924Board.org

whywhywhy · Joined: 12 Jul 2009 Posts: 33 Location: Brisbane, Australia

Hi all,

My '78 N/A typically runs pretty hot and it's something I want to fix. I've read many of the existing topix on here for help so far. The questions that are bothering me are thus:

1. When engine is running, the guage on the dash says it's on 3/4 to red. But when I switch the engine off and leave the key in ON position the dial immediately drops 1 tick mark - why? What is the correct reading?

2. When you switch the engine off on a modern car, the radiator fan keeps running - is this supposed to be the case with my 924? When I switch off the car, the fan stops - should it?

I plan to fix the issue with number 2 above by wiring in a turbo timer to spin the fans for an extra 2 mins after shutdown - is this OK? I originally planned a voltage switch so the battery didn't run down but have decided on this as a more foolproof path.

Does anyone have trick for rewiring the A/C fan to run as a cooling fan (my A/C is stuffed anyway

)

Thanks
_________________
Dreams of Porsche ownership ended in flames

Rich H · Posted: Thu Aug 06, 2009 9:31 pm Post subject:

Stop looking for complex problems!!

Switching the engine off drops the voltage from 13.8 to 12V sounds like you have a duff connection. Pull the das gauge and clean up the pins and sockets on the back, also you can strip the unit down and clean all the ocntacts in there too.

Next find the temp sender bug, it's under the dizzy next to the Thermo Time switch, it's a tiny metal stud with a spade connector on it, about 3/8" high maybe, hidden underneith, hard to reach. Pull the spade connector off and clean it all up.

also clean up and repalce the engine earths, give both sides of each a good clean and lube with vaseline/petroleum jelly before reassmbly.

Try the temp trick again...

As for the fan if it is running with the engine on it will continue to run when the engine is switched off. Testing the fan is easy, front of the car, on the rad at the side by the ignition unit is a brass lump with 2 wires. Short them together (Might spark a little) fan should then run. If the electrics are on it'll run fast, if the electrics are off it should run slow.

If it doesn't run slow thne the resistor is probably goosed. The resistor is a circular grey thing above the aux fuesbox, find it and check it over with a meter, should be a resistance between the 2 contacts. Clean it all up and try again.

Rich
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

!tom · Posted: Fri Aug 07, 2009 3:25 am Post subject:

In short, yes, the factory configuration has provisions for the fan to run after shut-down with the key out.

If yours never does, suspect wiring issues with your factory wiring. Correcting this may be easier than making your custom addition, depending on what hack job any previous owners have done to your car.
_________________
78 924 NA
5-lug

whywhywhy · Joined: 12 Jul 2009 Posts: 33 Location: Brisbane, Australia

Thanks for the advice Rich & Tom.

All the easy answers are searchable on here & you'd get jack of me asking all the silly ones

Big weekend planned now:
1. Front struts replace
2. Rear shocks replace
3. Rad header tank replace
4. Brake master cylinder replace, system bleed etc
5. Temp system cleanup
6. Work out why LH taillight just stopped working
7. Remove shonky PO wiring from now working ignition switch
8. Replace top steering column bearing so it stops rattling

Will post some pics of progress.

Cheers
_________________
Dreams of Porsche ownership ended in flames

Rich H · Posted: Fri Aug 07, 2009 5:21 pm Post subject:

_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

whywhywhy · Joined: 12 Jul 2009 Posts: 33 Location: Brisbane, Australia

As promised...

Here are my goodies for the weekend's efforts

Installed Sachs rear shocks

Flogged out original Koni's. Both stay put at fully compressed position.. So that's why it felt like it was running on the bump stops all the time

Here's the installed rad header tank - pretty white instead of crap yellow with pinhole cracks

Front bump stops were completely worn out

But replacing was a challenge 'cos the new fronts (KYB) did not have same shaft diameter. Found these at local auto shop - fits and does the job... and yellow is cool

Also put in the steering shaft bearing and pulled the back end out of the boot to play electrician tomorrow.
Last jobs are new brake MC, new timing belt, and sorting the thermostat issue.

Oh, and here's a pic of my machine...

_________________
Dreams of Porsche ownership ended in flames

Paul · Posted: Sun Aug 09, 2009 12:02 am Post subject:

Nice work!

It's normal for a shock absorber to stay put in any position unless it is a gas shock.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

whywhywhy · Joined: 12 Jul 2009 Posts: 33 Location: Brisbane, Australia

hmmm... still not finished.

Did a couple of things not expected get done - 10 stacker now works, oil pressure now works. more time spent putting new exhaust on little bro's suzi swift.

Fixed tail light electrics.
Why won't my rear wiper work????
Checked temp guage in dash & terminal under dizzy.

HELP ME WITH THIS - where is the bloody resistor for the cooling fans??? Do I have to remove the fuse setups and try to uncoil the spaghetti behind it??? arrgghhh

_________________
Dreams of Porsche ownership ended in flames

datatrain · Posted: Mon Aug 10, 2009 1:12 am Post subject:

The resistor on mine is in front of the top of the radiator mounted to the body work. Very close to the thermo switch.
_________________
'78 924 NA with Collector plate
33 year old car, with me for 21 yrs
Mint '92 318i BMW
Near mint '98 Buick LeSabre
VE7HFR

Portporschedon · Posted: Mon Aug 10, 2009 3:16 am Post subject:

On my 83 NA the resistor for the cooling fan is under the dash, tucked up and behind (to the rear of the car) the auxiliary fuse box.
It is a round grey ceramic thing.

Good luck

Don
_________________
White 1983 924 - Renovated to near original condition and my daily driver

Dolomite 1986 924S - Coming to the end of a 4 year refurbishment.

Life is not a rehearsal

Rich H · Posted: Mon Aug 10, 2009 4:53 am Post subject:

Above the aux fuseboard in both of mine.
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

whywhywhy · Joined: 12 Jul 2009 Posts: 33 Location: Brisbane, Australia

OK...

Resistor looks like it doesn't exist. I have located 2 unconnected wired coming out of the same wiring loom as the temp sensor, LH headlights etc. There is definitely nothing under the dash that resembles the resistor in PET.

Since mine is '78 like datatrain's I hope that when I get said resistor & plug in all will be fine. fingers crossed.

Turned car from this yesterday

to this tonight - fired up straight away

_________________
Dreams of Porsche ownership ended in flames

Rich H · Posted: Mon Aug 10, 2009 11:35 pm Post subject:

got one here somewhere off the scrapper - yours for a beer and postage

_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

whywhywhy · Joined: 12 Jul 2009 Posts: 33 Location: Brisbane, Australia

Rich you have a PM.

Car ran pretty good today - except for now the battery light is coming on grrr. Where to look now? I did remove the starter (including undoing wiring) a few weeks ago to replace engine mounts.
_________________
Dreams of Porsche ownership ended in flames

whywhywhy · Joined: 12 Jul 2009 Posts: 33 Location: Brisbane, Australia

I have checked out this topic http://www.924board.org/viewtopic.php?t=29937 and will go over the wiring connections & get the alternator tested
_________________
Dreams of Porsche ownership ended in flames