az_lynx

I'm new to the FD but when I got home I let it sit for a while and cool down and then turned it off and poped the hood so it could cool off in this damn AZ weather

When I poped the hood it sounded like the coolent in the radiator was boiling or stiring around quite a bit. Is this normal or do you think I might be low on coolant or another problem? (when it cools down more I'll pop the cap... what should I look for... if it's dry?)

TIA
Chris.

Tommy

Let your car run longer when you're cooling it down, before you shut it off. Might not be a bad idea to check your coolant level either.

Pressurized

Well, you could have a few different problems.

Normal coolant has a boiling point around 260+ degrees, which is easy for our cars to get too. One problem could be your thermostat, which is a common problem on our cars, they quit working and the engine gets a lot hotter than it should be.

However, I would start out with the simple stuff, which would be that you have air somewhere in your coolant lines. All you have to do is flush the system, get your owners manual out, it will explain how to do this.

Or may be a problem with your AST(air seperator tank)....but I doubt it.....

SilverR1

If you have the .9 bar AST cap you might want to try to get one that holds a little more pressure. I went with the 1.3 bar cap and have yet to hear my coolant boil.

az_lynx

Ok... some more info... I got in to work this morning and poped the hood again... It's not the rad thats boiling... it's the AST... I put my finger on the plastic box (yes I know.... it will be replaced but I just got this car yesterday and it's completly stock) and I could feel the coolant moving around in there.

Does this change anything? I do plan on flushing the system and refilling it (as w/ all the other fluids) but what should I use to refill it w/? bottle of water wetter and distiled?

Anyone have a site w/ info on how to flush? I don't have a Haynes or a shop manual YET...

SilverR1

Go to this site and download the shop manual. This is an invaluable tool in your long quest of upgrading and repairing your car. This will give you all the info you will need to do just about anything.

http://www.iluvmyrx7.com/Technical_I...ice_manual.htm

By the way I use Havoline antifreeze in a 50/50 mix with distilled water and 1 bottle of water wetter with no ill effects down here in southern Louisianna. Hope this helps. At your first oppurtunity upgrade that AST to an aluminum one or eliminate it altogether. This piece has been known to fail causing serious engine damage. RX-7 store sells the replacement for about $140 or you can go with the elimination kit from M2 for about $50. I went with the replacement just to be on the safe side.

maxpesce

Flush Your Coolant & replace w/ new 50/50 mix do NOT upgrade to a 1.3 bar cap without upgrading to an Alum AST ( or eliminating) Mazda changed to .9 Bar cap from orig 1.2 bar caps to reduce AST tank failures - It was part of the recall related to engine fires. so I repeat it is a BAD idea to use cap rated higher than .9 bar (12psi) unless you upgrade to a stronger AST or AST Elimination kit.

az_lynx

If I get the replacment (which I am btw...) should I invest in the 1.3 bar cap or does it come w/ it? Btw.. thanks for all the info guys!

pweizman

I am new to the FD also, but my car does the same thing.

I have replaced the plastic AST with the Pettit racing one..and it still does it. I also let the car cool at least 4-5 minutes before shuting it off, and it still does it.....

So, I am not sure if it is normal, or if it just the coolant draining back into the overflow, or moving around....

I know I need to flush and fill the system....

Patrick

Toadman

Mine does it and always has, even after a flush/fill/burp coolant.
It sounds like a coffee pot, and you can see the AST hose actually move with each pulse.

martini

I don't suppose you get freezing weather down there in AZ very often...but in Ohio, you HAVE to put the antifreeze and water mixture in for the winter. Not just Distilled and Water Wetter, like you should do in the summer. So if you don't have antifreeze, or don't KNOW that you have antifreeze, go get everything flushed out and replaced.

BrianK

I'd recommend AGAINST putting in a 50/50 mix of coolant/water. In AZ, it doesn't get hot enough to warrant that much coolant, and a lot of coolant is harder on your water pump, AND doesn't cool as well as plain old water (strangely enough). Especially seeing as how you're in AZ where it doesn't get much colder than 80, go with 35% coolant, 65% water and you'll be perfectly safe. (The mazda service manual has a mixing chart based on your temperature range if you'd like to get more specific). The only disadvantage with running 100% water is that it boils at a lower temperature and boiling water isn't very effecient at cooling (because of the bubbles).

Also, water wetter is pretty much just a lot of silicate, so only use it if you're using a silcate coolant (the green stuff). If you go with a silcate free coolant (the orange stuff), the water wetter may, in fact, hurt your cooling performance (tho, that last part is just speculation on my part).

gefins

I have the same thing but putting the higher pressure cap helped. I am running about a 30/70 anti freeze ratio with water wetter and made it through the summer o.k. I did find a little trick that seems to work pretty well. After I come home I shut off the car but leave the key on and let the fan run a few minutes. Then when I turn the key off if the fan goes off I leave it alone, if the fan doesn't turn off with the key off I re-start the car and let the fan cycle. Then I shut off the car and have almost "0" coolant noise.
Not to nag you about the AST. I rebuilt my engine at about 87,000 miles and didn't have enough left over for the AST about 2,000 miles later my AST let go, luckily I heard a hiss after I shut the car down and hadn't lost any coolant. Could have been a disaster.

'93 Red Touring

az_lynx

Once again guys... thanks for the info.... A new rad is on my list to get w/ all my mods (buying over the next week) AND the replacment AST

Either the Koyo or the Fluidyne which would work best if I was keeping stock IC for now and getting a large FMIC later?

I heard that Koyo has probs mounting w/ the stock IC but ok w/ a FMIC.... is it THAT much better then the Fluidyne that I should think about trying to get the Koyo and working it in somehow?

BrianK

I have the Fluidyne & no complaints (I have the stock IC). I got mine at www.absoluteradiator.com . I don't think there's much difference between the two other than the Koyo is more expensive. Someone posted in the 3rd gen tech support area about rad fitment with an FMIC - maybe you should search for it.

You might also want to look at getting an aluminum AST - I got mine (the Pettit AST) used for $50 on www.thepartstrader.com

and what's with the "Glendale, AZ" crap.... everyone knows Glendale is in CA.