**HELP**'86 base- Overflow bottle Filling ALL THE TIME
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Joined: Jul 2001
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From: Mid-Ohio
**HELP**'86 base- Overflow bottle Filling ALL THE TIME
'86 base
For some reason, my overflow bottle is filling up all the time to the top....so much that it tries to leave the bottle. Heres the problem....its causing my engine to heat up much more than it should and its starting to scare me
Why would half the anti-freeze be leaving the radiator and heading to the overflow and how do i fix this problem?
Since the problem started the only thing i have done is remove the thermostat (was trying to keep the engine running cooler as long as i can)
PLEASE HELP!
Ryan Radio
For some reason, my overflow bottle is filling up all the time to the top....so much that it tries to leave the bottle. Heres the problem....its causing my engine to heat up much more than it should and its starting to scare me
Why would half the anti-freeze be leaving the radiator and heading to the overflow and how do i fix this problem?Since the problem started the only thing i have done is remove the thermostat (was trying to keep the engine running cooler as long as i can)
PLEASE HELP!
Ryan Radio
One of two things is causing the problem. The best case for you is simply a faulty pressure cap that isn't holding pressure. This will let the fluid escape, and since it's not keeping the system pressurized will lower the boiling point of the coolant and cause the engine to run hotter.
Case two is a cooling problem of another (read: expensive) type that is cooking the fluid and causing it to boil over. Blown o-ring, water pump failure, clogged radiator, faulty fan, etc.
The easiest thing to do is to replace the pressure cap on the neck right above the thermostat (on the 86, think the 89+ has it on the radiator). See what that does.
FYI, some have different theories on removing thermostats. Other than their purpose of opening and closing at a certain temp, some agree that a certain amount of flow restriction is required. Having said that, the Racing Beat catalog says to remove the thermostat on full race motors because open flow is best. A street motor should have one though IMO. I'd replace the thermostat and pressure cap (read: cheap). Cross your fingers becuase if that don't work you'll have to break out the check book.
Chris
Case two is a cooling problem of another (read: expensive) type that is cooking the fluid and causing it to boil over. Blown o-ring, water pump failure, clogged radiator, faulty fan, etc.
The easiest thing to do is to replace the pressure cap on the neck right above the thermostat (on the 86, think the 89+ has it on the radiator). See what that does.
FYI, some have different theories on removing thermostats. Other than their purpose of opening and closing at a certain temp, some agree that a certain amount of flow restriction is required. Having said that, the Racing Beat catalog says to remove the thermostat on full race motors because open flow is best. A street motor should have one though IMO. I'd replace the thermostat and pressure cap (read: cheap). Cross your fingers becuase if that don't work you'll have to break out the check book.
Chris
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Joined: Mar 2001
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From: Ft. Worth, Texas, USA, Earth, Solar System...
Originally posted by C. Ludwig
One of two things is causing the problem. The best case for you is simply a faulty pressure cap that isn't holding pressure. This will let the fluid escape, and since it's not keeping the system pressurized will lower the boiling point of the coolant and cause the engine to run hotter.
Case two is a cooling problem of another (read: expensive) type that is cooking the fluid and causing it to boil over. Blown o-ring, water pump failure, clogged radiator, faulty fan, etc.
The easiest thing to do is to replace the pressure cap on the neck right above the thermostat (on the 86, think the 89+ has it on the radiator). See what that does.
FYI, some have different theories on removing thermostats. Other than their purpose of opening and closing at a certain temp, some agree that a certain amount of flow restriction is required. Having said that, the Racing Beat catalog says to remove the thermostat on full race motors because open flow is best. A street motor should have one though IMO. I'd replace the thermostat and pressure cap (read: cheap). Cross your fingers becuase if that don't work you'll have to break out the check book.
Chris
One of two things is causing the problem. The best case for you is simply a faulty pressure cap that isn't holding pressure. This will let the fluid escape, and since it's not keeping the system pressurized will lower the boiling point of the coolant and cause the engine to run hotter.
Case two is a cooling problem of another (read: expensive) type that is cooking the fluid and causing it to boil over. Blown o-ring, water pump failure, clogged radiator, faulty fan, etc.
The easiest thing to do is to replace the pressure cap on the neck right above the thermostat (on the 86, think the 89+ has it on the radiator). See what that does.
