Water Pump???

[mwatso34]

I have been having some overheating issues. I have a 2003 MP5 with just barely over 100K on it.

About a week ago I noticed just as I was pulling away from a light that the temp gauge was at 3/4, but dropped quickly down to 1/2 as I was moving. Over the next week it seemed fine, with temp gauge at 1/2, and the fan kicked on and off as it should. There were two time when the gauge would start going up again when I was stopped, but as soon as I let off the brake it would start going down again.

Today was little warmer, 55F instead of 45F like it has been for the past week, and on my way home I was stopped at a light just 10 min. after leaving my work and the car died. I started again and as soon as the car started the temp gauge started to climb so I immediately pulled over. The temp gauge was reading 1/2 when the car died.

I haven't noticed any puddles under the car, but I have to think it is the water pump. A year and a half ago I over heated on the way home from work; replace the thermostat and the temperature sensor and it worked fine until now.

 

[pcb]

It sounds to me like the fan isn't coming on every time when it's supposed to (or fans,... I don't know if they both come on without AC on). I would check the connector on the fan(s) for corrosion or some sort of bad connection.
Were your fan(s) running when the temp started to rise ?? I hear my fan(s) come on well before the temp gauge starts to move (I've never actually seen the temp gauge rise above half)
I'm pretty sure your temp sensor is working because your gauge is registering,... and I'm pretty sure your thermostat is working because it appears that the air through the rad is what makes the difference.
I'm thinking your fan isn't always coming on when it's supposed to, so I'm going with a bad connection of some sort.
I don't know why the car died ??? Did your CEL come on ?

In the mean time,... turning your heater on full snort goes a long way toward bringing the temp down,... you might have to roll down your windows so you don't melt, but it helps prevent core meltdown.

 

[rit14623]

Well, have you changed your timing belt? That would be a good time to change the water pump since the timing belt needs to be removed in the process.

 

[sleepwalker]

In the mean time,... turning your heater on full snort goes a long way toward bringing the temp down,... you might have to roll down your windows so you don't melt, but it helps prevent core meltdown.

This.

This is also very useful for determining if your car is overheating because the pump isn't pumping. If you crank up the blower and hot air comes out, and keeps coming out, you can be pretty sure that your water pump is still pumping water. If the air doesn't heat up, either your pump isn't pumping water, or there's no water to pump.

I hesitate to suggest something so elementary (for fear of being branded Captain Obvious - again) but double check to make sure your coolant isn't low. I haven't experienced it in my P5, but in my Neon way back when, I had a problem like that after I replaced the headgasket, and it turned out to be big air bubbles in the cooling system. They would get stuck in certain places - like right where the coolant sensor was - and play havoc with the temp gauge.

 

[mwatso34]

Thanks everyone.

pcb - The fan is coming on before the temp gauge ever starts to rise. It hasn't thrown the CEL.

rit14623 - I have not replaced the belt before. I think that is what I am looking at, replacing the water pump and timing belt.

sleepwalker - The heater puts out really hot air and doesn't cool down after running for awhile. I tried to get any air out and topped off the coolant, it wasn't low at all. That was a week ago and still having the same issue.

 

[pcb]

OK,... I'm thinking thermostat now. You can start your car from cold with the rad cap off and watch for fluid movement at the filler neck there will be no movement at first but you'll see something as the thermostat opens up. If the car is getting hot (fan comes on) but you can't see flow then I'm pretty sure it's the thermo. (again) (hell you could probably stick your finger in the filler neck and it won't be hot,... I'm not recommending that but I'd do it)
It's a good time to check for bubbles again.

Your thermostat could be intermittently working and it might be hard to diagnose. I'm still wondering why forward movement seems to cool it down, it could be an intermittent fan issue or some weird combination of both ???

You did "burp" it properly right ??

 

[mwatso34]

If by “burp” you mean, warm up motor – run at 2.5k rpm for 5 min – run at 3k rpm for sec., then yes.

So I drove it home from work today, 22 miles. It was mostly freeway (60mph 2.5k rpm). It warmed up quick, but then the temp gauge stayed at way until I came to a light, about 5 miles from home. Temp gauge started to rise so I put it in neutral and reved the motor to 2k rpm. The temp gauge dropped to and I made it the rest of the way home. When I pulled into my driveway I let it idle for 15 min. and the gauge didn’t move past .

I am not sure what is going on. Side note, I had the heater cranked all the way home just in case, but when I had it idling in the driveway I didn’t have the heater on.

 

[pcb]

If by “burp” you mean, warm up motor – run at 2.5k rpm for 5 min – run at 3k rpm for sec., then yes.

So I drove it home from work today, 22 miles. It was mostly freeway (60mph 2.5k rpm). It warmed up quick, but then the temp gauge stayed at way until I came to a light, about 5 miles from home. Temp gauge started to rise so I put it in neutral and reved the motor to 2k rpm. The temp gauge dropped to and I made it the rest of the way home. When I pulled into my driveway I let it idle for 15 min. and the gauge didn’t move past .

I am not sure what is going on. Side note, I had the heater cranked all the way home just in case, but when I had it idling in the driveway I didn’t have the heater on.

I don't wanna ask a dumb question but you obviously had your rad cap off during the "burp" right ??

I'm still thinking a bad thermostat.

