Temp Rising from thermo?

[Spanky2324]

Alright I was driving to work yesterday and noticed as I started going from 4th to 5th my car began to raise in temperature so I slowed down and it stopped raising and kinda sat a little below 3/4 of overheating. I decided to pull again in 5th and it would overheat so I got off the freeway finally and was on the street so I drove it and pulled it a couple times and it the gauge needle seems to site in the middle right above the 1st little water looking line on the picture. I leave work last night and I get back on the freeway and it does it again. My windows were kidna foggy so I turned the defrosters on and it seemed to keep the temp at a bearable state for me to get home. I would really like to know what is going on with the car and what I can do to fix it. I have a thermostat that I bought from jnz tuning but it didn't come with a gasket for it. Will flushing it and putting in a new thermostat fix this problem. I'm new to working on cars so I need some big help here. Thanks in advance.

 

[hahnsuper16g]

I got a 160 degree thermostat from autozone and that works great. Areas i would check other than thermostat would be water pump and your coolant level. If your heat isn't blowing check your heater cores.

 

[John_GST]

I had this same problem just a few weaks ago, it ended up being my thurmostat was sticking open not allowing anything to really cool off and it was just pumping hot water back through the engine. Mine would get to the point that it would boil out of the drain tube and I was unable to get very far at a time. I went ahead and flushed my radiator, put a new cap, and thermostat in. I also went with a 160 degree thermostat. It fixed my problems right away. Just as stated above go ahead and check your water pump also, an easy way to tell is that there should be some fluid leakage from it, but that isn't always the case. So if you have no leaks and after you change your thermostat and flush your radiator and you are still gettting a high temp reading. More than likely it will be with the water pump, but can also be random cunjunction of other things that can go wrong, but always start at the bottom of the line first and work your way up to the bigger things.

 

[John_GST]

You can pick up a gasket for your thermostat at any auto parts store just take it with you and make sure you get the right size.

 

[kenamond]

Alright I was driving to work yesterday and noticed as I started going from 4th to 5th my car began to raise in temperature so I slowed down and it stopped raising and kinda sat a little below 3/4 of overheating. I decided to pull again in 5th and it would overheat so I got off the freeway finally and was on the street so I drove it and pulled it a couple times and it the gauge needle seems to site in the middle right above the 1st little water looking line on the picture. I leave work last night and I get back on the freeway and it does it again. My windows were kidna foggy so I turned the defrosters on and it seemed to keep the temp at a bearable state for me to get home. I would really like to know what is going on with the car and what I can do to fix it. I have a thermostat that I bought from jnz tuning but it didn't come with a gasket for it. Will flushing it and putting in a new thermostat fix this problem. I'm new to working on cars so I need some big help here. Thanks in advance.

I think you're on the right track with the thermostat. I got mine from Autozone and it came with the gasket, so I'm not sure if they sell them separately or not.

The install is pretty easy. Get a Haynes manual while you're at the auto parts store, and you'll see how little you have to do. The one problem you may have is that the thermostat housing may be significantly corroded where the radiator hose clamps to it, and you might have a leak there as a result. I cleaned my housing up with sand paper. If the hose is in bad shape (the corrosion on the housing swells which puts "dents" in the inside of the hose), consider replacing it.

Good luck!

 

[Spanky2324]

Alright thanks guys. About the gasket on the thermo is it supposed to be already on around the thermostat ring or is it loose cause I bought the mitsu. oem thermostat to replace and I'm gonna order a new oil and radiator cap tonight being my oil cap is leaking.

 

[kenamond]

Alright thanks guys. About the gasket on the thermo is it supposed to be already on around the thermostat ring or is it loose cause I bought the mitsu. oem thermostat to replace and I'm gonna order a new oil and radiator cap tonight being my oil cap is leaking.

The one I got from Autozone was separate but included in the box.

 

[95CarbonEclipse]

Alright thanks guys. About the gasket on the thermo is it supposed to be already on around the thermostat ring or is it loose cause I bought the mitsu. oem thermostat to replace and I'm gonna order a new oil and radiator cap tonight being my oil cap is leaking.

Yes, they are separate parts and if you go to $atan, then realize that the gasket has a seperate part # then the thermo does.

As to the OP, I feel that the T-stat is most likely your culprit, but I wouldn't mess around and buy one that is lower then 180-185*. If you run too cold you'll never get out of closed loop and your performance/gas mileage will suffer because of it. If the T-stat doesn't do the trick, I'd do a coolant flush. Hell, you may want to do one anyway as they are not that hard/expensive and you're already 1/2 way done while changing the T-stat. Finally, if that doesn't fix it... start looking for a new water pump and T-belt.

 

[oldman]

If you run too cold you'll never get out of closed loop and your performance/gas mileage will suffer because of it.

You mean "get into closed loop" or "get out of warm up mode".

 

[95CarbonEclipse]

You mean "get into closed loop" or "get out of warm up mode".

I knew I was going to botch that as I was writing it. I can never remember which wich is witch. I just remember the part that makes your car go Poo!

Thanks!

 

[DSMopar]

No offense but the too much water flow theory is just a myth. Your stat was likely sticking closed.

Cooling problems can be a real pain to diagnose sometimes. It can be a real obscure reason that you'd never normally think of.

That said the most common things are:

- T-stat
- Junk in system
- Improper airflow
- Headgasket or cracked head

Now the t-stat is so cheap and easy that shotgunning it just makes sense .

Junk in systems not easy to diagnose or do but it's usually not a bad idea with an old system that probably has never been flushed. A plugged up radiator falls in this category.

