Coolant reservoir spitting out coolant (overheating issue).

Sailingsenses

Member
:
Mazda, Protege5, Stock, 2002
Hi there.

2002 Mazda Protege5
300,545 Miles!

I could use some tips...IF you have the time and desire.

Even when it was still well under 200K, the car has never like uphill climbs--but it has also never over-heated either. (Sidenote: I have a lot of problems getting the car to climb if the hill is steep enough. Compression was confirmed as factory specs).

Last weekend, we went camping and the site was (steep) uphill for a good 3 miles. On a particularly steep hill, it would not move almost at all and it began to overheat a bit. I immediately noticed the Temperature Gauge needle climbing, turned off the A/C, pulled over, and let it idle for some time; the needle dropped back to center VERY fast, which I think is a good sign.

By the time I reached the top, the coolant reservoir began spitting out coolant out of that little cap spout. I replaced some of it with pre-mixed coolant. Every time I made the hill climb, I made sure the A/C was off; this seems to help in the sense that the Temperature Gauge did not move from center. It only did that the first time, when I left the A/C on during the first climb on a warm/hot day.

A week+ goes by since camping, we have had some very hot temps, but avoid A/C because it doesn't work well anyhow. Today, it has been a cool day, 0% uphill steep or mild grade climbing, and a *very* short distance driven compared to our usual--and the darn coolant started to sputter out of the reservoir again. The Temp Gauge never climbed.

So, here's the deal:
NEW radiator, fluid, and cap on 9-Jun-2012.

I just bought a thermostat and gasket, but I don't know if it will resolve this issue. I was told to start there, as it's cheap enough and could benefit from this general maintenance item anyhow.

1.) Why would that camping trip kick off this problem? I HAVE smelled coolant on occasion, but never saw a leak. It just smells like hot coolant (sweet and caustic) on occasion, especially when it's hot out and I park (but not during driving).
2.) If it was the head gasket, what would I smell? I was told it would have a distinctive smell.
3.) Should I replace the radiator cap even though it looks very new and was installed 9-Jun-2012?
4.) When should the Cooling Fan kick on? I turned on the A/C to test it and it did not come on. I *only* waited approximately 2 mins, though and I was parked. Maybe it's not supposed to come on for a while or until a certain temp is reached?
5.) What do I need to consider when replacing the thermostat? I heard about air pockets and such, and would want to avoid problems.
6.) Water pump? Water pump and full timing belt service done on 3-Jun-2013.

Although my main concern is solving the coolant/temperature issue, I am also wondering:
1.) What would cause a car to not be able to handle steep uphill climbs? (I have a new catalytic converter, O2 sensors, cleaned MAF sensor, clean air filter, etc.). I've been told that this can't be resolved, and that the car is simply too old to handle such steep hills. As mentioned, the compression testing yielded "factory results". Any other ideas? Can it be resolved?
2.) Been having some fan clicking at certain temperatures when A/C is running. What to do?
3.) The A/C has never been serviced. Should I bother on a car this old? If I could even get a 25-30% improvement, it would be nice to have on warmer days.

THANK YOU SO MUCH FOR YOUR TIME IN ADVANCE!

- Sailingsenses
 
Last edited:
Hi there.

2002 Mazda Protege5
300,545 Miles!

I could use some tips...IF you have the time and desire.

Even when it was still well under 200K, the car has never like uphill climbs--but it has also never over-heated either. (Sidenote: I have a lot of problems getting the car to climb if the hill is steep enough. Compression was confirmed as factory specs).

Last weekend, we went camping and the site was (steep) uphill for a good 3 miles. On a particularly steep hill, it would not move almost at all and it began to overheat a bit. I immediately noticed the Temperature Gauge needle climbing, turned off the A/C, pulled over, and let it idle for some time; the needle dropped back to center VERY fast, which I think is a good sign.

By the time I reached the top, the coolant reservoir began spitting out coolant out of that little cap spout. I replaced some of it with pre-mixed coolant. Every time I made the hill climb, I made sure the A/C was off; this seems to help in the sense that the Temperature Gauge did not move from center. It only did that the first time, when I left the A/C on during the first climb on a warm/hot day.

A week+ goes by since camping, we have had some very hot temps, but avoid A/C because it doesn't work well anyhow. Today, it has been a cool day, 0% uphill steep or mild grade climbing, and a *very* short distance driven compared to our usual--and the darn coolant started to sputter out of the reservoir again. The Temp Gauge never climbed.

So, here's the deal:
NEW radiator, fluid, and cap on 9-Jun-2012.

I just bought a thermostat and gasket, but I don't know if it will resolve this issue. I was told to start there, as it's cheap enough and could benefit from this general maintenance item anyhow.

