Overheating when stationary or under load.

[Ben Up North]

Ben, the water pump is at the bottom centre of the front of the block. You have to pull the front of the motor apart to get at it.

Good idea to do the timing belt at the same time.

Ahh.. Timing belt only done 10,000k's ago. I wonder if we did the water pump at the same time.. I don't think so. will have to check, because that sounds like a pain in the butt to have to change if I don't need to!

 

[duncanm]

Can a thermostat be faulty and not open as much as it should? Or if it's faulty would it just not open at all (Or conversly, remain stuck open)?

OEM thermostat?

Aftermarket thermostats are generally smaller that the Subaru OEM ones.

 

[Rally]

Ahh.. Timing belt only done 10,000k's ago. I wonder if we did the water pump at the same time.. I don't think so. will have to check, because that sounds like a pain in the butt to have to change if I don't need to!

If the timing belt is replaced ar 100,000km, so must the water pump, tensioner, pulleys and seals.

 

[Rally]

Ahh.. Timing belt only done 10,000k's ago. I wonder if we did the water pump at the same time.. I don't think so. will have to check, because that sounds like a pain in the butt to have to change if I don't need to!

If the timing belt is replaced ar 100,000km, so must the water pump, tensioner, pulleys and seals.

 

[Ben Up North]

Well according to the ssticker on the car, the belt was last done at 155,000.
Gonna have to check the thermostat. for the cost of one, may as well just replace it. With OEM.

 

[El_Freddo]

Ben, are you just using the factory temp gauge as your reference to the increase in engine temp?

If so install an aftermarket digital or analogue gauge that's plumbed into the heater hose - just make sure you've got it plumbed into the hose that the coolant comes from the engine. To identify this hose, it's NOT the one that goes to the waterpump (via under the intake manifold and between the block and cam covers.

A scan gauge may work too - read what the ECU is looking at

You might find you don't have an issue to stress about.
Another trick I've heard of others doing is adding a "H" pipe between the in and out heater hoses. The pipe between the two main hoses is restricted and works like a bleeder that bypasses the heater. If there is a partial blockage of the heater core, this could be effecting the operation of the thermostat.

Oem thermostat is the only way to go in these machines

Cheers

Bennie

 

[Ben Up North]

Went for a run up one of the hills today (15min climb, windy roads) when the guage started moving I waited until it was almmost to the upper of the to middle marks and turned on the heater. Temperature came down to normal quite quickly.
Exterior Temp was probably about 5-7 deg cooler than the last time I went up, I think that might have made a little difference as the car didn't heat up so quickly. I was taking it a bit easier to though.
Turning on the heater definitely made a big difference, not sure what that signifies though, but seeing as it didn't used to get so warm in it's youth it might mean that the thermostat was at some stage replaced with an aftermarket jobby with less flow.

Might wait until next service before progressing further with the thermostat unless things change, because if a short blast with the heater is enough to get us up these bigger climbs I can live with that for a bit. Not sure what the missus will think though..!

 

[Venom]

This happens when you drive through mud and it splashes up and blocks the radiator fins. Run the hose through it (no pressure washer though), see how dirty the water is coming out the bottom. If it's really bad then pull it out and give it a decent hose.

 

[Ben Up North]

A scan gauge may work too - read what the ECU is looking at

I've been running Torque (light) for a couple of weeks. Average temperature (with guage in dash showing "normal") is about 96-97 degrees celcius.
From what i've read, this is high - other people seem to be running 10 degrees cooler. I think.

Occasionally it has hit 100, with the guage on the dash still not moving.

We did some towing a few weeks back, and unfortunately I didn't have Torque running. The temperature guage went up over the second indicator, as it didn't move at 100Deg, I hate to think what the temperature got to when the guage did move..

Oem thermostat is the only way to go in these machines

Cheers

Bennie

Going to replace the thermostat in the next week or so.
should I replace the water pump at the same time? Mechanic is under the impression that the water pump is fine. But he hasn't been able to solve miy heat issue either.

