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Overheating! -- Are 1984 944 AC Relay & Cooling Fan Relays the Same?

 
Old 07-06-2019, 10:34 PM
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David Bishop
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Default Overheating! -- Are 1984 944 AC Relay & Cooling Fan Relays the Same?

We're chasing down an overheating problem in our 1984 944 NA -- we've had it just a short period of time. Pukes all coolant on shutdown. Likely culprits are the Cooling Fan relay or AC relay.

1. Are the cooling fan relay and AC relay for a 1984 NA 944 the same? I just see the AC relay 944-615-113-02-OEM, for example, at Pelican Parts, not a cooling fan relay. Is there a good (quality can be trusted, decent price) source for these?
2. WHY would our car (new to us, and having cooling issues) have a Seat Belt Warning Relay labeled 928.618.102.02 and looking like the attached picture in position 1? Is this car special in some way, or did previous owner maybe mistakenly put the wrong relay in?


Seat Belt Relay/Buzzer

Last edited by David Bishop; 07-07-2019 at 11:28 AM. Reason: adding details about overheating
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Old 07-07-2019, 10:02 AM
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Default Also: Where is Seat Belt Relay supposed to go?

Related questions:

1. If someone put the seat belt chime/relay in position 1 where we're supposed to have a fan relay, where is the seat belt chime/relay supposed to go? I found 1 fragment of information that says it's behind the oil pressure gauge; that seems a bit odd location.

2. Is there a Bosch or Hella part number for the 1984 944 Cooling Fan Relay? I think the part numbers are like this:
944.615.113.00 — 944 1983 A/C relay -- that's in passenger footwell on these cars
944.615.113.01 — 944 thru 1985.5 A/C Relay
944.615.113.02 — another number for the -01? When I look this part number up, it ALSO says "A/C relay for 944 through 1985.5"
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Old 07-13-2019, 10:04 PM
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Default update

update: still having cooling issues, but things are improved...

turns out PO had somehow randomized the relays. so we pulled them (almost all), checked the positions and the part numbers, and re-installed correctly. Got a bunch of previosly non-op things working again, e.g. heater blower that we thought was going to be a complex diagnosis w/ the big resistor pack, etc.
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Old 07-14-2019, 01:19 AM
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Default

Just ran across this post....

Do both fans work when temp spikes ( somewhere over the center mark on gauge ) or can you make them both stay on by switching your center air-con switch on ?

Have you any info on when the water pump was replaced and is there a listing on any billing showing the brand of Waterpump ? And how about the thermostat's replacement and any knowledge if it is the cooler temp range on that stat ?
The 'Euro' brand of w.p. has been known to cause problems as well as several rebuilders. Pricing DOES matter when choosing these two parts. Get the best available.
Other things which can cause these types of cooling problems have also been traced to head gasket failures/warped heads, cooling system plugging from aluminum deposits and also aluminum flakes plugging passages and heater cores, radiators filled with mineral deposits, and improper changeouts of anti-freeze. Like wrong brands, type mixings, old anti-freeze, muck from coolant and oil mixing still in the system from a 'milkshake' moment .....

Also don't forget about the radiator temp sensor and it being the lowest possible temp setting, as well as the wrong radiator cap ( Series 1 and 2 are different pressures and are marked on the cap ) ---- IF it is an o.e. BEHR cap. Replace with this Porsche O.E. brand only and throw away any others especially if they have that little lever for pressure release. They are ****e.

Cracked or warped plastic reservoirs ( so cap doesn't seal correctly ) can also cause overheating issues.....

And I am sure there are other things as well; like timing, etc., etc., etc. The possibilities seem endless

Best wishes with your sourcing the problem(s) and the cure
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Old 07-14-2019, 08:35 AM
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We're not overheating, per se
BUT: immediately upon shutdown, almost all the coolant pukes on the ground from the expansion tank.
This comes with a gurgling/bubbling like something is injecting air into the expansion tank.
Car runs fine up to temperature, through several cycles of fans on / thermostat opening. Seems to hold temp with upper hose near 80°C.
This is a 1984 944 NA with A/C

-- Yes, we've considered continuing to drive, never stopping or shutting off the engine --

What might we try / fix next? We're stumped.
Things we've done / tried / diagnosed:
  • Every coolant bleeding procedure on the internet including Clark's, factory manual, using pressure tester, elevating front end, etc.
  • Compression test - 140-140-140-140 across all cylinders
  • Put all relays in proper position, since PO had several in the wrong positions
    • This gained us proper cooling fan operation and interior blower operation
  • Used a block tester to test for head gasket failure -- liquid stayed blue and/or bulb didn't expand
  • Tested expansion tank cap; replaced with new OEM cap. This is the correct 100 KPa cap.
  • Used a pressure tester to pressurize the system to 10PSI
    • Replaced radiator drain screw (plastic) with a new one; that stopped 1 leak
    • Tightened hose clamps on any leaking radiator hoses
    • All we're left with is a trickle (1 drip every 2 seconds) that may be from the junction between the radiator and the plastic side on driver's side (hard to see from the front because of the AC condenser; hard to see from the rear because of the fan shroud)
Questions:
WHY is everything fine until shutdown? It's almost instantaneous (like 3-5 seconds).
WHY didn't we discover this on our test drive? What might we have changed (duh, other than the clutch which was on the limp home tabs when we purchased car)?
MUST we buy a new radiator? We're willing, but want to ensure that's the problem.
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Old 07-14-2019, 09:28 AM
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N/M reading comprehension issue
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