What Liquid is Leaking? (SE.5a)

Venting a little coolant doesn’t necessarily mean there is a problem; with older cars I always used to fill the cooling system and let the excess be ejected.

Same with racing dirt bikes , you just fill the radiator up , and let it blow off the excess ( it will only do it the once , till the level has gone down to a certain level ) . Road bikes ( and newer cars ) use an expansion tank which does ensure the radiator stays full at all times ( with some benifits ) , but mostly is just there to ensure antifreeze isnt dropped onto roads .
If the engine was allowed to get a little hotter than it ever has been since the radiator was last filled , then ejecting some coolant will be normal .

The cooling system on the SE5 is fine as it is, it’s been venting coolant once it gets hot for as long as I remember (at least 15 years) and I think this is down to only having a small header tank on the radiator, and it has a small overflow tank in the leading edge of the centre section if I can remember right.
The SE is the only original one flying and has just had a rebuild to make it as original as possible so I don’t think modifying the system is on the cards, but as it only runs it’s engine for about 30 mins at a time I imagine it will stay like this, in truth I would expect if SE’s were used exclusively at low altitudes during the war these problems would have been encountered as well.
No offence taken or meant with my explanation I don’t claim to be an expert on the aircraft but I’m just trying to explain what I understand about this aircraft.

No, that’s cool – I was just thinking of something to try and not so much prevent leakage, but to prevent engine damage – a temperature gauge off the scale is never a good thing!

I completely understand the desire to keep it as original as possible.

Thanks for your explaination.
Kind Regards,
Scotty

Oh I think it does have thermostats, one for each bank of cylinders and yes it does have manually controlled shutters on the radiator.

The cooling system on the SE5 is fine as it is, it’s been venting coolant once it gets hot for as long as I remember (at least 15 years) and I think this is down to only having a small header tank on the radiator, and it has a small overflow tank in the leading edge of the centre section if I can remember right.
The SE is the only original one flying and has just had a rebuild to make it as original as possible so I don’t think modifying the system is on the cards, but as it only runs it’s engine for about 30 mins at a time I imagine it will stay like this, in truth I would expect if SE’s were used exclusively at low altitudes during the war these problems would have been encountered as well.
No offence taken or meant with my explanation I don’t claim to be an expert on the aircraft but I’m just trying to explain what I understand about this aircraft.

I doubt that the loss of a little coolant would affect the cooling of the engine (or increasing the flow rate); the real factor surely is airflow through the radiator. I doubt if the engine of the SE5a even has a thermostat but seem to recall some radiator shutters which may even be manually controlled.

Venting a little coolant doesn’t necessarily mean there is a problem; with older cars I always used to fill the cooling system and let the excess be ejected.

Forgive me for possibly teaching somebody to suck eggs, but would it be possible to fit a larger expansion chamber to prevent the leakage? Or perhaps a small electric driven pump to the coolant system to give better circulation of the fluid to prevent overheating, particularly if you had a larger reservoir of fluid?

I know that it may be that the aircraft has to stay original, but my line of thinking is that once fluid has leaked out through the blow-off, there is then less coolant volume, meaning less efficient cooling. Perhaps a small spring loaded bladder, but then that would slightly pressurise the coolant system. I have to use similar things for hydraulic fluid which at the surface can be up to 30 – 40C, then at depth underwater goes to anywhere between -2 to 5C. The bladder helps us regulate the system, as well as compensating for seawater pressure.

This would help if the aircraft has to be run on the ground for a bit longer than normal..

Just my curious mind I know nowt about SE 5’s, hope no offence taken…

Kind Regards,
Scotty

Yep it’s coolant coming out of the overflow from the engine coolant system, as with all of these aircraft if you operate them low down at highish power settings they will get warm, and unfortunatley the se5 was running on the ground for a while while the 60 moth displayed and landed, which wouldn’t have helped. As for damage caused none at all, coolant needs to vent off from all liquid cooled engines, if it doesn’t then you will get damage :confused:

🙂 It’s not just what it is ,it is why did it do it,what damage may occur in what time period because it’s venting out.
Better safe than sorry.

The pilot actually said afterward that he had to get down a.s.a.p because he noticed that the coolant temp. went over limits as soon as he took off

As said it is glycol ( coolant) if as said above the temp has gone over the limits it has simply vented overboard as it boils.

What’s draining in the photo is obviously what in the U. S. is still called antifreeze, although it’s routine year-round engine coolant, like Glycol used to be. It comes in two varieties, made by a number of different manufacturers: one colored vivid orange and the other an electric lime green, exactly the color of what’s in that picture.

Yeah, it certainly was a firm landing. But in the wind with a serious engine problem I think it was the best option.

Thanks carpetbagger for the photo help. And thanks for all the answers guys 🙂

🙂 Lets hope he got down quick enough before any damage was done.

Too quick, I think!-it bounced about 5 feet!

🙂 Lets hope he got down quick enough before any damage was done.

The pilot actually said afterward that he had to get down a.s.a.p because he noticed that the coolant temp. went over limits as soon as he took off

100 octane fuel left over from the war?

Antifreeze / Corrosion Inhibitor?

I bet the SE5a cooling system isn’t pressurised so there will be an outlet to atmosphere, probably located high-up on the upper wing. As the coolant heats up it expands and the excess is vented from the outlet. That’d be my guess.

How about this?

Copied from Flickr account, all credit to Cometguy.

John