Cooling/Coolant system issues
08-04-2009, 01:49 AM
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Cooling/Coolant system issues
Right oh learned members I need to pick your brains!
I have been having issues with the coolant system on my car for a few weeks now and am starting to get hacked of!
The car started to run hot and ended up spitting the coolant out the expansion bottle not the rad cap! It clearly expands in the system fills the expansion bottle then overflows from there, very annoying cleaning it from the engine bay.
The first things I did were replace the coolant with an uprated one recommended by opie oils and also an additional addative to aid the cooling, I also cut the side louvres from the bumper and ducted additional air onto the rad as the intercooler and SC oil cooler sit in front of it. All seemed well until the temp gauge on the dash would shoot into the red within two minutes of starting it.
Cue bleeding of air from the system with the front end as high as I could get it etc, as well as adjusting the EMS so the rad fans kick in at a lower temperature.
I thought I had it sussed but it still seems to be expanding into the overflow reservoir and then never getting sucked back to the rad. It is almost as if it is sucking air in from another location?
It has been suggested that it may be a head gasket issue although there is no evidence of contamination oil to water/water to oil, leaks etc. I do plan on changing the rad cap, thermostat, fan switch but would also like other opinions whilst going through those steps.
Thanks in advance.
I have been having issues with the coolant system on my car for a few weeks now and am starting to get hacked of!
The car started to run hot and ended up spitting the coolant out the expansion bottle not the rad cap! It clearly expands in the system fills the expansion bottle then overflows from there, very annoying cleaning it from the engine bay.
The first things I did were replace the coolant with an uprated one recommended by opie oils and also an additional addative to aid the cooling, I also cut the side louvres from the bumper and ducted additional air onto the rad as the intercooler and SC oil cooler sit in front of it. All seemed well until the temp gauge on the dash would shoot into the red within two minutes of starting it.
Cue bleeding of air from the system with the front end as high as I could get it etc, as well as adjusting the EMS so the rad fans kick in at a lower temperature.
I thought I had it sussed but it still seems to be expanding into the overflow reservoir and then never getting sucked back to the rad. It is almost as if it is sucking air in from another location?
It has been suggested that it may be a head gasket issue although there is no evidence of contamination oil to water/water to oil, leaks etc. I do plan on changing the rad cap, thermostat, fan switch but would also like other opinions whilst going through those steps.
Thanks in advance.
08-04-2009, 01:55 AM
#2
So your are running an SC, ECU etc but on the stock rad, rad cap, fan switch, thermostat???
Any ideas what the coolant temps were? must be approaching 107/108???
IIRC coolant starts to boil at 110c.
Any ideas what the coolant temps were? must be approaching 107/108???
IIRC coolant starts to boil at 110c.
08-04-2009, 02:57 AM
#5
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Change the rad cap. It's not holding enough pressure so the temperature the coolant boils at is lower than it should be. This means the coolant is getting too hot, expanding and overflowing into the expansion vessel.
08-04-2009, 02:58 AM
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If it's coming out of the expansion bottle within 2 mins of starting from cold then you have a head gasket issue.
There wouldn't necessarily be any oil/water or water/oil contamination if you have blown the gasket between cylinder and water jacket.
Try a compression test and better still a leakdown test on your engine.
Failing that, there is a tester that you can buy to check for combustion gasses in the coolant.
With the way that the S2000 cooling system is set up, the coolant will flow into the expansion bottle first, rather than lifting the rad cap. This is because it takes a fair amount of pressure (as stated on the cap) to lift the cap against spring pressure, but only a low pressure to expand coolant into the tank. The idea is that the rad cap lifts in the event of the coolant boiling, rather than it just expanding.
During normal usage, this is not a problem - coolant expands by x% of its overall volume at or slightly above operating temperature. Cunningly, mr Honda has designed his tank to cope with the total coolant volume multiplied by x% plus a safety factor.
If (eg) the rad is blocked and the coolant boils, it will first piss out of the expansion bottle and then when the whole system reached boilingpoint, the rad cap will permit steam to vent at a higher volumetric rate.
