Rx8 Overheating, please help.
 

So last night after running my car pretty hard on the highway, driving in high rpms the car began to overheat. It went a little over the halfway mark on my temp gauge but it def moved past the normal spot.

Once I saw the needle move I slowed down and started coasting at 65mph at around 3k rpms and the tempture went back down to normal after about 15 seconds.

Heres a few hints that may help you guys figure out what the hell is wrong.

1- I change every 3k miles. However, this time when I changed my oil, I didnt change the filter so, the filter has Bout 5k miles on it at this point.

2- One of my coolant hoses was leaking, so I changed it and there is no more leaks.

3- My radiator is fairly new with about 3k miles on it.

4- My serpentine belt the other day, and the belt was replaced.

5- Car has enough coolant and oil in it.

The car only overheats if I drive it hard. It doesnt overheat when cruising or idiling.

So I have two questions...

1- Even though the car didnt overheat that much, could I still have caused damage to the engine?

2- Why is it overheating?

bump, still need help on this please. thank you.

I suggest you start with this...

https://www.rx8club.com/series-i-tro...o-i-do-258334/

It is in the sticky section. Just above this post.

Then, some data on what was going on. Speed, outside temp, AC on, type of beer in the cooler.

We can help from there.

I read that entire post before making this post along with about 10 other overheating threads, none of which had a similar problem to mine. Which is why I made my own thread.

From what I read on your post, high load means you are having trouble with your water pump. The OEM pump is known to cavitate at 7k+ from my understanding. I would suggest getting the one Mazmart sells. It has been said to prevent this problem. They are also VERY highly reviewed. If you don't have time/mulah for this, then give more information about your car. Do both of your radiator fans work? Ambient temperature when it happened. Do you have foam around your radiator? If so did you remove the one on the right side to create good air pressure? Was the A/C on?

Oghhh wow, I didn't even see your post, my bad.

I'm thinking it's something to do with the water pump too. Normally if you're overheating at high speeds, it's the water pump.

Foam around the radiator is a good one. It really helps to lower coolant temps. It forces air to go through the radiator, not around the radiator. Check around the radiator to see if the stock foam is still there.

You can get a cheapo Bluetooth OBD2 scanner, pair it with your android phone and check the exact coolant temp. Then you can tell when it goes up, at what speeds and conditions. Post it up here and we'll help :)

Yeah overheating a rotary is very bad. But if it dropped back down in 15 seconds, I don't think you suffered any engine damage. Just don't let it overheat again. That's where the OBD2 scanner comes in. You can catch it before it actually overheats. The stock temp needle doesn't move until the coolant temp goes over 230F. When your scanner is showing 220-225F you know something's wrong. Then you back off the throttle. That's what I do :P

Good luck :)

I once pegged the needle and I got away with only minimal engine damage and a completely busted cooling system. Just moving the needle should be fine. Forums and shops like to say that the needle moving at all in an 8 can cause damage (and there is some truth in that, as the stock temp gauge is rubbish),. This can happen (if you are really unlucky), but if you catch it early you can save it. Just try not to do it often. I would personally not recommend driving it until you get you fix the issue to save the cooling seals..

Thanks everyone for the reaponses.

After reading the replies, I was pretty comvinced that I had a bad water pump, but Im not seeing any leaks anywhere... wouldnt that be the only way to tell if my water pump has gone bad?

No, it doesn't always have to be a leak. It could possible be the fan looking thing inside of it. Or many other things.

The fan thing inside the water pump is an impeller. It will wear down but not in a human's lifetime unless you put the wrong coolant and sand in it.

Then that is eliminated, so next I would suggest is the actual flow caused by the impeller. Isn't that the issue with OEM? They don't flow as well under highload/RPM

Pull your thermostat and put it in boiling water to see if it opens correctly. Also check your radiator cap, and the reservoir neck under it. You want to make sure the reservoir is not cracked and the the rad cap holds pressure. Also a rad cap is like $2 so easy thing to eliminate by replacement.

Can a bad radiator cap make the car run hot but not let any water out?

Are you a mechanic? Rather than deciding, based on conjecture here, to replace your water pump, why not take your car to a qualified mechanic and have him diagnose the problem, as mechanics are trained to do? That way, you won't end up paying - in money, time and frustration - for a new water pump that, in the end, may not solve your problem. I know, that's considered crazy talk 'round these parts; but I'm a crazy kind of guy.
;)

Nothing wrong with this.......BUT, I would never trust my car to the Mazda dealer, regular mechanic, or an average joe. Unless, it is for alignment tires changes (I'm lazy) or something basic that I don't feel like doing. I'm not a mechanic or very experienced, I just read alot , as well as taking my time to try and figure these things out, so I save money.

+1 what Loki said.

more likely to be the thermostat.

Cooling systems are pretty easy to diagnose.

1. Obstruction
2. Faulty fans, fuses, and/or relays
3. Ineffective or boiling coolant
4. Water pump faulty or cavitation
5. Thermostat does not open completely
6. Ineffective/inefficient air flow

I have an S2, so I can't relate to the faults with the early water pump. But I do live at high RPMs, and I know people who have S1s and track them with me. They ALL run Mazmart or S2 water pumps. There must be a reason.

You didn't mention the age of your car, so I can't make recommendations based on that, other than to say, if it is an older car, it is probably time to replace the water pump and thermostat anyway.

Otherwise, make sure your radiator is sealed with foam on 3 sides (leave the exhaust manifold side open), and your undertray is not missing or sagging.

Check all of the electrics. Fuses and relays good? Fans turn on properly and spin at appropriate speeds?

Cooling system holds pressure?