If the restriction is in the radiator, you could easily have the flush simply bypassing the clog and not actually getting flow through the clog, thus a "clean" flush without solving anything.

Flushing lines is easy, if you remove them and use a hose

 

Thanks for all the info. I am leaning towards it being a radiator issue then. I assume this is the stock radiator in the car, it looks farly old and doesnt have any branded names on it so it looks like its just an OEM one. I took a second look and did see a few small bent fins but nothing major.

 

This pic is while moving right? Stock intake? The coolant temps are slightly high but nothing crazy. The intake temps are very high unless this pic was taken after sitting still in traffic for a bit.

 

It was after parking in the underground parking lot, yeah sitting for maybe 1 minute straight. It eventually got to 160 degrees but it was at 143 when I watched it as I drove into work towards the end of my 8 mile drive in.

I have been trying to abide by what i have sene on here by letting the car warm up at least 5 minutes before driving it and then sitting for a few minutes before turning it off. Otherwise I typically will do a rev to 7K and shut it off from there or rev to 3K and hold it for 10 seconds then shut off.

 

Hmm, well them the IAT's are normal but sitting at 45.5% load at idle is not. 1.02 is a little lean as well, but you would need to average that over a 30-60 period to get an accurate picture.

 

yeah I sometimes wonder about the accuracy of the scangauge since I have see crazy load % even at idle or when normally driving and it will flip/flop around a lot.

I have another picture I just looked at with the IAT at 141 at a stopped position after going a few miles in stop and go traffic. So I bet this current 150 reading was due to sitting for a minute straight.

granted this is probably not the corerct thread for this, but are my starting/stopping procedures correct from the experiences of others? Letting it warm up to temp before driving, or revving to 7K and shutting off or holding at 3K for 10 seconds before shut off. I had heard that helpd put oil in there to help with hard starts or no starts at all.

 

Is that the Scangauge or Ultragauge? Either way I bet it is accurate since it is OBD data. At idle, you should be in 25% range for load. Was your AC on by chance?

I see you have the AEM intake so that explains the high intake temps, more so if you removed the plastic tray under the intake.

 

Did you remove the stock airbox tray when you installed your AEM? That tray serves to block heat, and removing it will result in higher than normal IAT readings.

 

Oh sorry yeah I meant ultragauge not scangage. That little thing is pretty badass with all that it reads.

For the intake I do have the lower intake tray in there. I'll actualy say what I think is the cause of these high intake temps and is something that really sucks. I have the CAI but the prior owner was in a front end accident that bent the front support beam inwards so there is not enough room to put the last section of the CAI in that goes between the beam and the front frame area (the large S shape piece). The bumper is replaced by me but te beam isthe old one. So I only have it as a short ram with the filter inside of the engine bay but above the lower plastic tray.

I really wish there was a ay to get the filter outside of the engine bay but with the beam being bent there isn't an option for that. I also lef the stock VFAD thing in there as well with the intake tubing that runs along the top of the beam and the connetor for the flutter thing that opens. Rather than taking that entire unit of and out.

This is most liely the cause of my high IAT for sure. Since here is a lot of heatsoak in the engine bay and thats exactly where the filter is.

 

Well that explains some of it. Heat soak will happen with any intake if it is hot and you are at idle, I have seen bone stock RX-8's intake temps get to 150F sitting to wait to get into a car show in 90-100F weather. But it takes a lot longer, cars with the AEM get to those temps much quicker.

When I made my custom intake for the Greddy Turbo setup I played with and tested a few designs and saw huge differences in intake temps with different setups but finally figured out it had to to with the tray more than the pipe used, coatings, etc. But even with my setup it will get heat soaked if I sit at idle long enough.

 

It looks like I need to rip out that VFAD system and tubing and cap the connector at the throttle body and then figure out how to get that filter outside of the engine bay.

With that damn support beam being bent in just enough that I cannot fit the S shaped tube in there to get the filter to locate below the beam and in front of the radiator. Looks like I may need to UNFORTUNATELY buy one of those ebay accordion intake tubes that I can use to connect to the current tube and then run it out of the engine bay and squeeze it between the beam and the firewal piece so I can put the filter where it is supposed to be.

I have read IAT should be somewhere around 10 degrees over ambient temps. but if I was running 143 when the temps outside were 75 then something is wrong and it's got to be that filter in the engine bay

 

Yeah at cruise your IAT's should be within 10F of ambient. At idle it depends. Replacement crash bars are pretty cheap.

 

I looked into a replacement bar when I had the front end apart for a new bumper for a few weeks thinking I could get one and put it on there but couldn't find any cheap haha.

Again I am sorry for straying off topic on the thread!

 

Well crap man I straight up asked if you had any intake mods. That filter in the engine bay is a mod and is the reason for your high intake temps.

 

Sorry man I replied that I had an AEM on it and its in my signature as well. It unfortunately just isn't a cold air at this time until either I can replace that support beam or figure a way to get the S-curved piece to fit in there behind the bent beam.

I may see what sort of temps I can get out of the stock airbox back in there. Unfortunately there was oil in the ribs and on the filter when i got it which was the reasoning I went with this aftermarket intake. The oil was from an overfilling job.

 

IT's no big deal.

Pull the bar out and hammer it out. or go to a body shop and get them to use a port a power to pop it out a bit. They cost about 150 dollars on ebay.

