Overheating
 

Hi all, I have a 2004 RX-8 w/ 120K miles and 6spd

Let me describe my situation. Car can drive with A/C fine as long as it's in motion. Most it'll reach is 215.6

However, if i'm idling with A/C on, it will have no trouble reaching past 215.6, at that point I quickly turn it off.

Planning on cleaning up my radiator so i'll drop the radiator and check out the fans while i'm at it.

I perform yearly coolant flushes from the overflow and also the engine block. Didn't help.

OH RX-8club TREE OF KNOWLEDGE. SHED YOUR LIGHT ON ME.

Are your fans running at idle?

@ Green,

Check the Congrats you got an 8 thread in this forum, or the $100 thread in my signature (both the same). If you are comfortable, do the stuff related to cooling, specifically foam and fans on low. The rest would not hurt for an 04.

Gotta run. Let me know how it works.

Half of the stuff in that thread is complete useless BS and I have no idea who decided it should be a sticky.

Greenman69,

Think of your cooling system as just that, a complete system. If you are unsure of your cooling systems maintenance history then I recommend starting fresh. New radiator, new water pump, new thermostat, coolant flush (block drain as well) with factory FL22 or a good 50/50 coolant, new hoses, and insure the sealing around the radiator and under tray are in good working order and test the fans (follow FSM) to insure they are working as they should. And I recommend all OEM or OEM equivalent parts unless you plan on tracking or adding forced induction. It will cost you around $300.00 (using parts store OEM equivalents from amazon, etc.)to do all this but doing it all at once will save you many headaches later if you plan on keeping the car for a while.

Preventive maintenance is key. There are DIY's on this page for most of this stuff but you can also follow the factory service manual here:

M A Z D A

Make sure you bleed the coolant system using the procedure outlined in the factory service manual.

When it reaches 215 yes.

Yeah bro, I got the air out.

i agree with 9k, he helped me out when i upgraded my entire system a few years ago. what was causing my issues is probably not common. heres what happend to me. pulled my car out of winter storage to do spring maintence including a coolant flush. while flushing the system a small piecs of rubbery debris of some kind got stuck in the restrictor on the small top line of the coolant tank causing my car to overheat.

that was enough for me to upgrade everything with 9ks advice and what part to buy. he knows what hes talking about and has tried many different parts (along with the sarx crew)

I have seen some nasty coolant jacket crud build up on torn down engines, if you have done yearly coolant changes then that is not likely if you did a full change but you could still have a clogged up radiator. Have you always ran straight coolant? If it were me I would start fresh with new components.

damn

I run 50/50 pre-diluted. I wouldnt know if i had clogged rad. Should I get the cobb salad? Seems many have had success with it. 3 bills aint bad for new components i was expecting a grip

http://littlefun.org/uploads/5223ab6...883a8e_736.jpg



Also, you're not listening. I assume you mean Cobb AP, and it is not $300.00 new and it will not fix a problem in your cooling system.

LOLWTF

the accessport

Oh you mean $300.00 for the rad, etc. Yeah not bad for parts with a lifetime warranty.

a cobb isnt going to help if you have a coolant system problem unless you want to see temps/lower fan turn on. sounds more like a faulty system part

3 hoses total?

theres three main hoses (big ones) and a bunch of smaller ones. since i got the mazmart t stat and w/p, mizu rad, rb cooler screens, mizu hoses (3 big ones) i relpaced all the smaller ones with oem since everything else was new and my issue was with a smaller coolant hose. also if you dont have a cat when doing the t stat its a good time to ditch the air pump

I reckon it's your fans. See if you can spin them freely when you drop the radiator. Could be your motor's as well. Maybe invest in some Flex-A-Lite fans?

So a little update. Got the Cobb and had the fans to run at 188. Worked great, for a while. But just today the fans wouldnt turn on? I reached 210 or so and when I shut off the car and walked away I didn't hear the fans running. I think it could be the relays or motors. I hope someone can validate so I can rest easy. I'm not gonna drive it until I can fix it.

Do they turn on when the car is running... they don't always stay running when you shut the car off.

You can test fans from the fuse box. Just pull the relay and jumper the larger of the two connectors. I think there are 3 relays. The $100 thread (congrats you got an 8) tells which one to use to get them on low. I leave it that way in the summer.

I had the Cobb to have both fans run at 188. When the fans were still working I didn't see anything above 200. One or both of them may not be working since my car will easily see 210 or more. Havnet seen anything past 219.
This seems rather difficult. I was planning on spinning them both by hand, see if they're connected, if anything is blocked etc. Do I have to drop the radiator to change the cooling fan motors?

Is it possible you don't have any actual problems, but are seeing higher temps because it's been like a thousand degrees out here? I noticed a major drop in gas mileage when the heat came up, but there's nothing wrong, it's just hot outside. See what happens with the AC on today, it's only 85, yay :)

Not that hard...

the relays are identified on the cover. Turn on the key, pull the engine compartment fuse box cover, pull the relay associated with Cooling Fan 1.

There are 4 sockets, 2 little one (for the control) and 2 large ones (for the fan). The little ones trip the relay, and it completes a circuit between the big ones.

You are going to be the relay. the fancy way is to put a spade terminal on each end of a 12 to 14 gauge wire and plug it into each of the big slots. Fans should spin on low. If you do the same with relay 2, they will spin on high. I seem to recall that if Relay 1 you are kind of hosed. I do not remember if you need 1 on for them to go on high when 2 energizes at a lot higher temp.

If you do not have spade terminals, you can use a piece of solid 12 or 14 gauge wire, just gently work it in. This is not a long term solution, but will let you know if the fans are working.

If they do not spin, then you got something else going on. If you are not comfortable doing this, then do not. You may or may not get a little spark. If you use really small wire, it may get hot, or it may burn, so stay away from 22 gauge speaker wire or phone wire.

good luck.

Fans are definetely not working. Cruised at night in the low 80's and got up to 213. Only way I got it to go down was drive it so it could get air into the rad. I haven't heard them run after shutting off since this issue happaned.

Do you have a plastic undertray in place? That was my original issue.

Yessir, plastic tray is still there.

Fans then.

Check relays and fuses. The test above is the first step. Do you have a volt meter? If you do, you can check for power on the larger sockets (one should have power with the key on). If now power, you need to find out where it went. If there is power, jumper the big ones and see if the fans turn.

No power at relay, look for electrical.
Power at relay, jump, no fans, look at fans and wire to fan.
Power at relay, jump, fans come on, bad relay, or bad connectors. re-install relay and see if it works.

This is a good test point in the middle of the circuit, that is easy to get to and helps break down the problem. If you are not comfortable doing it, that is cool, but you need to find someone who is.