Improper airflow can be fairly common. Causes are just plain junk in the radiator, hair, dirt etc can really disrupt airflow. I usually take off the fan and spray water/compressed air from the back side into the front to make sure it's all clear. Often people install god awful body kits that were designed by some idiot with no analysis on airflow, and now your radiators not getting near as much airflow at speed. Also big intercoolers with not enough flow through them can cause issues. Another very common problem is fans that aren't working. Yes some cars need them even at speed so make sure they're turning on and kicking on the high range for A/C or when the temp hits the range where the high speed is supposed to kick on.

Head gasket or cracked head/block is fairly uncommon but possible. Typically these will cause white smoke out the tailpipe and or a over-pressurized cooling system.

So theres your most common ones. Water pumps are probably the most over-replaced part next to starters. I've only seen maybe a couple situations where the WP caused an overheating issue (impeller broke loose from shaft and was spinning freely WTF ). If it's not weeping it's probably not broken... so don't fix it.

Engine conditions obviously can create more heat than the cooling system can dissipate. Heavily modified engines with high compression can do it (not likely on a turbo motor ), incorrect timing, detonation etc. But it sounds like your car is mostly stock and was running OK so we'll assume theres no problems.

Considering your car seems to run cooler if you keep the revs up vs airflow i'm going to wager it's a coolant flow problem which would be thermostat or plugged up radiator.

 

[Defiant]

No offense but the too much water flow theory is just a myth.

Not all agree.
http://www.dsmtuners.com/forums/showthread.php?t=130293

 

[DSMopar]

They may not, but most of them have no thermodynamics or heat transfer backround. More mass rate = more heat transfer, FACT.

For the "myth" to be true the air exiting the radiator would be cooler and the engine would be hotter...

 

[oldman]

They may not, but most of them have no thermodynamics or heat transfer backround. More mass rate = more heat transfer, FACT.

For the "myth" to be true the air exiting the radiator would be cooler and the engine would be hotter...

I'm not understanding what you're trying to say, are you suggesting that the thermostate is useless?

 

[kenamond]

They may not, but most of them have no thermodynamics or heat transfer backround. More mass rate = more heat transfer, FACT.

For the "myth" to be true the air exiting the radiator would be cooler and the engine would be hotter...

I'm not sure what the specific statement of the myth is, but running below normal operating temperature is still not good.

If the myth is that more flow causes the car to run hotter, I'm not so sure that it's a simplistic as "More mass rate = more heat transfer, FACT." I actually disagree with that statement. The facts are:

1) The energy flow out of the coolant has to be equal to or greater than the energy flow into the coolant by the motor or the coolant temperature will increase.
2) The rate at which energy is removed from the coolant system via the radiator is dependent on the temperature difference between the coolant and the air temperature, the convection and conduction properties of the radiator, and the air flow rate through the radiator.

That is not as simple as coolant mass flow. If we look at what's going on where heat is being removed, you can make a few observations. If the coolant is flowing through the radiator faster, there is truly less time for that heat transfer to take place, but the coolant is cycling around the system more times per minute, so it passes through the radiator more frequently at high flow rate than at low flow rate. Also, the heat transfer properties of the radiator are certainly dependent on the fluid velocities both inside and outside the radiator, as this affects convection.

There are very similar things occurring where heat is being added to the coolant (in the motor). Usually, increased fluid velocity increases convective heat transfer. However, the reference to boiling pockets sound like fluid dynamics effects that give pockets of coolant that are stagnant eddies (whirlpools) that linger in one spot rather than flowing with the rest of the coolant. If these develop at higher flow rates, then you effectively insulate the engine at these locations leading to local hot spots in the engine (probably not good).

So it's not a simple thing, and you'd need a lot of mass and heat transfer as well as fluid dynamics analysis to make any definitive statements based on theory. And it sounds like there are other components in the cooling system that are dependent on the flow rate of the coolant (water pump).

I think that folks should run with whatever works (and there's a lot in that word, "works").

 

[DSMopar]

I never said the thermostat is useless, of course it's needed to get the car up to temp and keep it there.

I merely was stating that removing the thermostat will not cause an adequate cooling system to over-heat. If it's overheating with no stat it'll overheat with one (a good one).

Of course there's more factors but obviously i'm keeping variables the same. Keepibg air convection from radiator, heat generation from motor, temps constant etc. More mass rate of coolant moving = more heat transfer. Yes you can have pockets etc but you'd have to have a real high flow water pump to do it. And even if this were the case you'd see even less temp in the cooling system because of the lack of transfer from these hot spots.

The point of my post was not to complicate it, it's merely to debunk the myth that no stat = less heat transfer.

 

[oldman]

I merely was stating that removing the thermostat will not cause an adequate cooling system to over-heat. If it's overheating with no stat it'll overheat with one (a good one).

The point of my post was not to complicate it, it's merely to debunk the myth that no stat = less heat transfer.

I thought that would be common sense, didn't know there was a myth stating otherwise, which post were you debunking in this thread anyway?

 

[DSMopar]

I had this same problem just a few weaks ago, it ended up being my thurmostat was sticking open not allowing anything to really cool off and it was just pumping hot water back through the engine. Mine would get to the point that it would boil out of the drain tube and I was unable to get very far at a time. I went ahead and flushed my radiator, put a new cap, and thermostat in. I also went with a 160 degree thermostat. It fixed my problems right away. Just as stated above go ahead and check your water pump also, an easy way to tell is that there should be some fluid leakage from it, but that isn't always the case. So if you have no leaks and after you change your thermostat and flush your radiator and you are still gettting a high temp reading. More than likely it will be with the water pump, but can also be random cunjunction of other things that can go wrong, but always start at the bottom of the line first and work your way up to the bigger things.

 

[oldman]

Then make sure you quote the person you're disputing next time to avoid confusion, much information was posted after that post which had pretty much indirectly disputed that particular post.

 

[DSMopar]

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Since only one person mentioned it, logically you'd think I was talking to him .