JR RX8

Im driving a 2005 AT with a relatively new stock radiator (replaced over a year ago) and all original AC equipment. I just completed a full-service engine check/inspection by my dealer of 19 years which included a complete fluids check, hoses, wires, plugs etc. The car has been running fine since then. Yesterday while driving in stop-and-go traffic during the hottest day of the year to date ( 94F - with a 100F index in NYC ) I had the AC on and the cabin fan dialed to 2. As I was crawling along over a local bridge which is always jammed, I noticed it started to get hot inside the cabin. Alarm bells went off and I immediately looked down to see the engine heat rising above the mid mark into the high zone. I immediately turned the AC off, rolled down the windows, and turned off anything else I could to conserve power, both mechanical and electrical. Since I was on the downward side of the bridge, I even disengaged the transmission, and when I needed to move just let the car roll with gravity. Within about 90 or so seconds the temps started to slowly fall back into the safe zone. After getting off the bridge with the engine temps back in the normal range and reaching a road where traffic was moving normally, I tentatively rolled up the windows and turned the AC back on this time dialing to 1. While not on a highway and constantly moving, I was moving from light to light and getting through intersections without major problems and drove the last 3 or 4 miles without a glitch. Naturally, after I parked and turned the engine off, the fans continued to run and as an extra precaution, I popped the lid to let some of the heat out as well and went upstairs.
Long story I know but I felt the context was necessary because I'm now considering upgrading the radiator and fans to some high-performance grade stuff ( Mishimoto? ). Questions are as follows: 1) would doing this and spending the cash make a significant difference? 2) Is there another way of enhancing the current systems' performance ala AC refrigerant additives, completely draining and replacing the coolant with something higher performing, better thermostat etc? to improve the engine's cooling capacity and not worry about getting stuck in traffic again and having the thing fry on me?
I'm open to any suggestions and recommendations as it appears the current and future temps outside are going to be brutal this year and most likely the next. I'm using the car as a daily driver, mostly on the highways ( 30 miles a day back and forth) but sometimes, like yesterday I have to take slower local roads to get home and don't want to damage the engine by continually overheating it. Thanks in advance to all for your thoughts and ideas.

Shaozhou Zhang

Search about fal420 fan. Our stock fan will slow down over time.
Do not use FAL440 as I believe it's a pusher fan.
Hood vent and battery relocation will also help

JR RX8

Shaozhu ---By "fal" 'm assuming you mean Flex A Lite? I was on their site and they don't list the RX8 as a car they service, only the RX7. I'm not racing so I'm not inclined to modify the hood, although that's a good idea. I take off the big black plastic engine cover under the hood which helps I'm guessing as well. I just found some old threads on here that talk about this and the FAL 420 is mentioned as a good replacement. Also since I'm not racing the car and trying to keep it as "stock" as possible, moving the battery doesn't work for me either, although I get the point. I think the fan /s upgrade is a good place to start, but I'd hate to do the fans only and then find out it's still now cooling any better since the stock radiator, in my opinion, is not the best ( I've gone through 2 already in 20 years, one failing catastrophically while driving ). Thanks for your advice, I'll call FAL tomorrow to see about the fans.

samakijoe

.
I did a number of updates to my 2006 after learning that heat is the killer of
these engines. Here is a URL to a good write up on this issue. Give it
a read...................

https://rotaryperformance.com/blogs/rx-8-tech-support/87851716-how-to-double-the-life-of-your-rx-8-engine
.

JR RX8

Thanks. Good Read.. I've been using 5-20 synthetic Mobil Oil. I live in the northeast so the 5 weight works well in the winter but the summers are getting mighty hot lately so bumping up to 30 sounds theoretically a good idea as long as it does its job in the colder temps. Since this engine runs hotter than the average Joe's it also makes sense. I never even thought about or heard about doing anything to the oil COOLER, again a very idea. I ve used Seafoam Premix in my gas for some years to no detriment but my mechanic suggested I stop. I used to dump about 1 can of Seafoam pre-mix per fillup every couple of tanks. Let me look in all of these suggestion as they all make sense and sound logical and simpole to do. Thanks again!

Loki

iTrader: (1)

Definitely bump it up to 10w30 or 10w40. At least the 5w20 you used was synthetic.

Not everything in that article still stands up today. Oil has changed and continues to change, and I can't see a valid reason for changing spark plugs every 8000 in a healthy car. The synthetic=bad story goes back to the 90s, but oil from them and oil today have nothing in common.

I wouldn't add seafoam that often. Maybe once a year, after the winter to pick up water in the fuel tank. It doesn't do much when added to fuel or aspirated. I would however consider premixing 2-stroke oil, especially as the car ages and the oil injectors wear out.

JR RX8

Sound and easy advice. The 5-40 oil change makes lots of sense. Ive changed the plugs last year and see no reason to change them now, they're fine with no carbon buildup. I've not put any seafoam gas additive since last summer so we're on par there. Thanks for your input. So far I've not done anything save for adding some coolant to the system, topping off the oil, and making sure i don't dial the air to 2/3 unless i'm moving at least 35+ steady on a highway. So far so good. What are your thoughts on AC coolant additives?