If you have bled the system correctly, then my money is firmly on a head gasket. Coolant systems do not (generally) draw in air and even if they do, the system is designed to eventually deposit this air in the expansion bottle. If it is drawing in enough air to cause an airlock, then you would expect a big coolant leak from somewhere... unless its the head gasket that has gone and the "air" in the system is combustion gas.
There wouldn't necessarily be any oil/water or water/oil contamination if you have blown the gasket between cylinder and water jacket.
Try a compression test and better still a leakdown test on your engine.
Failing that, there is a tester that you can buy to check for combustion gasses in the coolant.
With the way that the S2000 cooling system is set up, the coolant will flow into the expansion bottle first, rather than lifting the rad cap. This is because it takes a fair amount of pressure (as stated on the cap) to lift the cap against spring pressure, but only a low pressure to expand coolant into the tank. The idea is that the rad cap lifts in the event of the coolant boiling, rather than it just expanding.
During normal usage, this is not a problem - coolant expands by x% of its overall volume at or slightly above operating temperature. Cunningly, mr Honda has designed his tank to cope with the total coolant volume multiplied by x% plus a safety factor.
If (eg) the rad is blocked and the coolant boils, it will first piss out of the expansion bottle and then when the whole system reached boilingpoint, the rad cap will permit steam to vent at a higher volumetric rate.
If you have bled the system correctly, then my money is firmly on a head gasket. Coolant systems do not (generally) draw in air and even if they do, the system is designed to eventually deposit this air in the expansion bottle. If it is drawing in enough air to cause an airlock, then you would expect a big coolant leak from somewhere... unless its the head gasket that has gone and the "air" in the system is combustion gas.
08-04-2009, 02:59 AM
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The symptoms you describe can be cause by coolant boiling somewhere within the engine.
Possible causes for this are:
Cylinder head gasket blown
Poor coolant flow due to failed water pump
Engine running hot due to wrong fuel / air mixture
Failure to remove heat from coolant due to partly blocked or choked water radiator.
Cooling system leaking. (only needs to be v tiny!)
Lack of pressure in the cooling system
Airlock in the cooling system.
What happens if you run the heater on max hot with full blower? does this aleviate any of the problems you mention?
Possible causes for this are:
Cylinder head gasket blown
Poor coolant flow due to failed water pump
Engine running hot due to wrong fuel / air mixture
Failure to remove heat from coolant due to partly blocked or choked water radiator.
Cooling system leaking. (only needs to be v tiny!)
Lack of pressure in the cooling system
Airlock in the cooling system.
What happens if you run the heater on max hot with full blower? does this aleviate any of the problems you mention?
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08-04-2009, 03:47 AM
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Originally Posted by Kawasakivtec,Aug 4 2009, 09:49 AM
I do plan on changing the rad cap, thermostat, fan switch but would also like other opinions whilst going through those steps.
08-04-2009, 04:23 AM
#9
If its going into the red within two minutes of starting it sounds suspiciously like a stuck or sticking thermostat.
If the thermostat is failing to fully open and open at the right time then it doesn't make any difference how good you cooling system is if the hot coolant isn't getting into the rad.
Failed or failing water pump could also give the same symptoms. Its not been unknown for the impeller to break up or snap off the shaft. But that would give consistent problems rather than the gradual worsening or erratic problems that i think you're describing.
But I'd be changing the thermostat as a priority.
If the thermostat is failing to fully open and open at the right time then it doesn't make any difference how good you cooling system is if the hot coolant isn't getting into the rad.
Failed or failing water pump could also give the same symptoms. Its not been unknown for the impeller to break up or snap off the shaft. But that would give consistent problems rather than the gradual worsening or erratic problems that i think you're describing.
But I'd be changing the thermostat as a priority.
08-04-2009, 04:59 AM
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Thermostats on Hondas do tend to stick quite often. I haven't changed one on an S yet, but this is the only Honda I haven't done one on.
Get a sniffer test done on your coolant to see if your headgasket is gone.
But after reading your symptoms, my first thought was the same as Lower's - the impeller had broken up on the water pump.
Lots for you to test, all of it for next to no money though!
Get a sniffer test done on your coolant to see if your headgasket is gone.
But after reading your symptoms, my first thought was the same as Lower's - the impeller had broken up on the water pump.
Lots for you to test, all of it for next to no money though!