Radiator overflow/expansion, whats typical here?

[southwind25]

Ok another question.
The car was recieved with an overflow bottle losely tied into the frame in front of the engine. more or less laying there.
i believe this is an overflow tank and perhaps not an expansion tank sincetheres no cap on the tank.
Its a 1600 with the cap on the thermostat on the engine, with the overflow tube right below the cap
does it matter where or how high i mount this?
should it be an expansion tank?or this is open overflow is normal for the birkin as well?

[Davemk1]

My car has a Zetec and the overflow bottle is right below the pedal box almost under the steering shaft. seem fine and never really thought of it.

Dave

[slomove]

I have the overflow bottle in front of the engine and I think it does not really matter where or if it is installed high or low as long as it secured well. I did replace the huge original plastic overflow tank with a quart size aluminum bottle (drinking water bottle for a bicycle) with the suction tube going through the cap to the bottom. An earlier experiment with a clear polycarbonate plastic bottle failed because the glycol attacks and cracks the polycarbonate. But it would have been nice to see the coolant level inside.

Gert

[xflow7]

Many xflow installations (including mine) have a simple overflow bottle arrangement as you describe it.

However, conventional wisdom (at least among the BlatChat crowd) is that converting to a true expansion tank arrangement is a worthwhile upgrade. A common approach in the UK is to use the expansion tank from an XR2 Fiesta or VW Polo and mount it right in front of the pax side firewall. I have a hard copy document somewhere describing one approach with pictures. I had it as a softcopy, but not sure if I still do unless its hiding in my Gmail somewhere. I'll have a look and send it if I can find it.

Alternatively, I can see about having my hardcopy scanned sometime this weekend.

Dave

[pierats]

Dave,

I'd be interested to see that document if you can find it.

What advantages do you think this kind of setup provides? I understand that you could run a higher pressure (the stock Caterham cap is just a couple of pounds). Thoughts?

[BobDrye]

The design of a cooling system is very vehicle dependant. You need to find a way to keep air out of the system. In many late model cars the only way to keep the air from being trapped inside the cooling system is to vacuum the system and then allow the vacuum to slowly pull the coolant in. On BMWs we measure the amount of coolant that we vacuum into it. We know how much coolant each type of car takes and make sure that we put that amount back in. How much does the coolant level raise as it gets hot? Is there a place to bleed the air out from a high point in the system? Most people think that if they have 2 pound cap on the system the whole system runs at that pressure. The intake side of a coolant pump usually has a vacuum, but the pressure side of the pump on a cold morning could have an instantious pressure of over 1000 pounds. If you could see the coolant on the backside of an exhaust valve you would see it turn from a liquid to steam. If the system that is on the seven works I’m not sure that I would change it. If your seven has an addational bottle and it fills with coolant when the seven gets warm then the origional reservoir probally wasn't big enough. My seven uses 2 bottles.


----------------------------------------->:7head:

[JohnK]

The design of a cooling system is very vehicle dependant. . . .

Have you had occasion to look at the cooling system that Carroll Smith sketched out in his "Prepare to Win" ?, and, if so, what do you think of it? It's clear that different manufacturers (engineers?) implement different looking systems, but I was wondering how "general" the Smith approach is. I used it as a guide in putting together a system for my Honda S2000 engine and got good results - in particular it self-bleeds if you hook up the "engine top bleed" to a surge tank that's higher by 1/2 than the bleed. I absolutely agree with you about carefully measuring how much coolant you put in. It's the only way I ever found peace of mind about trapped air in the cooling system.
Cheers,

[xflow7]

Dave,

I'd be interested to see that document if you can find it.

What advantages do you think this kind of setup provides? I understand that you could run a higher pressure (the stock Caterham cap is just a couple of pounds). Thoughts?

Hi Tom,

I found the document soft copy. Happy to email it if you PM your address.

Same goes for anyone else who'd like it.

I think the primary benefit is that you are assured that though the coolant may expand as heated, it remains in the cooling system. With the conventional overflow bottle, any coolant that escapes as the temp/pressure rise in the cooling system may not be effectively sucked back in as the system cools.

[BobDrye]

I think the primary benefit is that you are assured that though the coolant may expand as heated, it remains in the cooling system. With the conventional overflow bottle, any coolant that escapes as the temp/pressure rise in the cooling system may not be effectively sucked back in as the system cools.

As long as the hose goes to the bottom of the bottle, and the expansion of the coolant doesn't overfill the bottle you should be fine. You just don't want to ingest air into the system.


:7drive:

[stevet]

Bob, I remember nearly catching one of your overflow bottles on our West Va blat - was it coke or Pepsi?

:d

[BobDrye]

Bob, I remember nearly catching one of your overflow bottles on our West Va blat - was it coke or Pepsi?

:d


Pure Avian! I was trying to pass you a drink.


<=============== :7fume:

[stevet]

:cheers:

[gjslutz]

Robert, as you know, I'm in the area and mine was set up for the track. I can turn the heat on for Mary also. You have 6 days to see it. Gary