I have a problem with my car overheating when going up grades or traveling on the freeway. The car is completely stock & just started this the other day. Here is a list of checks I did...

Radiator: completely clear of debris & bent fins
Leaks: none (no visible leaks anyways)
Fluid: clean & green
Fluid level: completely filled to base of neck (no bubbles whatsoever)
Hoses: both seem to be same temp (relatively warm/hot)
Heater: blows hot (helps cool off motor quite well)
Fan Switch: works
Fan: blows in proper direction
Cap: not hot to the touch
Reservoir: level never changes up or down (stays at "min" mark)

The only odd things seem to be the radiator cap not getting hot & the reservoir level never changing. Would any of the experienced members like to shed some light on this for me...

The things that come to mind are: Bad Radiator Cap (not bleeding off pressurized fluid), clogged up radiator, and finally a bad thermostat. The later two seem odd though because I would think the reservoir level would still go up & down. I've read that a bad cap can cause overheating, but I'm not exactly sure how...


Modified by 94eg! at 2:48 PM 9/13/2006

 

My car did the same thing a while back. I ended up needing a new radiator. You might be in that same boat.

 

Dang! I was hoping it wouldn't have to come to that. Were you able to tell by looking into the filler neck weather or not the radiator was clogged? Was the gunk visible?

 

drain it hose it out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94eg! &raquo;</TD></TR><TR><TD CLASS="quote">Dang! I was hoping it wouldn't have to come to that. Were you able to tell by looking into the filler neck weather or not the radiator was clogged? Was the gunk visible?</TD></TR></TABLE>

Everything looked great with it, fluid was clean, everything. I ended up replacing water pump and thermostat before I did that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sicky &raquo;</TD></TR><TR><TD CLASS="quote">..I ended up replacing water pump and thermostat before I did that. </TD></TR></TABLE>

So replacing just the pump & thermostat didn't fix the problem then?

 

Be sure and check the front of the radiator also for bug and road objects and also for bent fins. Backflush it and replace the cap would be cheap to do.

 

How old is the radiator and thermostat?

 

to tell if your radiator is blocked you get the car hot and then feel the radiator with your hand up and down. if it is cold at one end and hot in the other you no you have a bocked rad

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by -Gary- &raquo;</TD></TR><TR><TD CLASS="quote">How old is the radiator and thermostat?</TD></TR></TABLE>

The car is a 2002 Mazda Protege-5 (bone stock), and I find it hard to believe the rad could get clogged in just a few years. I guess anything is possible though.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16a2civicesi &raquo;</TD></TR><TR><TD CLASS="quote">to tell if your radiator is blocked you get the car hot and then feel the radiator with your hand up and down. if it is cold at one end and hot in the other you no you have a bocked rad</TD></TR></TABLE>

It's kinda hard to do that when it's sandwiched between electric fans & a A/C condensor... Perhaps I can get the fans out & see whats up...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxmatt &raquo;</TD></TR><TR><TD CLASS="quote">Be sure and check the front of the radiator also for bug and road objects and also for bent fins. Backflush it and replace the cap would be cheap to do.</TD></TR></TABLE>

That was the first thing I did (added to list). The thing looks good w/ only a few small bugs here & there. Also the condensor is in front so the radiator won't take any damage from rocks...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94eg! &raquo;</TD></TR><TR><TD CLASS="quote">

The car is a 2002 Mazda Protege-5 (bone stock), and I find it hard to believe the rad could get clogged in just a few years. I guess anything is possible though.


...</TD></TR></TABLE>

I agree with you. I thought we were talking about a mid 90's honda...

 

Story: My brother took the car (his car) to the Mazda dealership & they told him the radiator was clogged & leaking and needed to be replaced. They also wanted $700+ for the job. I got a really weird vibe from that because I know the radiator isn't leaking. I am completely **** about leaking fluids on my driveway, and that car was dry as bone (until I opened the radiator cap ). They also said they were gonna replace the thermostat, like it was an afterthought. I think I'm just gonna replace the thermostat & see if that fixes it (only a $20 OEM part). If not, then I suppose I'll move on to the radiator...

I hope the thermostat is easy to access in that thing. I don't know mazdas...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94eg! &raquo;</TD></TR><TR><TD CLASS="quote">The car is a 2002 Mazda Protege-5 (bone stock), and I find it hard to believe the rad could get clogged in just a few years. I guess anything is possible though.
</TD></TR></TABLE>

You know that kind of info would be really useful if we would have known it in the first post. Especially when you post it in the 92-00 Honda Civic forum.

 

That's not really the case. How did knowing the vehicle was a Protege make a difference in how a cooling system behaves in your mind?

Anyways... I knew as soon as I mentioned it was a Mazda, all the help would dry up...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94eg! &raquo;</TD></TR><TR><TD CLASS="quote">That's not really the case. How did knowing the vehicle was a Protege make a difference in how a cooling system behaves in your mind?
</TD></TR></TABLE>

It's completely the case. Your user name is 94eg, you don't post a car so we all assume it's a 12 year old car not a 4 year old car. There is a big difference in diagnosing a stock 12 year old system over one that is not old enough to have problems like I menioned like buildup or bent fins. Also evey cooling system is different. If you would have this problem and it was a 88-98 full size truck I would tell you it's a water pump or possible intake, 3800 GM V6 could have the same intake issues, Neon it could be the headgasket, Altimas have radiator issues, it goes on.

Next time don't be a smart *** about it, just post the info.