Coolant overflow issue
03-31-2007, 01:49 PM
#27
50/50 ethylene glycol (EG) coolant boils at 269 degF at 15 psig system pressure
100% NPG-R propylene glycol (PG) boils at 400 degF at 7 psig system pressure
as noted by Polak, the system has to be cleared of any water-based coolant and water cannot be added afterward or it will lower the effectiveness of the Evans coolant. It is a bit expensive to start, but everything performance related has it's price. The issues in general are having more around when it's needed and keeping some idiot from pouring regular coolant or water in it. They supply stickers stating not to add water or regular coolant to the system. You can add water or EG coolant in an emergency, you'll just have to start over again flushing it out afterward.
Flushing the system completely is not so bad now that we know where the low-point drain bolt that's not listed in the service manual is located. You'll drain the old EG/water coolant, fill with Sierra PG coolant (about $10-$11/gal from Ace Hardware, can order online and they deliver free to the local store), run the car up to operating temp and let cool, then drain the Sierra PG coolant from the system, then fill the system with the Evans NPG-R coolant. The Evans NPG-R costs around $33/gallon. The Sierra coolant step helps dilute/remove any water that was still in the system from the first drain. It's a lower temp PG coolant that is compatible with the Evans.
100% NPG-R propylene glycol (PG) boils at 400 degF at 7 psig system pressure
as noted by Polak, the system has to be cleared of any water-based coolant and water cannot be added afterward or it will lower the effectiveness of the Evans coolant. It is a bit expensive to start, but everything performance related has it's price. The issues in general are having more around when it's needed and keeping some idiot from pouring regular coolant or water in it. They supply stickers stating not to add water or regular coolant to the system. You can add water or EG coolant in an emergency, you'll just have to start over again flushing it out afterward.
Flushing the system completely is not so bad now that we know where the low-point drain bolt that's not listed in the service manual is located. You'll drain the old EG/water coolant, fill with Sierra PG coolant (about $10-$11/gal from Ace Hardware, can order online and they deliver free to the local store), run the car up to operating temp and let cool, then drain the Sierra PG coolant from the system, then fill the system with the Evans NPG-R coolant. The Evans NPG-R costs around $33/gallon. The Sierra coolant step helps dilute/remove any water that was still in the system from the first drain. It's a lower temp PG coolant that is compatible with the Evans.
04-02-2007, 06:19 AM
#31
Smooth Criminal
Thread Starter
Originally Posted by TeamRX8
it's a pressure cap, it's not going to allow fluid to get out unless the pressure is great enough to overcome the cap spring, not even if you hold it upside down ... so the bottle moving around is irrelevant
Thanks for all of the input. I appreciate it.
04-02-2007, 11:39 AM
#34
no, a number of autox cars have the problem since two years ago, including both of ours, the red car is now slinging coolant all over the engine covers
you can try the cap, it won't hurt, just didn't change anything for me, you may want to try the higher pressure cap even
you can try the cap, it won't hurt, just didn't change anything for me, you may want to try the higher pressure cap even
04-02-2007, 11:47 AM
#35
Smooth Criminal
Thread Starter
How old are your two cars that have the issue? I wonder if it gets worse with time. I am now at almost 60K miles. I autocrossed for the better part of a whole season, have done multiple track days, and gone round in circles on a skidpad quite a bit, and never had coolant end up all over the place, until recently. I guess I just need to have the cooling system checked out, to make sure there are not other problems with the car.
04-02-2007, 05:02 PM
#37
Lubricious
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Originally Posted by PoLaK
does the cap actually increase pressure in the system? If so, wouldn't that mean that the temperture would go up as well? (pv=nrt?)
If you mean, does it raise the boiling point -- yes.
04-02-2007, 08:53 PM
#38
it started happening during my 1st autox with the white 2005 car; 1600 miles then, under 5000 now
the red 2004 car has 22,000 miles on it, I haven't been around it but the last 3000 miles or so
I've seen 16psig and a 19-21 psig mini caps available from most performance places
the red 2004 car has 22,000 miles on it, I haven't been around it but the last 3000 miles or so
I've seen 16psig and a 19-21 psig mini caps available from most performance places
04-02-2007, 09:53 PM
#41
Although NPG-R is safe for all metals and contains no water, an annual coolant change is suggested for racing vehicles. For maximum corrosion protection, high performance street driven vehicles running NPG-R should change coolant every other year.
04-02-2007, 10:28 PM
#42
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Sometimes, what works on racing cars is not the best for street cars... If you simply change the 50/50 coolant to pure propylene glycol (i.e., Evans), you will run a hotter engine (because water has a much larger heat capacity than either ethylene or propylene glycols, hence it removes the engine heat more efficiently). On a racing car, you replace the radiator to prevent increased temps (due to its higher surface or better materials used), plus the engine is not meant to last 100,000 miles without a rebuilt.
Just my $0.02
Just my $0.02
06-05-2007, 05:50 AM
#45
Smooth Criminal
Thread Starter
and I have done nothing to it, just left it, and as far as I can tell, it has stopped. I am wondering if the dealer overfilled the reservoir a little. 
06-05-2007, 12:45 PM
#48
Ever since I changed my Radiator (to Koyo), I have lots of overflowing issues. When I open my hood every other day, I can see trails of coolant squirt all over the place. Never had a chance to go to the home depot to get a hose, so I can redirect it to somewhere like what MM did.
What kind of cap you guys got anyway? I have a feeling that the stock cap is not good enough for the job. Im looking for something like 1.3 bar.
For those who have Koyo Radiator, how many gallons of coolant you added ?
What kind of cap you guys got anyway? I have a feeling that the stock cap is not good enough for the job. Im looking for something like 1.3 bar.
For those who have Koyo Radiator, how many gallons of coolant you added ?
06-08-2007, 01:17 AM
#49
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Well with the temps in vegas rising I started to notice a little build up on the side of the tank and filter cover. After our last autox in hawthorne and drive home back to vegas i checked the oil and noticed that there was enough coolant loss to spater the engine cover and part of the battery cover. doesn't look like the coolant level has moved down at all though
I took a pic before cleaning everything to see if maybe it was just overfilled and started to do this because of the recent heat. can't get the pic off my phone but was thinking of taking to the dealer to have them look at it
I took a pic before cleaning everything to see if maybe it was just overfilled and started to do this because of the recent heat. can't get the pic off my phone but was thinking of taking to the dealer to have them look at it
Last edited by WRXtoRX8; 06-08-2007 at 01:22 AM.