Cooling System Expansion

[Guest robin]

Not strictly a new topic, but still a few questions on the cooling system.

I happened to find a capri in my local scrappie and whilst robbing it of the throttle cable for my 32/36 dgav, I noticed it had a very simple expansion bottle with a min/max indicator. It has one small outlet coming from directly underneath and went straight to the rads overflow pipe outlet.

The cap on it is similar to that of a washer fluid cap and means the bottle does not get pressurized. Does this matter?

 

My thinking was that as the cooling system heats and expands, the cap on the rad opens and excess hot water (instead of being thrown over the road) is pushed up into the bottle, and when it cools down it flows back into the rad via the one way valve in the cap.

 

I hope this is an o.k method of cathing and returning the water as I have already bought the bottle incase someone else got it before I got back there.

 

Is there anything else that could be handy off a capri (apart from instruments as they were already missing!!!)?

 

cheers Robin

[Peter Bell]

Robin, that is exactly what you need, if you do a search on here you will find lots of info to that effect. Just make sure you have the right type of cap on the rad.

Peter

[Guest Bob Rowell]

Robin, I was running that system but found that it was marginal for overheating in traffic, usually running about 100-120 degrees. I have dumped my overflow tank and fitted an expansion tank on the bulkhead instead. I then removed the insides from my rad cap before re-fitting it, next I ran a length of small bore pipe from the rad overflow spigot to the top of the expansion tank, and a length of 15mm pipe from the bottom of the expansion tank into a T-piece I made up to go into the heater hose.

With a 15lb cap on the expansion tank the boiling point of my cooling system is now approx 120 degrees. The final part of the job was to change the fan switch for one operating at 95/87. I have only run about 60 miles since making these changes, but most of that was in heavy traffic, with a 5 mile run on the by-pass at about 70 ish. The cooling is definitely much better with the temp barely reaching 100 deg.

[Guest salty_monk]

I'm now running exactly that system. See here: Dave Andrews Oil &Water

 

Seems to be moving fluid to the expansion tank & back again ok (like an old Cortina I believe)

 

The cap should control the boiling point of the water whatever a 15lb cap is a 15lb cap. You should be OK with your buy...

[Guest Petemate]

Hi Bob

I second that. Wanting to mimic good ole Henry's system, I fitted to mine 1) an expansion tank from an Astra (nice little round one, fits neatly in front of the battery {front-mounted - sorry Bill}),2) rad fan (from a CVH Sierra really good puller behind the rad) 3) Maxi rad cap on the RHSC single core rad 4) small pipe from the "overflow" to the top of the exp tank 5) 16mm hose from a tee-piece in the bottom hose to the lower connection in the exp tank and 6) fan control from Car Builder Solutions. I've run the engine in my car port out the back in blazing hot weather for 3/4 hr with the fan cutting in and out appropriately - no overheating. Job's a good 'un.

HTH

Pete (oldgit)

[Guest Ant]

Perhaps its worth mentioning at this point that there are two common setups for expansion bottles. One where the bottle is pressurised as described by Pete above, and another where the expansion bottle isn't pressurised. The pressurised system is on Sierra's. The non-pressurised system was on 2.0 pinto capri's and is the same aas Dave Andrew's web site design.

 

There are hoods out there running both systems without problem. Just make sure you know which design you're following. Overheating problems are more likely related to radiator position and air flow, fans, and radiator capacity.

 

Ant

[Guest salty_monk]

Robin,

 

With the expansion tank you have bought you need to follow the Dave Andrews system same as me. Your tank will not work under pressure due to the type of lid.

 

As well as Capri's, Cortina's also used this design I believe.

 

If your rad has a 15lb cap it will not vent water until that pressure is reached, this is identical whatever system you are running so the boiling point of the water should be exactly the same!

 

Dan