My MSP Overheats when NOT RUNNING

[ChopstickHero]

i vote thermostat too. i've gone up a mountain nearby and the elevation is like almost 6000 ft. depending on traffic, i'm moving anywhere from 30mph to 45 mph. usually, driving with boost for lots of twisty action. no overheating.

 

[Rally Ninja]

Scott, did u fix it yet? Saturday night man. MSP VS MSP? at PIR. Tell Dusty to bring his stir fried Rabbit too!

 

[mp5van]

its thermostat...i got the same problem last summer....however on my case it just overheating so i changed the thermostat aswell as coolant sensor....its cheap doh and easy to install......

 

[MrDiggler]

Ok, so me and some buddys took the rifles up for some shooting

We climb a mountain to get to where we shoot.

well the first time we went i took The MSP, and everything was all fine and dandy, we got to the top, and i let the car run for about 2-3 minutes as i always do.

When i turned it off i got out of the car and popped the trunk, well as i go to put my head in the trunk i heard a weird BUBBLING noise, thought it was weird so we tracked it to under the hood, by this time it sounded like a grimlin on crack. i pop the hood and the overflow was boiling and shaking eraticly i checked the temp gauge and its all the way at the top.

so i was like what the hell... i started the car and it IMMIDIATLY cooled down.

thought it was weird, but the next weekend it did the exact same thing, but this time i kept my eye on the temp gauge. and let it sit running for 5 minutes. and it tryed to do it again, as soon as i shut the motor off the gauge started climbing rapidly.

It only does it on the hill i go up.(shocked)

I'm not sold on a bad thermostat. I'm also not saying it might not be bad, either, but... My car has acted somewhat like this since day one. When you drive up a mountain (I do often) and have extra weight in the car like he did, the load causes a lot of heat to build in the motor... maybe more heat than our cooling system can get rid of during that time frame. When I put my car through this scenario and then shut it off after a couple of minutes (Was the fan running during that time? Very important piece of the puzzle.), my radiator cap will often get pushed open and coolant will bubble noisily into my overflow tank. It doesn't bother me, as I rather expect it and it lets me know the system is functioning as designed.

It's a known fact that extra heat built in the motor right before shutoff will soak into the coolant after shutoff. I'm thinking: 1) If your thermostat was hung open this wouldn't be occurring, as the system wouldn't build this extra heat as readily. 2) If your thermostat was hung shut the extra coolant pressure wouldn't even make it to the radiator and then to the cap to be purged to the overflow tank, it would be trapped in the block.

I may be completely wrong here, it's just a hunch.

 

[Shift_Lost]

I'm not sold on a bad thermostat. I'm also not saying it might not be bad, either, but... My car has acted somewhat like this since day one. When you drive up a mountain (I do often) and have extra weight in the car like he did, the load causes a lot of heat to build in the motor... maybe more heat than our cooling system can get rid of during that time frame. When I put my car through this scenario and then shut it off after a couple of minutes (Was the fan running during that time? Very important piece of the puzzle.), my radiator cap will often get pushed open and coolant will bubble noisily into my overflow tank. It doesn't bother me, as I rather expect it and it lets me know the system is functioning as designed.

It's a known fact that extra heat built in the motor right before shutoff will soak into the coolant after shutoff. I'm thinking: 1) If your thermostat was hung open this wouldn't be occurring, as the system wouldn't build this extra heat as readily. 2) If your thermostat was hung shut the extra coolant pressure wouldn't even make it to the radiator and then to the cap to be purged to the overflow tank, it would be trapped in the block.

I may be completely wrong here, it's just a hunch.

Well i had the thermostat replaced under warranty and has not done it since so....(ughdance)

 

[TheMAN]

**** the thermostat, put on a new radiator cap first! if anything, a high pressure one... high altitudes will have reduced air pressures, the pressure differential between the cooling system and the air will be high, causing reservoir tank expansion to happen sooner

shutting off the engine will cause an immediate pressure rise in the system because coolant is no longer flowing and all it can do is sit there and heat soak, raising temperatures and thus causing it to boil.... the gauge may get inaccurate due to air bubbles to form when the water boils, and that's assuming if your system is not 100% free of air (which is practically impossible to get)

using a lesser mix of antifreeze will also reduce boil over protection, having 50/50 mix increases the boiling point of coolant a lot more over straight water

a high pressure radiator cap will further increase the boiling point, thus when the engine is shut off and the pressure spikes, the coolant will be kept mostly in the system instead of going out into the reservoir tank

a faulty radiator cap which is below pressure specification will cause boiling to happen sooner because a lower fluid pressure means lower boiling point, this is especially true in high altitude areas... replacing it with even just a new stock radiator cap will usually fix these problems, but on performance vehicles where the engine tends to run hot, a high pressure cap maybe needed

 

[SergMSP]

Im also over heating again....when it first happened we replaced by thermostat and did a flush...then it started happening again and we had to do a mod to this POS weapon r coolant tank i have, it was fine for a while but now its ******* overheating again...
i put it 50/50 mix almost once a week...it slowly goes up to H while im idling but then when i start to drive again, the higher i rev the faster the needle on the temp gauge goes back to the middle...

i just bought the 1.3 bar rad cap from pg...im also planning on putting back the stock coolant tank...any other suggestions before i break my ****** car?

 

[MP3Architect]

turns out my problem was actually the meter itself. mazda replaced mine under warranty...although it also ended up replacing the total gauge cluster and in doing so reset my miles. i dunno. its strange.

 

[540James]

i need to try the new radiator cap thing that you are talking about, where do i find a high pressure radiator cap for a p5 radiator?

 

[azeli73]

http://mazda3online.web.aplus.net/index.php?cPath=21_32_179

 

[mazdaspeed_kid8]

hey guys i have a similar problem but i tried everything and it still overheats wen i turn off the car and once i start the car it goes bak to half i even went as far as puttin in a brand new engine fully forged engine with new head gasket and everything and it is still doin the same thing, i also bought the all aluminum radiator from corksport removed the thermostat and i still have the problem, wat i found is that wen i turn off the 2 coolant hoses from the turbo are bubbling no other hoses on the car bubbles except the 2 turbo coolant hoses i took them off the see if they were blocked and they are not blocked coolant is flowing free do anybody know wat this could possible be because i basically have in everything to keep this car cool it is stayin cool wen i am drivin but once i turn off the temp goes up and i have a additaional gauge and drivin normally the gauge reads 208F max wen i turn off the car gauge goes to 230F which is overheatin wen i start bak it goes bak to 208F. Also when i use the A/C and i go in traffic the temp goes up as well if i dont use the A/C in traffic everything is gud i am out of stuff to change because i changed everything

 

[ucMP3]

Holy Run-on sentence to revive this thread from the dead!