Hey Everyone, I think I may be having some water temp problems. I had a feeling that my car always ran a little hot, my old gauge always looked a little high (200 degrees F) when driving around town, I thought it may just have been the gauge.

Fast forward to last weekend (first time starting the car since December), I now have PLX gauges and a new sensor, which means i have a nice clear digital readout.

I haven't taken it on the highway yet, just about a mile around town, only about 2 stop lights, weather has been about 75 degrees.

I let the car warm up in the driveway, then i took it out, not really boosting at all and my temp is around 200-204 degrees F (95.5 degrees C for you PFC guys out there). My fans are always on as soon as I turn the key (not sure why it was ever wired this way), so I know its not a fan problem.

I have a koyo radiator mounted in the stock position, a large SMIC with a duct, and greddy T78 single turbo. I also have a C-west front end so there shouldn't be a problem with air getting to the radiator. I've also taken the radiator cap off a few times after driving to get rid of air bubbles (i had taken out the heater for a bit this winter and lost some coolant during the process), but now it is full every time i remove it, so I'm pretty sure I don't have any air bubbles left.

So my question is, am I running hotter than I should be for just 10 minutes of driving? I've done some searching, and some guys are running around at like 20 degrees F (10 degrees C) than I am.

 

You are running to hot. Are you sure your fans are working while driving, what about ducting to the rad? One thing you could try is to run more water in your system 70-30 and throw in some water wetter. Oh yeah have you checked your thermostat? It could also be stuck closed not alowing the coolant to pass.

 

Thermostat.

better question is it a rock solid 200-205 or does it climb. if your rock solid I would have no problem with that temp

 

I changed the thermostat last year, so I don't think that is the problem. I had checked it in water on the stove and it seemed to work at the right temps. I thought if the thermostat wasn't working my temps would be more like 220.

I'll get it on the highway and see what the temps do, I really haven't driven it long enough to see if they climb higher than 205 yet.

My ducting is more of a lack of ducting, I don't have the undertray installed yet, but isn't that to keep temps down when driving at speed when there is actually airflow? I was thinking the fans are doing all the work when in traffic.

Once I get the car back from paint i'll flush the system and put a higher concentration of water in. Hopefully that helps. Thanks and any more thoughts are greatly appreciated.

Oh and I just remembered, since my temp sensor is on the radiator side of the thermostat housing, last year I could easily tell that the thermostat was working because it would stay at a low temperature and the rise rapidly when the thermostat opened. I have not paid attention to that lately, so next time i start it from a cold start I'll be able to verify that the thermostat is working.

 

If your temps are stable at 95C (and don't climb much above that during hard driving), I wouldn't worry at all. The thermostat isn't even fully open until that temperature. And there's nothing wrong with the thermostat temp range, Mazda has been using those temps for 40 years.

 

Do you have one of them burping funnels? I did a rad hose swap the other weekend flushed the cooling system as best I could ( the crap that came out of the rad was impressive ) Then filled the system using that burping funnel, let the car run for a few mins and the amount of air that came out was crazy! If you do not have a burping funnel you need one! Definitely worth the 20 some bucks.

 

I don't have one, but i've always been succesful just starting and stopping the engine after it heats up a bit and re-filling. usually if there is an airbubble, when you start it after its been hot your coolant will be low. At least thats what I though, but if this isn't correct i'll get a funnel.

Another note about my car, I don't have an AST.

 

My car runs 210F - 215F all the time for the past 3 years....I tough that was normal?

 

Well that is reassuring

 

Granted I haven't exactly driven my car hard at all yet, but it was in the 80s last time I took it out and I didn't even hit 90c once. I'll have to keep an eye on things as I drive more and it gets hotter this Summer though, but the fans kick on around 88c and seem to do a good job so far.

 

I'm having the same problem... Drained the coolant while doing some work to the car this past winter and now its running constantly 90-100c, and its only like 15c outside. Last summer when its 30+ outside I never saw higher then 95c. I'm thinking I still have air pockets in the system, I added water wetter, and am running a 50/50 mix of prestone, seems weird.

 

http://www.amazon.com/Lisle-24610-Sp.../dp/B001A4EAV0

use this funnel to get the air out, it forms a watertight seal with the filler neck and you can see the bubbles escape

 

Do you think that air pockets are the problem? We never changed anything so I don't know what else it could be. The funnel is definitely worth a shot though.

 

Okay took my car out for a ride again tonight and its like 6c outside and I was still running at 102 down the highway cruising at a steady 100km/h. Also weird thing is that I have a PFC and a digital temperature gauge and they were always a few degrees apart. I don't know where the sensors are located but I'm starting to think theres something wrong with my thermostat maybe?

 

I'd change the thermostat. Could be that the thermostat that's in there is an aftermarket one that opens later.

My thermostat opens just past 80 deg. C, and general driving temps are always 80-85c, sneaking up into the low '90s with the AC on and VERY hot in summertime. I have a CSF aluminum radiator, Apexi front mount, belly pan installed, fans set to come on at 85 and 95.

I don't think you've got bad air pockets, everything really points to either a bad thermostat or (more unlikely) a clogged or bad radiator.

Dale

 

hmm i see about 180-190 everywhere i go. (cooling fan always on) on real hot days it never goes past 200 degrees. and im running one of those billion thermostats

 

Okay so it definitely wasn't my thermostat. We rigged up a homemade burping funnel and got all the air out, fabbed up a nice aluminum under tray, and realized my fans were running backwards! Haha we had extended the fan wires to run beside the rad instead of over, and made a couple wrong connections. I'm back down to nice temperatures in the 80's

 

I took mine for a 200 mile cruise yesterday. it was about 75 degrees outside. My temps stayed between 198 and 208 the whole time, really no difference between driving in traffic and on the highway.

There was a huge difference in the oil temps though. They'd run at 140-150 on the highway and then almost 200 after sitting in stop and go for a while. Looks like the coolers work really well.

I guess i don't see similar changes in the coolant temps because my fans are always on?

 

The stock fans have 3 speed settings, maybe yours are on speed 1 or 2?