the coolant from the overfill is supposed to be sucked back into the filler neck right? What actually creates the vacuum to suck the coolant back to the filler neck? If there is a pinhole leak somewhere could this be causing the overfill to constantly fill and not discharge back to the engine? That would make sense to why the filler neck is always about the same amount empty and causing the cooling system to seem like its always low on coolant?
But then I still have the problem of it overheating when its completely filled with coolant (like when I make sure its topped off before I go for a drive).
07-06-07, 03:02 PM
#80
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If there is a pinhole leak somewhere could this be causing the overfill to constantly fill and not discharge back to the engine? That would make sense to why the filler neck is always about the same amount empty and causing the cooling system to seem like its always low on coolant?
Dave
07-06-07, 03:08 PM
#81
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A non-sealing pressure release cap (around its outer edge), or a small leak in the line to the O-F tank would allow air to be sucked back instead of coolant. The vacuum is created by the hot coolant in the engine cooling off and decreasing in volume as a result. However, as you said, gasses leaking into the system thru a bad o-ring could take up (at least some of) that space as they expand and not allow coolant to be sucked back.
Dave
Dave
Thanks for the heads up. I got a new 13psi cap at lunch and I will inspect the overfill tank for any leaks in the line. The only line feeding the overfill is coming directly off the nipple on the filler neck, so I will check that line for any leaks.
But even if I find a leak, and the system stays full, I still have some overheating issues.
Thanks again for the help, any is greatly appreciated. Josh
07-06-07, 03:11 PM
#82
... For some reason it will not discharge back into the engine.
I suppose that if there is an o-ring leak the pressure from the exhaust gases could be pushing the coolant into the overfill tank and not letting it come back when it cools down. But then why is the filler neck always low?
Correct me if I'm wrong, but the overfill tank is just an expansion tank so when the car is warm expanding coolant flows into the tank. Then when the engine cools the coolant from the overfill is supposed to be sucked back into the filler neck right? What actually creates the vacuum to suck the coolant back to the filler neck? If there is a pinhole leak somewhere could this be causing the overfill to constantly fill and not discharge back to the engine? That would make sense to why the filler neck is always about the same amount empty and causing the cooling system to seem like its always low on coolant?
But then I still have the problem of it overheating when its completely filled with coolant (like when I make sure its topped off before I go for a drive).
I suppose that if there is an o-ring leak the pressure from the exhaust gases could be pushing the coolant into the overfill tank and not letting it come back when it cools down. But then why is the filler neck always low?
Correct me if I'm wrong, but the overfill tank is just an expansion tank so when the car is warm expanding coolant flows into the tank. Then when the engine cools the coolant from the overfill is supposed to be sucked back into the filler neck right? What actually creates the vacuum to suck the coolant back to the filler neck? If there is a pinhole leak somewhere could this be causing the overfill to constantly fill and not discharge back to the engine? That would make sense to why the filler neck is always about the same amount empty and causing the cooling system to seem like its always low on coolant?
But then I still have the problem of it overheating when its completely filled with coolant (like when I make sure its topped off before I go for a drive).
07-06-07, 03:31 PM
#84
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I just got off the phone with Atkins.
I just wanted to run this by them to see what they thought.
The guy I spoke to said it sounds like a typical o-ring failure starting.
They want about $3,000 to $3,500 for the rebuild. Ouch.
I also sent an email to Rotary Resurrection.
I have a DVD on the way from Atkins on how to rebuild, but its more for me just to learn than actually tear my engine apart. I mean I could probably do it, I just don't have the tools and instruments to do a proper evaluation of the housings and so forth. Better leave it up to the pros.
I just wanted to run this by them to see what they thought.
The guy I spoke to said it sounds like a typical o-ring failure starting.
They want about $3,000 to $3,500 for the rebuild. Ouch.
I also sent an email to Rotary Resurrection.
I have a DVD on the way from Atkins on how to rebuild, but its more for me just to learn than actually tear my engine apart. I mean I could probably do it, I just don't have the tools and instruments to do a proper evaluation of the housings and so forth. Better leave it up to the pros.
07-06-07, 03:32 PM
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Sounds like your exhaust gas is forcing out through your seals and pushing your coolant out. Internal gasket leak. It won't show up in a litmus hydrocarbon test because the concentration is too minute. The exhaust gas doesn't mix in your coolant quick enough. Try a shop with a real sensitive hydrocarbon sniffer.
Reason for conclusion - this guy has pressure tested his system numerous times and flushed his coolant more than necessary. The leak can't be anywhere else in the system.
Atkins is way overcharging you for a simple O ring replacement. Contact my mechanic Jesse Parker at Vision Speed Factory. He will do it for a nominal labour fee. PM for his contact info.
Reason for conclusion - this guy has pressure tested his system numerous times and flushed his coolant more than necessary. The leak can't be anywhere else in the system.
Atkins is way overcharging you for a simple O ring replacement. Contact my mechanic Jesse Parker at Vision Speed Factory. He will do it for a nominal labour fee. PM for his contact info.
