The first step in solving a cooling problem is to identify which of the 2 basic cooling problems you have(both are possible):
1. Coolant not circulating at an adequate rate.
2. Engine producing too much heat for the fitted (combination of radiator and airflow)
To test for 1: (Coolant not circulating at an adequate rate)
When the motor is above thermostat opening temperature the difference between the entry and exit temps of the coolant from the radiator is an indicator of coolant flow, with the proviso that there is a reasonable airflow through the radiator�electric or engine fan.
And the following applies
High difference in temp: >10C inadequate flow
Low difference in temp <10C adequate flow.
In extreme examples the difference can be felt by hand when comparing top and bottom radiator hoses. More accurate methods would have sensors in bottom and top tanks of rad or measure the temps of top and bottom hoses with an IR sensor(yes rubber is not a good conductor of heat��.however, the hose will be closer to the temp of the water than the surrounding air and it is the difference that is of interest)
If your results indicate a coolant flow prob, then concentrate your efforts into finding the cause, possibilities:
Flow constrictions: clogged passages in rad and or engine, thermostat
or simply the water pump is not moving enough water.
If you problems are at speed, then do the temp comparison when the motor is at 3000rpm rather than at idle.
If you have adequate flow, then your problem is
2: Engine producing too much heat for (combination of radiator and airflow)
Finding the cause of the prob here is the tough bit:
Some Possibilities:
Engine tune
Combustion products in coolant
Overbored motor
Not enough airflow through radiator
Not enough radiator.
Solutions can vary: overbored motor��replace motor or fit better rad, larger fans etc.
Cooling problems diagnosis
Started by
_devilsadvocate_
, Apr 06 2007 11:16 PM
8 replies to this topic
#2
TerrA LX
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Posted 06 April 2007 - 11:24 PM
you have said it a thousand times and that pretty much sums it up, creates a good sound foundation to base diagnosis on.
cheers DA.
cheers DA.
#3
_dave720gtr_
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Posted 03 July 2007 - 01:02 PM
well i have had a read of all the thread regarding cooling .
this is what i cam up with for my holden six turbo / supercharged . or N/A race engines. the front of the engine were the water pump bolts up is 5mm alloy plate
with a -20 fitting welded in the senter 90% fitting leading to a remote CSR 168L per min pump. and pump speed controll . 26 inch crossflow alloy radiator with 16inch front mounted fan . i will let u now how it all goes
My Webpage
this is what i cam up with for my holden six turbo / supercharged . or N/A race engines. the front of the engine were the water pump bolts up is 5mm alloy plate
with a -20 fitting welded in the senter 90% fitting leading to a remote CSR 168L per min pump. and pump speed controll . 26 inch crossflow alloy radiator with 16inch front mounted fan . i will let u now how it all goes
My Webpage
#4
_slr4me_
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Posted 23 June 2012 - 09:02 AM
Can anyone offer some advice on a problem i am trying to solve. i have a standard 253, new 3 core radiator, new water pump, new thermostat, new temp sender, new heater core and the temperature gauge reads 1/2 to 3/4 at operating temp. (never gets hotter). the top hose is hot (too hot to hold hand on it), but the bottom hose varies between cold and luke warm. Temp gauge has been tested to be OK. I do not beleive the engine to be running hot.
i feel that there is an air pocket in the cooling system, but despite best attempts cannot remove it.
Any suggestions would be appreciated.
i feel that there is an air pocket in the cooling system, but despite best attempts cannot remove it.
Any suggestions would be appreciated.
#5
ZUSE
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Posted 28 June 2012 - 10:57 AM
hi matt to remove air from system make sure heater is on position? remove radiator cap start engine and allow to reach operating temp which is determined by thermostat should be 74c summer or 84c winter ?you can also place a piece of cardboard in front of radiator to achieve normal operating temp ? suitable for diagnosing once temp is reached looking in to rad you should see water start to flow with a increase in revs slight but constant flow should increase therefor removing any air in the system ? check heater hoses are both equally hot ? fill to desired level hope this helps
cheers
cheers
#6
ls2lxhatch
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Posted 28 June 2012 - 11:09 AM
Have you checked the engine temp with another temperature gauge or a IR temperature gun?
How did you confirm the factory gauge is correct? What temperature is the engine at when the factory gauge reads 1/2 - 3/4.
You could just have the wrong sender for the factory gauge.
How did you confirm the factory gauge is correct? What temperature is the engine at when the factory gauge reads 1/2 - 3/4.
You could just have the wrong sender for the factory gauge.
Edited by ls2lxhatch, 28 June 2012 - 11:09 AM.
#7
_slr4me_
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Posted 01 August 2012 - 07:44 PM
i had a VDO gauge mounted under dash which never read over 95 degrees. i removed this and fitted a new temp sender (in the same place that the VDO sender was). I have had the temp gauge checked by with an old school VDO testing device and it checked out OK. the temp in the radiator top tank via a thermometer type radiator gauge does not exceed 95 degrees at operating temp. What is throwing me is that the bottom hose only ever gets luke warm at best. this has led me to beleive that the coolant is not circulating properlyand or there is an air pocket in the cooling system? or is the radiator too efficient? i have still not solved this issue. the car has been off the road for 2 months but i have now started driving again.
#8
S pack
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Posted 01 August 2012 - 07:58 PM
i had a VDO gauge mounted under dash which never read over 95 degrees. i removed this and fitted a new temp sender (in the same place that the VDO sender was). I have had the temp gauge checked by with an old school VDO testing device and it checked out OK. the temp in the radiator top tank via a thermometer type radiator gauge does not exceed 95 degrees at operating temp. What is throwing me is that the bottom hose only ever gets luke warm at best. this has led me to beleive that the coolant is not circulating properlyand or there is an air pocket in the cooling system? or is the radiator too efficient? i have still not solved this issue. the car has been off the road for 2 months but i have now started driving again.
What issue? If the cooling system wasn't working properly you'd have overheating problems, so all sounds good to me.
Be happy that your cooling system works efficiently.
#9
Belly68
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Posted 13 August 2019 - 11:30 AM
Hi, forgive me if I am reviving an old topic. I have a LH 308 that has cooling issues when it gets a bit hotter, still running the 4 blade fan. I am replacing this with the old 7 blade clutch fan with a shroud and am running a 3 core radiator. My question is what size fan spacer do I need with this system.
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