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2003 Protege5 coolant temperature

Just wondering, I've recently got a P5 with 228k on the original rad and after reading a thread or two I saw that our temperature gauges aren't reliable, after doing some unrelated troubleshooting I crossed the two electric plugs for the intake valves and the car ran like crap (big dummie :ROFLMAO:) I remembered reading that about the coolant and opened torque to check if maybe I was getting too hot and even after fixing that and getting the new solenoids in, when I climb a steeper grade at about 55 the coolant gets up to 210 (before cleaning the rad it would get to 224) I am reasonably experienced mechanically and before I go and try a new t'stat or look into the water pump impeller being erroded away I thought I would ask and see if y'all have any data on the "normal" temps. The biggest reason I ask is in the cars I have ever looked at the ect they all never got above 200 on that same hill most never got even above 196.

A little extra info...

Hot idle w/o AC: 198-203, fan on at 203-205
Hot idle w/AC : 186 to 194
Hill climb w clean rad at about 86 ambient 208 max reported temp
 

i12drivemyMP5

___ 323F ___
Contributor
Could vary a bit depending on what thermostat you are running and if the one you have is functioning properly.
 
After driving it a bit more and putting a little more thought into it, I am leaning toward thermostat. from what I gather it's calling for a 180deg stat and it never settles down toward 180. I'd bet when I get it in and test the old one I am going to see it only partly open. I have been doing a daily temp check on what I will just call "the hill" and it's settled into 208 to 213 on any given day. Heard hoof steps and thought unicorn when it may have just been a horse. lol
 

pcb

The Diagram Dude
:
2002 MP5
I tried to get some numbers for you but my Bluetooth OBDII reader won't pair with my new phone.


I've got this for you though...


20210806_110859.jpg
 

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Make sure you have a thermostat with the "jiggle pin" for your FS engine and it is positioned properly as shown in the lower part of the illustration.

1628267955656.jpeg
 
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I've also noticed that on your instrument cluster water temp gauge, the bottom line is 100*F and each hash line above it is 10 more degrees.

So counting the lines up from the bottom line the normal operating temp is around 190* and a quick glimpse at it will be just below the gauge pointer pointing at the 9 o'clock position.
 

pcb

The Diagram Dude
:
2002 MP5
I've also noticed that on your instrument cluster water temp gauge, the bottom line is 100*F and each hash line above it is 10 more degrees.

So counting the lines up from the bottom line the normal operating temp is around 190* and a quick glimpse at it will be just below the gauge pointer pointing at the 9 o'clock position.


Our temperature gage is a dummy gage and isn't linear.

I remember checking the numbers years ago and the needle rose to just under the halfway mark and stayed there but the actual coolant temperature kept rising until the fan came on.

I was reluctant to unplug the fan to see how hot the car needed to be before the temperature gage started to rise above the halfway mark.

It has to be REALLY hot for the needle to rise above the halfway mark.


You can probably use the scale between the halfway mark and the "H" mark to judge how much your head has warped. Lol
 
thanks y'all i am going to look in a little bit and get it ordered, I 've got to source the neck on the rh side of the engine for the lower rad hose, it's corroded and leaking at the hose.

I was already familiar with the dummy gauge, seems to be a popular thing, even on fords the oil and coolant gauges are dummy, if it's got pressure the gauge goes to the middle.

maybe get a pot of hot antifreeze so you can heat it up past boiling and stick the sensor in there
 

pcb

The Diagram Dude
:
2002 MP5
I found this at Rockauto...
It looks like you can get a 170°F or 180°F thermostat.

Screenshot_20210806-141821_Brave.jpg



Here's the fail-safe version.
It sounds like a good idea.

Screenshot_20210806-141511_Brave.jpg



PS... I remember a lot of guys that have overheated their engine but I don't recall anyone finding a failed impeller on their water pump.

The impeller blades are metal (at least mine were) and the only way the pump failed, was to start leaking at the failed bearing.