07-06-07, 03:39 PM
#86
Initially like you, I thought that I may just have a bad cap or leaky hose somewhere, but what confirmed O-ring failure for me was getting a pressure tester from AutoZone. They rent them for free here in AZ. I pressurized the system to 17 psi and after less than 15 minutes the pressure had dropped to approximately 14-15 psi. I repeated the test two or three times with the same result. Then, when I disconnected the pressure tester, replaced my cap and went to start the car, I got the rough start (running on one rotor sound) along with a good-sized white cloud out the back for nearly 30 seconds. Try this same test and see if you don't get a similar result.
07-06-07, 03:44 PM
#87
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Sounds like your exhaust gas is forcing out through your seals and pushing your coolant out. Internal gasket leak. It won't show up in a litmus hydrocarbon test because the concentration is too minute. The exhaust gas doesn't mix in your coolant quick enough. Try a shop with a real sensitive hydrocarbon sniffer.
Ok, I'll look into that. The only thing is that I am taking the car up to ND tonight and I doubt anywhere in the huge town of Beulah ND has a sniffer. But maybe? I'll check it out.
07-06-07, 03:46 PM
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Initially like you, I thought that I may just have a bad cap or leaky hose somewhere, but what confirmed O-ring failure for me was getting a pressure tester from AutoZone. They rent them for free here in AZ. I pressurized the system to 17 psi and after less than 15 minutes the pressure had dropped to approximately 14-15 psi. I repeated the test two or three times with the same result. Then, when I disconnected the pressure tester, replaced my cap and went to start the car, I got the rough start (running on one rotor sound) along with a good-sized white cloud out the back for nearly 30 seconds. Try this same test and see if you don't get a similar result.
That sounds like a good test. I will call Checker right now and see they have one for rent. Thanks a lot for all of the help and insight. I appreciate it. Josh
07-06-07, 03:55 PM
#89
If you want to verify your leaks, you could always add U/V dye to the coolant and then look for the leak(s) with a U/V light.
Depending on where you find the U/V dye, it can tell you which O-ring/seal is leaking, although if it's entering the exhaust, it will most likely be burned-off. Don't forget to check the engine-oil for U/V dye as well.
I wonder if a conversion to Evans coolant may give you some life out of the motor, since it is "zero pressure" coolant.
If you've been replacing the coolant, fill-up with some Sierra "eco/pet-friendly" coolant, run that for awhile, and then switch to Evans with ZERO pressure coolant & AST caps.
:-) neil
PS: dont' forget to place the heater in the HOT position to flush out all of the old ethyl-glycol-based coolant.
Depending on where you find the U/V dye, it can tell you which O-ring/seal is leaking, although if it's entering the exhaust, it will most likely be burned-off. Don't forget to check the engine-oil for U/V dye as well.
I wonder if a conversion to Evans coolant may give you some life out of the motor, since it is "zero pressure" coolant.
If you've been replacing the coolant, fill-up with some Sierra "eco/pet-friendly" coolant, run that for awhile, and then switch to Evans with ZERO pressure coolant & AST caps.
:-) neil
PS: dont' forget to place the heater in the HOT position to flush out all of the old ethyl-glycol-based coolant.
07-06-07, 03:59 PM
#90
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If you want to verify your leaks, you could always add U/V dye to the coolant and then look for the leak(s) with a U/V light.
Depending on where you find the U/V dye, it can tell you which O-ring/seal is leaking, although if it's entering the exhaust, it will most likely be burned-off. Don't forget to check the engine-oil for U/V dye as well.
Depending on where you find the U/V dye, it can tell you which O-ring/seal is leaking, although if it's entering the exhaust, it will most likely be burned-off. Don't forget to check the engine-oil for U/V dye as well.
Good idea on the UV dye. I just called every garage in Beulah, ND and none of them rent out a pressure test kit and I can't locate one here in Rapid City either.
I will make some calls and see if I can find the UV test.
07-06-07, 04:09 PM
#91
You might also check with them on the pressure test, they have various tools they rent out. Worse comes to worse, you could just buy a pressure test kit. Sears sells one for about $80. Not a bad tool to have in the garage.
07-06-07, 07:44 PM
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Well if your o-rings are really bad after 20K on a rebuild, either the mechanic or the driver have some explaining to do 
If the o-rings are starting to go I suggest switching to Evan NPG+ coolant and drive it till it's dead. Sometimes the engine can go a long time before it completely blows the coolant seal.
If the o-rings are starting to go I suggest switching to Evan NPG+ coolant and drive it till it's dead. Sometimes the engine can go a long time before it completely blows the coolant seal.
Last edited by Silverstone; 07-06-07 at 07:56 PM.
07-07-07, 11:27 PM
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Well if your o-rings are really bad after 20K on a rebuild, either the mechanic or the driver have some explaining to do
If the o-rings are starting to go I suggest switching to Evan NPG+ coolant and drive it till it's dead. Sometimes the engine can go a long time before it completely blows the coolant seal.
If the o-rings are starting to go I suggest switching to Evan NPG+ coolant and drive it till it's dead. Sometimes the engine can go a long time before it completely blows the coolant seal.
But if I can't get the thing to stop overheating on the highway it really ain't worth even driving it.
Also, can I do more premanent damage to the motor if I let it just go?