FYI, some have different theories on removing thermostats. Other than their purpose of opening and closing at a certain temp, some agree that a certain amount of flow restriction is required. Having said that, the Racing Beat catalog says to remove the thermostat on full race motors because open flow is best. A street motor should have one though IMO. I'd replace the thermostat and pressure cap (read: cheap). Cross your fingers becuase if that don't work you'll have to break out the check book.
Chris
Also, to check for a coolant seal problem... remove the pressure cap from the thermostat neck, and start the car. Does it blow coolant out? If so, you need to rebuild the engine. If not, the problem is probably something small.
Brad
HAILERS
Joined: May 2001
Posts: 20,563
Likes: 27
From: FORT WORTH, TEXAS,USA
I agree with Ludwig that you should use a thermostat. That said, I'm running two cars without a thermostat right now. I plan to put them back in when I get off my dead bottom. Both cars run with the needle in the lower 1/8th. A good reason for leaving it in, is that the car was made to run efficiently at the higher temp. I notice that the thermo wax and fast idle cam do not work right with the thermo out. Water just does not get hot enough to melt the wax. It also effects the tps setting due to the fast idle cam and thermo wax not performing like they should. I imagine that the car is probably running rich. I got two new and overpriced thermostats from Mazdatrix yesterday. Ludwig is right about the rad cap. Also check and make sure that hose b/t the overflow and filler is secure. If it is cracked it will not suck the water in the overflow back into the radiator when the car cools down. Its the radiator cap. Yup.
Passenger
Posts: n/a
Originally posted by rx7_ragtop
Let me add one comment to this: DO NOT BUY A THERMOSTAT FROM THE LOCAL PARTS STORE! Get one from the Mazda dealer. There IS a difference!
Also, to check for a coolant seal problem... remove the pressure cap from the thermostat neck, and start the car. Does it blow coolant out? If so, you need to rebuild the engine. If not, the problem is probably something small.
Brad
Let me add one comment to this: DO NOT BUY A THERMOSTAT FROM THE LOCAL PARTS STORE! Get one from the Mazda dealer. There IS a difference!
Also, to check for a coolant seal problem... remove the pressure cap from the thermostat neck, and start the car. Does it blow coolant out? If so, you need to rebuild the engine. If not, the problem is probably something small.
Brad
Senior Member
Joined: Mar 2001
Posts: 287
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From: Marion, AR 72364
Coolant Loss
The above answers ignore your basic problem. Even if there is an overheating problem the coolant should be sucked back into the system when the engine cools off.
The coolant expands when heated. It flows into the expansion tank. When it cools, it returns to its original volume and should be "sucked" back into the engine/radiator. If it is not, then the problem most likely is due to a faulty cap or plumbing in the recovery system.
Look at your radiator cap. You will notice there are two gaskets on it. One is spring loaded. This "lifts" off the seat in the filler neck at approximately 14lbs. pressure and allows coolant to escape where it is piped to the recovery tank. There is another gasket that is located next to the cap body. This gasket is for sealing the system against outside air leakage. If this gasket is defective the result will be air getting into the engine rather than the coolant in the tank. The end result of all of this is a "one way" trip for the coolant into the tank. It will flow into the tank when it expands, but due to the bad cap it will not be sucked into the engine when it cools off. Consequently the engine is constantly filling the coolant recovery tank up but never removing any coolant from it.
Check the tubing leading from the filler neck to the tank. A leak here will have the same results, though it is more likely to manifest itself as an external leak. I will bet your cap is bad.
I am speaking from experience. I had the same problem as you and the radiator cap would check OK for pressure release. The test never checks for the uppermost gasket leaking air. I would bet a close examination of your cap will reveal the problem I am referring to.
The coolant expands when heated. It flows into the expansion tank. When it cools, it returns to its original volume and should be "sucked" back into the engine/radiator. If it is not, then the problem most likely is due to a faulty cap or plumbing in the recovery system.
Look at your radiator cap. You will notice there are two gaskets on it. One is spring loaded. This "lifts" off the seat in the filler neck at approximately 14lbs. pressure and allows coolant to escape where it is piped to the recovery tank. There is another gasket that is located next to the cap body. This gasket is for sealing the system against outside air leakage. If this gasket is defective the result will be air getting into the engine rather than the coolant in the tank. The end result of all of this is a "one way" trip for the coolant into the tank. It will flow into the tank when it expands, but due to the bad cap it will not be sucked into the engine when it cools off. Consequently the engine is constantly filling the coolant recovery tank up but never removing any coolant from it.
