Frustrated -- Boiling Coolant
 

So, ever since going Greddy I have turned my ultra reliable Miata into a problem fest. Every time I add something new, it seems like I add ten more issues. In any event, after installing my Tony DP and my cat replacement pipe (stop gap until I can have a new high flow cat made), which, BTW, did not fit right (now my exhaust is moved way to the right), and driving home from my friend's shop, I heard what can only be described as a gurgling sound. I popped the hood and noticed that the fluid (I call it fluid, b/c I am quite sure that coolant should not be brown) in my coolant resevoir appeared to be boiling. WTF? I am no mechanic (in fact I think my mechanical skills seem to decrease as I get older), but I cannot imagine that boiling coolant is a good thing. I am ready to sell the Greddy and do a 1.8 swap.


Any ideas about the boiling coolant? Also, anyone want to buy a Greddy kit?

1) do you have AC if not im pretty sure you need a bigger radiator to cool

2) flush it prolly all gunked up

3) I unno

The bubbling in reservoir is caused by pushing air out of the radiator. So the question is how air got in the radiator? Suggest a flush and changing coolant. While at it, spring $6 for a new radiator cap, burp the system and see if it is leaking coolant.

My first major suggestion would be to change out that radiator cap. If the car is overheating prematurely - basically at times that it shouldn't be, there are several things that can be wrong, but the simplest is that the old radiator cap just can't hold pressure any more. Lower pressure means lower boiling temp - 10* for every 1 psi iirc.
Get a new one from Kragen/NAPA/Autozone. I highly suggest one of the ones that has one of those butthole plugs. the big ones. with the latch that clamps down after you tighten it.
If that doesn't dothe trick the only thing left to assume is that your cooling system isnt up to the job of cooling your engine. So, that means either your H20 pump is bad, or your radiator needs to be upgraded. But i would lean towards the radiator cap.

Also, the brown water is obvisouly bad. Flush it and fill it with 50% h2o / 50% antifreeze when you change the rdaiator cap.

-Ryan

Unless he lives in Alaska, I'd fill with 70:30 or 80:20 water:coolant.

Lack of maintenance........:(

I have a few questions. are your fans working ? was the water brown like rust or like chocolate? if it rust color it needs a flush & if its chocolate color its might be oil in the water which is a bigger problem.

Read this.

https://www.miataturbo.net/forums/showthread.php?t=3723

Thanks! I will follow the steps outlined above. I haven't checked the color of the fluid in the resevoir yet. I plan on doing that shortly. Ever since we had a kid, I have not been able to spend any time working on the Miata.

Took a couple of flushes for me to eliminate the milky coolant. Years of poor habits on the car meant that scale and crap had built up. This added crap also diminishes the efficiency of the cooling system, and helps cause the boilover. The higher heat created by running a turbo seems to disolve much of the accumulated junk, so flushing is fairly effective.
A higher pressure rad cap didn't do the trick, nor a new water pump. One of the few things to help reduce the coolant temps was to seal around the radiator, top and sides. This helped to force air throug the rad, which gets reduced air flow thanks to the front placement of the intercooler. The bigger the intercooler, the more restriction in air flow to the radiator. Hopefully you still have the plastic undertray installed, this will help create a low-pressure area behind the rad, helping air flow through the rad.
A good, large capacity, dual core rad will go a long way to helping remove heat from the motor and may just be the ticket.