Radiator Ducting

[Garry]

On the continual quest to improve the efficiency of my air conditioning I have discovered that when my car is stationary and the cooling fan is running hot air is being sucked from the engine bay around the side of the radiator then back through the condensor/radiator. So I was wondering if my car is missing some ducting from around the radiator? Particularly in the area to the side of the radiator where the power steering cooler pipes run. There is a gaping hole that runs straight into the engine bay and that seems to be where the majority of hot air is coming from. Having an intercooler taking up most of the mouth doesn't help so I guess the air is taking the path of least resistance.

Has anyone else noticed this or do they have something blocking the hole beside the radiator?

[adamjp]

I have built a duct that runs from the bumper bar to the radiator, completely enclosing the 'inlet' side of the radiator.

The pipes for the A/C and my oil cooler were a real pain and I still have not worked out how to seal them off easily, but effectively.

I will look at it more when I get my new radiator. I will also take measurements so you can consider making your own.

Simply put, you will need a sheet of lightweight aluminium about 110cm x 30cm. Try for no thicker than 1mm, it is easy to work at home.

[Garry]

Thanks Adam

[Garry]

Yeah Steve, that was the first mod I did several years ago. My A/C works quite well while the car is moving but cant cope in stop start traffic on hot days. With summer approaching I've been looking at ways to get the cooling fans to flow more air through the condensor when the car is stationary. Having hot air from the engine bay blowing through the condensor wont be helping it condense very much.

btw, you have you're pipes mixed up.

A/C design 101........The gas gets compressed in the compressor and gets heated up. It goes through the condensor (radiator at the front of the car) and the gas is cooled somewhat This is the small diameter high pressure pipe. It then goes into the reciever dryer that filters and dries the gas. Then it goes into the cabin to the expansion valve where the gas expands, as it expands it gets a lot cooler. It then goes through the evaporator (small radiator inside the cabin to cool the cabin) and back through the larger pipe (which is the colder low pressure pipe) to the compressor to do it all again. There are a couple of high and low pressure safety switches in there as well as a thermostat, but basically thats how it works.

The colder the gas is before it gets to the expansion valve the colder it gets when it expands. Thats why I'm trying to get more airflow through the condensor.

[Okibi]

Gary, how about putting better fans on your radiator ?

More flow will cool the condenser better when sitting at the lights.

Are there \"aftermarkets\" condensers that work better and you could upgrade to?

[Garry]

I was thinking about new fans Okibi, that may be the only option.

[Garry]

Nice job drifter. Though you might want to kep an eye on the foam. I've used that stuff before and if it gets hot enough it shrinks.

I had a good look at what Mazda did in the NC today. It's much better sealed than the earlier cars

[Garry]

I did a bit more radiator work today.

My car was missing the foam seal that seals the radiator to the plastic undertray and this is where most of the hot air was coming from. I made up a new seal and some ducting to fit down the side of the condensor to stop hot air being sucked around the radiator from the engine bay. I also moved the intercooler away from the condensor as it was extremely close after an altircation with a bird a few years ago.

After a drive around the suburbs my A/C was cycling when idling and ambient air was being sucked from the front of the car rather than hot air from the engine bay. Fingers crossed it's sorted.

[TieNN89]

Ybtw, you have you're pipes mixed up.

A/C design 101........The gas gets compressed in the compressor and gets heated up. It goes through the condensor (radiator at the front of the car) and the gas is cooled somewhat This is the small diameter high pressure pipe. It then goes into the reciever dryer that filters and dries the gas. Then it goes into the cabin to the expansion valve where the gas expands, as it expands it gets a lot cooler. It then goes through the evaporator (small radiator inside the cabin to cool the cabin) and back through the larger pipe (which is the colder low pressure pipe) to the compressor to do it all again. There are a couple of high and low pressure safety switches in there as well as a thermostat, but basically thats how it works.

The colder the gas is before it gets to the expansion valve the colder it gets when it expands. Thats why I'm trying to get more airflow through the condensor.

So if i get some of that foam stuff and wrap it around the warm pipe the a/c would be cooler?
what if i did it to both the warm and the cold pipe would that make it any better?

[Garry]

The NB8A return pipe (bigger cold pipe) is already insulated where it runs past the exhaust manifold so you might not notice much improvement. You could try insulating the smaller warmer pipe and see how that goes but with a non-turbo car you dont have the extreme under bonnet temps that the turbo cars generate so it may not help much.

First thing I would do before you start doing anything is to go to a reputable A/C place and get them to make sure it's fully charged. A fully charged system will make more difference than pipe insulation.

Well after 5 years I've finally got my A/C sorted. It's blardy freezing now.

[TieNN89]

First thing I would do before you start doing anything is to go to a reputable A/C place and get them to make sure it's fully charged. A fully charged system will make more difference than pipe insulation.

Good point

Will it cost anything to get them to check if its fully charged?

[Garry]

I guess so. Most places charge a fixed fee for an A/C service regardless of what they do.

[TieNN89]

DAM!!

I'd be around $100 I'd assume

[TieNN89]

oh yeah

I noticed these knobs things on the pipe line what do they do?

One has snapped off and the other one is still on there with an L on it

[Garry]

My last A/C service was around $80 from memory. Shop around and get some prices.

Those knobs are the things that they use to add gas and check the pressures in the system. The one with \"L\" on it is the low pressure side, you also need one with a \"H\". You might be in trouble if the high pressure one isn't there any more. Does the A/C system work at all? Has all the gas escaped?