Mechanics

UNEXPLAINED OVERHEATING PROBLEM

Mazda Other

The problem started 3 weeks ago.

On the passenger side there was some burnt smell while driving and it was intermittent.

The heat gauge was at the center and indicated no overheating. I constantly watched the parking space and found no stains or puddles.

I opened the hood and kept the engine running, there was no signs of coolant spill or anything like that. But then the could get the burnt smell whenever the radiator fan switched ON. The smell died whenever it switched off automatically.

I wasnt using the heater since the alternator was bad.
After changing the alternator, switched on the heater and cold air was blowing. I came back home and parked the car and opened the hood to see a trace of coolant on the air intake duct (right next to the coolant reservoir or the hood-opening latch.

The next day on my way to office the heat gauge went to full and I parked the car and opened the hood to see that it had just started smoking on the inside and coolant had spilled out from the radiator cap side(The cap was intact) and it was white.

I got it towed to a mechanic and they did a pressure test for any leaks and found there were none. They filled coolant and the kept the engine running for 20 minutes and the gauge stayed right on center. It didnt pick up instantly either and behaved normally ruling out thermostat issue.

The fan switches on and off correctly.

The mechanic suspects it could be a water pump problem and have given estimates for replacing it. They are not sure though.

The car had a water pump and timing belt replaced a year ago and has only 3500 miles on it.

After this incident I have driven the car for 5-6 miles at a stretch for a couple of days without any overheating after they filled the coolant. I also didnt notice any loss in coolant in this limited time.

Could someone please advise me on what I could do next.
Avatar
Adu
December 28, 2006.




Vehicle model, year and engine size would help alot

Cosmo. Mazda TEch

Tiny
Cosmo
Dec 28, 2006.
Mazda 626 (V6) - 1995
135000 miles

Apologize for not mentioning this information.

Tiny
Adu
Dec 29, 2006.
When an engine's coolant boils, the condition is referred to as a " boilover" Coolant can boil over and spill out of an engine with white steam pouring out from under the hood.
When an engine overheats and coolant begins to boil, the boiling action creates air pockets in the system. The air pockets increase the pressure in the system. The pressure quickly rises so much that coolant is forced out past the pressure cap, overflowing the recovery tank and spilling all over the ground. That is what happened to you the next day on your way to the office.
Now we have an overheating situation but you said this" After this incident I have driven the car for 5-6 miles at a stretch for a couple of days without any overheating after they filled the coolant. I also didnt notice any loss in coolant in this limited time.

Could someone please advise me on what I could do next.&Quot; If your car stop having overheating problem, what do you need help for?
Maybe impurity in water could have caused the problem.
However certain ignition timing can also cause engine overheating. If the ignition timing isn't correct, the air -and -fuel mixture in the cylinder could burn at the wrong time. When the mixture burns at the wrong time, it could cause the engine cause the engine to run at higher temperature than normal because you said this" The heat gauge was at the center and indicated no overheating" hope this help/ good luck and happy new year.

Tiny
Mathiaso
Dec 29, 2006.
Do this remove the Stat don't worry about what the computer thinks. Run engine stationary for 10mins and then shut it down-tell me do you hear any boiling at the recovery bottle, radiator-is the temp gauge past the half mark? Hence if you're not losing it then its being burn.

When the last time you check the oil- is it milky?

During the pressure test, did they check for a combustion leakage-the needle will tell if it is. Or they just looking for an actual leakage within the cooling system.

A Bloc Chek will finger a combustion leakage. Did they check the pressure cap release point.

Tiny
Rasmataz
Dec 30, 2006.
I had a cooling system diagnostic test done and they found that the radiator cap wasnt according to the specification.

The following tests were done: Visual inspection under the hood
Block test
Introducing a dye and visual inspection for leaks.
Pressure test of radiator cap.

One last thing.
What is a block test?
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Tiny
Adu
Jan 4, 2007.
The Bloc Chek- a tester for the cooling system that changes color when a combustion leak is present

Tiny
Rasmataz
Jan 4, 2007.

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