Overheating Problem #2

[POS Racing]

Should both fans be blowing at the same time, or is one just for the AC?

Yes both fans should be running are they??

[POS Racing]

Hey did you put new coolant in it Jiggerachi?? I don't see any mention of flushing the system??

[juxt3r]

The saga continues...

Ok, I changed the thermostat & upper/lower hoses 2 weeks ago & the problem is still there...& untill today in the heat has been far less severe. Any more ideas??

I've been digging through a few threads on the board for similar situations over the past couple of days. A common suggestion is to replace the radiator cap to keep the fluid pressure/boiling point where it should be. (mine should be arriving in the next couple of days)
Another idea I noted, though I only saw it once, was to remove the weather stripping at the hood/cowl area. I guess the reasoning behind this is pretty obvious.

A friend at work said he had a similar problem that "turned out to be air in the coolant lines", any idea if this could be the problem? If so is there a trick to flushing the air bubbles out, other than flushing the system a few times?

I'm able to burp some air from the cooling system now & again by leaving the radiator cap off as the engine runs from cold, and occasionally squeezing the upper hose. Did this on Saturday, as the engine temp has been going a bit higher than I like of late. Don't leave the cap off for too long, though, as you'll just end up with a coolant spill on the ground.

I need to get this fixed soon, preforably tonight or tomorrow, or I wont be able to drive the car to work. I had to sit through 121 traffic on the way home in this 100+ degree weather with the freaking heater on , so if anyone has any ideas id really appreciate them...

My first suggestion here would be to remove the friggin' stop lights from 121. You've already mentioned the temp sensor and thermostat as possible culprits.
I'm wondering why my '92 gets up to 3/4 on the temp gauge while cruising at 65 on the GB tollway, yet sits nicely just below 1/2 in stop/go, city street traffic. Strikes me as backwards, but whatever. If the replacement rad cap doesn't help, my next steps will be the sensor on the water neck and praying that the water pump that went in a few, short months ago isn't playing with my heart (read as wallet).

[POS Racing]

Another idea I noted, though I only saw it once, was to remove the weather stripping at the hood/cowl area. I guess the reasoning behind this is pretty obvious.

That foam direct the cold air in from the front of the car thought the radiator, if you buy a new OEM radiator (like I did for my '92) all that foam was on the top and bottom. My thinking is why would Mazda waste the money if it wasn't required. The OEM plastic underbody tray also helped cool down my '92 at speed. YMMV.

Cap sounds like a great starting place on your car!

Hey Jiggerachi have you replaced the cap?? I also wonder if you don't have a partially plugged radiator, it's not like the one in it now is new. Some history.

[Titus]

Yes both fans should be running are they??

Actually, the fans are independent of each other. One only comes on when the AC is on, and the other only comes on when the temp gets up. NAs without AC actually come with only one fan. There is a procedure to re-wire them in parallel here.

[POS Racing]

Actually, the fans are independent of each other. One only comes on when the AC is on, and the other only comes on when the temp gets up. NAs without AC actually come with only one fan. There is a procedure to re-wire them in parallel here.

On the early NA's it fired both fans when the A/C was switched on.

Plus if it's getting hot and the A/C is on Jiggerachi should see both fans turning.

[Titus]

On the early NA's it fired both fans when the A/C was switched on.

Plus if it's getting hot and the A/C is on Jiggerachi should see both fans turning.

Being that he had the heater on to keep temps down, I sure hope he had the AC off.


P.S. I vote for a plugged radiator.

[juxt3r]

That foam direct the cold air in from the front of the car thought the radiator, if you buy a new OEM radiator (like I did for my '92) all that foam was on the top and bottom.

Guess I should clarify. The item in question wasn't the foam around the rad but rather the rubber strip near the base of the windshield and under the hood. Top of the firewall, even.

