924Board.org

Minus000 · Joined: 29 May 2003 Posts: 363 Location: Sidney, B.C.

Hello. I haven't done much on the cooling system other then having it pressure tested when I smelled something sweet from the engine last year. Luckily it held pressure very well and their didn't seem to be a problem. I do need to flush my coolant though and just want to be clear on procedure.

1. Remove radiator cap.
2. Remove radiator drain plug.
3. Drain radiator and reinstall plug
4. Fill with water. Start Car.
5. Run car until thermostat opens and water is pulled into engine, top off radiator with water if needed.
6. Shut of engine and allow to cool.
7. Remove radiator drain plug.
8. Refill radiator with antifreeze / water.
8. Reinstall radiator cap.

Is this correct? I know people have spoken about removing the radiator hoses at the bottom of the radiator to use a garden hose to flush it out but I haven't found enough directions to understand this procedure. My coolant system hasn't been fully flushed in some time, is it worth taking to a place like Midas that has specialized equipment? Does anyone here anticipate they will know enough to do a proper coolant flush?

Ozzie · Posted: Sun Mar 13, 2005 3:59 pm Post subject:

It depends on the level of flushing you require.
Generally I do as much as you do as well as:
I remove the lower hose from the radiator, jam a garden hose and a rag to help seal of the hose and run water into it.
Pull the hose and rag out several times until the water runs clear when it drains from the engine.

I find no matter how many times it still has a slight green tinge to it.
Flush out the top as well.
A radiator place will remove and clean the core of the radiator if you wish. About $100 to $150 in Aust.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

I believe the Haynes manual also calls for the removal of the bleeder valve plug on the hose that goes from the thermostat to the upper rad hose...make sure you properly bleed the system of air. When I did mine, I also used a Prestone-brand flushing product, which called for draining the system, then adding the flushing fluid, filling with water, running until the car reach normal temp, allowing to cool, draining, repeating the procedure with just water, draining, and then adding the proper mix of coolant / water and bleeding.
_________________
erstwhile owner of just about every 924 variant ever made

augidog · Joined: 03 Mar 2003 Posts: 1360 Location: New Jersey

I did this twice already.
This was from an old post but worked great for me, supposedly it was from a Porsche Mechanic.
Drain
Fill with tap water
2 squirts of "non-phosphorus" dish detergent
Run for 100 miles
Flush
Flush
Fill with 50 % non-phosphorus fluid/50% distilled water and bleed.
You will be amazed at the oil and crud the detergent will get out and leave in the plastic tank.
_________________
1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

The detergent is a *great* idea ... I'll add that to my recipe next time!
_________________
erstwhile owner of just about every 924 variant ever made

numbbers · Posted: Tue Mar 15, 2005 11:11 am Post subject:

Well, I learned this from my Dad, and I am an old fart, but the best radiator flush is laundry detergent. Works great.
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1980 924 Turbo

speedsta2003 · Joined: 12 Nov 2002 Posts: 302 Location: Lincoln, Nebraska

I always went to jiffy lube and spent the cash to let them do it. WORTH IT
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My Old Porsche Thats Sold
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Minus000 · Joined: 29 May 2003 Posts: 363 Location: Sidney, B.C.

I Flushed everything out today and refilled / bled the system. Everything seems to be in good shape. Thanks for the tips guys.

JackRabbit · Posted: Tue Aug 26, 2008 2:24 pm Post subject:

can anyone post a pic of the radiator drain plug or at least tell me exactly where it is. I'm looking at what I think might be it, but before I go removing things I'd like to know for sure.

my expansion tank has been getting emptier and emptier and I'm not seeing any green puddles on the garage floor.. so where is it going?

I'd like to flush the radiator today, but I'm expecting a Haynes manual in the mail any day now, should I wait for it or is this simple enough to do without?
_________________
'79 Porsche 924
'05 Honda Civic
'07 BMW K1200R
'78 Honda Express
'52 Willy's
'58 Wheel Horse

968rz · Joined: 21 Aug 2006 Posts: 537 Location: S. E. Wisconsin

I should be right in the top rad hose near the t-stat, most are red plugs with a hose clamp holding it in.
_________________
Rick
79 924 coupe Petrol Blue 3spd auto (wife's DD)
93 968 coupe Amazon Green 4spd Tip (my DD)

Bumblebee77 · Joined: 09 May 2008 Posts: 372 Location: Brisbane

Rich H · Posted: Tue Aug 26, 2008 5:51 pm Post subject:

Valve seals keep oil out of the head inlt and exhaust tracts, head gasket keeps water/oil/combustion chamber all seperate. Or it could be a leaky pipe, rad or heater core.

_________________
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

JackRabbit · Posted: Tue Aug 26, 2008 7:00 pm Post subject:

yeah... the radiator drain plug... laying on the floor of the garage, I was trying to find it but with no luck... perhaps the car is just too low but there seems to be some kind of face plate that covers the whole area where the radiator is and I'm wondering of the drain plug is under the cover?

I've read that some people leave the plug alone and remove a hose instead... anyone weigh in on this and care to point out where the hose is?
_________________
'79 Porsche 924
'05 Honda Civic
'07 BMW K1200R
'78 Honda Express
'52 Willy's
'58 Wheel Horse

968rz · Joined: 21 Aug 2006 Posts: 537 Location: S. E. Wisconsin

Duh!

Guess I was reading backwards or something. I pointed out the vent yes. The DRAIN sould be on the drivers side of the rad but it may not be red and may not be what you are used to on US cars, it may just be a plastic plug with slots on the head like a large screw.
_________________
Rick
79 924 coupe Petrol Blue 3spd auto (wife's DD)
93 968 coupe Amazon Green 4spd Tip (my DD)

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

One add'l thing that needs to be added to the original post is that the heater control should be set all the way to ON in order to get all of the fluid to circulate and drain out of the heater core.

If you have coolant slowly and mysteriously disappearing from your expansion tank, but you insist that there are no leaks anywhere under the engine compartment, then there are two likely suspects:
1. Heater core
2. Head gasket

If you smell the sweet maple syrup smell, particular in the passenger compartment, you can be pretty certain that the heater core is on its way out, if not leaking already. FYI, it is a royal PITA to remove in a car with factory air. Haynes calls for removal of the dash, but it can be done by unbolting some of the A/C stuff so that you get enough flex room to move things around. You have to be REALLY careful with the new heater core not to damage the fins during reinstallation using this technique, as it is VERY tight under there.
_________________
erstwhile owner of just about every 924 variant ever made