temp gauge rising and falling frequently.

[98mitsubishigst]

So i was driving back up to my college, its 50 miles total at about 40 miles i turned my heat off because i had it on whole way and it was hot as shit, and i noticed my temp gauge go up a little over middle, not 3/4 of way but close, then it went back down.. not sure if it went back down because i turned heat back on or not.

I then parked the car after the 50 mile trip, and i sat in driveway for 10 minutes in park on idle and it never rose back up..

I ended up going back outside and taking the rad cap off for a few minutes and let any bubbles come up, the coolant levels are topped off, i don't smell any coolant so i don't think I'm leaking any.. and the fan is working.. i then took it for test drive for 6 miles and it would do the same thing, it would creep up a little over halfway and fall very frequently..

Then i tried sitting at a stop sign, i put it in drive, and i would hold the brake pedal down while pushing the gas to ilke 2000 rpms and it would do this…

Wtf - YouTube


I also noticed when I'm cruising going down a hill and i let off the gas, sometimes my temp gauge would go up slowly then fall back.. also when i put the heat on it seems to help lower the temps.

What could it be?

 

[DogWhistle]

Odds are that you have a cooling system leak that is allowing the coolant level to drop and create air pockets. Those air pockets cause the fluctuation in the temp gauge reading.

Now finding the leak may take a little work. Could be a pin hole in the radiator, a bad radiator cap, a leak in a hose, a loose hose clamp, a leaking head gasket.

Refill and purge the system and look for leaks while it idles once its warmed up. If there aren't any external leaks, it could be a leaking head gasket.

 

[98mitsubishigst]

Odds are that you have a cooling system leak that is allowing the coolant level to drop and create air pockets. Those air pockets cause the fluctuation in the temp gauge reading.

Now finding the leak may take a little work. Could be a pin hole in the radiator, a bad radiator cap, a leak in a hose, a loose hose clamp, a leaking head gasket.

Refill and purge the system and look for leaks while it idles once its warmed up. If there aren't any external leaks, it could be a leaking head gasket.

its not leaking anywhere outside that i can see or smell.. it doesn't need coolant, its filled and hasn't been loosing any coolant.

 

[eclipsyco]

I really wouldn't worry much about it! If you are 100% sure that there are no leaks and the car drives fine!
Check DSMlink and see if you have that same fluctuation and wiggle the cable a little bit see if it's loose or something!

 

[98mitsubishigst]

I really wouldn't worry much about it! If you are 100% sure that there are no leaks and the car drives fine!
Check DSMlink and see if you have that same fluctuation and wiggle the cable a little bit see if it's loose or something!

Not trying to be a dick, but I'm not driving the car around if it could potentially be a engine failure like a head gasket going..

I don't have dsmlink on this one. this is my talon tsi i just bought..

 

[DogWhistle]

If the coolant level is full why did you have to let bubbles out of the system? What is the level in the overflow box?

 

[98mitsubishigst]

If the coolant level is full why did you have to let bubbles out of the system? What is the level in the overflow box?

i just tried it out, I'm not sure if there were bubbles. it didn't seem to do anything. overflow is in middle when i filled it to a while ago.

 

[Derk_272]

Try replacing you thermostat.

 

[98mitsubishigst]

Try replacing you thermostat.

im gong to replace the thermostat and the rad cap tomorrow..
wanted to see all your opinions though.

 

[eclipsyco]

Not trying to be a dick, but I'm not driving the car around if it could potentially be a engine failure like a head gasket going..

I don't have dsmlink on this one. this is my talon tsi i just bought..

No problem and sorry a saw your profile thought you had link on that car!
A gasket failure would probably cause overheat and coolant lost plus smoke from the exhaust.
Is your coolant reservoir empty? Maybe is sucking air when it gets hot
When was the last time you flushed the system?
If you are worrying about engine failure check for oil-coolant mixture

The cluster temp gauge is resistance type sensor the colder they are the highest resistance they have and viceversa and is really odd for that kind of sensor to fluctuate that fast as shown in the video so the sensor it self maybe failing so you might want to check that out first. I'm just trying to help.

 

[AWDPetmitsu]

I think the thermostat is acting up as well. I suggest an OEM thermostat only; no aftermarket as they don't maintain an accurate and stable temp.