Definitely do NOT remove the foamy goodness from around the radiator! It is our friend. Should the stuff happen to rot out, as it did on my OTM, there's a similar substance to be found at any decent hardware store that has window & door frames and related items. It's got adhesive backing, too! Good stuff.

[POS Racing]

Being that he had the heater on to keep temps down, I sure hope he had the AC off.

P.S. I vote for a plugged radiator.

Yea but he should see them both actually run to help prove the fans actually work. Does the jumper trick work on the newer NA's?? I know you could force one of the fans on with a jumper on my '92.

I agree with the plugged radiator theory!

[Jiggerachi]

I replaced the cap a little over a year ago...can they go bad that fast?? I would be happy if thats all it was. Is there a way to tell if its bad, or just replace it?

Yes I replaced the coolant with brand new Prestone/distilled water, 50/50 ish mix with the hoses & thermostat.

Plugged radiator...hmmm...anyone know a good(CB) radiator mechanic? Or can inspect and/or fix this myself??

[channelmaniac]

No easy way to fix the stock radiator... Can't get the stock endcaps off to run rods through it like in the old days. Just replace it with an aftermarket all-metal one. If you get a multi-core stock radiator or the radiator that fits the automatic transmission model Miata it will help keep the car cooler.

RJ

[POS Racing]

No easy way to fix the stock radiator... Can't get the stock endcaps off to run rods through it like in the old days. Just replace it with an aftermarket all-metal one. If you get a multi-core stock radiator or the radiator that fits the automatic transmission model Miata it will help keep the car cooler.

RJ

That's not exactly true, most radiator shops can handle the new style radiators. You may want to call around.

[black roadster]

Here is where I got my all metal radiator and it has worked great!

Their price looks to be about $130-$150 bones you might be able to find a better price though.

[Majik]

I got an OEM from Mazdaspeed for around 150 last year. That is after I put an aftermarket all metal that started leaking around the bottom mounts after just a few months.

[Jiggerachi]

Man, $150 is definately not what I want to hear right now. Im going to see how much it would cost to get this one repaired first.

I remembered I had a spare cap...not sure if it was the one I bought a year ago, or the one that came with TurboDuane's radiator. Either way if the cap is part of the problem it should act differently, better or worse. I threw it on, we'll see if it does anything different.

[POS Racing]

I got an OEM from Mazdaspeed for around 150 last year. That is after I put an aftermarket all metal that started leaking around the bottom mounts after just a few months.

Yea I was just going to sing the praises of the OEM radiator. Mine came with a new cap and all the cool foam stuff! See!

[POS Racing]

Jiggerachi can you see in the radiator does it look like it has "stuff" in it?

Did you ever figure out if your fans work correctly??

And finally did you get my e-mail?

[Sharpie]

What's the ratio of coolant to water. Miatas don't like a 50/50 mix, needs to have a more water. I usually do 60% water 40% antifreeze or 70/30. I've known of 3 miatas that got hot due to this and it's fixed them everytime. Good luck.

Drain, some coolant, add distilled water and let me know what happens........

[cruz]

Man, $150 is definately not what I want to hear right now. Im going to see how much it would cost to get this one repaired first.

I remembered I had a spare cap...not sure if it was the one I bought a year ago, or the one that came with TurboDuane's radiator. Either way if the cap is part of the problem it should act differently, better or worse. I threw it on, we'll see if it does anything different.

I know it's fun to work on your own car, but why not let a Mazda Mechanic diagnose the problem for you? Then if the fix is reasonable, let them fix it. If not, you know where to start, rather than changing every piece of the cooling system one part at a time. They have the advantage of being able to try parts to see if they fix the problem.

An overheating engine isn't exactly a low-risk problem. I blew a BMW 1900 engine that way in the 1980's.

[SilverToy]

I was glad to see this post--My 99 overheats every summer in traffic, I overheated yesterday in the 98degree heat. Today I got a new flush and fill (50/50) and added Waterwet, never tried it, but I'll see what happens and re post.