fishdan

Had my '85 4X PU for 25+ years. We been through Hell and back together. She's getting beat up but so am I.
2 years ago I paid a shop to replace original heater core --she went a long time--cost a lot of $$ I thought, but guess it takes a long time to do the job. Now the new one is leaking and am kinda ticked about it. Warranty is gone, so now thinking of doing it myself. How hard is it? Or wondering if some stop leak could get me through the winter. Any thoughts on the use of stop leak? Worth it and what brand would you recommend?
She's about to turn 495K miles!! Not original motor.
Thanks for any comments.

millball

If you value your machine USE NO STOP LEAK of any kind.

It will cause more problems than it might solve.

I don't have personal experience changing out a heater core in your vintage truck, but if it was mine, I'd do it myself, no matter how hard.

muddpigg

iTrader: (1)

I would leave the stop leak crap alone.

removing heater core is not that bad, a couple hard to reach bolts to remove dash. Well one in particular. I’ve had mine out multiple times. Most likely cause of leak is the little o-ring that seals the pipes to the core. The o-rings are compressed on flanges that are held together by a c-channel clip. They’re a real PITA the first time. With luck you previous mechanic screwed you over, charged you for new heater core but just replaced o-rings. I can’t find a replacement for my heater core. It seems to be an oddball size. And the aftermarket heater cores didn’t want to mate to copper pipes.

wyoming9

iTrader: (1)

I would go without heat before attempting to change another heater core.

This is because of my size I need to pretty much strip the cab seats and both doors at the very least

If your lucky not having AC does make the job much easier

fishdan

I have always stayed away from stop leaks, but was hoping there was some new miracle product out there to save me a lot of work. Maybe I'll take out the current one and give it a good look before buying a new one.
Thanks for the replies guys.

L5wolvesf

Read this
https://www.yotatech.com/forums/f115...emoval-263039/

fishdan

Thanks!
Good info there. Don't have A/C so mine will not be too bad.

fishdan

After studying these excellent tutorials I'm starting to think it might be the O-rings that connect the tubes to the core. The core is only a couple years old. What a pita it will be just to replace O-rings, but looks like no choice.