 

[98mitsubishigst]

No problem and sorry a saw your profile thought you had link on that car!
A gasket failure would probably cause overheat and coolant lost plus smoke from the exhaust.
Is your coolant reservoir empty? Maybe is sucking air when it gets hot
When was the last time you flushed the system?
If you are worrying about engine failure check for oil-coolant mixture

The cluster temp gauge is resistance type sensor the colder they are the highest resistance they have and viceversa and is really odd for that kind of sensor to fluctuate that fast as shown in the video so the sensor it self maybe failing so you might want to check that out first. I'm just trying to help.

i just bought the car last week. The car is all oem, at 109k miles.. The fluid coolant bottle is sitting with coolant at halfway and has stayed that way since I've owned, i been keeping track.. and i haven't flushed the system yet.

hmmm, what do you mean about the resistance in the sensor??

and i know thanks man!

Is there a thought that it could be weather related? My temps won't even get steady above 185* (normally 200-205*) while its a quality 20 degrees out on average. If I watch the gauge sometimes I can see it go to 190* and then the therm opens and it drops, sometimes up to 10-15* at a time.

If you don't have leaks and its not losing coolant, not burning coolant, and you haven't had recent issues with the system or performance... I'd chock it up to that. Winter does harsh stuff to vehicles.

It is 29 degrees here, and i did go out in the snow in the car today but it was fine all day.. i have no idea! hahah I'm so confused

I think the thermostat is acting up as well. I suggest an OEM thermostat only; no aftermarket as they don't maintain an accurate and stable temp.

ill be changing that this weekend!

 

[Breezio69]

i just bought the car last week. The car is all oem, at 109k miles.. The fluid coolant bottle is sitting with coolant at halfway and has stayed that way since I've owned, i been keeping track.. and i haven't flushed the system yet.

hmmm, what do you mean about the resistance in the sensor??

and i know thanks man!



It is 29 degrees here, and i did go out in the snow in the car today but it was fine all day.. i have no idea! hahah I'm so confused



ill be changing that this weekend!

I actually misread what you originally wrote, sorry man. I thought you were saying it didn't get up to regular temp. But you are saying its going above... I missed that part or skimmed over it.

If you are going above it very well could be a thermostat. If you wanted to test it you can drop it in a pot of almost boiling water and see if it pops open... sometimes its not worth it though since its such a cheap easy part to replace.

 

[eclipsyco]

I have personally bench-test these sensors and I know for a fact that they would take around a second and a little more to display changes in resistance! Your video show immediate response as soon as you rev your engine.
Temp (C/F) K-Ohms
0/32 5.9
20/68 3.5
40/104 2.7
80/176 0.3

Good luck!

 

[98mitsubishigst]

I actually misread what you originally wrote, sorry man. I thought you were saying it didn't get up to regular temp. But you are saying its going above... I missed that part or skimmed over it.

If you are going above it very well could be a thermostat. If you wanted to test it you can drop it in a pot of almost boiling water and see if it pops open... sometimes its not worth it though since its such a cheap easy part to replace.

yeah I'm going to do that.. if its not overheating, and just going up an down .. and it isn't going to 3/4 of way on the gauge, do you think it is something smaller? i can't imagine it being head gasket..

how can i tell if water pump is shot or not?

I have personally bench-test these sensors and I know for a fact that they would take around a second and a little more to display changes in resistance! Your video show immediate response as soon as you rev your engine.
Temp (C/F) K-Ohms
0/32 5.9
20/68 3.5
40/104 2.7
80/176 0.3

Good luck!

i hate to sound like a moron or a noob here, but you completely lost me. What does this mean!

 

[Derk_272]

Good luck.

Also you can run without a thermostat if needed. You wont have heat in the car. You wont be over heating that way.

 

[98mitsubishigst]

Good luck.

Also you can run without a thermostat if needed. You wont have heat in the car. You wont be over heating that way.

i can't live without heat, haha my 165 pound body can't take this cold.

 

[Derk_272]

Lol I understand that. Just go pick a new one up and put it in. If it doesn't help your not out much $.

