Excelsior

Hi Guys. I'm the proud new owner of a 91 964 white with black top and interior cab (yes, pictures will be forth coming from this proud papa).... I have a couple of questions that I could really use some help with.

1. Air Conditioning. I took the car to our local p car mechanic and ask him to look the ac over. He said that I have the old R12 system and I should convert to R138. I assume this is the right thing to do but could use some guidance here. How much will it cost? I was quoted around 350 to 380 (includes charging). It this a good cost?

2. The previous owner used Valvoline 20W30 Race oil (non synthetic). Should I switch to synthetic Mobile 1? Advice on this would be greatly appreciated...

3. When I cut the car off, there is a motor noise (sounds like its behind the clock). I never noticed it until today. Can some one give me some insight? Is this normal? It may be happening after I put the top up, but like I said the noise is coming from the dash (behind clock) not from top motor.

4. How quiet are your spoilers as they raise and lower? My spoiler motor seems pretty loud with the engine off. With it on I never hear it...

5. I replaced the spoiler curtain the other day, its a complete easy DIY. Anyone needing info, feel free to contact me.

6. DID I MENTION, I LOVE THIS CAR!!!!!

7. Adrien, if you are listening, your book was a huge help in my purchase. Thank you, thank you, thank you....

bhensarl

Welcome, Excelsior! Please do post your pics soon!
1. I believe when switching from R12 to R134 you need to replace the receiver/dryer ($80?) and expansion valve ($?) and evacuate/refill the system. I think if you include labor to install the two pieces and evacuate the system, you're probably about right.
2. Choice of oil will depend on where you live. A lot has been said about the trials and tribulations of switching from dino to synthetic, but it really comes down to this: if you switch to synthetic and get leaks, switch back. Other than that it comes down to personal preference. A list of Porsche's approved oils was recently posted (By Bill Gregory, I believe) so that's a good list to choose from. I personally use Mobil 1, and I believe it's 15W-40 or something close to that.
3. Hmmm, a motor noise coming from behind the clock. I'm going to go out on a limb here and say that it's the clock running. That's what I've always assumed it was, anyway. Nothing I worry about.
4. Try greasing up the spoiler gears with some lithium grease. Access is via the black plastic cover. Just remove the two phillips head screws on the right side and pop it free.
7. Good on you for mentioning that you already have Adrian's book. That should save about a dozen threads encouraging you to buy it!

Oh, one more suggestion: Become a Rennlist member! It's worth it!
Brian

Marc Shaw

Welcome - I have nothing to add to what Brian has already said except and look forward to seeing some pictures.

Marc

jimq

The motor is the fan that blows air over the temp sensor. It will run 15-20 min after shut off.
Welcome to the world of fun!

bhensarl

Jim raises a good point. The rear blower will run after shut off if the engine temp is still high enough, but the blower is in the engine compartment, so I wouldn't think you would think that noise comes from "behind the clock". The blower definitely sounds like a fan running, whereas the noise I'm talking about sounds more like a whirring noise that I believe is the clock running.
Brian

PC2

I think Jim is correct, it's the small fan behind the CCU. BTW, welcome to the board!

bhensarl

Let me get this straight, there's a small fan behind the CCU in the dashboard that runs for 15-20 minutes after shutoff? What purpose does that serve?
Brian

dutchcrunch

i still have r12 in my car and it works great. if yours is still working why not leave it till it quits. you can have the system topped of with r12 for about 100 dollars. there are ac people that still do it its just a little more expensive.

John Boggiano

It's in the same circuit as the rear blower engine-temp. monitoring stuff.

Computamedic

Brian,

There is, indeed, a small fan (approx 1 inch diameter) attached to the rear of the CCU. It draws air across a temperature sensor - and, maybe cools the CCU. It is intended to run for around 15 mins after ignition off.

I have heard of situations where the fan gets clogged with dust and sometimes stays on longer than it should (causing battery drain) and sometimes doesn't run at all (causing other problems).

Hope that clears it up.

Regards


Dave

bhensarl

Okay guys, so the fan is running while the rear blower is running (since it's on the same circuit)? That sounds reasonable to me. Wouldn't want the CCU overheating, now, would we? It's got enough problems to begin with. Thanks guys! Learn something on here every day!

Brian

jimq

The rear fan doesnt have to run when the little fan up front is. The little fan seems to run about anytime if not everytime I use the car and turn it off.

warmfuzzies

I thought that little fan draws air across the CCU to register the proper cabin temp, otherwise how would the CCU understand the subtle changes that occur??

It also runs for about 20mins after ignition off.....engine cooling etc/

kevin

Marc Shaw

Here are a couple of shots of the CCU (back and top) for those who have not pulled it out (I have a spare as I'm still working on why my engine bay blower runs on high all the time).

You can see the ccu fan hanging off the back.

Marc

John Boggiano

No, but the little fan runs whilst the rear blower is 'active', that is during the period when it 'would' run if the engine temp got too high.