 

That's the rx8 my friend. The rx8 runs very hot and there's pretty much nothing you can do about it. The worst thing is that when the engine temperature reaches 220°f if u turn it off you're gonna have to wait a few minutes to start otherwise you risk killing your starter and battery. I own one and dealt with it for the past 4 year. finally two months ago i found a solotion which is a fan kit that turn on the fans at high speed at 180°+ f and my 8 never reaches the 200°f. I got the idea from the rx8 forum and bought it from ebay.
If you're in the caribbean dealing with jam traffic every day it will definitely change your life

 

That's not an entirely true statement.
With a healthy engine and components, the 8 has no issues starting with the engine at 220*F operating temps.
Just want to clear that up so false information isn't spread...

 

And there's plenty that can be done to lower the temps. It's called basic maintenance. After 10 years most cars need some. Flush the radiator and replace hoses. Or replace the radiator. Make sure you have the right mix of coolant and the fans come on at the right temps. Make sure the fans are moving a lot of air. They fail over time. Make sure the splash guard is in place. If all else fails replace the radiator. In 110 deg heat I have no problem staying in 180-190 range.

 

I am boosted, and live in South Texas and I struggle to get my car above 210F driving hard in the middle of the summer. There is plenty you can do to address cooling. And for an NA street RX-8, the factory cooling system works great. If everything is working as it should be.

 

First off, the RX-8 has a pretty weak cooling system. It cannot keep the car below 220F in hot humid weather. At least, that's what I (and everyone I know of with a stock cooling system) know. I have a 2012 with 2000 miles on it and when stuck in traffic in 95F weather, the car hits 220F gradually. I have to turn off the AC to drop it back down.

Second, that cooling fan kit won't help him. At 220F, the fans are already on high speed (they go on high speed at 213.8F). If the temp keeps on climbing after 213.8F, turning on the fans before that isn't gonna help. He's either not moving enough air across the radiator, or the radiator itself is clogged.

Third, what the heck did I just read about the starter motor and the battery burning out!?!? That does not happen because you go over 220F.

If you're only overheating while idling, changing the thermostat will not help. If it's a stuck thermostat, you should overheat after 10 minutes of starting the car, no matter what you're doing. Cruising down the freeway or idling, you should overheat.

Solution?

If you're ONLY overheating in when idling, for example in traffic, you must look at the only component that turns on when you're not moving. That's the FANS.

Your fans might be working, they might be loud, and they might be fast. But they might not be spinning fast enough. The stock fans are known to slow down over time. Electric fans don't just stop spinning. They slow down over time, moving less air, until eventually it's just not enough to keep the car cool. So, first off, check the fans.

You need to seal around the radiator. A lot of people think the foam around the radiator is only in place to keep air from going around the radiator when moving at speed. True. But it also helps when you're idling. When idling, there's no air hitting the radiator from the front. Your fans suck air through the radiator. That's the only way the radiator cools down. So the air in front of the radiator gets sucked in from the fans, through the radiator. And as it passes through the radiator, because the radiator is hot, that air gets heated up. So you get a lot of hot air at the back of the radiator, and they have no where to go. What happens? That hot air crawls back to the front of the radiator from the sides, top and bottom of the radiator. And then what happens? That hot air gets sucked in AGAIN from the fans. And then it leaks to the front again. And then again it gets sucked through the radiator. So the air the radiator gets keep getting hotter and hotter. You don't want that. You need COOL air. The foam stops this from happening. It keeps the hot air from coming to the front of the radiator. So proper sealing around the radiator is CRUCIAL. Stuff foam into every gap you see. To get it perfect, start up the car and feel around the front of the radiator for hot air. Cover those areas. Even duct tape will work.

Don't let your car get to 230F. It's pretty bad for our engines. A temporary solution is to turn on the heater on full blast and turn off the AC switch. The heater acts as a secondary radiator. It won't drop the temps by 30F. But it should help, and stop you from getting a new engine.

Try the sealing method first. It should bring your temps down a lot.

 

I keep seeing recommendations to replace radiator. Why is this? what goes wrong with it? Properly maintained (correct fluids, no electrolytic corrosion) the radiator 'should' last the life of the car.

 

220 at a stop in traffic in high ambient temps is well within the normal operating range. For a hot running rotary 220F is pretty good for that scenario. Do you own another car? If so see what those temps are under normal operating conditions and you will see that 220F is completely normal, and actually quite low (my Jeep sits at 215F even in cold weather at idle, my bosses SLS around 225-230F) even for pistons engines.

Also completely sealing the radiator is not recommended either, some air needs to be able to escape (go around) at speed. 230F is not bad for our engines unless you are running 230F all day, every day. The occasional 230F is not going to hurt anything, plenty of track guys see that every race weekend. The Factory service manual states 243F is the danger zone, which is why the coolant gauge doesn't move until then.

 

I am going to disagree with this somewhat. Mazda used a thick block of foam on the bottom of the radiator, and thin foam strips on the top and sides for a reason. Some outside air is supposed to reach the engine compartment to cool the other bits from the heat created by the exhaust manifold. Completely sealing around the radiator prevents outside airflow into the engine compartment, and that is not a good thing.

When I replaced my OEM radiator with an upgraded Koyo, I sealed it completely with pipe insulation. The result was cooler coolant and insanely high engine compartment temps. I went back and removed the top foam completely, then cut 2" gaps in both sides to allow some outside air to reach the engine compartment. That brought the ECT's back down to normal.

 

I replace the engine, new radiator, new fans. Same issue. And i still have the car still love; but the true is the true. Anything above 110° F the car will not start easily. That'st the rx8 wether you love it or not. The only reason haven't set this car on fire is the fan kit that i istalled. When you have to deal with a shity situation like that with such a good looking car and fun to drive machine believe me it's beyond frustrating. If you're an rx8 owner. You know what I'm talking about. By the way i leave in miami. My new engine is not even a year old.