Radiator Overflow and no power after highway

[isuzutoo-eh]

Hi all,
I have two dilemmas to discuss.
IIa 2¼ petrol, Solex carby, near-new SIII radiator.
Every time I shut down my Series after coming up to temperature on a drive, she piddles.
Then when cool I top up the radiator. Again.
I drilled two holes in a soft drink bottle lid and mounted said bottle alongside the radiator with the overflow in the larger lid hole. The bottle is only 500ml. I seem to be topping up about a litre at a time.
The top and bottom radiator hoses squeeze tight/collapse as the block cools, thus isn't sucking coolant from the overflow bottle very well.

Is the piddling a normal things for a 2.25P to do?
Should I be sitting idling for an extra minute or two to cool down? The queue at the service station might not be so happy waiting :p
The water temp gauge indicates 190 to 212 degrees Fahrenheit, so just on the boil when working hard and slow.
Is 1 litre loss about right?




The other problem is after say an unbroken 200km on the highway, i'll pull up to the first traffic lights and lose power. Low range 1st will get me out of traffic's way but high range just isn't happening unless I rev it up and slip the clutch and even then it isn't likely to keep pulling enough to get second gear. Pull the choke a bit and she'll stall dead. Restarting is not a problem but the power doesn't immediately return. Given a minute or two idling she'll come good as if nothing ever happened though. The Solex carby isn't cold, so it isn't icing up. It isn't hot enough to burn my fingers on either.
Does this sound like fuel vaporisation?

Only way around it so far is to keep revving the engine as I sit in the traffic but i'd rather not do that.

Thanks for any advice :)

[bee utey]

Cut the overflow hose into the bottle with an angle cut, stop it sucking to the bottom of the bottle.

Check that the rad pressure cap has a small easy-to-lift button in the centre, this allows the coolant to be sucked back in. I have seen these gunk up and jam shut.

Filling the radiator to the top will always cause some coolant to escape with expansion, generally older radiators were designed with bigger top tanks that were filled about half way.

Your carby may still be icing up, probably the idle compensation channel. Is it blowing black smoke as you attempt to move off?

[isuzutoo-eh]

Cut the overflow hose into the bottle with an angle cut, stop it sucking to the bottom of the bottle.

Check that the rad pressure cap has a small easy-to-lift button in the centre, this allows the coolant to be sucked back in. I have seen these gunk up and jam shut.

Your carby may still be icing up, probably the idle compensation channel. Is it blowing black smoke as you attempt to move off?

Thanks Bee Utey,
Just gave the overflow hose a snip. Now that i've done that, i'm not feeling very smart as I don't think the radiator cap does allow return. The 'button' is held down by a fairly stiff spring:
https://www.aulro.com/afvb/images/imported/2012/05/361.jpg
https://www.aulro.com/afvb/images/imported/2012/05/362.jpg


I haven't noticed black smoke, but I am usually more interested in trying to get moving than to see what's following :p
If it is icing up is there a way to prevent it? I don't have any more long trips in the Series planned so not sure when i'll get to test any theories :(

[bee utey]

Actually your cap has a centre button, just lift the small brass dome thing in the middle of the cap lower face and clean all the gunk off. Also check the overflow hose isn't blocked with yuck, I see a lot of it in the photos of the cap. Time for a flush and new coolant?

The main way of preventing icing is to direct warm air into the carby, usually off the exhaust manifold area. Newer vehicles' carbies all have warm air feed in winter to stop icing up, usually controlled by a little thermostat spring thing on the air cleaner intake.

[isuzutoo-eh]

Gotcha Bee Utey, I learnt something new about radiator caps :thumbsup:
Just emptied the radiator and stuck the hose in the bottom to back flush it, should get rid of some of the filth, this coolant had been sitting in the vehicle for a year prior to running so it's a little stale.


I suppose with the carby icing, just knowing when to expect it to happen and how to counter it retroactively is about the only way? I don't want to go changing things too much. I thought bolting straight onto the exhaust manifold would be enough!

[Blknight.aus]

problem a, wrong radiator cap, blocked recovery hose and possibly failing radaitor hoses.

problem B, possibly over heating of the fuel pump output line feeding vapour up to the carby. Try holding High idle when you come to a halt and see if that solve it, if it does the problems not icing.

