Hi, my name is Sergio and I have bought a RX8 few weeks ago. I like a lot this car, but is a lot of work to do on it until it will works perfectly. I have some issues that I need to resolve, and I would like if you can help me. I do not very well english but I will try explain.

1- Coolant get out from expander tank. Cap seal well, but when car is stopped with engine on, tank get too much preasure and it throws coolant out by the natural place for this purpose, even with a new cap. It is not much coolant to the floor. Car do not get overheating, at least in the dash the engine temperature shown is normal always. Maybe it have too much coolant in the system, but I dont know.

2-The air vents blows air a little bit hot with ac turn off. I feel the air similar to 30 degrees. Even if I select minimum temperature, the air is not cold like it should be. I can increase temperature, and the air is blows hotter. If I turn on AC then air is blows completly cold and ok. It looks taking air directly from the engine bay, is it normal? now is summer, but even so I think it is not normal.

3-The gear box is a little bit noisy. It is ok, do not sound too much noisy or loud, and I know that is normal that this sports cars have realitive noisy gear box. When Im about 3500 or 4000 rpm and Im decreasing speed (no breaking) I hear a sound similar to an ambulance, it is not very loud to worry, but I would like if it is really normal. Recently I changed gear box oil to Red Line 75w90 gl4, and shift now have improved a lot, but noise has not decreased, I have done less than 100 km, it needs more time. Is it normal if car is moving between 15 or 25 km/h and I shift to first gear (I know this is not recomendable) I hear a sound like syncros, a little bit feeling forced....

4-The driver windows is strange... If I press button parcial to down it, window goes down a little bit, it stops for 1 second, and then it continue go down. Is it normal? If I press button completly windows goes down without this stop until the end automatly.

Thanks a lot, sorry for my english, I hope to resolve at least the issue number 1, because I think it can be very dangerous.

 

Welcome..

question, how long have you run the car since you got it? If you just picked it up, it could simply be over filled. With it cool, pull the cap and look inside. The water level should be, I think, about 70 mm below the lip inside the tank. If it is up against the top, drain a bit (piece of hose, siphon) and see if the problem goes away.

If it is not the case, hate to say this, but issue number 1 may be a big deal. One of two things could be happening. First, the car could be over heating. Can you tell if the fans are on or if they temp gauge has moved from where it usually is? A great tool is some kind of OBD adapter and an app like Torque for a mobile device (phone). The factory gauge really is not that helpful. The app will tell you the actual temperature of the coolant. If it is getting hot and doing that, check out https://www.rx8club.com/series-i-tro...o-i-do-258334/

If it is not getting too hot, and it is not overfilled, I suggest a compression check. There may be a seal that is bad.

 

I have OBD2 and torque. Temperature never goes up 100º, always is between 90 and 100. Today I tried remove posible air inside the coolant system, but when I remove cap, start up car with cold engine, coolant level between low and high or sometimes even below, I wait 7 or 10 minutes and car get working temperature, coolant gets overflood from expander tank (without cap).If I put cap, I drive car for a while, I stop car, this afternoom with stopped and cold car, expander tank is without coolant.

I am thinking the worst issue posible.

 

I'm not convinced you have an issue. Was coolant changed recently? Boiling over with cap open can happen if you have too much coolant. Spitting up coolant through the overflow, likewise. I don't think there is enough information to conclude anything yet.

I'd suggest getting a coolant exhaust gas test. It's pretty simple, any garage should be able to do it, or you can buy the test kit yourself, its very simple. It will tell you if there is a coolant seal failure.

 

Dude said he is losing coolant with the cap on.

I think the cooling fan kicks on at 98 C, no? During idling my coolant temperature is normally between 98 C and 93 C.

 

To answer your questions correctly.

1, you are overflowing coolant out the overflow tube.

If you are still running FL22 or some form of antifreeze smell sniff the exhaust while the engine is running and if your smell a sweet smell coming from the exhaust and sweet smelling water residue is present at the exhaust tips theres a good chance the water jacket has failed due to an over Heat episode.

Your thermostat probably has failed Your fans are not getting a chance to kick in properly due to the coolant in the radiator side of the system cannot get to temperature in the radiator caused by a failed thermostat not opening up to allow the coolant to circulate round the cooling system once the engine has warmed up.

I would replace the thermostat and make sure when you have refilled the cooling system run it with the front end of the car jacked up to help burp any air out the cooling system until warm. Once warm put it back on the ground and top up to the full mark line then run it to make sure the fans kick on. if the fans are not running look into having seized fans or blown fuses for the fans.

2 This is normal for the system to have warm air flow coming out of the vents if the HVAC system isn't on and running.

I set the temperature **** of the HVAC system to what I want it to be before I actually turn it off to fix this issue. Autumn and Winter are ok for some hot air to flow out the vents. Summer not so much it will flow warm air even if you set the temperature **** to cold due to the outside temperature being hotter but not the hot air coming from the heater matrix. What I do to get round the warm air from outside coming in is to keep the recirculating button on all summer.

3 Yes gear roll over noise is normal good to here you put Redline into the transmission but the Redline 75W90 GL4 will make the transmission notchy and a little bit louder/noisier. Put Redline MT90 in the transmission it will make it smoother and quieter. Redline 75W90 GL4 should be put in the rear Diff.

