pinbill

Hello,

I bought my first Porsche the other day. Its a 1983 944. Its not a rocket ship but it looks great, stops quickly, and handles real well. The previous owner didn't have a ton of service records so I don't know exactly what has been done over the years. It needs the back window resealed and the moon roof seal is damaged but it is in real good original condition. I am not familiar with these but I was surprised at how much car you could get for the money.

There is a problem with the cooling fans. There is a lot of info on this on the web and I read a lot of it. Please be patient with a noob. The car stays cool when moving. At stop light or traffic the temp gauge will rise to the 3/4 mark and sometimes both fans will kick on. If you turn on the AC on both fans come on. Once both fans come on the temp drops very quickly.

Under the dash the number one relay (top left) was missing the metal cover so someone had tried to get it out before. I had to pry on it to get it out and the circuit board broke. Without the relay in the drivers side fan comes on low with the AC on.

I have seen 944 615 113 00 on the original metal ones and others for sale ending in 01 and 02. Which is the correct part number? or are they interchangeable.

I may change the thermostat and thermoswitch when I change the coolant just to be safe. I live in Denver we have four seasons. Is the 87-92 thermo switch the one I should get?

Thanks for the help,

Bill

Swenny

Welcome to the club. Nice find. Your trouble sounds like the thermo switch in the radiator (found in the driver's/left side). At least you're describing the same trouble that I've had several times in the past. Pull it out and there is a test that you can do to verify that's the problem. Or just replace. Careful with the fan(s) because that switch can turn them on at any time. Disconnect the battery before you replace. Here's a link:
https://www.pelicanparts.com/More_In...=0&SVSVSI=1014

dr914

I would bleed the cooling system, heater control valve on, add a new thermo switch (left front of the radiator) and replace the cooling fan relay. With that you should be all set. The rear hatch can be reglued with urethene, have fixes a bunch of them. Sunroof seal is an easy replacement

If you buy a new thermostat get the stock one, (need a special circlip tool) but they are a bit of a hassle to change, so I would actually not do it unless you experience failure of the part

pinbill

Thanks for all the replies,

I installed a new oem thermostat (it is a bit of a job), new relay, new thermo switch, and bled the system using the bleed valve with the heat on. It is still behaving the same way. The drivers side fan only turns on low speed with the relay removed. It doesn't turn on low speed with the relay in. With the relay installed, both fans kick on when the temp gauge gets to 3/4. The temp drops quickly and then both fans shut off when the temp gauge gets back to 1/2.

The clarks garage write up says to test the resistor if the drivers fan doesn't come on low speed. Is there a way to test the resistor without taking the gauge cluster out?

Thanks for the help,

Bill

pfarah7

Bill,
I've been reading your post and am a little confused with your issue. From what you've explained, both fans kick on high @3/4 temp while the engine is running, then shut off at 1/2 temp. This is correct / normal operation. The only time a single fan will run at low speed is if you turn off the ignition switch while both fans are running high. This allows the engine to keep cooling when exiting the vehicle; the fan will maintain low speed until temp reaches 1/2 mark or so.

pinbill

Thanks for letting me know. Its surprising to see such a high temp swing. I thought the low speed driver fan was supposed to come on then both fans would kick on at 3/4. The clarks garage write up on early 944s with AC makes it seem like the drivers side fan should come on at low speed before both fans kick on. Clark needs to get his stuff together.

"When the coolant temperature reaches a preset value (normally 92 °C or 198 °F), the temperature switch (normally referred to as the thermofan switch) closes and cause the driver's side fan to run. We'll refer to it as the primary fan. Since the resistor in series with the fan is still in the circuit at this point, the fan runs in slow speed. The fan will run as long the temperature remains above the setpoint, regardless of whether the ignition is turned on. This is a common problem area which will be discussed later. "

Thanks again for the help. You just saved me pulling the gauges. Its also good to know the car wasn't overheating for the previous owner. He wasn't very mechanical and may not have noticed. Today I am going to shut the car off hot before the fans kick on to confirm the low speed function. I may even keep the car. There are no records of the timing belt being done, but I don't mind doing it. I bought it as a flip and am in it right. It corners well, has four seats for the kids, and is better on the highway than my 240z. I have a four post lift coming for the garage and can store everything inside.

Swenny

Well, venting frustration at Clark Fletcher won't win any friends on this forum, he has passed away and the site is being maintained by Dean and George from what's stated on the home page. My experience with the fans is both come on at 3/4 and shut off at 1/2 unless the fans are running when the ignition is on then the low speed kicks in on one fan after the car is shut down. But when it's 110°F+ out (where I'm at) the low speed won't do much until the car is off. If the switch is faulty the low speed can stay on until the battery is drained. I've experienced this with my first 924S. My learning curve,thanks to my brother that pointed the switch out to me.

pinbill

I appreciate the help from this forum. I didn't mean to offend anyone here. The website makes it seem like the drivers side fan should come on slow before both fans kick on. I will send a message to Clarks-Garage and inform them of the discrepancy.

Bill

pfarah7

I typically wait until the fans turn off before shutting down the engine.

pinbill

I did some more snooping around the car today. Please excuse all the questions, I have never owned one of these cars. The fans came on around 3/4 on the gauge. I shut the car off with both fans on and the passenger side fan was on low with the key in the off position. That was a good sign. It was 50 degrees outside and both fans came on. Is it normal for the aux fans to come on with the outside temp being 50?

Tomorrow I will do some more testing. I am going to jumper the wire on the thermoswitch and my buddy is stopping by with an infrared temp gauge. That should answer any question about my gauge. I think the sender is acting funny it jumps slightly when it gets close to 3/4. I don't think its a ground because it always happens at the same spot. I am going to start cleaning grounds tomorrow too.

The clarks garage website had the temperature readings across the gauge for comparison. I really do appreciate all the help on this site and Clarks Garage and I realize it is for free. Thank you for the help.

I came across an disconnected black vacuum line and hooked it up to the thermo valve. There is a connector on the right that is not hooked up. Does the connector go to anything on the early cars?

MAGK944

The outside air temperature has nothing to do with the fans which are only looking at the engine/coolant temperature for a signal.

I don’t own an early car but if it’s similar to the late cars then that connector is just a factory test point and is not connected to anything. Also that disconnected vacuum line looks like the one that goes to the vacuum reservoir/canister by the battery and which stores vacuum for the climate control servos inside the car.

pinbill

Thanks for letting me know about the test port. I found the vacuum line is supposed to go to the thermo valve.

Bill

Tiger03447

Nice looking car.and welcome to the forum.....I hope that when I finish my '83 project, it looks as good as yours does..BTW, when you get around to cleaning grounds, next time, pull the main grounding strap that is in the picture. That connection appears to be a bit fuzzy with corrosion. Just sayin'

tempest411

if you're referring to the two-conductor plug in the top-right of your picture, that's the 12V feed to the O2 sensor heater. Someone put in a 49 state sensor. I'd swap it out for the correct California sensor as it'll go to closed-loop operation sooner.

I do notice a black cable or tube against the firewall that looks like it's been cut. I'm guessing it's the plumbing from the fuel tank vapor recovery system? Or something else..I have an '84. I'll look at it later.

pinbill

Thanks for the info on the o2 sensor. It looks like the sensor without the heater is cheaper. Probably why they did it. The black line is the vacuum for the thermo valve. I hooked it up and the car runs the same.