1.) Why would that camping trip kick off this problem? I HAVE smelled coolant on occasion, but never saw a leak. It just smells like hot coolant (sweet and caustic) on occasion, especially when it's hot out and I park (but not during driving).
2.) If it was the head gasket, what would I smell? I was told it would have a distinctive smell.
3.) Should I replace the radiator cap even though it looks very new and was installed 9-Jun-2012?
4.) When should the Cooling Fan kick on? I turned on the A/C to test it and it did not come on. I *only* waited approximately 2 mins, though and I was parked. Maybe it's not supposed to come on for a while or until a certain temp is reached?
5.) What do I need to consider when replacing the thermostat? I heard about air pockets and such, and would want to avoid problems.
6.) Water pump? Water pump and full timing belt service done on 3-Jun-2013.

Although my main concern is solving the coolant/temperature issue, I am also wondering:
1.) What would cause a car to not be able to handle steep uphill climbs? (I have a new catalytic converter, O2 sensors, cleaned MAF sensor, clean air filter, etc.). I've been told that this can't be resolved, and that the car is simply too old to handle such steep hills. As mentioned, the compression testing yielded "factory results". Any other ideas? Can it be resolved?
2.) Been having some fan clicking at certain temperatures when A/C is running. What to do?
3.) The A/C has never been serviced. Should I bother on a car this old? If I could even get a 25-30% improvement, it would be nice to have on warmer days.

THANK YOU SO MUCH FOR YOUR TIME IN ADVANCE!

- Sailingsenses

1. The moon was in the right phase...
2. You can't smell a blown head gasket. The first major symptom is bubbling and overflow from the reservoir.
3. I wouldn't bother, but a parts store can test it.
4. The fan should come on when the engine temperature reaches 205*, and shut off at 199*F. Check the plug on the fan motor if it's not coming on.
5. If the thermostat has a jiggle pin, install it in the 12:00 position. While filling, squeeze the hoses to help work the air out. Start the car with the cap off, run until the thermostat opens (the upper hose will get hot). Shut the car down and top it off, then go for a drive. Check the coolant level again after it cools. You'll want to run the heater on hot throughout this process.
6. If it's not leaking, it's not likely to be a problem. There's nothing to fail in a water pump except the seals and bearings, neither of which affect its pumping ability until they're severely neglected.

I would borrow a hydrocarbon tester from a parts store (you'll need to buy the fluid for it) and test the cooling system for combustion gas with it. This will identify a head gasket leak if you have one. I'd perform this before doing anything else.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7001006_0361073538

My car handles hills a lot better than some others that I've had. I'm in the Ozark mountain region and don't ever have to downshift to climb a hill on the highway. Is yours an auto or manual?
 
Last edited:
Also, re: #1...not being literal about that particular trip. It struck me as odd that I went from not having an issue, to having one...on account of climbing a few hills on some hot days.

I suppose there's no such thing as "sudden" when it comes to car problems.

Thanks.
Sailingsenses
 
I would do the thermostat and find out why the fans are not running. They should both be running as soon as you turn on the AC. Without AC mine has to idle for quite awhile before coming on but does cycle on it's own once car is warmed up. As far as head gasket, I have been thru a few of those on other cars and it always started with discolored oily antifreeze in the overflow bottle, oily inside of radiator cap, slow loss of coolant from it getting into cylinder and burning making a definite eyeburning exhaust smell, weird colored oil on dipstick or a little of all of these. Had one let go enough to make steamy smoke from exhaust. Not on this car but older ones I had when younger.
 
Hi all,

Thank you to all who have contributed. Today hasn't been fun. The mechanic found nothing apparently wrong and he did not recommend installing a new thermostat. He said that the car would overheat almost immediately if it were the thermostat, which remains cool to the touch after running with the A/C and idling for a while.

So he sends me on my merry way with a new radiator cap (only), which he said wasn't functional anymore. I parked at work for hours, drove under five miles, no A/C, pulled into driveway, and put it into park/idle. The hood filled with white smoke and the stench of hot coolant steam. The reservoir did not bubble over, but coolant was dripping from the bottom of the radiator (left side facing engine block).

Could it be that the uphill battle (literally) cracked the radiator (which is merely three years old), but it did not entirely crack until today? Does stressing the car out crack a radiator like that?

Anyway, we poured more coolant and watched it just dribble out. The coolant in the reservoir remained at the same level, but half a gallon of coolant dripped from the bottom. The car never overheated...no needle climbing whatsoever.

Side note about the Fans: I was told the cooling fan won't kick on until the A/C is running for a while and I'm idling, when it reaches 210 degrees Fahrenheit. The other fan is running all the time, it seems.

