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_ HalfDork
6/15/19 6:47 p.m.

Nearly stock (not built) 1.8 miata (1997). Ambient temps are 84°. I’m using my obd2 dongle to monitor temps. Casual driving is around 190°-200°. Hard driving and traffic will see 225°, and I’m sure it would go up from there. Brand new stock radiator, fresh fluid. Working water pump. Unknown thermostat (been in there since I bought it). All shrouds, radiator ducts, and a flat bottom (to the rear of the cross member) are intact. 

bentwrench
bentwrench SuperDork
6/15/19 6:50 p.m.

If it is not lifting the cap it is not overheating.

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_ HalfDork
6/15/19 7:30 p.m.

Yeah, no boil over at all, brand new cap. 

alfadriver
alfadriver MegaDork
6/15/19 8:05 p.m.

225 isn't that hot.  

But the only traffic it should get to that is where there's little airflow going over the radiator- slow stuff.

So it's not overheating, but it seems like there may be an issue.

_
_ HalfDork
6/15/19 10:15 p.m.

I’ve been suspecting a HG leak for some time, for right now I’m just sending this thing at AX. #dontcare. #bettertimesahead. #whouseshashtaganymore?

jfryjfry
jfryjfry Dork
6/15/19 10:30 p.m.

It might not be hot enough to damage anything but if it usually never does this then I’d think something happened

222
222 New Reader
6/16/19 7:53 a.m.

My mostly stock 96 1.8 Miata runs 195-199 when driving 60-70mph at about the same ambient temp.  I can hear the fan kick on at 206-207 if I am sitting still in traffic or idling in the driveway. Can you hear your fan kick on?

alfadriver
alfadriver MegaDork
6/16/19 8:15 a.m.
_ said:

I’ve been suspecting a HG leak for some time, for right now I’m just sending this thing at AX. #dontcare. #bettertimesahead. #whouseshashtaganymore?

As I've experience it- a HG leak pressurizes the cooling system, pushing coolant out.

But if it can survive the season, then it's a good off season project.

rslifkin
rslifkin UltraDork
6/16/19 9:56 a.m.

IMO, overheating is either when you start to vent the cap majorly and it starts to boil.  Or when it reaches temperatures where that engine design is known for having issues (like warping heads, etc.).  It's not a universal temperature, so one engine might be perfectly fine at 240, another might have the "oh E36 M3" point at 230. 

RevRico
RevRico PowerDork
6/16/19 10:28 a.m.

That sounds a Hell of a lot like my first NA out in California. Replaced radiator, all hoses, vacuum lines, and thermostat, never made the issue go a away.

At least on the NA I could manually kick on the AC fans when sitting in traffic or the drive thru, and that took care of the temperature needle rising.

I was actually going to make a thread asking wtf at one point, but since I don't own the car anymore, it seemed like wasted effort.

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