 

[toppertopper]

i had this same problem and it was the head gasket , start the car toss heat on full let it warm up it will foam/bubble ..if not i dont know

 

[Breezio69]

i had this same problem and it was the head gasket , start the car toss heat on full let it warm up it will foam/bubble ..if not i dont know

This isn't completely true, I had a small leak in a heater core hose that produced bubbling with the cap off. I WAS losing coolant, had bubbles, though it was a hg... had everything in a list ready to order then I looked one last time and found it. No more bubbles, no issues since. So that's not a 100% way to call hg.

You can check out if the pump is going out in almost the same way, with the cap off the housing the coolant should flow like a little stream. If you rev the engine it should push the coolant and overflow at a fairly quick rate.

Also, he (above) is implying, that with your car running at operating temperature, if you ohm test your temp sensor, then you should get a reading of .3ohms resistance.. if its off or fluctuating then the sensor itself could be the only culprit. He based this off the fact it raised and lowered with rpms in your video which is usually because of spikes in voltage with raised rpms. Like jumping another car and revving the engine to give the other car more juice, same principle with power to a gauge or sensor. Thats why there are tests for them.



Actually, what's funny is I've been driving my jeep xj since its been snowing.... when I put it in part time 4wd, the temp gauge drops to zero, then back to 2wd, I reads normal... coincidence? Haha

 

[98mitsubishigst]

i had this same problem and it was the head gasket , start the car toss heat on full let it warm up it will foam/bubble ..if not i dont know

If you read, i can sit at idle just fine and have my heat on and it makes the car cooler..

This isn't completely true, I had a small leak in a heater core hose that produced bubbling with the cap off. I WAS losing coolant, had bubbles, though it was a hg... had everything in a list ready to order then I looked one last time and found it. No more bubbles, no issues since. So that's not a 100% way to call hg.

You can check out if the pump is going out in almost the same way, with the cap off the housing the coolant should flow like a little stream. If you rev the engine it should push the coolant and overflow at a fairly quick rate.

Also, he (above) is implying, that with your car running at operating temperature, if you ohm test your temp sensor, then you should get a reading of .3ohms resistance.. if its off or fluctuating then the sensor itself could be the only culprit. He based this off the fact it raised and lowered with rpms in your video which is usually because of spikes in voltage with raised rpms. Like jumping another car and revving the engine to give the other car more juice, same principle with power to a gauge or sensor. Thats why there are tests for them.



Actually, what's funny is I've been driving my jeep xj since its been snowing.... when I put it in part time 4wd, the temp gauge drops to zero, then back to 2wd, I reads normal... coincidence? Haha

hmm looks like their was a stream coming from it.. could it still be bad?

 

[Breezio69]

A stream coming from what? If the engine and coolant is cool, take the cap off and start it and watch the coolant. The coolant will flow by the radiator cap filler neck. If it starts to froth up and come out of the hole then its a potential issue. If it just streams by (not overflowing) with no bubbles, not too suspect. At the same time, with the cap off, if you don't see bubbles etc etc, then you can give the throttle a blip and the pump "should" send a rush of coolant out the filler neck. That lets you know the coolant is being pushed by the pump.

 

[98mitsubishigst]

A stream coming from what? If the engine and coolant is cool, take the cap off and start it and watch the coolant. The coolant will flow by the radiator cap filler neck. If it starts to froth up and come out of the hole then its a potential issue. If it just streams by (not overflowing) with no bubbles, not too suspect. At the same time, with the cap off, if you don't see bubbles etc etc, then you can give the throttle a blip and the pump "should" send a rush of coolant out the filler neck. That lets you know the coolant is being pushed by the pump.

I see a stream come by, and it won't bubble out of the neck or overflow..

 

[Derk_272]

I see a stream come by, and it won't bubble out of the neck or overflow..

I think this is because your thermostat is stuck closed.

 

[98mitsubishigst]

http://youtu.be/xS_pTS-0ZDA

^^ Video

Replaced the thermostat, and the rad cap.. i replaced the thermostat with a 170 degree one as well.. what do you all think? it has a little stream moving along at idle so I'm assuming that means the pump is pushing coolant through.. Also you can see me rev it up it'll bubble up and out! so its definatelly pushing..

No bubbles, i let the car idle and sit while i put more coolant in to burp the system, isn't leaking anything, and still has full coolant.

What do you all think?