Overheat again!

[olzed]

What don't you understand?

[d240zx2]

One solution to air entrapment may be to park the car on a fairly steep incline, front of the car up. After the engine has cooled a bit, remove the radiator cap and restart the engine. Allow to return to operating temp. All the air "should" gurgle to the highest point, the open radiator cap, thus purging the air from the system.

I read about this technique somewhere on this forum.... I think from ZsOndabrain???

[Z train]

That method is actually in a FSM of another make.

[d240zx2]

Cool. I try not to plagiarize whenever possible.

[Zs-ondabrain]

here's a clue... Water transfers temperature better than air. If there is an air pocket at the thermostat, the Tstat won't open, if it won't open, it'll over heat. By removing the hose from the Tstat housing, you bleed the air out and it's replaced with water. "Burping" the system so to speak.

Most shops have a funnel with an adaptor to lock the funnel to the top of the radiator. Fill it with water, run the motor and when it opens up, the water fills and keeps the radiator topped off after a few openings and closings. Basically burping the system by forcing water in and leaving no room for air, to overheat the system.

Dave

[Zs-ondabrain]

I read about this technique somewhere on this forum.... I think from ZsOndabrain???

Yup, it was me and it works awesome. Gravity CAN be a great thing.

And I also love to use Water Wetter by Redline. Cools the system by up to 10 to 15% by volume. Great stuff in the heat

Edited August 26, 2010 by Zs-ondabrain

[ozconnection]

Not owning a Z, I can't comment on the specifics of coolant system purge for your cars but I'm reading a lot of stuff here that seems like a lot of effort, at least more than seems necessary.

Whenever I do a coolant change or the system gets opened up (that even means taking the radiator cap off), the way I purge the cooling system is by taking the car for a drive with the heater on. The fluctuating revs and added vibrations from driving for 15-30 minutes will get the air pockets to the radiator header tank. I then park the car and let my engine cool completely. At this point I used to take the cap off and fill the radiator with extra coolant. Now, and I always had this on my Datsun, is a coolant recovery system. I make sure that the tank is filled with coolant to the full mark and as the engine cools, it draws in coolant into the radiator via the radiator cap. Two or three cycles of this and the cooling system is completely purged of all air. Don't take the radiator cap off to check the coolant level, at least I don't anymore. I don't have to, the coolant level in the recovery tank is now my coolant level measure. :bulb:

Air under the thermostat can happen by using a thermostat without the little bypass that some thermostats come with. I always use the bypass type to avoid the 'air under the thermostat' malady.

Like mentioned by Zsondabrain, water wetter is a good thing!

Cheers

Edited August 27, 2010 by ozconnection

[Z train]

Water-wetter is NOT designed to be used with glycol.

[steve91tt]

Water-wetter is NOT designed to be used with glycol.

From the waterwetter (Red Line) web site...

"Compatible with new or used antifreeze (including DEX-COOL and long-life versions) to improve the heat transfer of ethylene and propylene glycol systems"

As I understand it, it's just a blend of anticorrosives, wetting agents and lubricants that allows you to run more water and less glycol in your cooling system while still protecting your system from everything but freezing. Water has a much better heat transfer efficiency than glycol therefore you get better cooling without the danger (lubricity, corrosion) of running high water levels. Not so good for freeze protection so I would not run high water levels in a freeze prone climate.

I've always used Waterwetter with great results in glycol based coolants.

Edited August 27, 2010 by steve91tt

[Zs-ondabrain]

AND.... I leave it in during the winter. Never had an Overheat issue while using the Water Wetter. My Z is parked inside during all times of the year so I can't give proper conclusions for Freezing during the winter with the Red-Line.

With the new Aluminum Radiator, Dual 12" fans, $50 Polished aluminum Over-flow tank, Clear 1/4" tubing going from the radiator top and tank, I Don't overheat, I can see the coolant and any air in the line going to the overflow.

Dave

you can see the Tank and line and NO air bubbles. The electric Thermostat is the dial on the left of the radiator

[Z train]

From the waterwetter (Red Line) web site...

"Compatible with new or used antifreeze (including DEX-COOL and long-life versions) to improve the heat transfer of ethylene and propylene glycol systems"

As I understand it, it's just a blend of anticorrosives, wetting agents and lubricants that allows you to run more water and less glycol in your cooling system while still protecting your system from everything but freezing. Water has a much better heat transfer efficiency than glycol therefore you get better cooling without the danger (lubricity, corrosion) of running high water levels. Not so good for freeze protection so I would not run high water levels in a freeze prone climate.

I've always used Waterwetter with great results in glycol based coolants.

"Compatible"-all that means is there is no adverse reaction.Doesn't mean it was DESIGNED to enhance a water/glycol mix.Proper cooling system care trumps all.Bottom line the stuff is not needed.

[steve91tt]

"Compatible"-all that means is there is no adverse reaction.Doesn't mean it was DESIGNED to enhance a water/glycol mix.

It will allow you to safely run more water and less glycol therefore significantly enhancing the cooling efficiency of your system. That's a benefit to me and being in a warm climate I see no down side.