 

[duncanm]

Going to replace the thermostat in the next week or so.
should I replace the water pump at the same time? Mechanic is under the impression that the water pump is fine. But he hasn't been able to solve miy heat issue either.

thermostat is eleventy times easier to replace than WP.. just pull off the housing and pop in a new one.


WP - timing belt needs to come off.

 

[Ben Up North]

Righto. Thermostat first it is then.
Cheers!

 

[subyroo]

Occasionally it has hit 100, with the guage on the dash still not moving.

Do not, I say again, DO NOT, rely on the dash temp gauge.
Get something like a Scangauge or an UltraGauge to keep a check on your water temp etc..

Boxer Service in Brendale (Brisbane) told me to never rely on the dash gauge as it not reliable enough with a Subaru.

My 2003 XS Radiator was 50% blocked with sand (?) and couldn't be cleared by a radiator specialist, I had to replace it. Overheating only reared it's ugly head when I was towing a trailer with a golf cart on a hot & humid day.

 

[duncanm]

I'm not so sure why you're against the standard temp gauge.


Sure - it won't give you a number comparable to another car, but every driver knows instinctively where the 'right' spot is on the gauge for their car after driving it for a reasonable amount of time. When the thermostat and cooling system are working properly, it'll hover pretty close to this.



Anything significantly higher than that spot (eg: more than 1/4 of sweep) is overheating. Full stop.

 

[Ben Up North]

What temperature actually is too high though?
is it 100? 105? 110? I've read on a number of sites that 110 (230deg F)isn't over the top, but my mind think's that is dangerously high..

 

[Beachworm]

What temperature actually is too high though?
is it 100? 105? 110? I've read on a number of sites that 110 (230deg F)isn't over the top, but my mind think's that is dangerously high..

Safe operating temp depends on pressurisation of the cooling system. The higher the pressure, the higher the temp can go without boiling. As soon as the coolant boils, it looses efficiency because steam doesn't conduct heat as well as liquid coolant.

If your pressure cap is working as intended it's OK for temp to go above 100 C but if the cap is faulty or there are any leaks in the system that will allow pressure to escape, anything over 100 is a problem.

The OBD2 reader I've fitted gives me an engine temp readout in degrees. It's worth investing in one.

 

[Beachworm]

Discussion on subaruforester.org seems to indicate that normal operating temp should be under 90 degrees C

 

[Ratbag]

Oil temperature is even more critical than coolant temperature. Oil viscosity ratings are for an oil temperature of 100C. Anything over this and the viscosity drops rapidly.

 

[duncanm]

Thermostat opens by about 80C, fans turn on at 95C

That should give you some indication of 'normal' operating temperature range.

Standard radiator cap is 1.1 bar - about 120C boiling point for water. 50/50 EG knocks that up by about 5%.. so say 125C max before your cap starts venting.

I know I've run mine well into 'that's noticeably higher than normal, better back off' (on my inaccurate Subaru temperature gauge) territory on a 48C day hauling up a big hill , and lost no coolant whatsoever.

 

[Ben Up North]

The OBD2 reader I've fitted gives me an engine temp readout in degrees. It's worth investing in one.

That's what I'm currently using to read the temps. seems to average around 95-97, went up to 101 when stationary after driving for about 20 minutes, then 10 minutes stationary.
Temperature increases doing 80 in 5th, drops when I go back to fourth, so I guess the increase in tyre size and (and weight) is also playing a part.

Haven't done any 100kph runs recently, last time I did temp was sitting around 97-98 with 650Kg trailer (maybe less) and loaded car. Unfortunately I didin't have the obd connected when the temp gid shoot up according to the oem guage..

 

[Beachworm]

That seems a bit high to me. I towed a fully loaded dual axle trailer 200 Km on the highway in Brisbane summer and there was no significant rise in temp. If you've checked that the radiator fins are clean and undamaged and the system has been flushed you should look at getting a new radiator.