cavemancan

Everyone talks about it but I am having a hard time locating all this information under one thread. I admit that I have a motive aside from a general discussion of cooling as it appears I have some cooling gremlins lurking in my engine bay.

I went to lunch today and parked for about 15 min and decided to hook up the Cobb AP to check out my coolant temps and holy crap!!! The temperature outside was 89 deg F and the Cobb was showing my coolant temp at 239 deg F. So you see my motivation. I clearly have an issue with my cooling system. I want this thread to both discuss aftermarket cooling as well as be a general all around "this is what you should do when..." thread.

Things to post in this thread (Information is gathered from all members and consolidated):

Any Custom work to improve cooling efficiency

- Intake sheilding (Greddy Turbo application): DIY: Intake Sheild
- Manually configure fans: this is for those individuals who do not have a flash tuner or any other programming device DIY: Rewire Fans

- Relocate battery: promote flow out of radiator
- Remove stock air box undertray

- Stock fan mod: the fans are ok, but they need to be better utilized. Turning them on earlier is good and works for some. For me in a hot climate and with a FI car, it didnt. I had to wire the fans in a parallel fashion using a "flex a lite" dual fan variable adjustable speed control. This way both fans activate at once and it made a profound difference (Copy Pasta...Thanks OD).

- Thermostat Upgrade: Stewart Warner barrel type 180F thermostat (modification required)

Ducting

- foam around radiator: promotes a pressure difference between the front/rear sides of the radiator that causes flow (Copy Pasta...Thanks 9k and OD)
- Filling gaps around intake tubes that exit the stock intake passage??
- plastic behind Oil Coolers: cut slits/holes to promote flow of air through the cooler DIY: Imrpove Oil Cooler Air Flow
- venting rad air out of vented hood (not sure if this was done)

Electronics (Fans, ECU setup, and Tuning)

- Flash tuner to modify fan turn on or enrichen fuel mixture to cause a cooling effect

General Suggestions/Cautions

- Max coolant temperature is 220F measured at the oem factory sensor/top radiator hose site. If you use the racing beat site that uses the heater hose add 10 degrees to your reading (Copy Pasta...Thanks OD).

- Verify the stock system (Copy Pasta...9k):

• cooling system has been properly flushed and refilled recently (2 years 30k miles)

• thermostat is opening

• fans cycle on and off at correct temps ( 2 speeds, 2 different temps)

• make sure your radiator and ac condensor are not covered in debris or heavily damaged (bent fins)

• foam needs to be in place around the radiator

• make sure your plastic underpanel is in place and tight against the radiator

Liquids (Coolant vs water)

- coolant discussion thread (searching for thread but feel free to post if you know where it is)
- Coolant recommendation: a mixture of 70% water and 30% coolant is recommended (by OD)
- Evans coolant? (Some indicate it's primary benefit is the much higher boiling point over standard coolant mixtures which will help prevent overheating situations but has a side affect of running at a higher average temperature)

Misc. Cooling Threads

- https://www.rx8club.com/series-i-trouble-shooting-95/redline86s-coolant-issues-plus-major-summer-project-218810/

Pumps (This should be easy as there is only one pump that I know of)

- Mazsport thermostat
- Mazsport Water pump
- Underdriving??? (Possible reduction in cavitation at high RPM's)

Radiator Setup (Includes any coolers)

- additional oil coolers: DIY: Additional Cooler
- additional rad
- aftermarket radiator to replace stock unit
- larger oil coolers

Highway8

iTrader: (11)

Verify the stock system is working properly. Holds pressure, radiator cap holds pressure, cooling system has been properly flushed and refilled recently (2 years 30k miles), thermostat is opening, fans cycle on and off at correct temps ( 2 speeds, 2 different temps) with the Cobb AP you can lower the temps to improve cooling. Make sure your radiator and ac condensor are not covered in debris or heavily damaged (bent fins). Foam needs to be in place around the radiator, you can add more to improve air flow. Buy the garage door stuff from home depot, it has adhesive on 1 side. Make sure your plastic underpanel is in place and tight against the radiator.

Once all the above checks out, the cooling system should work well for most conditions.

