Engine temperature?

[Bacchus]

Hi all you clever guys.
I want to fit a bigger radiator on my Aerotrike 582. (About 550mm x 350mm). Its basically the VW Golf size radiator.
I want the engine to run cooler and make sure it does not overheat on a hot day or with long trips. Now someone told me that it is too big and that the engine must not run too cold as it will increase wear. Personally I dont think that the engine will run THAT cold that it would increase wear and tear. What is your opinion?
I am not mechanical at all , so I will never know if I'm right or wrong.

[DarkHelmet]

Leave it as designed by the manufacturer - why tinker with stuff you have no clue about (not intended to be condescending)

[RV4ker (RIP)]

Had similar debate wih AMO and those who are in the know regarding running engines cooler. Not on Micro, but Blik C182. I owned a share in upgraded 250hp C182. We flew it by the book and never pushed the cht or egt higher than recommended in POH. Had a digital egt/cht fitted and ran it by the recommended numbers. After 1000 hrs (40% of TBO) we had glazed cylinders and had to overhaul the top because the engine was running too cold. Moral - Stick to manufacturers suggested parts and operating temps. Don't know if shock cooling is a problem in ML's but it very expensive in bliks. Too cold is maybe even worse than a little too hot? Is it overheating or do you feel it just running too hot? Have Rotax guys open it u and have a look. they will soon be able to tell if there is any wear on the eng parts indicating overheating.

[Microwave]

The thermostat is installed for the sake of preventing overheating. When it reaches a specific temperature the thermostat opens and increases the water circulation through the radiator.

Your concern is obviously, when the thermostat is fully open, is the water temperature still too hot? Most microlighters are using the standard radiators and are getting excellent wear from their engines.

Why do you feel your engine is overheating? Maybe you need to check your temperature sensor, this may be faulty and is being erratic or causing a higher temperature reading. It is also possible that the thermostat is not opening correctly.

I would agree with the other guys, stick with the standard radiator, but check out the temperature sensor and temp gauge. Are they the correct gauges and sensors for the engine? Take out the thermostat and check to see that it is functioning correctly.

[John Young]

The thermostat is installed for the sake of preventing overheating.

Microwave, nearly, but not quite right ….

The principal reason for a thermostat being installed in the cooling system is to expedite the time required for an engine to reach normal operating temperature. The thermostat [wax pot to open and spring to close] will open progressively at near normal operating temperature and start closing below normal operating temperature.

An engine with the thermostat removed from the cooling system may never reach normal operating temperature. This is never recommended – a cool engine will perform poorly [power and / or consumption] and excessive [premature] parts wear will be a direct consequence.

[Bacchus]

I will do as you guys say. Stick to the manufacturers specs.
It is running a little bit too hot for my comfort, but never thought of checking the thermostat. Will do that a.s.a.p!
THANKS guys.

[Microwave]

Ooop sorry John Young I do try my best though

I am glad that we have some guys on the forum who know the facts correctly.

[MADDOG]

The engine manufacturer designs the engine clearances around the ideal operating temperature. If you run the engine colder, the clearances will not be correct and this will lead to premature wear, distorted cylinder bores and even cracked pistons.

Best stick to what Rotax say - they know their engines better than us.

[Morph]

Shouldn't you see if you're running too hot by looking at the plugs?

Bachus, if you're not sure get Tommi Coupe to check it out, (he's a Cape Town AP who services our motors for us 0833961826) maybe it just needs a coolent added to the radiator water. When was the last time that was done. It will definately effect the temps.

CLU-less had problem running too cool, and he was recommended to change the coolent/water ratio or tape up a piece of the radiator. The taping up part didn't work because it then boiled.

[RudiGreyling]

Start with the thermostat it can cause both too cold and too hot conditions if it does not operatre correctly.

If the Thermostat is working correctly you should not ever get a too cold indication after initial runup.