[Warb]

Not related to LR's but I have found that water forcing passed the radiator cap AFTER the engine has been shutdown is (must be) caused by an increase in pressure. The only way that I can see, or have experienced, for the pressure to increase after the engine is switched off is for there to be a hot spot somewhere. Under normal conditions, with water circulating through the system, there is enough cooling for that hot-spot to not boil the water. When the engine is switched off, and the water around that hot-spot is no longer constantly being replaced, the coolant gets locally hot and boils, increasing the pressure and causing the radiator cap to lift.

I had an A-series engine that did exactly the same. It would run all day without a problem, but boiled the instant it was switched off. The water channels in the block were almost, but not quite, blocked around one cylinder. When the water was circulating there was just enough cooling to prevent boiling, but as soon as the water stopped flowing, it boiled. In that engine (and being careful not to get burnt!) you could put a stethoscope against the block and hear the bubbling....

[Blknight.aus]

doesnt just have to be a block gallery causing problems to give that effect, anything else that limits the flow of coolant at low engine speeds can do it.

[clubagreenie]

problem a, wrong radiator cap, blocked recovery hose and possibly failing radaitor hoses.

problem B, possibly over heating of the fuel pump output line feeding vapour up to the carby. Try holding High idle when you come to a halt and see if that solve it, if it does the problems not icing.

Agree with doesn't look like the right cap. As a comparison, a Toyota Crown I'm working on at the moment has a overflow/expansion tank. The radiator has a two way cap that allows overflow at a lower pressure than the expansion tanks cap (9 vs 13 psi by memory) and also allows return vacuum as the engine cools to let the fluid suck back into the system. This should be the difference between the cool/lower level and hot/higher levels in the expansion tank. The expansion tank cap allows fluid to expel if it's too full. Not sure if it allows suction of air back into the tank or not. Suspect it might as otherwise it may collapse the tank. And for a car from Toyota, in the 60's like this (triple SU's, fridge, auto dimming lights, a/c, power steer, 4 wheel discs, AM/FM/SW/8 track) it's unlikely they would allow that potential.

[bee utey]

Agree with doesn't look like the right cap...
Indeed, I just saw it's not a recovery system cap. It should have a rubber seal around the top of the cap too, if it has to suck coolant back in.

[Warb]

doesnt just have to be a block gallery causing problems to give that effect, anything else that limits the flow of coolant at low engine speeds can do it.

Agreed, I was simply using that A-Series as an example. But for the engine to lose significant amounts of coolant after it has been switched off, but not when running, the coolant pressure must increase when the engine stops. The only way for that to happen is for something in the system to have enough heat to boil or significantly heat the coolant when the flow stops. That is not part of the normal operation of an engine and so might be worth investigating.

[geodon]

Hmmm! *strokes his chin thoughtfully*

Did the 186 Holden need an overflow tank? I lose half to one litre of coolant as it idles to warm up after topping up cold.

The rad is the orig 2.25 LR one with what looks to me like a very substantial "header" tank up top. From memory, Holden ones were quite puny.


https://www.aulro.com/afvb/images/imported/2012/05/236.jpg

https://www.aulro.com/afvb/images/imported/2012/05/237.jpg

[bee utey]

If you top up your radiator to the very top you will always lose coolant with every warm up. If you fill the rad only to the mark half way up the top tank you shouldn't need a recovery tank. If you insist in filling it right up you need a recovery type pressure cap and a recovery tank.

BTW what I see in your rad isn't coolant as I understand it, it looks more like what you would have dredged out of the Darling river bed before the flood. Flush and corrosion inhibitor needed, ASAP.

[geodon]

Errrrmmm!

Mate you're looking at PURE BRASS! The radiator is fresh from workshop. The coolant is clear water at this stage.

And I've only filled it to the top twice. Once when I started it up and again to confirm what was happening.

Can I leave the Naughty Corner now?

[bee utey]

Errrrmmm!

Mate you're looking at PURE BRASS! The radiator is fresh from workshop. The coolant is clear water at this stage.

And I've only filled it to the top twice. Once when I started it up and again to confirm what was happening.

Can I leave the Naughty Corner now?

Aaah, I was looking at the rubber part of the cap, I assume it's from before the clean?:)

No worries, proceed to enjoy your toy!:p