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Hi everyone, it's been a while.

Firstly the background surrounding my issue. Last week i had a small busted hose for the coolant system, which I found after my car overheated. After buying a replacement hose and upgrading the clamps, i decided I would change the coolant.

After this, everything seemed pretty good on the test drives around town, only 5-10 minutes each, with no leaks etc.

Then when I assumed everything I decided to drive a 40 minute journey.

After being on the highway doing 100 @ 3000 odd revs, the engine temp rose up fairly rapidly and steadily, then, quickly rose up to near, or in the red, fluctuating as I drove.

So this continued as i limped to my destination and back home, with stops to make sure i didn't cook the car. The weird thing was the rapid changes in the temperature, where the needle would shift up and down in a short period, whilst the engine use was not necessarily in sync (if that makes sense

So after some research i figured there may be an air pocket in the coolant system (This is still a possibility, is there an air bleed on the coolant system for my car, a 2000 Liberty RX EJ25)

So i tried to burp the car, which didn't seem too effective, as it wouldn't take much more fluid.

Also, at this point when the car was hot ( needle above horizontal), the 'Check engine' light would occasionally come on for a few minutes then disappear. Accompanying this was really poor performance, like the computer in the car was in safe mode, making the car totally gutless and running very rough, and the 'acceleration' was not smooth at all. This has occurred repeatedly.

So my next conclusion was the thermostat was broken. I figured this as the car was fine around town, with the needle sitting steady on the normal running temp just below parallel.

So today i purchased a new thermostat, which i had to drain and refill the coolant again to install.

After this process, i go for a test drive, and again the same thing happens, normal running temp, followed by a quick rise in temperature, then fluctuations in the high temp range.


The problem only arose after the initial burst hose/changing coolant, which makes me think that it is an air pocket?

Prior to this the car always kept its cool.

The other possibilities I've narrowed down to are the sensor, head gasket or ....?

What is wrong with my car?

thanks in advance,

Jack

Hmm only one thing came in my mind - did you tilt the car slightly upwards to a hill, where the bleed valve points up that way if you had any bubbles will lead that way to the bleeding point? It can take upto half hour to get it all out, same thing happened to my EJ22 a while back...

I dont believe your SHOC EJ25's headgasket has this problem like what DOHC used to have.

Cheers
AP

Where is the bleed point on my car? / Is there a bleed valve?

Cheers

Best way is to drain the radiator completely and park the car facing up-hill (should be easy to find a hill in Nambucca)

The remove the top hose from the radiator and rotate do it points upwards (still connected to the engine)

Then slowly fill the radiator (by pouring into the radiator ) until water comes out the top hose. Because the engine has filled from the bottom up, all air should have been forced up and you will have no bubbles.

Then reattach the top radiator hose an fill the rest of the radiator.

Run the engine till up to operating temp incase there are a few bubbles in the heater box. When all bubbles are gone, replace the radiator cap

Hate to say it but more than likely a head gasket from the first hose going, a very common symptom is it's fine around town but the minute you hit the highway it'll overheat, happened to my ex's 2.2 and my 2L turbo & plenty of others but lets hope it's an air block, try squeezing the top hose quickly a few times with the cap on and repeatedly check to see if the air will come to the top of the tank but if you can't squeeze the hose there's probably no air in the system.

Okay, refilled the car using the above method, still the same problem. I'm going to take it in to my mechanic tomorrow and hopefully he can pin point the problem. Its either a semi blocked/broken radiator, a broken sensor or the dreaded head gasket.

I'm with dgen, subies seem to have fragile head setups, overheat once and if you are lucky you will only have blown head gasket.
The symptoms are typical 0f that.
It might run for months like that, or blow up tomorrow.
Take it to your mechanic and get him to run a diagnostic sniffer on the radiator water this will detect combustion fumes which indicate head gasket leak.

Also unlike most cars you rarely get oil in the water or water in the oil when you blow a head gasket.

What was the result libertywagonrx?
Cheers
AP

Sorry havent gotten back yet. not a whole lot of progress. Took it in to the auto electrician to have diagnostics run. 3 stored codes, none of which were related to the heat problem. The problem still persists. Going to see my mechanic monday when he finally gets off from holidays XD. The car seems fine around town however. if my mechanic can find it, my next bet is on the sensor, which is going to cost $68 to replace, an idea which the auto electrician seemed to think was good. Ill be back with an update mid next week. Thanks for the help everyone. Im trying to rule out everything before jumping to the head gasket problem.

If the temp sensor is not throwing a code I highly doubt that it is the problem. Have it tested as per the manual's specs. Also have the coolant tested for exhaust gases as this will most likely confirm a head gasket issue without all the hassle of running around looking for other issues first...

All the best - hope its not a head issue!

Bennie

Sorry but if theres nothing wrong with your thermostat, and the engine occasional operates without the needle registering an overheat, then the combustion chamber has been compromised!!! But never fear, its not all doom n gloom, head gaskets have life spans, hopefully yours is not brand new.
Otherwise, the only reason this could all be happening is a faulty coolant temperature sensor/sender, but they dont typically decide to stop working at a particular temperature, usually the wax inside them stops expanding, and you end up with a completely wrong reading all the time.
For the time being, stick some of this product in your radiator!
http://www.supercheapauto.com.au/online ... 68#details
It contains small copper filings which bond and seal cracks and metal/metal imperfections. I have had 100% success for minor head gasket problems using this seal up stuff.
However I've never owned an engine for more than 2000ks after using it!!

Thanks for all the advice everyone. Basically after the car continuously getting 'hot' my dad noticed that the engine wasnt that hot, and the fans weren't cutting out. So after spending a fair bit of cash at the auto electrician and on parts, we tested the actual dash readout gauge thing to find that it was not giving out a correct reading. Dont know what caused this to happen. :-S

Poxy thing hey.
that is good news, are you saying the sensor was fauly, or the dash?