PSS... If it's time for a new timing belt, you could replace your water pump along with your belt.
(Get the full timing belt kit with gaskets, T-belt, idler pulley, tensioner pulley, and that all too important tensioner spring. My old pulleys were really wobbly.)
 
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pcb

The Diagram Dude
:
2002 MP5
maybe get a pot of hot antifreeze so you can heat it up past boiling and stick the sensor in there

I remember a guy who's car was running like crap and had a couple of mechanics look at it and they couldn't figure it out.

The one mechanic suggested maybe a contaminated ECT sensor, so he removed it and cleaned it with a wire wheel on a drill and he fixed his car.

The ECU was getting false information from the ECT sensor because the corrosion was insulating the probe and it wasn't reading properly.
 
Finally got it done this morning. I didn't get the fail safe stat as they were OOS when I looked. I got the MAHLE stat and It was much beefier than what I pulled out of the car.
I had to clean up the gasket area and the neck for the hose as they were really corroded. I will likely need to replace both housings as there was some pretty deep pitting on both sealing surfaces and the old t-stat seal was looking pretty narly. I decided to boil the old and new stat to compare opening and closing temperatures, my thermometer was busted so I couldn't collect that data. the old stat opened right with the new stat but the new stat has a larger hole and does open a little more than the little one. I think someone just got the wrong stat somehow even though it was a 180deg one.
 
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pcb

The Diagram Dude
:
2002 MP5
Keep a real close eye on your temperature gage.
If it ever rises above the half way mark, you're in trouble.

You can go from normal operating temperature to a warped head in minutes.
 
oh, I do, I have an obd scanner and torque pro with some gauges set up, I've been watching it daily going up the hill OMW home. from 180 to 223 that needle never moved. (223 was the highest I ever saw it and I backed out of power rather quick)

Thankfully I've got about a decade worth of working on my own stuff to back me up but I still get to enjoy learning something new now and again.

what would you say is is the warning temperature and danger temperature for this engine? I believe I can set those up somewhere in torque, it'd be nice to have that going so I am not staring it so much.
 

pcb

The Diagram Dude
:
2002 MP5
what would you say is is the warning temperature and danger temperature for this engine? I believe I can set those up somewhere in torque, it'd be nice to have that going so I am not staring it so much.


I have no idea.
All I can suggest is to unplug your fan and check to see when the needle of your temperature gage starts to move.

I wasn't willing to do that to find out. Lol

Some guys have saved their car from a warped head by turning the heat on full blast when the needle starts to rise.

PS.. Turn your AC on too. That turns on both fans to help with cooling.
(that kinda sounds counterintuitive because you'll be adding more heat to the engine bay, but the compressor shouldn't kick in with the interior fan set to hot.)


I'm almost positive that as the needle just starts to rise above half, you are in the warning zone.

The guys who warped their head, had their needle pinned at hot.
 

pcb

The Diagram Dude
:
2002 MP5
oh, I do, I have an obd scanner and torque pro with some gauges set up,...

You might want to consider something like this...

20210904_170050.jpg




This is what Jackie chan did...

It's a tablet installed in his radio spot.

You can customize your screen to see what ever you want and set all kinds of alarms for different things.

You can even set it up as a "head unit" with music to run the stereo.
 

pcb

The Diagram Dude
:
2002 MP5
... I think someone just got the wrong stat somehow even though it was a 180deg one.

It's probably aftermarket or ebay.

It fits and works (sort of) but it isn't built properly to factory OEM specs.

It would probably work fine for me.
I live in Canada where it's cold and I don't drive up hills. Lol
 
I'm down here in north alabama. hot and humid so ac on recirc most of the year. we are only just starting to see less humidity. it's about prime time for me to gut the interior and clean the seats, carpet, and even the headliner. prev owner was dirty but thankfully not a smoker. I wish I was making the money I used to make, I've wanted to do that for a good while with the tablet.