How to Improve cooling system:
Fans, lower cycle temps with Cobb AP.
Ducting and airflow: more foam and type up holes in underpanel. You xan also cut more holes in plastic behind the oil coolers to improve air flow. Removing the stock air intake and installing an AEM or mazdaspeed intake improves air flow out of the radiator. Relocating you battery to the trunk does the same thing.
Radiator: The BHR and mazmart radiator are bolt in upgrades that will help a little. If your radiator is original or needs to be replaced I would go with one of these upgraded units. There are much larger race radiator out there but they are not bolt in.
Waterpump and t-stat: If it ain't broke don't mess with it. Exception is underdriving the waterpump helps reduce cavitation at high rpms.
Other: if your in a hot climate and track the car, adding a small out cooler plumber into the heater core and placed on the underpanel will improve cooling. Basically its a second radiator.

cavemancan

Ok, so I am trying to hunt down my cooling issue but keep in mind this may or may not be a constant problem. I just recently started using the Cobb AP so who knows how long this has been happening.

Environment:
Engine: 9k miles (Mazda reman)
Mods: AEM intake, BHR midpipe, Greddy exhaust, Cobb AP, BHR ignition (not currently installed.
Current CEL's: P0076 - Intake valve Control Solenoid Circuit Low (Bank 1)

Note: not sure if this matters but I started noticing that the engine bay temperature (unmeasured) seemed significantly hotter after the AEM was installed. Not sure if anyone noticed this as well. I think I noticed some others experienced this as well (looking for links to post under the main post). Also, I shut off the car at times with the coolant temp around 210 to 219 and the fans don't come on but they do work. During normal stop N go traffic the temps never exceed 220 on a stock cooling system and that was only maybe once or twice in 90 degree weather. It spends most of the time around 195 to 205 where it should be.

cavemancan

How can you test if it's holding preasure? The car just had a new engine put in about 9k miles ago which means they had to put new coolant (does not mean it was done right). Even if the thermostat was bad it would be stuck in an open position. I am not sure what the correct temp's are for the fan cycle. I know you can alter when the fans come on but I am not sure how to do that yet. This could be resolve on Wednesday anyway as I should be doing another tuning session with MM. While I agree I should check out the debris and sealing the rad...I do not think this is the issue based on the cooling system performance at speed. The issue only surfaces at idle for long periods of time.



I'm heading down the path of tracking probably in the neighborhood of once a month so I need my cooling system in semi-race prep.

I was thinking about the following:
BHR radiator, Mazmart water pump and thermo, coolant solution (dont know yet), second radiator, custom ducting, and a vented hood. I also noticed some guys eliminated there second oil cooler and used that spot for the second radiator but I am left thinking fine coolant temps stay consistant but what about oil temps? I realize one can affect the other but just not sure how efficient that setup is?

Highway8

iTrader: (11)

With the stock inbox moved the under hood temps seam higher.

Your thermostat might be sticky. If its original a replacement might be in order.

cavemancan

I think your right...After posting above I thought about it a bit and removing the air box basically altered the flow of air to the top of the engine bay. It makes you wonder if that's hurting intake temps? I am sure it is...One day I popped open the hood and almost burned myself on the latch to open the hood. It was that hot. I think a vented hood is in order and/or some heat shields. I probably should have had the AP installed before the intake but did not think of it. My goal is to log all changes made from now on. It should help this thread.

As far as the sticky thermo...wouldn't that affect temps during normal driving? Note that I drive like a crazed lunatic and frequent very hi speeds and engine load.

cavemancan

I forgot to add...My coolant light is on but that is due to a bad sensor. Coolant level is otherwise ok.

I am also adding a list of cooling suggestions to the first post that have yeilded good results if memory serves. I will remove/add as we go along.

olddragger

iTrader: (3)

good idea to lump all the info into one thread. I have a lot of info. I am at work now and I dont have time to post it all. i will post tonight.
I have found over the years in dealing with this issue that this car doesnt need as much help with cooling as I once thought.

redline86

iTrader: (7)

My thread might be helpful as well for something, I have had cooling issues in the past.

https://www.rx8club.com/showthread.php?t=218810

9krpmrx8

iTrader: (46)

More is less (did I just say that? ). The factory cooling system is very good but you have to look at it as a system. I was chasing cooling gremlins forever and it ended up being a small coolant seal leak the whole time that was actually determined by a very simple oil analysis and then a coolant system pressure test.

Now if your components are worn and in need of replacement then upgrades are probably a good idea if you choose well. Be careful what you read, many products are knocked or endorsed without any real testing and may be blindly endorsed or blindly bashed. I am running the Mizu aluminum radiator, secondary Long brand radiator, Mazmart water pump, and Mazmart thermostat, and custom oil cooler and oil thermostat setup, so we shall see just how that combo does on a boosted 8 in Texas heat.

