Author Topic: Coolant leak  (Read 238 times)


  • Active Forum Member
  • *
  • Posts: 315
Coolant leak
« on: November 29, 2021, 03:10:27 PM »
Happy Thanksgiving!

My 79’ TA (all original 403) has started to leak coolant and I see the leak coming near where the transmission joins the motor (best guess without removing anything). It’s drips down the starter and also hitting the exhaust pipe (see video).
I also see some yellow gooey buildup near the starter (I assume it's due to the coolant leak).

Any ideas/suggestions are greatly welcomed.

Thanks in advance

5th T/A

  • Active Forum Member
  • *
  • Posts: 591
Re: Coolant leak
« Reply #1 on: November 29, 2021, 03:28:27 PM »
From the video it looks like it has been leaking for a while. There are lots of possibilities. I would start looking at the top of the engine first. It could be a heater hose, heater control valve, intake manifold gasket, head gasket, freeze plug in a head or the block. I think there are three freeze plugs on each side of the block, with one being above the starter. I would use a cooling system pressure tester, you can borrow one from many auto parts stores for free. This way you don’t have to have the engine running or a hot engine while trying to determine the source of the leak. You probably will have to remove the starter to get a better view.
1980 T/A with a Pontiac 461

Gone but not forgotten;
1973 T/A 455
1975 T/A 400
1978 T/A W72
1982 T/A cross fire injected

Two wheel toys;
2014 Harley Ultra Classic Limited
2013 Honda CB1100
2010 Yamaha Vmax
1982 Yamaha Seca 750

Re: Coolant leak
« Reply #1 on: November 29, 2021, 03:28:27 PM »
You can help support TAC!