c900 cooling system issue on 1983 8VT

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Craig's Saab C900 Site - 16 Jun 2006 06:47 GMT

Hi everyone,

I think the cooling system on my 1983 8VT has a problem. When I had the
engine running yesterday the coiling system boiled over (fan still ran
though), and what was strange was that all the hoses were hot except the
small overflow hose after the engine had warmed up.

That suggests there could be a radiator blockage - anyone agree? I've got a
spare radiator (pulled from the 1983 gli), and a new radiator too (scoop
purchase from a place in Hawaii), but I'm hoping if it is a rad blockage
that a simple flush with the usual jet-of-hose run into various parts of the
cooling system to wash out left over gunk may fix it.

Failing that it could be a stuck thermostat. I have a couple of new spares
(thanks to the folks at PFS via my last order!) on hand.

I will also check the radiator fan fuse and wiring and the thermoswitch as
well just to make sure all those parts and associated wiring are not the
cause.

Can anyone offer some more suggestions? I hope it'll be a simple fix but if
not I can take time to dismantle some of the cooling system to deal with
whatever isn't working right.

Thanks,

Craig.

Signature

Craig's Saab C900 Page at | Craig's Classic Saab Workshop - Sydney .au
http://lios.apana.org.au/~c900 | http://www.classicsaab.net and other URL's
Email: c900@lios.apana.org.au | For Saab 99/C900/9000 Enthusiasts World-Wide!
Alternate: saabonaut@gmail.com | Web-forums, galleries, library, links, etc.

Reply to this Message

Charles C. - 16 Jun 2006 09:57 GMT

> Hi everyone,
>
> I think the cooling system on my 1983 8VT has a problem. When I had the
> engine running yesterday the coiling system boiled over (fan still ran
> though), and what was strange was that all the hoses were hot except the
> small overflow hose after the engine had warmed up.

The big hoses hot system runs

> That suggests there could be a radiator blockage - anyone agree?

yes but not the way you mean it. See end of message.

I've got a

> spare radiator (pulled from the 1983 gli),

It will be as bad (probably).

and a new radiator too (scoop

> purchase from a place in Hawaii), but I'm hoping if it is a rad blockage
> that a simple flush with the usual jet-of-hose run into various parts of the
> cooling system to wash out left over gunk may fix it.

Maybe. You may also find that it leaks like a sieve after you flush it.

What do you intend to do with the new rad. Hung it on the wall as a
work of art?

> Failing that it could be a stuck thermostat.

hoses were hot thermostat was open.

> I have a couple of new spares
> (thanks to the folks at PFS via my last order!) on hand.
[quoted text clipped - 8 lines]
>
> Thanks,

On my long gone to heaven c900 1983 vintage 8v etc when I replaced the
radiator because I was getting bad cooling ... it disintegrated. I
think simply by now the radiator is gone. The rad. does not have a
single passage to get blocked it is full of many little passages ...
which GET BLOCKED :-) with salts and rust. The little copper(?) fins
which are stuck between the water passages disintegrate and you get bad
cooling.

> Craig.

It is helps at all.

Charles

Signature

Please remove _removeme_ to reply.

Reply to this Message

Craig's Saab C900 Site - 19 Jun 2006 01:08 GMT

Hi everyone,

Well after discussing this with a few other people I'm going to try using a
cooling system flush product (Nulon's one for those in Oz who know about
Nulon products) combined with some hose jets into various ports that I can
get to without lots of elastigirl-style arm bending. 8-)

If that doesn't unblock the radiator I'll remove the old one and put the new
one in it's place so I can take the old one to a proper radiator service
outlet and get them to figure out what the condition is.

Changing the radiator isn't going to be a huge job but there's a fair amount
of prep to be done before it can be changed. So avoiding that for the time
being at least would be a Good Thing!

Regards,

Craig.

Signature

Reply to this Message

Charles C. - 19 Jun 2006 08:25 GMT

> Hi everyone,
>
> Well after discussing this with a few other people I'm going to try using a
> cooling system flush product (Nulon's one for those in Oz who know about
> Nulon products) combined with some hose jets into various ports that I can
> get to without lots of elastigirl-style arm bending. 8-)

Watch very very very carefully for leaks after you flush it! Run the
car stationary until full temperature is reached.