Check the tubing leading from the filler neck to the tank. A leak here will have the same results, though it is more likely to manifest itself as an external leak. I will bet your cap is bad.
I am speaking from experience. I had the same problem as you and the radiator cap would check OK for pressure release. The test never checks for the uppermost gasket leaking air. I would bet a close examination of your cap will reveal the problem I am referring to.
Thread Starter
Junior Member
Joined: Jul 2001
Posts: 20
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From: Mid-Ohio
well....i replaced the radiator cap with a new one.....and im still having the same problem. It is filling up the overflow to a point then it does nothing more than push air thru the bottle causing it to bubble like crazy. It doesnt seem to be pulling the anti-freeze back into the system. I checked the whole system and i dont see any leaks anywhere or anyplace that the air could be getting in from. Dang this sucks Also the car is heating up Very high....too high for comfort. I would say about 3/4's of the way up. Im assuming thats because most of the anti-freeze being pushed into the bottle. Also, the radiator cap i bought was 13lbs. Any one else with more ideas?
Thank you everyone for your responses....i appreciate them all!
Ryan
Also the car is heating up Very high....too high for comfort. I would say about 3/4's of the way up. Im assuming thats because most of the anti-freeze being pushed into the bottle. Also, the radiator cap i bought was 13lbs. Any one else with more ideas? Thank you everyone for your responses....i appreciate them all!
Ryan
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From: Marion, AR 72364
Coolant Bubbles
If you are experiencing the "bubbling" of your coolant into the recovery tank then you have a serious problem. There are only two possibilities for this.
The first possibility is the coolant is boiling. This would create steam which has to escape, and the only route offered to it is through the tank. This would account for the bubbles you are seeing. At any rate, an operating temp high enough to cause the coolant to boil indicates a significant problem elsewhere. The temp required to boil coolant under 13 pounds of pressure is very high, I am just guessing here but I would imagine around 230 or 240 degrees F. This is much too high for normal operations.
The second possibility has been previously mentioned. This is the presence of combustion chamber pressure leaking into your cooling jacket. This would indicate a leaking combustion o ring. A complete overhaul is the only cure for this.
The main difference between the two possibilities I have mentioned are that the combustion pressure will build up even before the engine has started to run hot. This is due to the fact that the pressure leakage is independant of engine temp. The combustion problem will be putting its pressure into the cooling system from the moment of start up. The "boiling" of the coolant would indicate a problem with the system that might range from a collapsing hose to a plugged radiator, a faulty thermostat, faulty timing, lean fuel mixture, or many other causes. It is imperative that you find the problem quickly before you ruin your engine.
A decent repair shop will be able to pressure test your cooling system. This involves an adapter being placed where the radiator cap normally goes, and then using a hand operated pump to pressurize the system to 13 pounds pressure. A period of time is allowed to elapse, then the pressure reading is checked. Obviously if it has dropped then you have an internal leak. Not good, for it indicates a serious problem with the integrity of the cooling system passages or seals in the engine.
Do not oberlook the obvious here. Make sure your radiator fins are free of bugs, dirt, etc. Inspect the fan and its clutch for proper operation. Do you still have the fan shroud and air dam (the big plastic shield underneath the car) installed. These are necessary for proper operation. One other possibility is the water pump itself. I have seen more than a few of these with the fins on the impeller nearly gone from corrosion. This will drastically reduce the ability of the pump to circulate the coolant even though there are no external signs of leakage at the pump.
The first possibility is the coolant is boiling. This would create steam which has to escape, and the only route offered to it is through the tank. This would account for the bubbles you are seeing. At any rate, an operating temp high enough to cause the coolant to boil indicates a significant problem elsewhere. The temp required to boil coolant under 13 pounds of pressure is very high, I am just guessing here but I would imagine around 230 or 240 degrees F. This is much too high for normal operations.
The second possibility has been previously mentioned. This is the presence of combustion chamber pressure leaking into your cooling jacket. This would indicate a leaking combustion o ring. A complete overhaul is the only cure for this.
The main difference between the two possibilities I have mentioned are that the combustion pressure will build up even before the engine has started to run hot. This is due to the fact that the pressure leakage is independant of engine temp. The combustion problem will be putting its pressure into the cooling system from the moment of start up. The "boiling" of the coolant would indicate a problem with the system that might range from a collapsing hose to a plugged radiator, a faulty thermostat, faulty timing, lean fuel mixture, or many other causes. It is imperative that you find the problem quickly before you ruin your engine.