Now, if I was just getting started and had a relatively new stock RX-8, I would so custom oil lines to the stock oil coolers, an Earl's oil thermostat, delete the factory oil cooler thermostats, and run a secondary radiator with a bypass setup. But of course remember that I live in South Texas.

redline86

iTrader: (7)

Damn 9k, isn't that like using a nuke when a pistol would do the job lol? What are your regular ambiant temps? I see 90+ degrees most of the year and I can't get my temps above 205. Now I haven't tracked mine yet to see how it holds up under that stress but I do a lot of stop and go with with hard throttle in between with no issues.

9krpmrx8

iTrader: (46)

Normally in 90F+ weather 185-200F is normal driving around town from what I have seen and what other SARX guys are seeing. I have been driving Hoss-05's car and in the recent 70-80F weather I have been seeing 170F-185F even when doing a row through the gears to redline.

But when driving hard in the canyons(often for me, shut it Teamrx8 ) or stuck in bumper to bumper traffic (rare for me) in 100F weather getting to the 215-220F range is easy. If your cooling system is not operating as it was designed, getting above 220F is easy in the type of heat we see here during the summer.

redline86

iTrader: (7)

That makes me happy to hear, and very happy about the temps I'm running. I plan on trying to get into auto crossing after I finish my new brake setup in January so I"m curious to see how it will hold up in that heat. I will consider upgrading my oil coolers if the need should arise.

From what I can tell, the oil cooling system is equally as important, and good oil that can take the heat.

9krpmrx8

iTrader: (46)

Yep, oil cooling and the coolant system go hand in hand.

cavemancan

Excelent thread Redline...I added it to the main post as you accomplished about 80% of my personal goals with the cooling system. I hope to take a few steps further than this thow and possible relocate the AC condensor or add an additional radiator for when I am racing...Maybe even do some duct work to engineer the entrance and exit of air through all coolers.

In the mean time I will continue to gather all relevant information for this thread but in about 3 months (TAX RETURN) I will start my project and will add many of the parts discussed. I will more than likely create a thread on this and take tons of pics.

cavemancan

This is exactly what I am seeing with my car...It's only when I am parked for 15 min or more that temps get really high. I'm now wondering if BOTH of my fans are working or not. I'll try and replicate these conditions today to see if I can tell if both are running.

If only MM was reading this he could tell me how to change the FAN engagement settings on the AP. Sigh...I guess I have to search...

9krpmrx8

iTrader: (46)

Do you have Access tuner race? If so it's easy, and it's here if you search.

04Green

iTrader: (1)

Suggestion:

Cooling is covered in the $100 thread, as are grounds for the fans. The reason for the foam around the radiator is NOT to funnel the outside air through it, the foam is to keep the engine bay air (hot), that has already gone through the radiator once, from going around it and back through again and again when the fans are running and your are stopped, or barely moving. 180 degree air is not that effective in cooling the engine.

Even if you sealed around the radiator, if you pulled the stock air box, and did not fill the holes, you have the same thing going on. That thread($100) lists all that I have done cooling mod wise. Last summer I sat in a hot parking lot (105 on outside temp gauge) with the AC running for 20 minutes waiting on my kid. Engine never went over 190 (on my Cobb), car was 68 degrees inside, actually almost uncomfortable. Windows were starting to fog a bit on the outside.

Make sure the fans are running at top speed (grounds, check relays) and that you only use cooling air once (foam), and you should be good to go. Either of those not working will kill you.

Good luck.

ShinkaEvo

iTrader: (3)

Got vented hood, seibon STII.
Relocated battery and MS intake (without the intake under tray).
Basically there's nothing in between my radiator and vented hood besides few wires and MS intake.
And hot air travels upward, that's why at stop u get much higher temp with stock setup when the only opening is downward.
Rarely pass 200 with this setup. Still got stock radiator, BHR radiator will be my next cooling mod.

cavemancan

I bought the AP from MM with the calibration service...That is all I know. I haven't searched in the last couple of hours cause getting paid is a priority. I'll so some searching when I get home.