4 Yup this is Normal click the window switch lightly/briefly it will go down a little bit press and hold it will go all the way down. to get the window up you have to pull the switch up and hold.

Good Luck and happy motoring.

 

Hi Loki, I change few time ago the coolant. I do not have too much coolant in reservoir tank, event in the morning with cold engine the coolant level is near empty. Then if i remove coolant cap, I start up engine, I wait to warming between 7 or 10 minutes, then coolant level start to up until it reach the top and starts to go out from reservoir tank. No bubbles appreciated in this process, no oil appreciated with coolant. Also if I put the cap on the reservoir tank, then I drive, if I drive normal is ok, but if I drive a little bit sport, I can see coolant sprayed over the engine. I will check coolant exhaust gas test.

 

Good I feel better knowing except the number 1, all the another situations are normal. I will change thermostat , fans seem to work, at least after 10 minutes warming car, they start to sound. I will check also with gas test. But something that I find strange is, with coolant level near to be empty, I remove coolant cap, I warming engine car from cold, then coolant level starts to increases slowly, and after 6 or 10 minutes it reach the top and even it starts go out.

 

Coolant level is below low level in the morming. I change few time ago the coolant. Yes, I will try a gas test, I hope it will result ok .

 

With the thermostat not opening properly at the correct temperature the coolant temperature increases causing it to expand at a rapid rate this creating pressure behind the thermostat. The super hot coolant will eventually cause the faulty thermostat to open and because it is under pressure it will force its way round the thermostat and over flow the tank. Once cooled it will look empty.

The Coolants boiling point will increase significantly if the coolant is held under pressure. Release the pressure and expose to atmosphere it can be explosive.

Think volcano.

I wouldn't drive your 8 until you get the thermostat replaced the more times you over heat the cooling system the greater the risk of a damaging a water jacket seal or immediate failure.

Good luck.

 

If car is overheat , should temperature be shown in the dash or Torque app, right? In my dash I never see overheat, but maybe this cause is not shown there.

 

The overflow tank is attached to the radiator, after the thermostat in the circuit, so if coolant goes up gradually and starts to move below 90C your thermostat is fine.

If it rushes up, then yeah, thermostat suspect. You can also just test your thermostat in a pot of hot water before spending money on a new one.

By the way the overflow tank can look empty, this is normal. The low line is very low on it. The only actual problem I see here is some coolant comes out with the cap closed. Test with the cap open doesn't really say much, since the coolant isn't pressurized.

Is your overflow tank cracked at the top? This is very common and will cause coolant loss as you describe.

But, to confirm/deny the most expensive issue, coolant seal failure, get the gas test, or check the exhaust like scottish said, or pull the spark plugs and see if they have coolant traces.

 

Thank you very much, all people here helping me a lot with new posible issues and solutions. I will try all the advices and I will tell you the result. THANKS!!!

 

Unfortunately if you wait for the cluster gauge to respond its to late. I've seen coolant temps spike dangerously close to over heat on my aftermarket gauges and compared to the cluster gauge the needle had moved a little bit higher.

I rank cluster gauge useless OBD2 next and best of all analogue inline temperature gauge is the way to go but if you spot steam or fluid first before your gauges react awesome.

If its a small amount escaping then consider it as a pre warning of your thermostat is starting to fail or something far worse like coolant seal so don't ignore it.

 

Yeah you already taken the effort to dig the thermostat out and the possibility of the rubber getting damaged pulling it. They are cheap enough and its always good insurance to know its 100% reliable. By all means test away but replace anyways good or bad if you have it out.

 

Also about the air blowing hot. That's definitely not normal, I'm in my car right now in 24C weather and with AC off it blows cool (well, ambient).

There is a common-ish issue with the hvac controls ***** and/or circuit boards failing, but I don't know too much about the fix. Search here, people have had that issue.


Update: I was able to recreate the hot air issue. Fan set to 0, A/C off,if the temperature vent is set to cold, it blows ambient at speed, if it's set to hot, it blows hot at speed. At a stop it doesn't blow at all. Nifty,never noticed that before.

 

Thats what I mean ambient outdoor air temp. Based on his name and English he is in Europe some where and if he is anything like me anything above 21C feels extremely hot to me.lol

If you feel like pulling the stereo out as Loki says then HVAC controls do fail due to bad solder joints easy fix once you get it out re solder every joint. I have fixed a few but if I could adjust temp and directional buttons then it didn't make a difference.

There is something I vaguely remember about a HVAC reprogramming procedure to make it colder but I would have to look into it.

AC in the 8 is weak to begin with putting non flammable insulation around the aluminum pipe that runs across the firewall above the intake can help too.

 

Ok, engine is pretty **** up. Now the engine is being rebuilded, but I do not if repair will be well done and how long they will be repairing the engine. Only one month driving the car, and now I must go in bus.

 

That sucks, sorry to hear. Have to be careful buying used rotaries. Do you trust the people who are rebuilding it? Do they know rotaries? Because a poor rebuild will not last long, especially using parts from overheated engine. Everything needs to be properly inspected and clearanced.

 

They look good guys and profesional, they build some sport cars for races, but .... I do not really know them for really trust. So, I do not have more options, guarantee is covered there. Thanks all you for advices, when I will have again the car I will tell you my new impresions about repared engine.