If so, how?

Without getting into too much detail at this point, my water temp(stock gauge) is fluctutating around the halfway point after about 15-20min of driving. I am under the impression that if its going up and down while driving, that is usually related to air pockets in the system. But Ive tried to bleed out any air twice so far and hasnt changed anything. Someone suggested to me it could be related to my rad cap?

 

Are you letting the thermostat open all the way before putting the rad cap back on?

 

Yes. I have no clue how but it can. My accord overheated, when I took the cap off it was all flaky and falling apart, got another one and it hasnt overheated since..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dave_B &raquo;</TD></TR><TR><TD CLASS="quote">Are you letting the thermostat open all the way before putting the rad cap back on?</TD></TR></TABLE>

how do I know its open all the way?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clip the apex &raquo;</TD></TR><TR><TD CLASS="quote">

how do I know its open all the way?</TD></TR></TABLE>

When the fan kicks on the thermo is open. I usually let it cycle twice before I put the cap on...

 

i dont see why it would overheat due to the cap, loosing coolant that could happen.
You might still have some nasty airpockets there, re bleed it.

 

fan is definitely on...Ive tried to bleed it pretty much immediately after pulling over, careful not to scald myself.

 

This is simple. If your radiator cap has the ability to let coolant out, as the system expands and the pressure builds, this it will more than likely have the ability to let something else in to take up the coolants place. Air.

As the system cools, air will be sucked in while the coolant contracts while it cools back to it's ambient state. This air will fill the void. If air is not being sucked in, then there will be a negative pressure in the cooling system and you will be able to see it affecting the radiator hoses.

The hoses will not round because of the suction (compression) in the system. They will be flatened out a bit...some times not holding the right shape.

There shouldn't be ANY air in a cooling system. This is why a system needs to be properly purged. As the water expands when the system warms up it will push and compress the trapped air molecules and give your system weird readings.

The radiator cap is the last mechanism to hold in that pressure. A cap with an OEM reading is sufficient for DD cars, however I don't see a real point in aftermarket stuff unless your racing the car pretty regularly.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by walker111 &raquo;</TD></TR><TR><TD CLASS="quote">

When the fan kicks on the thermo is open. I usually let it cycle twice before I put the cap on...</TD></TR></TABLE>

No no my friend. Don't go by the fan. With the rad cap off, and the car running you can watch the bubbles. Once the bubbles go away AND the fluid level seems to drop just a bit, that's your indicator. It will usually bubble a bit more as the thermo is about to open, then it bubbles pretty good, then goes away. If your looking for it, you'll know what I'm talking about.

I had a buddy who had the same problem on his GS-T. He thought it was bled correctly. He even did it like 5 times only to have the car still overheat. It was that he never waited for the thermo.

 

The fan works. I understand where youre coming from though. If the system is empty then its easy to tell but if you are bleeding a full system then its a bit harder to tell.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by walker111 &raquo;</TD></TR><TR><TD CLASS="quote">The fan works. I understand where youre coming from though. If the system is empty then its easy to tell but if you are bleeding a full system then its a bit harder to tell.

</TD></TR></TABLE>

True. It is hard to tell. What I do is let the car idle. As the bubbles come out, I replace that volume with water. Periodically I'll give the upper radiator hose a few slaps and a squeeze.

Whn there are no more bubbles coming out, I wait and watch the coolant expand to where it starts spilling over the radiator fill neck. I turn the car off, then as the coolant contracts I'm there with a hose to keep the radiator topped off.

It takes a little while, but I feel this is the best method.

 

Brando, you are a better man with words than I. That's exactly how I do it. Watch the bubbles, some spilling over the neck. Refill that volume with water/coolant. Keep the process up until there are no more bubbles coming out of the system.

 

awesome, I wasnt sure what the actual function of the radiator cap was, and how it worked in conjunction with the overflow tank. I will try to rebleed and see what happens. I might not be topping off the rad enough because I dont like to make a mess and hate the smell of burning coolant

back to the original question, is a higher pressure cap better or worse? does it really matter as long as the overflow tank has fluid in it and doesnt let air into the system?

good information here

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clip the apex &raquo;</TD></TR><TR><TD CLASS="quote">back to the original question, is a higher pressure cap better or worse? does it really matter as long as the overflow tank has fluid in it and doesnt let air into the system?
</TD></TR></TABLE>

Personally, I think it's a waste on a daily driven car. Unless your racing your car in 90 degree + tempuratures and your really romping on it, I don't think its necessary.

In a nut shell, when you increase the pressure, your increasing the boiling point of the coolant. Think of a pressure cooker. What happens is that your car will run at a hotter temp without over heating. The added weight to the aftermarket radiator cap will simply hold in that extra bit of pressure created by the increased tempurature of the coolant.

If you feel it's absolutely necessary don't use the aftermarket cap unless you upgraded the hoses to something that can handle the extra pressure (SPOON, Samco..) and I'd change all the hose clamps to T-Clamps so there is a unified clamp on the hose ends.