07-08-07, 12:55 PM
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I haven't checked the water pump yet.
I have a new t-stat that I got from Malloy, but for some reason it didn't have the "jiggle pin".
I am working on the car as we speak.
I picked up a bottle of the dye to add to your coolant system and added it last night and ran the car up to temperature with the Lisle funnel attached.
It was low on water since the overheating a couple of days ago so I filled it up and burped it.
At lower temperatrures there are tiny bubbles like in my videos, but once the t-stat opens there aren't any bubbles and it holds really nice.
So at about 92C the coolant in the Lisle funnel starts to boil and make a mess so I shut it down.
This morning I can back out and checked the floor for leaks. There wasn't any coolant or dye on the ground, but I did find a little leak right where the overfill line connects to the nipple on the filler neck (86 RX7, AST elimination filler neck). So I cut back some of the line and replaced it on the filler neck. There was also a little dye sitting on the back of the upper radiator hose near the t-stat housing, so I refitted the hose and added another clamp to make sure of no leaks.
Then since it was sitting all night if there was an o-ring problem coolant should have been collecting in the rotors. So I pulled the leading plugs and turned the engine over by hand and there isn't a drop of anything coming out of the spark plug holes. I can hear and feel the compression but nothing is spitting out. Hopefully this is a good sign.
If it is an o-ring shouldn't coolant be coming out of the spark plug holes if I slowly turn it over by hand, especially since its been sitting all night?
What is my next thing to trouble shoot?
I have a new 13psi cap that I am going to try.
How can you check to make sure the water pump is functioning properly?
The belt is tight against the Greddy pully and it seems to spin freely.
I have a new t-stat that I got from Malloy, but for some reason it didn't have the "jiggle pin".
I am working on the car as we speak.
I picked up a bottle of the dye to add to your coolant system and added it last night and ran the car up to temperature with the Lisle funnel attached.
It was low on water since the overheating a couple of days ago so I filled it up and burped it.
At lower temperatrures there are tiny bubbles like in my videos, but once the t-stat opens there aren't any bubbles and it holds really nice.
So at about 92C the coolant in the Lisle funnel starts to boil and make a mess so I shut it down.
This morning I can back out and checked the floor for leaks. There wasn't any coolant or dye on the ground, but I did find a little leak right where the overfill line connects to the nipple on the filler neck (86 RX7, AST elimination filler neck). So I cut back some of the line and replaced it on the filler neck. There was also a little dye sitting on the back of the upper radiator hose near the t-stat housing, so I refitted the hose and added another clamp to make sure of no leaks.
Then since it was sitting all night if there was an o-ring problem coolant should have been collecting in the rotors. So I pulled the leading plugs and turned the engine over by hand and there isn't a drop of anything coming out of the spark plug holes. I can hear and feel the compression but nothing is spitting out. Hopefully this is a good sign.
If it is an o-ring shouldn't coolant be coming out of the spark plug holes if I slowly turn it over by hand, especially since its been sitting all night?
What is my next thing to trouble shoot?
I have a new 13psi cap that I am going to try.
How can you check to make sure the water pump is functioning properly?
The belt is tight against the Greddy pully and it seems to spin freely.
07-08-07, 02:09 PM
#97
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Its a Koyo and about 5 years old.
That is my next step to have it boiled/cleaned.
I wish I had an infared thermometer.
I'm gonna pull the radiator right now and while its out start on a shroud.
07-08-07, 02:10 PM
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You will do damage if you actually overheat the engine by not keeping enough coolant in there. Keep in mind that boilover does not necessarily mean you are overheating but it can cause overheating. Seriously, you should change over your coolant to Evans NPG+ coolant. It never boils over. Rated for 375 deg at 0 pressure. If you have never heard of it you should definately look into it. Do a search here and you will find some threads. It solved all my cooling system issues and stopped my boilover in its tracks. Even if you have an o-ring problem it could let you get a lot more life out of your engine while you save for a re-build. Your overflow tank will become virtually obsolete with the Evans because it does not expand the same way other coolant water mixtures do. It will also allow you to change your pressure cap to a 7 LB cap instead of a 13 LB.
07-08-07, 02:14 PM
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You will do damage if you actually overheat the engine by not keeping enough coolant in there. Keep in mind that boilover does not necessarily mean you are overheating but it can cause overheating. Seriously, you should change over your coolant to Evans NPG+ coolant. It never boils over. Rated for 375 deg at 0 pressure. If you have never heard of it you should definately look into it. Do a search here and you will find some threads. It solved all my cooling system issues and stopped my boilover in its tracks. Even if you have an o-ring problem it could let you get a lot more life out of your engine while you save for a re-build. Your overflow tank will become virtually obsolete with the Evans because it does not expand the same way other coolant water mixtures do. It will also allow you to change your pressure cap to a 7 LB cap instead of a 13 LB.
Thank you for the info. Right now I am going to pull my radiator and get it into a shop this week to have it tested and cleaned.
How does one test the water pump? I know about the seap hole and it does not look to be leaking.
Are there any aftermarket hi-flow water pumps that may help the system?
07-09-07, 07:36 AM
#100
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