If the Thermostat is working correcty and you get a too hot you need to increase airflow through radiator to increase heat exchange, or a bigger radiator to increase surface for better heat exchange.

my 2c

Rudi

[Windsock]

Hi Bachhus, had the same problem on my Aerotrike, the increased temperature is as a result of the location of the radiator - behind the tank, with very little airflow, a problem which I overcame by fitting air ducts on the side of the radiator to increase airflow.

But the original aluminium radiator sprang a leak and required replacement, but the same type radiator was no longer available (import). Rainbow Aircraft uses a local radiator, which is essentially an adapted Golf/Jetta Radiator, which I fitted. Problem then was that on this Radiator air ducts could not be fitted as on the previous radiator, and without them, with pax on long climb out, the temperature had to be carefully watched. Rainbow Aircraft supply an attachment deflector, that work with remote control cable, is attached under the aircraft to deflect the airflow onto the radiator, and with the cable you can determine the amount of airflow - little or nothing in winter, more when required ie. summer.

I did not fit this, but opted for an aluminium "aerofoil" that I fitted on the rear struts, this increased the airflow to the radiator, but I still have to keep an eye on the temperature gauge during a long full power climb out in summer. The temperature with this arrangement on my Aerotrike is between 70 and 80 Celcius (sometimes 82 Celcius max)

The main problem remain the location of the radiator, the position of the Rotax radiators on the Raptor seems to be ideal.

my 2c worth.

[Gaylord Focker]

I dont know much about it my self but u can get hold of Flo Momberg and he will be able to help you out he has experimented on many occasions with this sought of thing NB i think the golf GTI radiator worked the best
FLO MOMBERG 0826662000

[Aviation Engines]

The cooling circuit on the new 582 mod 99 with the blue cylinder head works very differently to the older engines.

The thermostat in the older 582 would restrict the coolant flow when the engine was cold and would start to open at around 60 degC in an attempt to maintain the temperatures between 60 and 80 degC. Many applications had radiators that were too big resulting in engines running at below 60 degC - the cause of many cold siezures.

The thermostat on the newer engine merely redirects the coolant flow. While the engine is cool, it will allow flow from the cylinder head, up into the hose that goes back to the water pump, thereby bypassing the radiator. This allows for quicker warm up periods and prevents cavitating in the water pump.

When the engine reaches approx. 60 degC, the thermostat will then start to direct a part of the coolant to the radiator for cooling. At temp. of aove 70 degC it will direct alomst all of the coolant to the radiator.

NEVER REMOVE THE THERMOSTAT on the new 582 blue top.
The system has been designed to maintain higher temperatures.

Under extreme cconditions the water temp. is allowed to up to 95 degC for a short time, providing that it returns to at least 80 degC in straight and level flight. Normal operating temp. should never be below 60 degC. If this is the case, the radiator is over cooling.

Always use a high qaulity glycol based coolant with a low silica content. Mix 50:50 with water. You use up to 80% coolant to help prevent boiling over but never more than this. Most conventional coolants will start to gel at higher temp. if used 100%

Water is able to disperse heat better than coolant, you may therefore use as little as 30% coolant to improve cooling but never less. The coolant is necessary to prevent corrosion and to lubricate the water pump seals.

the coolant system should be fluched and replaced at least every 12 months to help prevent the build up of the silica, this is the white powdery deposits left in the system.

If the engine is operated less than twice a month, flush and replace the coolant every 6 months.

regards
Niren

[Sad-Ham]

I have been flying my Aquilla 582 for the last 2 years now with the standard temparature guage fitted. The guage starts at 50 degrees C. When flying at operating tempatarure the needle seldom (if ever) goes over the 60 degree mark. Would it be advisable tape up a portion of the radiator to increase the temparature by 10 degrees or so?
Judging by what I have read here on this topic I am runnning too cold.

[Microwave]

I have just recently fitted a new temp gauge for my 582 (mod 99 blue top). During the weekend I flew quite a bit and noticed that the temperatures were reasonably constant between 60 and 70 degrees.

I previously had another temp gauge which indicated 80 degrees and higher for most of the time. I am now very relieved and understand how you must feel about the below 60 degrees. What gauge have you got and is it reliable?? Which engine do you have?