Coolant Header Tank Replacement

[lotusman]

Just after I put a No. 15 Chip in my '89 non-SE I started to get the high temperature warning light after the 82 C temperature was reached. Level was always there. Whenever I accelerated, it would go off but come back as soon as I reached a steady speed. Today I bit the bullet and drained the header tank to see if something was loose.

It was. There in the bottom of the tank was a big, flat piece of rust sitting over the outlet hole. apparently, when I accelerated it moved off and then was sucked back into place over the hole. No apparent damage, Thank God.

Now to fix it. The inside of the tank looks full of corrosion on the walls that will surely fall off later and plug something. Is there available a stainless steel replacement header tank? Or do I need to have one made? Is the tank the only carbon steel part of the cooling system?

Also has anyone done this fix? There are what appear to be rivets holding the wheel well cover in place that I need to remove to get to the nuts. What diameter hole is on the other side of the rivet?

Is there any other improvements I can make while I have the cover off? Ram air maybe?

My problem was much like the Black Death. The old saying, "No change, no problem", would say it was the chip. But like the Plague that had really TWO plagues going on simultaneously, pneumonic and bacterial, it was harder to till where the problem was. Just my philosophy on problem solving.

Thanks for the help,
Bob Kumse
'89 non-SE

[cnh1990]

Several of us has used the CLR treatment for the header tank. We disconnected it and blocked it off. Used a CLR cleaner or something like it. (I used CLR).
After diconnecting and rinsing it out I loaded it up with the CLR mix let it sit for a while and used a wet dry vac to suck it out. Reapeated the process many times and the tank came out very shiny. Just use regular coolant mix and change at the recomended intervals. The coolant PH does change over time and rust can set in.
Calvin

[5150neo]

Hi Bob,
I can't say for sure on the 89, but on my 91 the header tank is attached to the wall of the engine compartment via three studs welded to the tank bracket. The nuts are accessed through the wiring harness opening in the rear electrical box. It takes some very crafty hands to reach the nuts and restart the nuts once the tank is replaced. It just takes some patients. I too tried the CLR which works well, but in my case the upper portion of both tanks was rusted to the point of weakening the metal. So I replaced the tank. I also tried to find someone to fabricate a tank in Aluminum, but the cost was absurd.
Cheers
John