Overheating 3SGTE

[gt4dude]

My engine keeps overheating non stop, it used to spew its coolant out of the overflow but not overheat, now it spits out so much that theres not enuff coolant to cool the engine.. happens every drive now !

first time it happened it blew the top tank off the factory radiator, killed the thermostat, blocked the heater core and warped the rubber seal in the cap

sorted all that out and it ran great for a very long time... over 15,000 kms

then it overheated again and away went the oil seals in my turbo at the same time (smoked like a crackwhore)

suspected blown headgasket at the time so had compression test 180,170,170,180 , had radiator hydrocarbon test to check for presence of exhaust gas, passed that test, so had new turbo and manifold put in,

installed new trd thermostat, trd rad cap, new silicon hoses...

no leaks in the system, as releasing the cap when cold relieves vacuum...

now it overheats all the time.... im pretty sure i must have killed the new thermostat by now because the temp needle doesnt settle at the lower point compared to stock anymore... i cant figure it out

ive bought a large alloy radiator but i think its going to be a bandaid fix on some other problem and it wont solve it completely...


theres 3 things i havent ruled out yet but im doubting them...

1. the radiator flush i used (some powder shit from supercheap) might be still floating around in the system

2. the new turbo is producing too much heat/power for the stock cooling system to handle -- doubt it, but even if this makes the problem worse, the problem is still pre-existing. the new turbo is a gt28rs and from my research puts out very similar power to the ct20b and is a very close match for compressor maps, main difference being .. epic ball bearing spoolup

3. the amount of times its spewed out coolant and ive topped it up with water until theres very little antifreeze left... but this makes no sense either,... aside from some corossion shit maybe.... but the problem was pre-existing once again...

whats left?? do i have to make a swirl pot and header tank to stop this boiling steaming overflow shit or what???

[85AW20v]

Checked your waterpump? Maybe all the fins are missing off the impeller so no coolant is being circulated.

[Grrrrrrr!]

did they clean out the core on the radiator when the top tank was replaced?

Have you ever run it up to operating temp with rad cap off and seen water circulating?

Could either be blocked radiator, or stuffed water pump (missing impeller).

[gt4dude]

did they clean out the core on the radiator when the top tank was replaced?

good point, radiator could possibly be coated in shit and the new alloy rad will fix that straight away

or stuffed water pump (missing impeller).

hmmmmmm the first and 2nd major overheats happened between service intervals where i had the cambelt, waterpump and tensioner and all that replaced on 180,000... i would have definitely been informed of such the first time round, and im sure he used a genuine oem pump the 2nd time (does $80 sound right?) so probably not this

[matt dunn]

My bet would be an air lock.

my car does that if you dont bleed it properly.

[Babz]

Could be an air lock? Faulty thermostat? Have you done a compression test on the radiator with it in the car? The fact that it is spewing out of the overflow coolant could mean it is not circulating properly or at all.

[MAGN1T]

You get that?

suspected blown headgasket at the time so had compression test 180,170,170,180 , had radiator hydrocarbon test to check for presence of exhaust gas, passed that test,

??

Neither is a reliable test.
They're just to make money for mechanics who don't know what they're doing.



Steve

[gt4dude]

You get that?

suspected blown headgasket at the time so had compression test 180,170,170,180 , had radiator hydrocarbon test to check for presence of exhaust gas, passed that test,

??

Neither is a reliable test.
They're just to make money for mechanics who don't know what they're doing.



Steve

Then what? Some suggested BHG but theres no symptoms of such other than overheating... theres no white smoke, theres nothing under the oil cap, theres no mix of oil and coolant, good compression, good power.

[strx7]

My bet would be an air lock.

my car does that if you dont bleed it properly.

yip, sounds similar to the issues i had in my 5sgte, airlock was the issue.

run it up to temp with either a large funnel, or (a 2.25 coke bottle stuck upside with bottom chopped off) in the radiator filler neck to act as a large header tank. ( same way we bleed up subaru's) leave it in there, let it cool down and thermo syphon.

[Anth_555]

this is the same problem i had never did a compression test tho. never mixed with oil and ran mint everytime but would always overheat. pulled the moter down to find the headgasket leaking water into number3 and had 2 cracket forged pistions wasnt happy about that. pistons werent the problem i think the overheating cracket them

[sergei]

1) Does it over heat when idling?

2) Have you removed radiator and plugged a garden hose on one port and see if water comes out freely on other? (although not a good test, but will eliminated badly blocked radiator).

3) Is the heater blowing hot air?

4) Are the hoses "crunchy"?

5) Have you tried removing thermostat and running without to see if it overheating?

Compression test sometimes does not pick up blown head gasket.
You can see (barely) impeller on water pump if you remove thermostat.

It is either bad case of air lock (which would result in cold/barely warm air coming out of the heater) and/or blocked radiator (using heater will help in cooling down in that case) and/or BHG. It is highly unlikely that the water pump lost impeller (car is not that old, and normally water pump is changed with cambelt, and the impeller is stainless steel).

On cold remove cap, start the car and watch for constant stream of tiny bubbles, if bubbles increase with revs, then you most likely have BHG.