I don't seem to have any of the telltale signs of a cracked or blown head gasket, though. No steamy exhaust, no weirdness in dipstick, no oil in coolant...etc. If it's just a small crack, would all that stuff reveal itself, or one or some combination of those? I was told that even a crack would present some or all of these, so I'm feeling slightly relieved that it may just be a shot radiator. Funny how my original radiator lasted YEARS and 248K miles, but the new one only three years on the dot.

I took it back to the same shop that sent me home with a new radiator cap and they will check it out tomorrow morning.

The mechanic didn't bother with a combustion test, pressure test...nothing, nada...just felt the thermostat by-hand, looked at hoses and sent me home...to a steaming coolant facial some hours later. The car was running so cool that I was able to take the radiator cap off just a few moments after the steam show!

What do you guys think about all this? If he tells me my car is too old and it's likely to be the head gasket, I may tell him to ***uck himself. LOL
 
... we poured more coolant and watched it just dribble out. The coolant in the reservoir remained at the same level, but half a gallon of coolant dripped from the bottom.

If coolant was dripping out of what you are sure was the rad then you've got a bad rad.

Doesn't matter why or how. Replace it then go from there.

There's a good chance a new rad will fix all your problems.... Except maybe for having to get out and push your car up hills.... You may just have to get your passengers to get out and carry the heavy stuff to the top of hills.




Your new rad cap may have added more psi to your rad causing a tiny leak to turn into a dribble..
 
Last edited:
You can always try this stuff....

It'll probably plug the leak (as well as half the passages in your rad) but it should work in a pinch.

OR .... A big pinch of oatmeal in the rad if you wanna go all backwoods with it.
(No kidding... It apparently works... Worth a try if you don't wanna spend ten bucks on a two dollar car.)

 
Help!

Should I bother getting an all-aluminum radiator?

http://www.autohance.com/mishimoto-...adiator.html?gclid=CN-s0rbNkscCFRRlfgodGOsLsQ

Or just the usual aluminum core only with plastic body. The cap DID put too much pressure and they apologized for not testing it. Awesome call on that, guys.

If you could chime in on the all-aluminum vs. not, let me know. It bugs me that my original took 242K miles and YEARS to slightly crack (at top), while the new one lasted three years. For that reason, I'm thinking aluminum...
 
Last edited:
radiators are so easy to put in and the plastic one are cheap to buy. but if you want more, aluminum might be the way to go.

but you got 300k on the car, will it be worth it?

coolant is very toxic for the environment, try to fix the issue ASAP
 
Right. Agreed re: toxicity.

Thankfully, it's at the shop just sitting emptied now, and I didn't drive it around when the radiator burst/cracked. Washed off with water, and used a desiccant, too.

Since I have an automatic, there's no standard hose kit for the all-aluminum radiators. To make it work, I'd ALSO have to get a Transmission Cooling Kit to match the Mishimoto all-alum radiator...and it's simply not worth it.

Thanks for the tip!

Sailingsenses
 
Hi all.

The smoking gun revealed: *Busted cooling fan motor.*

Busted cooling fan motor --> uphill battle overheated/stressed --> cracked radiator --> new radiator cap pushed too much pressure --> radiator crack burst wider

Fixed as follows:
- New Radiator
- Replaced cooling fan motor
- New thermostat (why not?)
- Upper and lower radiator hoses + clamps

Lesson learned: Always pressure test and don't just throw a new cap on, and ALWAYS test the fan-- oh, and find mechanics who are not going to just tell you that your car is old and that it's the worst case scenario (i.e., head gasket...no evidence).
 
Hi all.

The smoking gun revealed: *Busted cooling fan motor.*

Busted cooling fan motor --> uphill battle overheated/stressed --> cracked radiator --> new radiator cap pushed too much pressure --> radiator crack burst wider

Fixed as follows:
- New Radiator
- Replaced cooling fan motor
- New thermostat (why not?)
- Upper and lower radiator hoses + clamps

Lesson learned: Always pressure test and don't just throw a new cap on, and ALWAYS test the fan-- oh, and find mechanics who are not going to just tell you that your car is old and that it's the worst case scenario (i.e., head gasket...no evidence).

The fan is generally out of the equation by 20mph.

My cooling fan wasn't working at all for 2 or 3 weeks.... Never overheated or even got close until I was talking to a buddy for about 15 minutes with the car idling. Then I looked down and the gauge was nearly pegged. The fan motor plug was loose (tabs broken). I epoxied it in there.

As I mentioned in my previous post, I recommend doing a block test. Had I been working on this car it would have been one of the first things I did before spending time or money on it.
 
Back