Engine overheating + heater not working

[Jakexvx]

Need to pick some brains. Bought a corolla t sport 1.8L from a mate, (been stood for a year or so)

The engine starts to overheat after 30-40 min of driving, however it doesn’t overheat when it’s idling, only driving. Along with that, inside heater isn’t working just blows cold air.

Sniff test showed exhaust gases in system (head gasket gone presumably) so tried some steel seal and upon doing Nee sniff tests, it comes back clean however still overheats.
I’ve also tried replacing thermostat, which also didn’t fix either of the issues.

I’ve flushed water through the cooling system using a hose, from one end to let it spew out the other end to ensure theres no blockage in the system.

Something I noticed is the heater matrix pipes behind the engine don’t seem to get hot like the other pipes? This would explain why there’s no heated air getting through the heaters but I don’t understand why the engine overheats still.

what should it try?

[oldcodger]

Hi,

There are still plenty of Tsport guys in the forum so they might be better able to advise on the head gasket problem, though what about any signs of creamy sludge around the oil filler cap or water level dropping, which normally indicate gasket problems ?

If it just overheats when out on run it kind of suggests that your radiatior my be partially blocked , so not being as efficient and /or the fans not kicking in when they should ?

Could also be a failing water pump or very slack fan/aux belt ?

As for the heater matrix, thats probably a separate problem, if you search this forum on "heater matrix" you will see plenty of posts on it and a very detailed one from some years ago,

Probably the easiest thing is to disconnect those two pipes in the engine bay and flush the matrix with a garden hose etc, that might shift either a bad airlock or muck.

[Jakexvx]

3 hours ago, oldcodger said:

Hi,

There are still plenty of Tsport guys in the forum so they might be better able to advise on the head gasket problem, though what about any signs of creamy sludge around the oil filler cap or water level dropping, which normally indicate gasket problems ?

If it just overheats when out on run it kind of suggests that your radiatior my be partially blocked , so not being as efficient and /or the fans not kicking in when they should ?

Could also be a failing water pump or very slack fan/aux belt ?

As for the heater matrix, thats probably a separate problem, if you search this forum on "heater matrix" you will see plenty of posts on it and a very detailed one from some years ago,

Probably the easiest thing is to disconnect those two pipes in the engine bay and flush the matrix with a garden hose etc, that might shift either a bad airlock or muck.

Appreciate the reply!

I don’t think it is the head gasket as the sniff test is coming back clean now and there’s no other signs of it being the gasket gone. The engine does only overheat when driving and cools down on its own when it’s stopped and idling. The fan seems to kick in when it should, and stops when it should do too.

Yeah as you said next idea is the water pump. When the engine starts the water level does decrease which I presume means it is at least working and not completely broken. 

I flushed a hose into the cap where you’d put the coolant, then let it spew out the hose right before it gets back to the radiator, presume this means it’s not blocked in any way if it makes it’s way through? 
However the heater matrix pipes behind the engine do not get hot at all, even though the other pipes do.

[oldcodger]

The radiator could allow a fair bit of water though as you did with a hose, but could still be partially blocked which means under the load of a long drive it cannot cool things down enough and / or the waterpump is faulty.

Assume you are seeing the temp gauge going up to hot on a long run,  but could it really be the temp sender or gauge thats actually giving the wrong info ?

Have you checked the external underside of the water pump to see of there is any signs of dried or wet coolant, indicating the seals/bearings are failing ?  Can you feel any play on its pulley or hear any bad noises ?

Think if its still got the original radiator and its been stood for a year then its likely partially blocked, plus at that age probably got a small leak as well, mine already had.

You could try back flushing the radiator , easy enough to pop out ( well on a 1.6 rolla ) and / or using a bottle of car radiator Unblocker, but always a slight risk it shows up smaller leaks ..

[Jakexvx]

7 hours ago, oldcodger said:

The radiator could allow a fair bit of water though as you did with a hose, but could still be partially blocked which means under the load of a long drive it cannot cool things down enough and / or the waterpump is faulty.

Assume you are seeing the temp gauge going up to hot on a long run,  but could it really be the temp sender or gauge thats actually giving the wrong info ?

Have you checked the external underside of the water pump to see of there is any signs of dried or wet coolant, indicating the seals/bearings are failing ?  Can you feel any play on its pulley or hear any bad noises ?

Think if its still got the original radiator and its been stood for a year then its likely partially blocked, plus at that age probably got a small leak as well, mine already had.

You could try back flushing the radiator , easy enough to pop out ( well on a 1.6 rolla ) and / or using a bottle of car radiator Unblocker, but always a slight risk it shows up smaller leaks ..

I’ll have a look at the radiator then I reckon. I doubt it’s the temp gauge showing the wrong info as I can physically feel the extreme heat from the overheated engine when I stop to let it cool down.

ill also have a look around the water pump too, see what I can find. appreciate all the help! 

[hubrad]

If it's been Sat for a year, I'd be inclined to do full coolant and oil flushes on principle,  for which suitable products are readily available. It's amazing how small an amount of sludge can cause problems.

Good luck!

[furtula]

Try some flushing solvent, looks like plenty of sludge. Who knows how old was the coolant was to begin with.