I have a 93 rx7, just recently replaced the rad and all the hoses, changed the themostat as well engine runs fine for about ten minutes then coolant starts pouring out of the overflow tank.

 

check when car is cold ,start the car and check the overflow tank for any bubbleling if there is sounds like a water seal.how about your water pump did you replace that.

 

No, I was thinking it might be the water pump.

 

-Start the car with the radiator cap removed.
-Have someone watch the temperature gauge.
-Look at the green coolant in the hole beneath the radiator cap
-Can you see the coolant? If no, add more. If yes, watch the coolant.
-When the car begins to warm up the thermostat will slowly open and you will see the coolant begin to flow. It will surge like the waves in the ocean.
-If your car overheats before the coolant starts surging then your thermostat is stuck shut. Replace it.
-If the coolant shoots out of the cap in pulses then you have a bad coolant seal. Rebuild your engine.
-If your car heats up to normal operating temp and you still do not see the coolant surging like the ocean waves then your water pump is bad. Replace it.

**Do these water pumps have weep holes that slowly leak fluid when the pump goes bad?



Ryan

 

my car does the same, it starts to get really close to the "H" symbol but wont cool down until i stop or slow down, usually happens on the freeway and im only going about 70-80 mph.

 

the first one sounds like a blown coolant seal. The later one sounds like a bad water pump but I would check the coolant with the cap off while running to make sure you dont see any bubbles.

 

I love you. Thank you so much.

 

i just did the test and with mine i started the car with radiator cap off, i see the coolant as i have had this car for a while and its always full , and as the car warms up the coolant just slowly rises up the radiator hole where the cap goes and will just pour out slowly unless i turn off the car, so does that mean my thermostat needs to be replaced?

Thanks


oh and also my radiator cap is also done for because the underside of the cap is always open and wont close dont know why though.

 

ive got an overflow hose that comes out of the top of my thermostat housing and leads down towards the bottom of the front bumper to nothing. i notice it leaks slowly out of here sometimes...... i get a low coolant buzz once in a while to and then it goes away after a few secs intermittenly

 

ive got an overflow hose that comes out of the top of my thermostat housing and leads down towards the bottom of the front bumper to nothing. i notice it leaks slowly out of here sometimes...... i get a low coolant buzz once in a while to and then it goes away after a few secs intermittenly. whats that about?

 

If the coolant rises slowly then the thermostat is fine. Just to clarify, when the cap is open the plunger is retracted and the spring is compressed. This exposes the overflow hole and that is how coolant overflows into the overflow container. If your cap is always open then you should replace it. I think you want a 16psi cap. If you're really paranoid about your thermostat you could try a 180F one...

 

You don't have an overflow tank for your coolant system? Your coolant overflows onto the street? Thats not right. You need an overflow tank. Go get one, install it, fill it to the "Full" line and top off the coolant in your radiator. I bet the buzzer will go away.

 

I thought it was a 13 psi cap that was recommended...At least I know that's what mine is. Also, +1 for the 180 degree T-stat...I just replaced mine a little while ago and it's running about 5-7 degrees colder.

Another question worth asking...Are you guys running AST's? I eliminated mine and used a pressure relief cap from an FC which now runs to my overflow reservoir. I had an aluminum Pettit AST and the cap still leaked like a siv.

As for the poster that said he has a coolant line running to nothing, that's just absurdly retarded. I know you didn't do that, but whoever did should be shot.

In what world does it make sense for a coolant line to be running to nothing dumping coolant all over the ground???

 

Is the FD overflow tank large enough to accommodate coolant expansion if you fill it all the way to the "full" line when cold? I was always taught to fill the overflow tank halfway between empty and full when the motor's cold, as to allow room for coolant expansion. Then, once the motor heats up it should read full, and when it cools down it should draw coolant back into the motor from the overflow. Please do correct me if I'm wrong.

 

Thanks i will change the cap and the thermostat, i was just wondering if my thermostat was really closed shut because like i said the coolant slowly rises but never stops it just starts pouring out of the radiator cap hole, even when the engine is warm.

and as for the radiator cap, which one is most recommended, the 13psi or 16psi?

 

lol i didnt explain well.... of course i have an oveflow tank. the overflow hose comes out of the top of my radiator to the tank. But i ALSO have a house running from the side of my thermostat housing right below my filler cap.......thats what is leaking is this stock? wheres it go?

 

.9 bar for the AST cap the coolant neck cap is not pressurized. change you're coolant line from your AST neck to the overflow tank sometimes this can get pinched. the best way to know if it is you're coolant seals are gone is to remove the coolant neck cap and turn the car on check to see if the coolant is bubbling search "champagne test". the other way to check is to smell the exhaust and there's a profound smell that tends to stick on your clothing that's coolant burning. or you can go to most local shops and get them to but a sniffer in your exhaust to see if it is coolant that's burning.personally i wouldn't recommend driving the car around catching a blown coolant seal early is a good thing or you can do more damage to you're engine. also don't trust the temperature gauge in you're cluster by the time this tells you're your car is overheating you're engine will pretty much be toast. it's basically the equivalent of a blown head gasket on piston engines. After awhile you're car will have difficulty starting it'll take a few cranks to get it going because coolant is pretty much just sitting in your engine. Hopefully it's not this but in rare cases it could be something small i hope it is for your sake. if not start saving your pennies it could be rebuild time don't always look at that as a horrible thing at least this time around you can take care of it properly and do the necessary mods/monitoring so this doesn't happen again good luck! get a after market water temperature gauge if you don't already have one.

it looks like you live in Toronto if you want i can help you out i actually went through this problem before if you need help just PM me i'm always here to lend a helping hand to the rotary community and if you do need a rebuild i can recommend you to a great shop.

 

stupid question, which cap is considered to be the "radiator cap", the one on the AST or the one on the thermostat housing?

 

i think the AST one is the one you want to use, because on my car, which is an S5, only has 1 cap and doesnt have the thermostat housing cap.

and since were talking about radiator caps, which one is most recommended, the 13psi or 16psi? i need a new one and want to know whats best recommended.

 

If you're talking about an FD, you're going to want to remove the cap from the filler neck/T-stat housing, not the AST.