overheating problem

[Eliminator]

Ive had this issue for a little while now am quite stumpedas to whats wrong with my vn running at 3/4 temp. So far a replaced the radiator, new cap, new thermostat, recently replaced water pump & gasket, no air leaks, fully flushed, 50/50 coolant, fully serviced and no air bubbles while running in the radiator.

i now run no thermostat as a test & it runs on the half way mark, sometimes goes up a bit more on a long drive on a hot day with a/c on..

What else could it possibly be?

[mundine]

have you had it pressor tested it could be your temp gauge

[TUF UTE]

test ya temp gauge... or start looking at a new block... could be ya water jackets. is it a 355 at all ? how many km,s

my vs 304 ran half then used to rise to 3/4 so i put a colder thermostat in... runs on 1/4 all the time now. if it gets warm it runs on half i love it

[commsirac]

Removing the thermostat has never solved a cooling problem.
Since you have appeared to have replaced everything, and want to solve this yourself, purchase an IR thermometer(what you should have purchased 1st) and start measuring the temps on both top and bottom hoses, engine block etc

[Eliminator]

its not the temp gauge, the motors actually heating up... with the new radiator the motor overheats where with the old one it would just go to 3/4 and stay there..

stock standard 304 v8 thats done 115,000km/s. cooling system was very dirty so i did suspect the jackets may of been blocked up... also has only been flushed out with hose water through the heater hoses, water pump passages and radiator...

I removed the standard thermostat and checked it in a stove pan with a thermometre, it didnt start to open until 95 degrees then still it wasnt even 1/4-1/2 open... should i go for a 80 degree thermo this time???


I have checked the radiator heat and the left hand side (top radiator hose side) was warm, where the passenger side was cool for a while then started to heat up..

Ever snce greenfoam gave me a new memcal the a/c thermofan doesnt engage without the a/c actually being switched on, would ths cause a drama???


I really am stumped on this one as i have replaced everything... would the dirty cooling system benifit from a flush with the proper flushing stuff?

[Phat VN]

is it going through water at all

[Eliminator]

not at all, ill check for a minute leak tonight though... really stumped on this one!!!

[VR38]

Well you need water circulating and air flow for the system to cool.

[stwist]

I have @ bottle's, I had to replace one of them becayse it was leking, but it runs as a vacum thing my temp gauge sits on the bottom line, unless u give it heaps, and, like me, have no water and oil at all

[Eliminator]

ts definately circulating and theres no blockages to my knoledge unless its in a heater hose or the water jackets etc.the a/c thermo doesnt kick in unless the ac is engaged and think maybe it could contribute to the problem but wouldnt think it would make it overheat that bad?

Im leaving it on a clean concrete floor tonight and will see if theres any minute water leaks

[Eliminator]

just found a small water leak where the drivers side heater hose runs, where it joins the rubber has swolen. hoping this is the problem as air in the system will create more heat but not sure it if would increase temps to 100 degrees on a hot day and be the main cause of it all?

[VR38]

Any loss of pressure will allow the water to boil.

[Eliminator]

the hoses go hard as a rock yet that hose has a tiny leak and theres no bubbles in he radiator doesnt make sense to me, ill fix the leak and assess it from there

[camstatic]

Make sure the clutch is working properly in that aeroplane prop holden call a radiator fan. Could be free-wheeling and not pulling enough air through the radiator... How's the temp at 60+kmh?

[delcowizzid]

or a partially blocked cat wouldnt be the first v8 on here with overheating problems caused by the cat

[commsirac]

I removed the standard thermostat and checked it in a stove pan with a thermometre, it didnt start to open until 95 degrees then still it wasnt even 1/4-1/2 open... should i go for a 80 degree thermo this time???

There is something wrong with a thermostat that isnt fully open at 95 degrees. Get another one, that is the suggested opening temp for your motor.

As I alluded to before, stop guessing as to what the problem may be and get yourself an IR thermometer. You can get the temp of the top hose in an instant and compare it with the bottom hose or any other part of the motor. If there is a large difference between them, ie 10C or more and the top hose is 100C+, then there is a circulation problem. If there is only a small difference, like 2C then there is a problem with the radiator exchanging heat or airflow through the radiator
If you have the system full of coolant, a small leak wont be causing enough pressure drop to be causing the coolant to boil(just squeeze the hoses if the are firm, there is still pressure in there)....the fact that it is leaking out being evidence that there is pressure inside the hoses.