worf928

It does logically follow. But, it also seems rather more experimental that just changing your coolant every 4-5 years.

worf928

Here is one of Charlie's heads after soda and after our Head Guy 'gouged-out' the damaged aluminum before welding so as to get most of the worm holes:



Here's a close-up where you can see some worm holes. (You don't have to completely remove the worm holes, but you need to 'close' them.)



And, done:

Hey_Allen

While this is not commonly used for cars, it is a routine maintenance item in heavy trucking fleets, from what I can from a fleet mechanic relative.
He started using the one available from Napa on his personal vehicles after using it for years for the fleet that he maintains.

NoVector

I'm guessing you already disposed of the coolant. Would've been interesting to put some litmus test strips in it to see the acidity and alkalinity levels. I'm guessing his expansion tank is very brown now from the rusting sleeve <lol>

worf928

I have no doubt. Big difference with a fleet though. One, spending 10s of k on coolant when you can spend less on a 'package refresh' makes the accountants happy. Two, fleet trucks get regular inspections and three there's a huge fleet dataset to mine to guide maintenance.

Whereas on our 928s I encourage 'my folks' to learn how to do their own fluid changes not only to save money but so that they get under the car periodically and inspect things.

More-or-less, yeah, it's gone. There's still some in a container but, it's probably too 'mixed' with traces from other cars to be good to measure.

And of course the tank is brown. Nothin' to do with the coolant though (it's as you point out, the steel sleeve rusting.)

chart928s4

The offending coolant was long gone before this job and the version we flushed was new bright green. The tank plastic yellowed due to age but there was no bath tub ring. Both are now brand new. So they should be good for the next 25 years.

Dave and I crossed in mid ether. Maybe the tank was rusty also. The old nasty coolant would have been well diluted with new at least twice and I think the damage was done a while ago.

worf928

Nah. You were responding for the past and I for the present.

Randy V

Cue Greg Brown. He knows first hand the damage lack of coolant changes cause on our engines.

GregBBRD

I know enough to know that I kn

GregBBRD

I've seen engines that I was absolutely certain would have terrible corrosion, which had nothing. And I've seen engines that I thought would be OK which had just the fire rings left.

There's only a few things I'm relatively certain of:
1. If the heads are leaking around the perimeter of the gasket, it's not going to be pretty, when the heads come off.
2. If the heads are leaking around the perimeter and the car is a 16 valve version, the corrosion will have migrated up the studs and you are going to be in for a real fight. (I once spent an entire day getting one head off an engine.)
3. If the engine has been removed from a vehicle, the coolant did not get drained, and the engine sat for any extended period of time (over 6 months), the electrolysis is always worse...and will begin attacking the cylinders.
4. When the above occurs, "green" coolant will turn into gel and turn an iridescent green color....your first thought is to back away and go grab a hazmat suit and breathing gesr. After staring at it for awhile (from a distance) you can convince yourself that this is actually alien life.
(I will find a picture of this....it's remarkable!

drooman

Do we know the chemistry of the factory fill coolant, and if it changed over the years? Wondering if a bad combination of water, coolant, gasket material, and aluminum could have got started at the factory.

928 GT R

Sooooooo,

My 90 GT has had regular and excellent coolant maintenance over its 29 year life. There is little doubt that it has been over-maintained since I bought it in 2002. The engine runs great and shows no signs of leaking or corrosion in the cooling system. I am coming up on a TB/WP service and the heads have never been off. Should I really tear this engine down at this point?

Given my personality, I'd end up going all in and this would become a stroker motor with all of the issues that go along with that... OR - should I just maintain it and find out how long one of these engines can go with excellent maintenance?

>

Schocki

Absolutely what you said in bold... That´s what I will do !
Here is a picture of my GTS during the last TB job 2014 with about 120 kmls on the clock. No corrosion in the coolant circuit. I'm using the G13 coolant from my VW/Audi dealer. I was told that this is the stuff the factory filled it with...

SwayBar

Not unless the engine is smoking, an indicator of worn valve guides. Just keep driving it!

Wisconsin Joe

Heavy trucks have several differences in the coolant and maintenance of it.

One is that they have a 'filter cartridge' that includes the additives. The coolant is never changed, unless it gets 'lost' (spilled or leaked).
They also aren't running aluminum heads or blocks. Steel is tougher than aluminum.
There's lots of engineers and research scientists doing lots of work to find the best, most effective and cheapest solution for this. Truck makers, coolant makers, companies. There's tons of data on it.

And, more than the 'acquisition' costs is the disposal costs for the old coolant. My understanding (and I could be wrong on this) is that it costs almost as much to dispose of old coolant as the coolant cost to begin with. As a 'person', I can get my local county landfill to take small amounts of hazmat, including old coolant. If I was a 'business', I'd have to pay.