Other than my Koyo radiator, everything is OEM and I have no cooling issues at all. I would rather increase the amount of coolant in the system rather than increase the pressure.

 

OK its starting to make sense. The cap that came with the radiator has a "1.3" stamped onto it. Im assuming thats pressure (bar?). If that is a higher rating than the stock cap, that means I am probably running higher pressure in the system, which means the coolant temp itself is hotter, which would indicate a higher temp on the gauge, correct? However, I did not let it go too far past halfway, I pretty much pulled over at that point. That would also mean more stress on the motor and coolant hoses, which would possibly explain a small leak on the lower radiator hose. Ill pay close attention to the clamp areas and see how much they are being stressed.

Is it possible that it WONT continue to rise past that point once the temp and pressure is consistent throughout the system? Would changing to a different thermo help or make it worse?

 

there is nothing wrong with a 1.3bar cap. A leak wouldnt cause it to overheat but u would notice a decrease on the amount of coolant in the reservoir. Is that happening btw?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clip the apex &raquo;</TD></TR><TR><TD CLASS="quote">OK its starting to make sense. The cap that came with the radiator has a "1.3" stamped onto it. Im assuming thats pressure (bar?).</TD></TR></TABLE>
I want to say off the top of my head, that is 1.3kg/cm2. I think OEM is 1.1.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clip the apex &raquo;</TD></TR><TR><TD CLASS="quote">If that is a higher rating than the stock cap, that means I am probably running higher pressure in the system, which means the coolant temp itself is hotter, which would indicate a higher temp on the gauge, correct?</TD></TR></TABLE>
Yes, yes and yes.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clip the apex &raquo;</TD></TR><TR><TD CLASS="quote">However, I did not let it go too far past halfway, I pretty much pulled over at that point. That would also mean more stress on the motor and coolant hoses, which would possibly explain a small leak on the lower radiator hose. Ill pay close attention to the clamp areas and see how much they are being stressed.</TD></TR></TABLE>
If the OEM hoses cannot hold in the pressure they will burst. By the nature of the OEM clamps, just looking at them tells me they are not sufficient enough to hold increased pressure. If your using an OEM radiator, keep a watchful eye on the end tanks. They are plastic that are adhered to the metal core and over time will seperate or crack at the seams.

As far as the temp rising to the half way point...I wouldn't worry about it. If it goes over the half way point, I'd worry about it. Sounds like you have air in the system.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clip the apex &raquo;</TD></TR><TR><TD CLASS="quote">Is it possible that it WONT continue to rise past that point once the temp and pressure is consistent throughout the system? Would changing to a different thermo help or make it worse?</TD></TR></TABLE>
Anything is possible . I've done lots of testing with different aftermarket cooling products Vs. OEM and every time I stick with OEM parts. Even when my R was turbo charged and had combustion tempuratures of 1400 degrees F and up, the OEM stuff worked best.

Seriously if your worried about temps, change the radiator to a quality aftermarket dual core unit and keep the cap, fan switch and thermostat all OEM.

 

I noticed a SLIGHT decrease in the amount of coolant in the overflow tank.

Brando I am using those screw clamp things, not the stock clamps.

Im going to bleed it one more time and see if I can work out any air pockets and make sure the rad is full. Ill report back the results.

Thanks for the information

 

The over flow tank being emptied is a sure tale sign that your steaming off coolant somewhere in the system. It is critical to get the leak fixed. I know your not going to forget about the problem, but it might catch up to you when you least expect it...like in traffic or something.

 

mine was consuming coolant due to some bubbles, once the coolant took their spot no more coolant drop.

 

Using a higher pressure cap raises the boiling point of the coolant, but shouldn't really cause the car to run hotter by itself. It merely allows the possibility of higher coolant temps without boiling.

 

after a closer examination this evening, it looks like a bit more coolant has disappeared from the overflow tank than I originally thought. does this indicate air in the system being replaced by that coolant? Its about 2.5-3 inches lower than where it was when I filled it.


Modified by clip the apex at 7:50 PM 7/6/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clip the apex &raquo;</TD></TR><TR><TD CLASS="quote">after a closer examination this evening, it looks like a bit more coolant has disappeared from the overflow tank than I originally thought. does this indicate air in the system being replaced by that coolant? Its about 2.5-3 inches lower than where it was when I filled it.</TD></TR></TABLE>

Definately means you have a leak somewhere. Just top it off, and let the car idle up to running tempurature. Check everything and see if you can spot any steam coming out or a coolant drip.

 

I have a slight coolant leak at the neck on the head. its very slight, like a drip.

 

1: I use worm gears on my radiator hoses.
2: I have a mugen cap (got it for free), I noticed that my guage doesnt fluctuate once I'm at NOT like it did with the stock one. Its stays constant, a tick mark under half.
3: I have stock hoses. Soon will upgrade to Samco
4: Fix that leak asap, no leak is ok, whether it be small or not.
5: Once you fix ur leak I'm sure you'll be fine.