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I have a right hand drive, Japanese 1990 rx7 savanna. It is cold now and I didn't notice this until recently.
The radiator light will occasionally come on for a bit and turn off. Usually it stays off after that but sometimes it will come back on and turn off again. My stock temp gauge stays at the middle position always and never goes higher than that.
I checked the coolant tank on the passenger side and it is completely empty, save for a tiny, tiny bit in the lowest point. It says on there "if coolant is below the low level line, add 50/50 coolant and water.". Would i need to follow this exactly, because i see coolants that say to not mix with water. Is this referring to the tank or the radiator itself? Also not sure where the radiator coolant fill is.
The car seems to idle erratically around 600-1000 rpm. Could low coolant be the cause of bad performance?
That's all I can think of. If you have questions to help me, please ask and I'll answer with what I know.
Typically, "coolant" refers to a 50/50 mix of antifreeze and water (preferably, distilled).
Used to be you did the mixing yourself but many brands today are already water/antifreeze mixes and don't need further dilution.
I find the stock coolant sensor to be flaky and only use mine as a plug for the rad hole.
Much more useful is watching the reservoir- coolant should flow in after shutdown and get sucked out later...the tank should not run dry.
Check your rad cap and the hose connecting the tank and the rad.
Thanks for the reply. I did pull off the radiator cap earlier today and it seemed to have pretty good suction. The rubber was all intact and no cracks.
So by buying green coolant that is already 50/50, I should be ok? I have the haynes manual, so I'm gonna follow its guide.
I'll try to remember to see if anything flows in the reservoir tank after I shut down. How long usually does it take until it flows in there? But you say it shouldn't run dry and since it was empty, I'm guessing I'm really low on coolant. I never see any spots under my vehicle, so I don't know if I have a leak or if the mechanic did a shoddy top off.
Originally Posted by clokker
Typically, "coolant" refers to a 50/50 mix of antifreeze and water (preferably, distilled).
Used to be you did the mixing yourself but many brands today are already water/antifreeze mixes and don't need further dilution.
I find the stock coolant sensor to be flaky and only use mine as a plug for the rad hole.
Much more useful is watching the reservoir- coolant should flow in after shutdown and get sucked out later...the tank should not run dry.
Check your rad cap and the hose connecting the tank and the rad.
How long it takes depends...
The process you see is this:
After shutdown, with the pump no longer circulating coolant and no airflow, the coolant will heat up as it absorbs residual engine heat. Hot water expands and may (or may not) surpass the 13psi pressure limit of the rad cap. If it does flow out, pressure is relieved and the temp will fall. As the system cools, the system, now under vacuum, will suck the coolant back from the reservoir into the rad.
Just fill your radiator and reservoir and see what happens over the next few days.
Ok, Nd when I fill the radiator, I fill it while the engine is cold...I know that. But how far do I fill it? Up until about where the cap screws on? Also using same mixture as reservoir?
Originally Posted by clokker
How long it takes depends...
The process you see is this:
After shutdown, with the pump no longer circulating coolant and no airflow, the coolant will heat up as it absorbs residual engine heat. Hot water expands and may (or may not) surpass the 13psi pressure limit of the rad cap. If it does flow out, pressure is relieved and the temp will fall. As the system cools, the system, now under vacuum, will suck the coolant back from the reservoir into the rad.
Just fill your radiator and reservoir and see what happens over the next few days.
Alright. Filled radiator and reservoir today. Will observe over the next few days to see if anything is different. The book says to fill the rad and reservoir while cold, leave the rad cap off, start the engine and put heater on high and observe if the fluid drops when the engine starts to get hot, if it does top off the fluid. I forgot to do this step, so I may do it tomorrow.
No, it's not the same with the cap on, then it's a closed system and the air has nowhere to escape! You want that cap off so when the air pockets surface, they escape to atmosphere.
There are several tricks people use, if it's your first time some that may help you include:
- raising the front end of the car up to help with spillage/pocket evacuation
- using a tall, tight fitting funnel to keep coolant from spilling when the air pockets escape
- slowly squeezing the upper radiator hose to help trapped air escape
At a certain point, you're correct, there will be no more air and coolant will just start making a mess everywhere if you're not quick with the cap . Just pay attention and you should be okay.
Also for reference, any "how to" you find via Google for a coolant flush will explain everything you need to know, probably with pictures.
Well, I did as instructed, I let it run for about 20 minutes after it got to operating temp and no air bubbles came at all, all that happened was the coolant in the rad fill tube slowly overflowed and was only drilling out. I tried lightly squeezing the tube leading to the engine and it just would make it overflow more, like squeezing a plastic bottle full of liquid.
Either, there really wasn't any air bubbles, I didn't wait long enough, or something else is wrong. But it doesn't seem to run badly and as the photo shows, that is the temp that it stays at once it's at OT.
Fact is, the S5 temp gauge is more an indicator than descriptor of water temp.
The needle will rise to the putative "NORMAL" position at about 160° and stays there till about 230°.
If it rises above center, just call a tow truck because the engine is dead.
Not a huge issue for a NA but pretty critical in a turbo...you should look into a real aftermarket temp gauge.
I've got some installed, but they suddenly died a while back. Then when I was cleaning off the inside of the windshield and bumped the spot near the clock and indicator panel and they switched back on again. Driving for about 5 minutes and they shut off. All plugs are securely plugged into the box. But I have no idea, and being overseas in Japan, there aren't as many mod shops as you'd think so I'm not really able to go anywhere. The one I used to go to closed down because they didn't get enough business. I have a feeling that there is a wiring problem or maybe one of the wires is exposed.
I've got some installed, but they suddenly died a couple months ago. Then when I was cleaning off the inside of the windshield and bumped the spot near the clock and indicator panel, they switched back on again. Driving for about 5 minutes and they shut off. All plugs are securely plugged into the box. But I have no idea, and being overseas in Japan, there aren't as many mod shops as you'd think so I'm not really able to go anywhere. The one I used to go to closed down because they didn't get enough business. I have a feeling that there is a wiring problem or maybe one of the wires is exposed.
They worked just fine for about a year. I'm set to go back to the states in late 2017, but I don't wanna go off of a whim for that long.. Not sure what box is installed, but I can take a photo later
02-25-16, 07:05 PM
. Just pay attention and you should be okay. 
