Temp fluctuation issue
 

Just bought an 08 speed 3 a few weeks ago. I noticed that my temp gauge goes almost up to H after it warms up. It will come back down to normal if I'm turning above 3000 rpm. This happens if I'm driving down the highway or when sitting at a red light. I'm thinking water pump?
Any thoughts would be appreciated.

Have you done anything with the coolant lately? After you've run the car for a while, are there bubbles in the reservoir? Has it thrown any CELs, and if so, what codes were tripped? Is the car tuned?

To me, it sounds like you might have some air in the system, and it might need to be burped.

Was going to respond, but seen @Vansquish browsing... and he took the words from my mouth.

+1 for air in the coolant lines.

I haven't done anything to the car since I bought it. I let it run with the coolant cap off. Never saw any bubbles. I was told before I bought it there was a Cobb tuner in it. Not sure if the tune is still in there or if it went back to stock.

No CELs

You sir, need to understand what it is you have bought.

An access port of even the torque app (with obd2 plug in) will give you enough information to start troubleshooting.

Do you have an AP?

If the car is tuned, then certain CELs could have been turned off.

What are the mods on the car?

No AP. I've been trying to read as much as I can since I don't know too much about the speed yet. Just got out of an 06 6s.

CNT 3" full exhaust, Cobb TIP, injen intake, eibach springs.

If you bought the car with a tune on it, but you don't have the AP that installed it, I would highly recommend getting yourself something with which to monitor the engine ASAP. There's no telling what was done to the car before you got it, and it's nearly impossible to determine if there's something wrong with the car without an AP. What I'm trying to say is that you might have a ticking time-bomb of a motor, and without some way to monitor/tune for whatever modifications are (or WERE) on the car, you'll never know it until it's too late.

So, with all that doom and gloom out of the way . . .

Is the coolant level low? (That should probably have been my first question, hehe.)

You might have a bad water pump, that's true too, but it seems not to match your symptoms completely if the coolant temps drop after you've got it up to above 3000rpm. That, to me, kind of sounds like the pump isn't engaging completely.

So, how's the tension in your serpentine belt? Does the pulley on the water pump spin freely, and without wobbling, etc.?


EDIT: More doom and gloom.

Do you know for an absolute fact that you have aftermarket high pressure fuel pump internals (HPFP internals)? If not, then STAY THE HELL OUT OF WOT. With your CNT full exhaust (including downpipe, I assume), you're risking blowing your motor every time you go WOT, as the OE HPFP cannot keep up with the demands of a downpipe.

I'm okay with the doom and gloom. At least I'm informed. I don't know if it has aftermarket fuel pump internals. Would I be able to tell that visually in any way? The tension seems okay on the belt. Removed the belt and the pump spins freely and does not wobble. Coolant level is not low. There are no obvious leaks that I can find either. Yes, it has the 3" down pipe too.

The only way you'll be able to determine if you've got an upgraded pump is to remove the HPFP housing, and dismantle the pump, separating the internals from the housing itself. The pump internals will be labeled so as to designate whether they're Autotech internals, or OEM.

I strongly recommend staying out of WOT. Without upgraded pump internals, the OE pump cannot keep up with the demands of a downpipe. The result of the increased flow will be that you are likely to be running dangerously lean (and hot) at WOT.

Thank you for letting me know. It always smells like it's running rich to me.
Any thoughts on the temp issue? Maybe the belt is slipping on the pulley? I don't have dimming lights or anything, just assuming if it was slipping on the water pump it would be slipping on the alternator too? Maybe not since the alternator is on the grooved part of the belt and the pump is on the flat side...

Actually, I don't know why I didn't say this before, but it could be that your thermostat has crapped out. It's a common issue on these cars.

Usually, they stick in the "open" position, allowing coolant to flow all the time. The symptoms are usually that the temp gauge is slow to move, and ECTs only ever hit around 158-165F when the car is moving and air is moving across the radiator. On the other hand, if you're at a stop with this particular failure, the failure mode causes the temperature to rise, though usually only to "normal" operating temperatures (between 180F and around 210F).

If, however, you've managed to have your Tstat get stuck in the closed position, the coolant wouldn't be circulating through the radiator like it should. The result, is that while coolant will be pumping through the motor, it won't be going through the radiator and cooling down as it should.

So, before you go investing in a new water pump, you might want to replace the thermostat. The parts are pretty inexpensive, and if you've got tiny Asian hands, you'll be able to replace it with hand tools, shortie wrenches, some coolant, and very little else.

http://www.mazdaspeedforums.org/foru...0/#post1231276

On RockAuto.com, you can find the thermostat for around $27.00, and the water pump for around $30-$45 (for a decent quality one).

The smell is what you'll have pretty much no matter what with a catless exhaust system.

I'll try a new tstat. I already bought one. That was my first thought, but I was confused that it changed with rpm. It does take longer to warm up than my 6 did. I'll start there.
Thank you for the quick replies.

Yeah, that's a bit perplexing, buuuut . . .

I think it still might track with the Tstat being stuck closed. If you idle, not much fluid moves at all, and it doesn't have a chance to dissipate heat through the block, turbo, and elsewhere. If you're running more or less "unloaded" at 3000rpm though, you won't be building boost, and the turbo will not really be heating up much, nor will the motor, so it's possible that there's enough heat transfer that the coolant actually cools down.

I'm just spitballing at this point though.

What asshole keeps a tune on the car and keeps the AP? He won't get a dime for it.. Join your local Nator if you're too broke for an AP. Maybe someone will be kind enough to uninstall their AP and attempt installing on your car. That will let you know if an AP is installed or not on your car. If not, great! If yes.. Well, not sure. I know Cobb can unlock the ecu so you can marry a new AP, but I'm sure that is a pretty penny.

tapatalkin

It happens more often than you might think (hence the rules in the F/S section).

Incorrect.

Gen 1 thermostats have a high failure rate, most likely the thermostat.

No.

You cannot determine if you have aftermarket internals unless you pull the pump and dismantle it. You can track HPFP Actual pressure, but the OE pump CAN produce more than 2000psi, however, it will quickly fail if that is demanded of it.

@Vansquish; is taking good care of you, just thought I might add there are a few variations people could go with for aftermarket HPFP internals. They may not say Autotech explicitly. Corksport, KMD, etc. If the plunger is the same diameter for the entire shaft, you need to get something else.

Just to throw some more info on this. I'll be pulling the fuel pump on Saturday and checking it out. Thanks guys for the info. Also, car did not overheat today. If I have the heat set to 90 and the fan on the highest setting the gauge never goes past half way up. Pointing to the thermostat I assume.

Thermostat should fix this.

Changed out the water pump and thermostat today. Water pump was fine, just figured I would change it since I was there and already had a new one. The problem was the thermostat. I read a few write ups here and some we're saying you don't need to remove the power steering pump to change out the thermostat or water pump. More power to ya if you can with it in there. I removed mine and it was so easy to change everything out. Ran out of time to take my fuel pump off to check the internals though. Thanks everyone for all the info and help.