A decent repair shop will be able to pressure test your cooling system. This involves an adapter being placed where the radiator cap normally goes, and then using a hand operated pump to pressurize the system to 13 pounds pressure. A period of time is allowed to elapse, then the pressure reading is checked. Obviously if it has dropped then you have an internal leak. Not good, for it indicates a serious problem with the integrity of the cooling system passages or seals in the engine.
Do not oberlook the obvious here. Make sure your radiator fins are free of bugs, dirt, etc. Inspect the fan and its clutch for proper operation. Do you still have the fan shroud and air dam (the big plastic shield underneath the car) installed. These are necessary for proper operation. One other possibility is the water pump itself. I have seen more than a few of these with the fins on the impeller nearly gone from corrosion. This will drastically reduce the ability of the pump to circulate the coolant even though there are no external signs of leakage at the pump.
Thread Starter
Junior Member
Joined: Jul 2001
Posts: 20
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From: Mid-Ohio
OK...here is what i did today and here are the results:
I think that i may have it narrowed down.
First....the overflow doesnt bubble until it reaches above normal operating temps. After the motor cools...it pulls most of it back into the radiator. The fan is an aftermarket electric one that i have set to run all the time. It is a VERY GOOD fan.
I put a new thermostat into the housing.
Checked all hoses.
Flushed the radiator and the hoses into the motor.
Used engine degreaser and removed ALOT of crap in the fins of the radiator and condenser and oil cooler.
Re-filled whole system with new coolant.
The car stays very cool when just sitting still....then when you get on the highway at higher RPM's it seems to run hotter...which should be complete opposite. I DID notice the car ran cooler...but i still got the antifreeze into the overflow. Car was still running halfway up the scale...and just a bit over. Yesterday it was 3/4 the way up the temp guage.
Heres a possible remedy:
WATER PUMP
The waterpump is working enough at lower RPM's and the engine can stay cool....but on the highway its not pumping enough water thru the system to keep it at normal operating temps.
Anyone care to comment on my rationale? Does this sound possible?
Thank you all!
Ryan Radio
I think that i may have it narrowed down.
First....the overflow doesnt bubble until it reaches above normal operating temps. After the motor cools...it pulls most of it back into the radiator. The fan is an aftermarket electric one that i have set to run all the time. It is a VERY GOOD fan.
I put a new thermostat into the housing.
Checked all hoses.
Flushed the radiator and the hoses into the motor.
Used engine degreaser and removed ALOT of crap in the fins of the radiator and condenser and oil cooler.
Re-filled whole system with new coolant.
The car stays very cool when just sitting still....then when you get on the highway at higher RPM's it seems to run hotter...which should be complete opposite. I DID notice the car ran cooler...but i still got the antifreeze into the overflow. Car was still running halfway up the scale...and just a bit over. Yesterday it was 3/4 the way up the temp guage.
Heres a possible remedy:
WATER PUMP
The waterpump is working enough at lower RPM's and the engine can stay cool....but on the highway its not pumping enough water thru the system to keep it at normal operating temps.
Anyone care to comment on my rationale? Does this sound possible?
Thank you all!
Ryan Radio
Full Member
Joined: Aug 2001
Posts: 182
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From: Somewhere
Thats one sweet looking engine! I wish I could help. My car is doing almost the same thing. So far I replaced the hoses, caps, catalytic converter, pre cat, and thermostat. When I get paied next friday I plan on getting an aluminum raidator and if that dosn't help than a new water pump.
Good Luck
Good Luck
Senior Member
Joined: Mar 2001
Posts: 501
Likes: 1
From: Lawrenceville,Georgia,U.S.
Hey, good picture of the RX7! Also of your problem, possibly. I noticed that you do not have an air pump on your car. Also, your alternator only has a single belt. Known problem, when you pull off the air pump, the remaining belt on the water pump slips! If you look at it, the alternator belt doesn't contact much of the pulley. My suggestion, get a dual pulley for the alternator, so that you have 2 belts driving the water pump. That should fix you right up!
Irv, Keith's dad
Irv, Keith's dad
Senior Member
Joined: Jul 2001
Posts: 585
Likes: 0
From: Columbus, Ohio
...
The car stays very cool when just sitting still....then when you get on the highway at higher RPM's it seems to run hotter...which should be complete opposite. I DID notice the car ran cooler...but i still got the antifreeze into the overflow. Car was still running halfway up the scale...and just a bit over. Yesterday it was 3/4 the way up the temp guage.