Good luck
Charles

> If that doesn't unblock the radiator I'll remove the old one and put the new
> one in it's place so I can take the old one to a proper radiator service
[quoted text clipped - 7 lines]
>
> Craig.

Signature

Please remove _removeme_ to reply.

Reply to this Message

Richard Sutherland-Smith - 19 Jun 2006 09:36 GMT

>> Hi everyone,
>>
[quoted text clipped - 5 lines]
> Watch very very very carefully for leaks after you flush it! Run the
> car stationary until full temperature is reached.

Go and get it rodded out properly by a radiator shop. It's not worth
half-doing a job in the long run.

Signature

Richard Sutherland-Smith
19 Webb Road, Wanganui 4500, NZ

Reply to this Message

Craig's Saab C900 Site - 20 Jun 2006 04:30 GMT

>>> Hi everyone,
>>>
[quoted text clipped - 8 lines]
>Go and get it rodded out properly by a radiator shop. It's not worth
>half-doing a job in the long run.

True, but I figured that since I need to flush the oil system as well,
running the engine to do that can also be used to flush the cooling system
and then if the radiator remains blocked it's not a totally lost cause since
I will have flushed and replaced the engine oil regardless.

First though I need to loosen the oil filter and at the moment it's
super-tight - using both hands gripped hard around it won't turn it.
Unfortunately it's got the Ryco version and not the genuine Mann aka Saab
version so my filter wrench isn't the right size (the Ryco filter is just a
few mm larger in case diameter)! I don't want to puncture the oil filter's
casing if it can be avoided so I'll try a long flat-bladed screwdriver with
a hammer applying turning force to the lip of the filter casing instead.

It's always fun and games!

Craig.

Signature

Reply to this Message

Charles C. - 20 Jun 2006 07:47 GMT

>>>> Hi everyone,
>>>>
[quoted text clipped - 24 lines]
>
> Craig.

Ehmm no. You just need the correct tool.
http://www.toolmix.com/browse/product.asp?gid=1004&pid=58130

You may need to tie a wire at the end of the chain to guide it round the
filter ... unless your hands are a lot smaller than mine.

Regards
Charles

PS. If you use a chain wrench you have to make sure you move it up and
down the filter otherwise you could cut through it. Usually if you get
it high up near the thread the filter is harder and it will grip without
bending too much.

Signature

Please remove _removeme_ to reply.

Reply to this Message

Craig's Saab C900 Site - 20 Jun 2006 11:26 GMT

>True, but I figured that since I need to flush the oil system as well,
>running the engine to do that can also be used to flush the cooling system
>and then if the radiator remains blocked it's not a totally lost cause since
>I will have flushed and replaced the engine oil regardless.

Well I've done both tonight, and the problem with the cooling system was not
a blocked radiator at all - it was the port where the small hose goes from
the expansion tank to the top of the left side of the radiator that was
blocked up. Once I ran the engine to heat it up and let the cooling system
and oil system cleanout products do their respective jobs, I changed the
coolant tank after draining the system and found the blockage, as well as
being able to look at how badly decayed the steel sleeves in each of the
hose ports on the old tank were. ewww. 8-)

I ran a *lot* of fresh water into the system via the large hose that joins
to the expansion tank and proved the small-hose port of the radiator wasn't
blocked because coolant and eventually clear water came out when I kept the
flow into the large hose up to completely fill the radiator with water.

As for the oil system, I ended up getting the old oil filter to loosen using
a flat screwdriver and hammer by making the blade bite into the filter's
base flange and using that as a force point to make it turn. It's only took
two 'bite' points to get it turned enough so it could be loosened by hand,
but whoever put it on must have really forced it tight. I was careful not to
damage the oil filter mount.

Now the car has a flushed and refilled oil system and the same with the
coolant system. Tommorow I'll check the clamps are all tightened properly
and also the oil drain plug is torqued to the right setting, and run the
engine to circulate the new oil (Shell Helix Ultra is what I use) and fully
bleed out any remaining air pockets in the coolant system. I've still got
about 2 litres of the 8 litres of coolant mixture left after bleeding using
the port on the thermostat housing, so it's probably the heater valve
circuit that is still full of air.

Craig.

Signature

Reply to this Message