I've been struggling for months to get ONE torx bolt out of the waterpump on my 88GT. I've been working at it for a while. Coolant was drained several months ago. I had to break the water pump in half to get it out of the car, around the stuck bolt. Finally got the pump off today, and I found all this crap inside the water pump...what happened here???
Corrosion due to the coolant additives breaking down and the water becoming conductive. Aluminium oxides and salts. I've seen quite a few old engines with this type of build up in the coolant passages. I've even seen Jaguar cylinder heads completely ruined with this type of corrosion / errosion of the metal. Cars that sit for long periods seem to be more prone to having the coolant break down and the electrolysis starting.
------------------ "Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero https://youtu.be/hUzOAeyWLfM
[This message has been edited by Frenchrafe (edited 11-04-2025).]
What is the last time you drained/flushed/filled the coolant system before draining it to replace the water pump?
The car sat from 2014 to 2017, when I revived it and started a complete restoration. I've kept good written maintenance records. I would have thought that I changed the coolant in 2017, but didn't see an entry for new coolant since I installed a new radiator in 2013. There's a good chance I drained and refilled the cooling system since, but couldn't find an entry. Coolant remained in the engine the entire time, until several months ago when I drained the coolant to change the water pump.
BTW, the reason why the car has sat so long without coolant is that I needed to figure out a way to remove that one torx bolt from the pump. Damn bolt still isn't out, but I basically broke the old pump up to remove it from *around* the stuck bolt. I'll probably have to drop the engine at this point, given the gel-like goop that might be inside the engine.
I'll probably have to drop the engine at this point, given the gel-like goop that might be inside the engine.
Before you do that, try cleaning around the bolt and getting rid of the electrolysis. It looks like it's been chemically welded so you may need to use baking soda to neutralise that stuff. (It looks like the inside of a flashlight where the batteries have leaked.) After cleaning try a penetrating oil, applying each day for 3-4 days then see if it moves. Sometimes they will tighten before they loosen so try each way. If it's still stubborn, you can try to apply heat to the block.
Once you have scraped off all the gunk and fixed the water pump, I don't think you will need to strip the entire engine? There aren't that many aluminium parts on a 2.8L in contact with coolant. Just run it and flush the cooling system a few times with fresh water. The gunk will disolve a little if there's any elsewhere. Just flush it out! Fill up with good coolant afterwards, and just use the car. (Keep an eye on the coolant colour to see if any impurities are left floating in there.)
On a side note, I disconnect my battery each time I lay up the car for a week or more. I once heard that the residuel charge in a static (unused) electrical system can start up electrolysis? To be safe, and not to have a flat battery as well, I just unplug it.
------------------ "Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero https://youtu.be/hUzOAeyWLfM
[This message has been edited by Frenchrafe (edited 11-06-2025).]