-Brian
Senior Member
Joined: Apr 2001
Posts: 364
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From: Omaha,Nebraska,USA
Those dual pulleys cost friggin 45ish dollars... Good lord!
well, at least at mazdatrix.. I will look at others. I am running a single belt on my waterpump/alternator right now...
I am running around 1/4 - 1/2 temp usually doesn't go higher than half.. even at autocross... But I currently have a pretty good sized coolant leak from my water pump housing to the engine.. I have the new gasket with me, and plan on replacing it this tuesday when I don't have work..
my overflow is full all time, and I have to fill my coolant up every morning, and during the day if I drive a lot that day.. I hate coolant and I think I should just get rid of it and turn my engine bay into a refrigerated engine bay... yea.... I could store my six packs of... er Soda in there, and candy bars..
well, at least at mazdatrix.. I will look at others. I am running a single belt on my waterpump/alternator right now...
I am running around 1/4 - 1/2 temp usually doesn't go higher than half.. even at autocross... But I currently have a pretty good sized coolant leak from my water pump housing to the engine.. I have the new gasket with me, and plan on replacing it this tuesday when I don't have work..
my overflow is full all time, and I have to fill my coolant up every morning, and during the day if I drive a lot that day.. I hate coolant and I think I should just get rid of it and turn my engine bay into a refrigerated engine bay... yea.... I could store my six packs of... er Soda in there, and candy bars..
Zoom Zoom Boooom
Joined: Mar 2001
Posts: 987
Likes: 0
From: Freakmont, CA
First off all I have to say is sorry if this is going to be your problem. It happened to me on my first RX-7 on a trip the same thing happened to me. I came to find out I blew a seal and exhaust was being pushed into my cooling system. The easy way to find out is to take your car down to any Billy-Jo Bob tech that has a smog machine. Have them put the machine on a scan mode to sniff for exhaust gas. Open up your reserve and let him take a big wiff or better yet CARFULLY take off you radiator cap and take a wiff of that. If he smells the exhaust time to rip the motor out. If not then good it is another problem and you are motor re-build free. Hope I helped late
Thread Starter
Junior Member
Joined: Jul 2001
Posts: 20
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From: Mid-Ohio
OK...here is where im at now.
I put a dual alt. pulley on and ran 2 belts in parallel. I also shortened both belts by 1 inch which in turn changed the angle the belt takes around the water pump allowing for more gripping. I have gone out and tested and here are my results.
The alternator is pushing out almost 14.8 volts....this is good because it was only registering 13.5V and the battery wasnt getting a good charge.
The temperature gauge, at the highest, only went 1/2 way and it never went further. Most of the time it stayed below 1/2. Mind you this is really reaming the snot out of the car. I even raced another car (and won) and the temp stayed in my safty zone. I believe that for the most part the problem is solved.
After further inspection i realize that the fins on the radiator still have some gunk in it...next step is to fully clean the radiator out. I believe this will also play a big part in the problem.
Next thing im going to do is remove the condensor. I dont run A/C, but never got around to removing it. Too much of a pain. But it will be done.
BTW...the car i raced was a Grandprix GTP. They sure are quick, but i had him by 2 1/2 car lengths from 10mph to 85mph and i was still pulling on him. I was very pleased with my car last night
Thank you ALL for your time and comments on this matter!
Ryan "RX-7" Radio
I put a dual alt. pulley on and ran 2 belts in parallel. I also shortened both belts by 1 inch which in turn changed the angle the belt takes around the water pump allowing for more gripping. I have gone out and tested and here are my results.
The alternator is pushing out almost 14.8 volts....this is good because it was only registering 13.5V and the battery wasnt getting a good charge.
The temperature gauge, at the highest, only went 1/2 way and it never went further. Most of the time it stayed below 1/2. Mind you this is really reaming the snot out of the car. I even raced another car (and won) and the temp stayed in my safty zone. I believe that for the most part the problem is solved.
After further inspection i realize that the fins on the radiator still have some gunk in it...next step is to fully clean the radiator out. I believe this will also play a big part in the problem.
Next thing im going to do is remove the condensor. I dont run A/C, but never got around to removing it. Too much of a pain. But it will be done.
BTW...the car i raced was a Grandprix GTP. They sure are quick, but i had him by 2 1/2 car lengths from 10mph to 85mph and i was still pulling on him. I was very pleased with my car last night
Thank you ALL for your time and comments on this matter!
Ryan "RX-7" Radio
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