olddragger

iTrader: (3)

already some good advice here. i will try to sum up all my thoughts on cooling in this car.
1- you cooling needs will depend on your environment and driving style. Hot weather, low humidity, high rpm/load , tuning, modifications, condition of your car and cooling system, coolant choice are all going to affect what will work for you.
2- a generally accepted max coolant temperature is 220F measured at the oem factory sensor/top radiator hose site. If you use the racing beat site that uses the heater hose add 10 degrees to your reading.
3- you cannot cool without airflow thru the radiator. it is pressure difference between the front/rear sides of the radiator that causes flow--not increased air flow to the radiator only. THINK ABOUT THIS.
4- the oem radiator will cool the car fine. it has the capacity if that capacity is used correctly.
5- the oem fans are ok too--if used correctly--also
4/5 discussion ---the radiator has to have all the foam secure around it so that the pressure in front of the radiator will stay at a higher level than the pressure on the rear side. This will cause the air to flow thru the radiator at its maxium potential. No ifs ands or buts about that one.
The fans... the fans are ok, but they need to be better utilized. Turning them on earlier is good and works for some. For me in a hot climate and with a FI car, it didnt. I had to wire the fans in a parallel fashion using a "flex a lite" dual fan variable adjustable speed control. This way both fans activate at once and it made a profound difference. I highly recommend this unit. Its interesting that I found that the fan harmonics were also affecting my eps harness, causing some lost of eps! I fixed that too!

7- coolant --a mixture of 70% water and 30% coolant is recommended
8- make dang sure the radiator cap is good and will hold the recommended pressure--it is a commonly overlooked but critical item
9- thermostat-- throw the oem away and do NOT use a auto part store replacement. They usually do not seal the bypass well enough. The Mazmart one seals very well and has a bigger opening for better flow. For the hardcore cooling fanatic the Stewart Warner barrel type 180F thermostat that requires some modification to the thermostat housing and the closing of the bypass system is the way to go. I could start a new thread on this mod on its own. I run this now and really really like it.
10 -- mazmart or series 2 waterpump is also a very good option to do.
11--stay away from underdrive pulleys for the water pump. We could actually use an overdrive pulley--yea some call me crazy.
There is more--but whew I am now tired---so maybe later
How some can get some use from all this

cavemancan

Light Bulb (Dispicible Me)

So I made a discovery towards solving my cooling mystery. The entire drive home the coolant temps stayed below 196 def F...In fact it was usually around 190 Deg F. So I thought to myself how do I replicate the issue I experienced before...I decided to drive to the local gas station and park for 10 minutes. So guess what? My temps dropped down to 187 to 190 Deg F. I was so confused at this point that I left the gas station when the "Light Bulb" came on...My AC wasn't on...Why would it be it's 78 Deg F outside. So I parked again and this time I turned on the AC and played a game on my iPhone for S&G's. Well after only 5 min my temps went to 199 Deg F and eventually got as high as 208 Deg F and was slowly climing. I turned off the AC and sure enough after 5 min the temps started dropping again down to 203 Deg F. I proved my point at this time and went home. By the time I got home (about 1 mile) the temp read at 197 Deg F.

Why would the AC cause this much of a spike? 9K...you mentioned being in extremely hot Texas weather showing an average of 190 to 210 with spirited driving. I assume your AC was on? I have a huntch what the issue is since I left out one more Gremlin. It appears there is a bad valve (part of the AC system that controls when the compressor turns on I think). My AC still cools but I can't run a full load of freeon or else the compressor engauges and disengauges too often and never conditions the air. So my mechanic intentionally removed some freeon to keep me going until I can get this fixed. I just can't put 1 and 1 together and figure out why this would affect temps so much.

olddragger

iTrader: (3)

uhhhhhh--the a/c condensor is right next to the radiator, SO when the condensor gets hot it affects the radiator. And when the compressor is on it places a load on the engine. Plus you are sitting still.

cavemancan

I've been following a few of your posts regarding cooling and I'm impressed with the knowledge you accumalated thus far.

Can you expand regarding the EPS (I assume you mean the electronic power steering)?

This is all really good info. I am adding much of it to the original post.



I guess what I meant to say is I don't know why it would be making "that much" of a difference but thinking it through more throughly it makes sense ofcourse. So over utilization of the compressor is making the condensor much hotter and that heat is transfered to the radiator? I just did not conceive that it would cause that much of a tempurature hike.

I need to get this fixed...Thanks OD!

olddragger

iTrader: (3)

eps--yep e power steering