DA62 coolant leaks

Any DA62 related topics

Moderators: Rick, Lance Murray

Post Reply
User avatar
jprhode
2 Diamonds Member
2 Diamonds Member
FIRST NAME: Jason
Aircraft: DA62
Registration: N62VV
Airport: KAUS

Posts: 31
Joined: Tue Oct 10, 2017 2:38 am
Been thanked: 11 times

DA62 coolant leaks

Post by jprhode » Wed Jun 13, 2018 9:08 pm

Hi,

Anyone else have issues with coolant leaking? I have, especially on longer flights and higher altitudes. My plane (S/N 62.010) had the original style coolant reservoirs, which I guess had issues - leaked both from the caps and pressure relief valves. We switched those tanks out for the newer style (introduced sometime before 030), which have a more robust cap. The caps no longer leak, but the valves still do, although very slowly. And, frankly, I don't see how they wouldn't leak - the valves are right at the fill line. The current plan is just let it leak down and see if it stops before the low coolant warning comes on. I don't really love that plan.

Any similar experience?

thanks
Jason
User avatar
rdrobson
3 Diamonds Member
3 Diamonds Member
FIRST NAME: Ron
Aircraft: DA62
Registration: N84LT
Airport: KFAR

Posts: 75
Joined: Thu Jan 25, 2018 2:16 pm
Has thanked: 25 times
Been thanked: 29 times

Re: DA62 coolant leaks

Post by rdrobson » Wed Jun 13, 2018 9:20 pm

I have about 100 hours on my a/c but haven't seen anything. Are the leaks observable during pre/post flight and if so where or is your only symptom the warning light?

Thanks,

Ron
User avatar
jprhode
2 Diamonds Member
2 Diamonds Member
FIRST NAME: Jason
Aircraft: DA62
Registration: N62VV
Airport: KAUS

Posts: 31
Joined: Tue Oct 10, 2017 2:38 am
Been thanked: 11 times

Re: DA62 coolant leaks

Post by jprhode » Wed Jun 13, 2018 11:28 pm

This far I haven’t had the warning come on.

I can see the right one leaking in flight - with the new tanks it’s just a little bubbling at the rear seam of the inboard nacelle cover. I’ve found this to be quite disconcerting to passengers...

It’s a lot slower without the leaking cap on the older style tank. With the older one I flew from Austin to Tampa and no light, despite the tank being quite low.
User avatar
CFIDave
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Dave
Aircraft: DA62
Registration: N62DV
Airport: KJYO

Posts: 1693
Joined: Wed Nov 07, 2012 3:40 pm
Has thanked: 81 times
Been thanked: 468 times

Re: DA62 coolant leaks

Post by CFIDave » Thu Jun 14, 2018 1:38 am

Interesting that you just mentioned this issue.

Last week for the first time (my DA62 is now one year old) I got a Low Coolant Lvl annunciation for the right engine immediately at startup. But after about 5 minutes of warming up the engines on the ground, the annunciation goes away, and it never shows up again during the flight or after landing. It now does this every time the engine is cold -- I don't even need to start the engine to see the low coolant annunciation, just turn on the Electric Master to boot up the G1000.

So before my last trip, I removed the engine cowlings to check the coolant level inside of the expansion tank on top of the right engine. After cutting the safety wire and unscrewing the expansion tank "radiator cap," I got surprised by the blue coolant shooting out under high pressure! (This with a totally cold engine that hadn't been started for days.) There's no way you could add any new coolant to top off the system, since the level is still all the way to the top of the opening. And before I did this, I could find no evidence of any leakage.

So I cleaned up the mess, screwed the cap back on, applied new safety wire, put the cowlings back on and went flying. I still get a Low Coolant Level annunciation that goes away after the engine warms up on the ground before takeoff. When flying, coolant temps are within 1 degree of each other on the left and right engines.

I never had a problem like this in 4 years of flying a DA42-VI also with Austro engines. I guess it's time to contact Diamond in London to figure out why I'm getting the temporary Low Coolant Level annunciation.
N62DV DA62 62.056
N42DA DA42-VI 42.N117 (sold)
N811ET DA40 XLS 40.874 (sold)
KJYO Leesburg, Virginia
Antoine
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Antoine
Aircraft: OTHER
Registration: N121AG
Airport: LSGG

Posts: 2001
Joined: Fri Oct 15, 2010 11:00 pm
Has thanked: 73 times
Been thanked: 189 times

Re: DA62 coolant leaks

Post by Antoine » Thu Jun 14, 2018 6:57 am

Just my 2cts from another water cooled engine operator.
The coolant circuit becomes pressurized when the engine is warm and it should not leak this pressure. This is the explanation of Dave's experience.

Pressure is critical to keeping the boiling point of the coolant higher. The higher you fly the greater the pressure differential between your circuit and the outside atmosphere - so the more likely it is to leak if anything is not ok.
Therefore, even a leak in the coolant circuit that only releases pressure without releasing liquid (for example if it happens at the level of the relief valve which would be above coolant level) is potentially nasty.
You do NOT want your coolant boiling.
When testing on the ground, it is necessary to overpressure the circuit to detect leaks that seem to only happen in flight when ambient air pressure is low. It is 0.5 atmosphere at FL180.
User avatar
DA62
1 Diamond Member
1 Diamond Member
FIRST NAME: Mike
Aircraft: DA62
Registration: N62NC
Airport: KGSO

Posts: 7
Joined: Tue Dec 20, 2016 4:48 pm
Been thanked: 1 time

Re: DA62 coolant leaks

Post by DA62 » Thu Jun 14, 2018 1:31 pm

Hello All
Before my 200hr/Annual in May I got the "low coolant annunciation" on the right engine before 3 flights. It went off as soon as engine got warm. I told Glen at Southtec what happened and when they removed the cap to check the fluid level it was pressurized and blew fluid out. They topped it off and I have flown close to 25hrs since and it has not happened again. I never had any fluid leaking. Glen is aware so you might call and ask him.

Mike
User avatar
neema
3 Diamonds Member
3 Diamonds Member
FIRST NAME: Neema
Aircraft: DA42-VI
Registration: N112NG
Airport: KFAT

Posts: 101
Joined: Fri Dec 05, 2014 5:43 am
Has thanked: 9 times
Been thanked: 11 times

Re: DA62 coolant leaks

Post by neema » Wed Oct 24, 2018 1:34 am

Sort of a thread resurrection, but we're in a similar boat with the "low coolant lvl" annunciator when engines cold--goes away after 3-4 minutes on our 42-VI. Added a little coolant to the reservoir and haven't had it come back, but we definitely didn't have any coolant blow out.
User avatar
CFIDave
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Dave
Aircraft: DA62
Registration: N62DV
Airport: KJYO

Posts: 1693
Joined: Wed Nov 07, 2012 3:40 pm
Has thanked: 81 times
Been thanked: 468 times

Re: DA62 coolant leaks

Post by CFIDave » Wed Oct 24, 2018 1:07 pm

After the experience I described above, I opened up the coolant reservoir a 2nd time (it didn't blow out under pressure this time) and noticed that the level was actually low. I topped it off with a very small amount of distilled water and no longer receive any Low Coolant Level annunciations.
N62DV DA62 62.056
N42DA DA42-VI 42.N117 (sold)
N811ET DA40 XLS 40.874 (sold)
KJYO Leesburg, Virginia
Post Reply