This is a picture of Hatchkittens bad thermostat:

I could see that crack hanging up in an intermittent kind of way.

I could still be a bubble but I don't think it's an intermittent kind of thing

The other thing is a bad water pump but I don't know if they fail in that kind of way,... they usually start leaking through the bearing seal.

 

[pcb]

Here's Hatchkittens symptoms:
Aaaaanddd 49996 miles on the car and it decides to spew coolant all over my nice clean engine bay... great...

On my way home from work today out of the blue the thing decides to start to overheat on the parkway home *crossed my fingers* and made it home OK
Only to open my hood and find green everywhere all over my intake, battery housing, fuse box gross.
Flushed the system and still overheats when holding revs @ 2500rpm for 5 min as per the service manual only made it to 2 1/2 minutes until it started to overheat.
It stays and normal operating temperature when at idle.
Did a little research on the forum and I am concluding the thermostat is stuck, going to Advanced Auto Parts and going to pick up a new one.
I'll have to replace it in the morning when I can see >.< UHG

So I got the car fixed this morning. Replaced my thermostat with a Stant 180* from Advance. 20 minutes later, no overheating, no spewing, no check engine light

 

[mwatso34]

pcb - Thanks for your help. I did have the rad cap off when I burped the system.

That is exactly what the thermostat looks like that I replaced a year and a half ago (I still have it), I mean the same cracks. I had replaced it with a Murray Ultra.

Mine is not spraying, dripping, or loosing any anti freeze. I have marked my coolant reservoir with a piece of electrical tape. When the car is cold the coolant sits at the full mark. When the car is at operating temp the coolant in the reservoir goes up to my tape marker. It hasn't changed.

I am not sure if it is the water pump either, like you said I don't think they fail that way. Every post I have seen on water pumps going out they had puddles of coolant under their car.

Side note, do you know how much coolant it takes to refill the system if it is flushed? I have PDF of the service manual but can't find the volume of coolant it takes.

 

[pcb]

A properly functioning coolant system automatically "pumps" the air out of the system and then draws liquid back in during the hot/cold cycling of the car.
It sounds like yours is functioning properly.

I couldn't remember how much to use,... I just remembered I used an entire 4 liter jug.
If you just get the un-mixed kind (cheaper) and pour it in the over flow jug to half of where it's supposed to be then all the rest goes into the rad then just top it up with distilled water from thew grocery store (cheaper) then top up the over flow with the water the fill the rad, you will have no left over stuff to worry about except the water (but you can drink that)
Your left with an almost perfect 50/50 mix but on the happy side of cold weather protection.

 

[pcb]

I just noticed that your from SLC,... I don't know what that means but I'm assuming you're from the US and your gallon jugs equal 3.785411784 liters, so that being mixed 50/50 would yield you 7.57 liters so you're still good. (dead on actually)
As I'm sure you know,... You can go up to 70% anti-freeze for more cold weather protection but then you'd need two jugs and have leftovers.

 

[tweety2300]

Remove thermostat and see what happens, even if its brand new it can fail and stick partially open.

 

[P-Funk!]

Or to test the water pump - open the radiator cap and bump the throttle - did the level go down? (and then rise back)

 

[P-Funk!]

What is the temperature difference between the inlet hose and the outlet hose?

Inlet hose should be hot (duh) but outlet hose should only be 'warm' to the touch for a perfectly functioning radiator....

 

[BRIAN_MP5T]

Like was suggested, remove the T-Stat and refill the system.

if it goes away then the problem is not the pump

 

[pcb]

^ what He Said

 

[mwatso34]

pcb - SLC is Salt Lake City, Utah. I am mixing 50/50.

P-Funk! - The inlet house going into the top of the radiator is hot, can't touch it for long at all. The outlet hose coming out of the bottom of the radiator is warm and grab onto it on hold.

I took out the thermostat tonight and tested it. It started opening between 175 and 183 F and was fully open by 200 F as it should be according to the manual. Put it all back together and went for a drive 2 miles to return the thermostat I got incase it was bad. Store was only 2 mi from my house. After returning it I got in my car and started it up. The temp started going up to 3/4 so while I was still in park I reved the motor up to 2k rpm and the temp came down. One other time on my way it started going up when I came to a stop but went down as soon as I started going. I thought I would pull into the driveway and put it in park and it would start going up right away, but it didn't. In fact I sent there with the car on and in park and the needle didn't budge.

I don't know what is going on!

 

[pcb]

What about a partially plugged rad ??? When the thermostat opens up it just "allows" the fluid to pass,... it isn't forced to. With a higher RPM,... it may add enough fluid pressure to "push" it through the rad. ???

So what about some rad flush ???

Any thoughts ???

What did it look like when you looked down the filler neck ??

A couple of pics of my old one:

 

[pcb]

Those things could very well be like our coils fussy and hard to diagnose.

Related Parts
2002 MAZDA PROTEGE5 2.0L L4 : Cooling System : Thermostat Price
BECK/ARNLEY Part # 1430724
ORIGINAL EQUIPMENT TEMPERATURE; INCLUDES SEAL NO; INCLUDES HOUSING NO; TEMPERATURE 180

CAD$8.60

It's a ten dollar part,... why didn't you just replace it??

Put it together without the thermostat if you wanna eliminate it as a suspect