Engine Overheating puzzler (Hyundai Elantra 2003)

I need some serious advice from the experts to figure out why my car’s engine is overheating. I would be a long post. So I’ll request you to bear with me …

A bit of history which might be relevant:

day 0 - all fine. AC works well and temperature stable and in limits.

day 1 - mechanic A did power steering fluid flush and normal oil change.

i drive 5-6 miles after the repair and AC still works ok.

day 2 - i discover that AC is not working almost immediately on starting the drive. suspecting it is just AC trouble, I drive ~30 miles. then happened to check the thermometer and it was past ‘H’!

Stopped immediately in a parking lot and waited for 2 hrs. Engine cooled substantially (temperature well below mid point). So I started driving and within 2 miles temperature was past ‘H’.

so i stopped and parked overnight.

day 3 - mechanic B looks at it first thing in the morning and finds that there was no coolant in the radiator. To troubleshoot he fills up the radiator with water and i drove it for 2 miles and again temp = ‘H’.

diagnosis - thermostat broken and i think the reasoning went like ‘one of the hose is hot while other is not …’

so i got thermostat changed and topped up coolant/antifreeze.

test drive of 2 miles does not cause overheating. AC started working too.

so we figured problem fixed.

not so!

i drove it for another 15 miles with AC on and (damn!) AC stops working (blows hot air) and immediately thermometer starts rising.

switching off the AC reduces the temperature by 1/4 of the dial over 2 minutes.

(all the while i was driving at <50 mph)

I stopped, and peeped under the engine and found leakage of some green colored fluid - the coolant !

So I am right in concluding that all the while the problem was the leakage of the coolant ?

Could mechanic A be responsible for it ?

Where should i look for coolant leakage ? is this problem common ?

( the car has 92K miles on it )

First off you need to find a quality mechanic. Apparently mechanic B is inept. You take your vehicle to him to diagnose an over heating problem so he fills the radiator and sends you on your way. This is illogical, the water had to go somewhere. He then tells you that a thermostat is needed. While it may have been necessary I would suspect that it began to overheat again do to air in the cooling system not a thermostat problem. You need to find a mechanic that will pressure test the cooling system and find the leak. It could be a radiator, hose, water pump, etc. Driving your vehicle with a water leak and having the temperature climb to the ?H? is a disaster waiting to happen. You could blow a head gasket or crack a cylinder head if you have not already.
Did mechanic ?A? cause the problem? Well that depends on where the leak is. Not knowing the service history of the car, or where the leak is makes that question impossible to answer. I suspect it is likely the water pump leaking. Have you replaced the timing belt yet? It is about time for both of those components to be replaced.

Rubber parts do deteriorate in 5 years. Why didn’t you put water into the radiator at your first stop? The second mechanic did what he could under the time constraints. Change the other hoses, also…you know, preventive maintenance.

Michael - i got the timing belt changed at 64 k miles ( i bought the car used at 62k miles)

hellokit - i didnt put water the first time because i was not sure after how long it is ok to open the radiator cap. it was still not at room temperature.

i’ll check under the car to see if i can see the leakage point. will be going to mechanic C (!) on monday.

Was the water pump replaced with the timing belt? Can you pinpoint an approximate location of the leak? Is it in the front of the car by the bumper, is it close to one of the tires, etc…

Hi Michael

I tried to look for the leakage point and i think i have a good clue of where it is but no idea why it is there.
am attaching some pictures too…

I filled up the radiator with 1/2 liter of coolant and while the car was parked started the engine and let it run for 5 min or so.

Looking around the engine i found a green fluid dripping at the location shown in the picture. Rate of dripping increased subsequently.

you can see the green puddle in the second picture which was taken 15 min after the start. in that duration temperature did not cross the half way point.

Does that help ?!

i could not pin point the precise location (exact pipe etc) because of the obstructed view.

by the way, water pump was not replaced with the timing belt.
also fyi, both radiator fans are working fine.

It looks like you have a hose or coolant pipe leaking but I do not have my cooling system information on this computer. I will check at the shop and get back to you.

Thanks Michael.

i am still wondering why the problem started immediately after the power steering fluid flush/oil change.

not that it will give me special satisfaction to blame someone but do you think it could be because of poor workmanship of mechanic A ?

i would like to think not since mechanic A is very conveniently located, reasonably priced and above all has 6 good reviews on this website !

waiting for your feedback. do let me know if i can provide any more info about this.


Potential leak points are numbers 1-7.
Photo #2 provided by you does not indicate a leak at points 1, 3 or 7.
Mechanic ?B? replaced the thermostat and gasket which should eliminate 2.
Based on the location of the antifreeze the most logical points for the leak are 4,5,6.

I would assume the leak is from the hoses that attach to points 4 and 5.
Can I blame mechanic ?A? for the leak? With the leak coming from the opposite end of the motor from the power steering system it seems unlikely. I am not aware however of how he went about flushing the system either. If he disconnected P.S. lines from the steering rack he could have unintentionally damaged a hose. I would also recommend that all hoses be thoroughly checked as the condition of them in the photos looks iffy.

got it! i’ll update you tomorrow.

Hi Michael

I went to mechanic A yesterday and he diagnosed the leak as one from the thermostat fitting. Apparently mechanic B used the wrong gasket.

so he changed the thermostat (again!) and the gasket and charged me $120 for it :(.

anyway problem seems to be fixed now. I have driven around over 40 miles without trouble.

thanks for your help.


Glad to hear you got your car fixed :slight_smile: sorry to hear it cost so much :frowning: