Sign in to follow this  
Followers 0
caseyweed

Temperature Fluctuation

66 posts in this topic

Sorry to be asking so many questions but I just got my car and am noticing a few little quirks I would like to see if they are normal or not. First off my car is a '95 626 with a v6 and automatic transmission. I notice sometime my temperature gauge fluctuates. For the most part, it's rock solid right in the middle and then sometimes I notice it climbs up in temperature pretty quick and then back down almost a fast as it climbed. -_- Usually it goes about 3/4 of the way to red when it does it but earlier tonight after I had gotten off the highway and slowed down it got pretty close to the red and then when back to the middle within a half a minute. Is this normal? Does it sound like a serious problem or just a problem with the gauge?

Share this post


Link to post
Share on other sites

I had sort of the same problem with my skyline before. If you are confident your car is not overheating then it could be a sensor problem. The temperature gauge gets its reading from the water temp sensor. It has a thermistor which changes resistance according to the temperature of the water. If somehow along the circuit, there is something that is making causing it to have less resistance. ie, short circuit between the two wires. You could get a high reading and then drop as soon as the short circuit goes away.

I think your car has something to do with the sensor cos water's temp can't go up or down that fast.

Share this post


Link to post
Share on other sites
I think your car has something to do with the sensor cos water's temp can't go up or down that fast.

yes it can ;) there is a lot of thermal energy coming off that block.... if you don't believe me, start your car, wait a few seconds and grab the exhaust header ;) couple this is low coolant and it can shot up quickly...

That being said. Top off your coolant. I had this same problem because I accidentally let some coolant escape (I forgot to put the cap on tight) and did not realize it. All it needed was a little more coolant and she was all better.

IF that does not work, try washing your radiator. Dirt and other debris on there acts as an insulator reducing its capacity to vent heat off ;)

--

You can always check the guage with a multimeter - check the repair manual for exact instructions B)

Share this post


Link to post
Share on other sites

^Agreed. First check your coolant level. Notice that there is a coolant filler cap. on the passenger side of the engine, next to the oil dipstick. When the engine is cold, open it, and check it is full to the brim.

Share this post


Link to post
Share on other sites

I had this same problem in my car, and all that it was was the temperature sensor. I would suggest trying that after making sure your coolant is topped off. I'm not sure about your car, but on my 98 the sensor was right beside the airbox on the block.

Share this post


Link to post
Share on other sites

Possible problems:

-temp sensor

-thermostat

-radiator clogged/dirty/empty

-electric cooling fan not operating correctly/broken

-weak/collapsing radiator hose

-serious ignition problem causing detonation problems/heat problems

-engine filled with sludge

One time i had an overheating problem with my Jetta. Turned out the problem was not so much mechanical, but a sheet of pollen and debris (looked kinda like packed dog hair) had formed covering the front of the radiator (behind the evaporator). I loosened the radiator, reached in and the whole sheet of nasty stuff just pulled right off. Problem solved.

Share this post


Link to post
Share on other sites

Thanks for all the responses. I topped off the coolant and was able to get about a half gallon in there including in the overflow. Driving home today the heater started to warm up right away. So far so good. I will report back in a day or 2 if it is not fixed.

Share this post


Link to post
Share on other sites
Thanks for all the responses. I topped off the coolant and was able to get about a half gallon in there including in the overflow. Driving home today the heater started to warm up right away. So far so good. I will report back in a day or 2 if it is not fixed.

if it took that much... I bet that was it :blink:

Share this post


Link to post
Share on other sites

you guys are right.... it's most probably be because the coolant level was low and once he reved, the air pockets hit the sensor and they are much hotter than the water. Shooting the needle up. I think so anyway......

Share this post


Link to post
Share on other sites

Great!

But now you have to ask yourself why you were able to add half a gallon!

Something wrong somewhere!

Flora

Share this post


Link to post
Share on other sites

I just bought the car so I hope nothing major is wrong with it! I haven't seen any leaks. Most of that 1/2 gollon went into the overflow. I'm hoping that maybe they just haven't filled it in a long time... :unsure:

Share this post


Link to post
Share on other sites

Hi!

yeah, it's possible that they never maintained it properly as the coolant will evaporate in hot weather, etc.

Just keep your eye on the level in your overflow tank, you might have to add a little since you just filled the system up...if you notice you're starting to add coolant every week, then start looking for other problems.

Good luck and happy motoring!

Flora

Share this post


Link to post
Share on other sites

Thanks for the help everyone. Hey flora, I thought you were'nt going to help me anymore? :P I'm just kidding, thanks for the responce.

Share this post


Link to post
Share on other sites

If one was to accidentally overfill the overflow container would the extra coolant drain out somewhere? The reason I ask is because when I filled it up yesterday I got it pretty full and when I went to check the coolant level this morning it

Share this post


Link to post
Share on other sites

I'm not 100% sure, but typically there will be a vent in case of overpressure ;)

It might have just been displaced air in the block :huh:

When you shut the car off (after it's nice and hot from running a little bit), what do you smell when you open the hood? Just kind of hover over a few areas and take a nice whiff and describe the smell (if any at all).

There could be a pinhole leak (which would only appear when pressurized). Water leakage might not make it to the ground, it could get stuck on top of the splash guards - so just check there for any shiny spots (indicating it is wet). You could always get a pressure test tool (rent from autozone). It hooks up to the rad cap, you pump the system and see if it holds pressure. If the pressure drops, there is a leak somewhere.

Share this post


Link to post
Share on other sites

I had the same problem. It started with a new thermostat that was installed at a local shop. The temperature would go up quite often. Anyway finally that thermostat blew stranding me. Replaced it with mazda parts and now it is running fine. I also had the problem with disappearing coolant. turned out to be worn out radiator cap. but ofcourse that never caused too much coolant leak.

cheers

Share this post


Link to post
Share on other sites
If one was to accidentally overfill the overflow container would the extra coolant drain out somewhere? The reason I ask is because when I filled it up yesterday I got it pretty full and when I went to check the coolant level this morning it

Share this post


Link to post
Share on other sites

Thanks for the help everyone. Everything seems to be normal. As tomithy said, when the engine is warm the overflow if full and when it's cool it drops down a little. It doesn't apear that anything is leaking. Whenever I get a new car I tend to be over critical for the first month or so that I have it, and I swear I imagine most of the problems I find. <_<

Share this post


Link to post
Share on other sites

OK, false alarm. Everything is not ok. The problem is back and my coolant is definitely low. I have notice a small puddle right in front or the front left tire. I'm wondering if my overflow it leaking. It has been raining cats and dogs ever since I saw the puddle and I haven't been able to look at it closer. I will keep you all posted. Besides the overflow, what else is on that side that it would be leaking from? Again, I really appreciate all the help everyone has been giving me.

Share this post


Link to post
Share on other sites

is that left side when you are sitting in the driver's seat? Or looking at the engine bay?

If it is the right side (whe you're sitting in the driver's seat) I bet it is the water pump leaking. When they start to go bad they will leak out of a weep hole to let you know its time to change. My WP lasted 400 miles (slowly leaking) before it started leaking too much that I could not drive further than 10 miles. Best to take care of it ASAP if it is the WP :blink:

Share this post


Link to post
Share on other sites

^Yep. Cracked reservoir is common. I'm trying to remember how you get at it. I think you remove the wheel, and splash guard.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0