All right. My engine is running about a quarter of the guage hotter than it did about a week ago. Not overheating becaus eI'm taking extra car to make sure it doesn't. It started a little while after I filled up last. I filled up with 93 octane as opposed to my usual 87 octane. I have also got an oil change and added coolant to the radiator and made sure the fan was working correctly. Could the excess heat be from the fuel? I just don't get it.

 

Anybody?

 

I know the higher the octain the hoter the fuel burns, but I dont think it would cause that much of a temp change. I would look in to the therastat and maybe even just replace it for the hell of it. It's a cheap part and easy to put on. If it solves the prob sweet, if not, it's just one part you wont have to replace again for a good while.

 

How long since your last coolant system flush. Mineral and rust deposits in the radiator can inhibit the cooling capacity of the radiator gradually causing the engine to run hotter and hotter. Also check to make sure that you have not sucked something up off the road like a piece of paper or plastic bag that may be restricting airflow through the radiator.

 

The last collant flush was when I had to get a new rad around a year ago. Maybe a little less. I also may have hit a bird. I haven't checked yet. Do that tomorrow.

 

Your stock gauge is not very accurate. Unless you measure the temp with another gauge, you'll never know for sure. Chances are it's just the gauge. On one of my 1st gens, my gauge would always stay almost to the halfway mark, switched the cluster and it was 1/4 of the way. Your thermostat could be acting up, cheap fix.

 

I would run the gas out and fill up with low octane again. If that solves the problem then we've all learned something. Good luck!

 

you could get a cheap electric sunpro gauge at autozone. costs $30 for it and it comes with the fitting to put it in the back of the waterpump.

I have one. it works good.

 

I don't think it's the guage. My theory is the higher octane fuel. I usually run only a quarter to a third of the guage. Seems real cool for what I put it through. I might get a new thermostat for preventative maintenance. I really should get an electric fan too, but that's so much money. You would think that a fan like the box fan I have in my room wouldn't cost that much but I guess with the mounting hardware and connections it adds up. Maybe I should ghetto rig the giant box fan from my room onto my rad. That would be funny. Prolly wouldn't fit though. What's the cheapest and easiest to install electric fan?

 

Get a fiero/taurus fan from the yard. $10. mount it with zip-ties. mines been like that for months.

 

There would be NO DIFFERENCE in the temperature that the gas burns between high and regular octane. None that you could detect anyway. That's not it.

 

First of all, why in hell did you put 93 octane in your car??? Newsflash, the higher the octane, the worse your engine will run. Man get that 93 octane outta there and put in 87.

 

I didn't know about the high octane = bad thing.

 

It's not bad, it's just pointless.

 

You have air in your cooling system from your last "flush".

 

Yes, I used to run high, but on a N/A it really is not needed. And, it never made a difference in my heat..

 

It's more than pointless. Or less than pointless, depending how you look at it.

http://members.ij.net/mrmazda/cfaqtext.html#ROCTANE

 

Meaning it doesn't make any difference, which is what I've said over and over in this forum.

 

flush the rad out ... it was -40 here last winter and mine was about to overheat 20 minutes after I started it ... I flushed it out at this shop where I used to work using the flushing machine .. works 100% !

Eric.

 

It does make a difference. Read the info in the link provided.

 

was at a track day in the not to distant past... and there was a lady there with a 87 GXL with an auto tranny... she was running 93 octane and running like 18.9 and 19.0's in the 1/4... i told her she shouldn't be running 93 at all, she should be running 87... she'd probly pull a faster 1/4 on 87... she tells me her car runs like crap on 87.... no matter what i told her i couldn't convince her she should be running 87... hell it was probly a timing issue or something like that that made it run bad on 87, i dunno... either way she was a rock... i was running faster times in a crappy 1990 nissan sentra than she was... sad

 

Wrong. But that's not the point of this thread and I don't want to side track it. Octane has been heavily discussed here:

https://www.rx7club.com/showthread.p...ghlight=octane

Suffice it to say that if the engine is running hotter, it's got nothing to do with the octane of your fuel.

 

From what I understand, rotaries require the fast burning low octane gas for quick combustion. Higher octane burns more slowly, so maybe its burning longer than it should and passing combustion heat to more parts of the engine than it should. Hell, I don't know. I would run that gas out and try the cheap stuff again before I started changing anything else around. Just my 2cents! Good luck!

 

he has air in the system that needs to be burped out.

 

Nope.