[MAGN1T]

You can't beat the blind trying to lead the blind when it comes to christmas entertainment.
Especially when everyone concerned seems to be self educated from google.
Why didn't you just fix the headgasket in the first place instead of causing yourself so much more grief?

Then what? Some suggested BHG but theres no symptoms of such other than overheating... theres no white smoke, theres nothing under the oil cap, theres no mix of oil and coolant, good compression, good power.

They're all known as "red herrings"

Steve

[Quint]

this is the same problem i had never did a compression test tho. never mixed with oil and ran mint everytime but would always overheat. pulled the moter down to find the headgasket leaking water into number3 and had 2 cracket forged pistions wasnt happy about that. pistons werent the problem i think the overheating cracket them

Yeap, I'd say this, seen it with a 1ggte. Stripped it down and it was leaking into 5 of the 6 cylinders.
Even a leakdown test showed all clear.

[gt4dude]

i ran it from cold and it doesnt look like water is circulating, but a little steak of steam starts wafting thru when it warms up,
if i hold the throttle on a little revs the water level stablises and that streak of steam disappears but it still doesnt look like its circulating. temp came up to its normal place just below half way..

i can drive it around on short trips okay without boosting at the moment

i might have killed my new thermostat from all this overheating


when i get round to putting in the new alloy rad ill get a better picture of whats going on with the tstat housing and hoses off...

im just hoping its a simple case of the radiator being full of crap after a few flushes, this is what happens to the heater core if u dont blast it out separately

would like to cover every last base before heads get ripped off

[gt4dude]

1) Does it over heat when idling?

no

2) Have you removed radiator and plugged a garden hose on one port and see if water comes out freely on other? (although not a good test, but will eliminated badly blocked radiator).

will find out what happens when i put in the new alloy rad

3) Is the heater blowing hot air?

yes

4) Are the hoses "crunchy"?

yeah they were, i replaced them with silicone hoses 20,000 ago, these ones are really good

5) Have you tried removing thermostat and running without to see if it overheating?

i suspect my new trd stat is toast because it no longer runs at the lower level on the gauge that it used to when i first put it in,, its alot closer to half way now like the stock t-stat

Compression test sometimes does not pick up blown head gasket.
You can see (barely) impeller on water pump if you remove thermostat.

It is either bad case of air lock (which would result in cold/barely warm air coming out of the heater) and/or blocked radiator (using heater will help in cooling down in that case) and/or BHG. It is highly unlikely that the water pump lost impeller (car is not that old, and normally water pump is changed with cambelt, and the impeller is stainless steel).

i got heat, i played around with heater on and off and watching the gauge, the drop it made was so tiny u have to have your eyes right up to the gauge to see the movement.

no matter what i do i cant get the air out, i park uphill heater valve open, leave the cap off overnight and fill it with a funnel, in the morning its dropped a few cm so i top that off and recap it and that never solved anything. it used to make it better ages ago, now it doesnt do squat

[Grrrrrrr!]

5) Have you tried removing thermostat and running without to see if it overheating?

i suspect my new trd stat is toast because it no longer runs at the lower level on the gauge that it used to when i first put it in,, its alot closer to half way now like the stock t-stat

Always wondered what the logic in doing this is.. why go for a lower temp thermostat in the first place?

I can under stand going for a thermostat that is bigger (higher flow) that might enable you to get away with a standard radiator for a bit longer before you need to upgrade, but what do you gain from permanently running your engine cooler than designed for?

[matt dunn]

Always wondered what the logic in doing this is.. why go for a lower temp thermostat in the first place?

The TRD thermostat's are designed for race cars not road cars,
and running a lower thermostat wont make the actual internals of the engine run much colder than normal as a "Race" motor is basically being thrashed all the time while racing,

but will let you run cooler under bonnet temps,
and in the case of the 20V the port that runs along the intake ports of the head,
will be a bit cooler which should make more HP.

For a road car though all a TRD thermostat will probably do is wear the engine faster and use more gas.

[allencr]

BHG. Radiators don't usually split from overheating, it takes some extra pressure & volume from combustion do do that.
The tops of the radiator tubes are simple to look at, you just can't look at too many but you will definitely know whether they are clogged or not with the small sample seen through the filler. More then 1/4 clogged is too much.
Possible to be clogged deeper down but unlikely. Watching it drain to see if they all seem drop down at the same rate should tell if the tubes are free of crap/debris/smegma on top but restricted inside.

Always wondered what the logic in doing this is.. why go for a lower temp thermostat in the first place?

There is no logic at all, just wishful thinking or lack of imagination or stupidity.
Hoping that if it opens sooner/lower, then any higher temps will be lower by a similar amount just isn't going to happen.
It sets a MINIMUM temp, with no affect at all for anything higher.

[sergei]

Most common case of radiator splitting is because of the deterioration of the plastic. Otherwise ~50% of cars on the roads have BHG...

[MAGN1T]

Most common case of radiator splitting is because of the deterioration of the plastic. Otherwise ~50% of cars on the roads have BHG...

Wrong.

They split due to too much pressure in the cooling system.

Exactly the same as the old copper / brass radiators also split at the solder seam with a BHG.
That normally happens after the hoses have popped and been replaced.

Steve