docmirror

So, you're facing overheating which is pretty important in W AU as I recall. Although this should be your winter time? Eh?

Yes, common that the power controller gizmo that runs the fans has gone out. There are some transistors in that unit that have a habit of failing, and will no longer adjust the fan speed. The transistors can be replaced individually(I give them away), or you can order a used or new asm from Roger that comes certain to work. Also, the fan motors wear out, and they can be sometimes brought back to life by disassembly, clean and lube, or again you can just let Visa or MasterCard do it's bidding for you.

Very likely, even common that the impeller in the water pump has come free of the shaft and isn't circulating the water. Maybe why the car was parked in the first place. also possibly a stuck thermostat. Let's hope it didn't do damage to the heads or head gasket in the form of a leak through to the combustion chamber. Much more costly to resolve.

At this point, you can go one by one fixing the systems you've found lacking to get it to cool, but please don't ignore the cam belt. Also, it's critical that you investigate the flex plate deflection before going hard on it as these failures can eat your engine completely without you knowing. Read the stickys, and search on Thrust Bearing Failure for info.

sydneyman

Welcome and congrats on the purchase! Loads of information and good advice on here!

awdmoke

I've run mine in summer here with no fan at all without getting hot - as long as I kept moving!
Sounds like water pump. Let me know if you strike trouble as I have a spare in the shed.

928Myles

Gary,
I understand that the WA (Perth) Porsche club has a long-term Porsche mechanic who currently has a 928 as a member. It night be worth contacting them as He could probably give lots of assistance with diagnosis etc.

Myles

westside oz

OK so I've signed up now. Reading plenty on water pumps, modified and otherwise. What I'm seeing and hearing is I'll be well advised to get in and change the timing etc belt, which of course would see me also taking out the water pump as a matter of course. Scott if my thermostat was stuck I wouldn't see any hot water in the top hose right so I don't think that's the problem but I'll check that too whilst I'm all up in there. I see the issues are aplenty with water pumps and it appears the Laso one is the way to go. A very kind offer to "borrow" then replace a pump if I find that to be the issue which is awesome. Everyone here seems to be as good to one another as they are on one of my Jeep forums.

westside oz

Ok so I just had a brainwave. I've been looking at pictures of how the cam belt is set up and I see this belt drives the water pump. I just last night when fiddling around got a BELT TENSION warning light. Is it possible this is why the pump's not pumping? I mean is there a tensioner that needs adjusting to a particular spec as opposed to a normal car that might have a rubber block tensioner which almost always applies correct tension?
I found a manual here but I think it's for earlier models.

928Myles

Gary,
1 - Belt tension would have to be so loose that the belt would jump teeth on the cam pulleys for the water pump to not be turned by it. If the pump is not turning then it is the most likely culprit.
2 - The 928 thermostat operate in reverse way to most so not sure your conventional conclusion is correct.
3 - Not sure that the Laso pumps are still available for your year car (with stock tensioner system). Lots of discussion on the currently available options and lots of varied opinions as well. Best to do you own research and come up with a solution that you are comfortable with.

Myles

The Deputy

Now that you are a member...let's see some pictures...please, pretty please with sugar on top.

Radiator may be plugged with sediment from sitting so long, too.

Brian.

dr bob

Mine takes a bit of fiddling sometimes to break the air lock in the water bridge after coolant replacement. Symptoms exactly as you describe. A combination of keeping the reservoir absolutely full, rev'ing the engine as it comes up to temp, squeezing and releasing the radiator hoses is what gets that air bubble moving for me. Also, I remove the hose from the radiator vent during coolant fill, so the radiator can completely fill with liquid.

The air bubble in the water bridge keeps hot water from reaching the thermostat, so it doesn't open to allow water from the radiator.

I'm about 50/50 on the system air-locking after a coolant fill. Coolant gets swapped every year or two in my car, so I can claim a statistically-significant experience sample set.

James Bailey

It is also possible that the water pump has seized and the t belt is now slipping on the smooth pulley it will then get so hot that the belt melts and vulcanizes to the pulley when you stop.....then you restart and break the belt...My son in law did that on an 83 USA 928 which fortunately is none interference Your S-4 is a valve bender !!

westside oz

Thanks folks and Dr bob I did consider that at first so there was plenty of massaging of hoses etc but eventually the water all just got displaced until I'd chicken out and she er down. Then a little later it would take 3 litres to get it back halfway up the bottle and start again
Repeat
Old oil sizzling on the block down in there is enough for me to bail out of that action.
Having said that I was doing all this on my slightly downward sloping driveway which probably didn't help.
Anyway plan today is to trailer it down to my shop, kick a few things out of the way and have it "up on blocks" for a spell.
Possibly humorous side not for yiz:
The term "up on blocks" we use when our Interior Ministers, girlfriends, mistresses, missus' etc are out of action due to lady lunar business. 😝
Another attempt at pix, here goes:
Nope, pares error message

westside oz

Trying something different with picture posting, lessee what happens....
Nope. Still won't work.

Anyways I trailered it to the shop. She's partially degreased and up on stands now. Before this though I tried one more time to fill with water completely. Lots of "hose massaging" and I though I had it beat but nup.
So now it's the tear down. Fans out, steering tank out, belts off, hoses off. Not necessarily in that order.

bogdann

Hi, look for Dwaynes posts on page 4 of the new visitors guides and he has timing belt water pump write-up, radiator flush etc etc. Well respected on this forum. Also Roger can sell you a cd with the full workshop manuals and many other interesting resources.

Look at all the fire threads - replace fuel and Power steering hoses unless they look in great condition.

Good luck

Dave928S

Tell us what you're doing and we should be able to help .....

Have you tried:
1.'Go Advanced' ... see button below
2. Click on 'Manage attachments'
3. Click on first 'Browse' button and select pic on your computer ..
4. Click on second 'Browse' button to select another .. and so on
5. Click on 'Upload' button
6. Click on 'Preview Post' to view complete post
7. If OK, Click on 'Submit Reply' ... if not, make any final changes, and then click on 'Submit Reply'

You can also insert a pic using the button in the header of the posting text box, and pasting in a url, to a pic on the Rennlist server, or a photo sharing site.

HTH

westside oz

So I've done some more homework after getting into it a bit. First of all here are a couple pics of the vehicle. Evident here in the morning sun is why I hate silver gars. NO ONE can match silver.


Before commencing tear-down a had another go at bleeding the coolant system but to no avail, still overheating so water pump it is. What I found though was this, not a good picture but the top most bleed port on the bridge was completely blocked. So much so that after much digging with a very small driver I couldn't get right through. I figured it's "possible" this is actually a blank port so stopped digging. Not convinced though.

So now I'm ding as suggested and reading the Newbies thread(s) and boning up on Dwayne's post to see what's up as I progress though this.
More pics later.
G