Cooling questions/issues

[IdahoDoug]

So I have 60,000 on this 84 944 NA. We live in a northern climate and day time temps in the mid 80s are about as hot as it gets with a few 90s days a year. So not a challenging cooling environment. Plus we don't use the A/C at all.

A few thousand miles ago when I bought it, I did the major timing belt service, plus installed the upgraded water pump, a new 87 deg Wahler thermostat, and a new Wahler 75 deg fan switch.

The reason I'm writing is two fold. I'm curious what mark on the temp guage your cars sit at, and my fan seems to come on high way to often and it never shuts off.

My temp needle sits between the 2nd and 3rd marks and will sometimes just touch the 3rd mark on a long hill. So what does yours sit at?

On the fan. It runs on high on the freeway on a 70 degree day. It runs on high driving gently around town. It's downright annoying. No fun pulling up in a cool car when all you hear is "Whooooosh" from the fan. When I shut down the fan almost always stays on low for a few minutes - even on a 60 degree day.

Just wondering if other's fans exhibit this so I know if its the nature of the beast. I've got a small radiator leak and am waiting for the cheaper radiator to come back in stock but have the feeling I made poor choices on the thermostat or fan switch here.

[drkshdw]

I don't know how different the early and late cooling systems are but my car (87) never gets above the first mark on the temp gauge. Even the past few days when it's been 100*, with the AC running and driving on the highway my needle never goes above the first mark (with an 80C thermostat).

As far as fans go, very rarely do they come on when driving without the AC, even in town. When they do come on it's not for very long. It has to be over 90 and in stand still traffic for them to come on and stay on. And I can't even remember the last time they've come on after I parked and shut down the car.

If you're having issues with your car running hot and the fans always coming on I'd suggest making sure your coolant is properly bled and that your radiator isn't clogged. Air in the system has always been the culprit whenever I've had issues with my cooling system but since switching to vacuum filling my system, I haven't had any issues with bleeding or cooling.

[djnolan]

My fan only runs when the A/C is on or in extreme stop and go traffic. Did you check Clarks for a description of how the fan switch works? There are minor differences between early and late cars so some of the advice you get might not fully apply.

As for checking the gauge, there is also a difference early/late. If you have an IR thermometer you can do a ball park calibration by watching the needle at cold startup and then at some measured point along the way.

I only see a very slight difference in the gauge from winter to summer to hills, etc.

[9FF]

Originally Posted by IdahoDoug

...A few thousand miles ago when I bought it, I did the major timing belt service, plus installed the upgraded water pump, a new 87 deg Wahler thermostat, and a new Wahler 75 deg fan switch...

I’m no expert but shouldn’t the fan switch be higher temp than the thermostat?

[vintageant]

My issue is A/C related. Without the A/C on, temps are all good and normal. With A/C on and at open road cruising speed temps are still good and normal. Once into stop and go city traffic with the A/C on, the gauge climbs into the danger zone until the A/C is turned off and it slowly gets cooler.

PS: All this in Miami 93 F daytime temperature!

All suggestions welcome!

[djnolan]

Check to see if both radiator fans come on when the A/C is turned on.

[Pauld_94S2]

IdahoDoug, haven't seen that you've been back to this thread, but:

Buy an IR thermometer gun (Harbor Freight - ok) and:
1. Measure the radiator inlet (top hose) temperature
2. Measure the radiator outlet hose temperature

Measure the temperature of the engine block at each DME and coolant gauge temperature sensors locations.

Let's find out if the temperature sender for the coolant gauge in your dash is telling the truth!

Something to read before bedtime:
http://www.clarks-garage.com/shop-manual/elect-19.htm

[onZedge]

Correct me if I'm wrong, buit I believe you should be using:
944-106-129-05 thermostat (opens at 80C)
823-959-481-F temperature switch (fan on at 92C / fan off at 87C)

With the combo you have now (temperature switch lower than thermostat), the temperature switch is trying to maintain the cooling system temperature instead of the thermostat. The fans are supposed to be for extreme situations (like hot day sitting in traffic, or other high loads like towing); and the fans also run continuously whenever the A/C is switched on.

[blaise84]

I have a 99 Boxster 2.5L with 150,000 (IMS bearing upgrade already done). It misfires on the passanger side. P001 p002 p003 are the codes I am getting. Also, if I hold the throttle for a second or two, past 1200 rpm, I get this loud rattle/ clatter noise. NOT rod knock but maybe a few bad lifters? It won't do it if I blip the throttle, but only when I hold it. Here are a list of things I have replaced to try and fix the misfiring
I didn't find the right solution from the Internet.
References: https://www.pca.org/tech/engine-misfire-all-bank-1-cylinders-lifter-rattle

Explainer Video Example

[9FF]

Originally Posted by onZedge

...With the combo you have now (temperature switch lower than thermostat), the temperature switch is trying to maintain the cooling system temperature instead of the thermostat.

+1 Like I said a few posts ago....

Originally Posted by 9FF

I’m no expert but shouldn’t the fan switch be higher temp than the thermostat?

[vintageant]

Originally Posted by djnolan

Check to see if both radiator fans come on when the A/C is turned on.

Yes, both fans come on when AC is on and/or running hot.