924Board.org

[OldDog]

Hi all. Would appreciate your advice. I'm getting my 86 924S ready for the road again after 4 years in storage.

Thought it was best to change the coolant even though the system was working fine - and think I've done some damage . I drained the radiator, refilled with fresh and tried to bleed the system. It took ages for the new fluid (different colour than old) to make an appearance at the bleed valve. When it did the fluid was full of air bubbles so I carried on bleeding. The level in the reservoir didn't seem to drop.

Then the car started overheating. I cut the engine and waited for it all to cool down. Now when the car has been running theres a coolant leak from the general engine area. Bloody difficult to tell where from though.

Do you think I've cooked the head gasket? And what did I do wrong in my coolant replacement to make it do this?

Thanks in advance gents. It's keeping me awake at nights at the mo thinking about possible damage I could have done!

[gohim]

You may not have caused any damage yet. What I would do if I were you is look for a leaking coolant hose and cure the problem before any more testing.

The thermostat may have been stuck originally, and you may have blown a hose because of excessive pressure in the system. What you need to do now remove the timing belt cover first to see if it is even safe to run the engine without replacing the timing and balance shaft belts. Once you have confirmed that the belts are good enough to try starting the engine, then you should replace all of the coolant hoses, and remove and test the thermostat.

Then you can try starting the engine and bleeding the air from the cooling system to see if you fixed the leak/s. and if the engine is still overheating.

If it turns out that you have fixed the cooling system leaks, and the engine is not overheating, then you need to IMMEDIATELY perform the front of engine service and replace the timing belt, balance shaft belt, waterpump, front of engine seals, and the rollers and pullies BEFORE you go back to driving the car regularly.

If you determine that the headgasket is damaged you should either take the car in and have the headgasket replaced immeditately, or stop running the engine until you replace the head gasket yourself, and perform the front of engine service.

Since it has been at least four years since the front of engine service has been done, the engine is already overdue for the service, and continuing to start and run the engine without having it done will be hazardous to the engine, and your wallet.

Leaking headgaskets usually do not show excessive external engine compartment leaks. Usually what you get is gassing into the coolant tank, or clouds of coolant out the tailpipe.

If the headgasket is blown, most probably the O2 sensor will need to be replaced, as coolant ruins O2 sensors.

[Paul]

While doing the bleeding did you have the coolant tank's cap thoroughly tightened?
_________________
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.

[OldDog]

gohim - thanks very much for the detailed reply. I was intending to have the belts replaced before putting the car on the road. They were changed just before storage (c.2000 miles). I just wanted to change the coolant in the meantime while I got the money together! Ironically in trying to keep the system in good order I may have made things worse.


Your post makes perfect sense, and I too think that the thermostat might have stuck. It's just odd when it was previously working fine, and now seems to have settled down again. With the exception of the coolant leak of course.

It's going to have to wait a while now. I've got another 924S and I'm really hesitant to change the coolant in this following my mistake. Did I do something wrong as I dont really want to spend £100/$200 on having Porsche or a specialist change it.

Will keep you updated and many thanks again for your time and help.

[OldDog]

Paul - in response to your question the truth is I don't know. I'm pretty sure it was on tight but I can't catagorically say it was. Wouldn't be the first time I've had a brain fart!

Would the initial symptoms (overheating, thermostat not opening) be in line with leaving it not tightened?

[Paul]

Could be since the cap must be sealed so that pressure has to be released through the bleeder thus allowing the motor and thermostat to fill with coolant.
_________________
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.

[gohim]

Why bother to change the coolant when the mechanic is going to dump it when the front of engine service is performed? You aren't going to get charged anything extra as the coolant is dumped and replaced because the hoses have to be removed, and the water pump is being replaced.

[OldDog]

Gohim - I needed to replace the coolant because I'm going to have the belts replaced but not the water pump. Recommendations as far as I know are replacement of belts every 4 years/45000 miles, replacement water pump every 90000 miles. Not so?

[gohim]

Belts every 3 years or 30K miles.

Waterpump recommendations very. Some say every belt change (which is what I recommend if you are paying for belt changes), and some say every other belt change (every 60K miles).

I say, the cost of a waterpump is a fraction of the cost doing the front of engine service over is less than 3 years or 30K miles, or a fraction of the cost of repairs if the waterpump seizes or leaks coolant onto the belts and they break.

If you do your own belt changes, and own the tools to do the job, check for leaks every week, and are able to stop driving the car immedately, and do the belt service as soon as you see signs of a water pump failure, then be all means, save the waterpump replacement, be diligent about the weekly inspections, and be ready to stop driving the car at the first sign of trouble, and making the repairs immediately on discovery.

Most people have not sunk the $700-$800 into the specialized tools that are required to do the job. They may discover a problem before the belts break, but they keep on driving, then post on this board to complain about what has happend or to post a For Sale For Parts ad.

[bcblase]

I think you can get away with $200-$300 for the tools to do the belts and water pump - maybe not the original Porsche tools, but tools that will allow you to do a decent job (so I am telling myself)...

I have 92k on the clock, and I know the water pump has been replaced at least once, because the belt guide and turbo block-off kit is on the pump.

The belts look fairly new - still has very clean printing on the belts. I keep inspecting the belts and pump area after every event for signs of leaks or problems.

I am hoping to make it through until the Fall without tearing the whole front of the engine apart. Without service records, is there any other way to gauge the age/condition of the belts and pump?

BC
_________________
1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver

[Rasta Monsta]

Prostrate yourself to the Inland Empire, your answer will come to you.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3