Author Topic: Coolant leak around exhaust headers?  (Read 1015 times)

0 Members and 1 Guest are viewing this topic.

Offline JNAP

  • Jr. Member
  • *
  • Posts: 1
Coolant leak around exhaust headers?
« on: October 30, 2020, 02:38:10 AM »
I've been working on an engine swap in my 1980 TA, replaced the original 301 with a 6.6L 400 built by Len Williams Auto Machine.  Just got it started up today, and as it warms up (after about 1 minute of running) I get increasing amounts of white smoke coming off the exhaust headers, it appears to be coming from where the header meets the block.  I'm fairly certain it's coolant, and I suspect that maybe I've got coolant leaking through the header bolts from the water jacket? Does anyone know if that is likely, do any of the exhaust manifold bolts thread into the water jacket? Thanks in advance for your expertise and time!

Offline Jefe

  • Jr. Member
  • *
  • Posts: 35
Re: Coolant leak around exhaust headers?
« Reply #1 on: October 31, 2020, 08:44:45 AM »
Never heard of a coolant leak from a header bolt. go get a coolant system pressure tester and see if the system will hold pressure. Also, check your oil for signs of coolant and your coolant for signs of oil. It is not uncommon for a newly built engine to smoke from any of the surfaces that are getting hot. New paint, oil on the surfaces from assembly, etc. Is there an exhaust leak at the header gasket? Most commonly, a bad head gasket will show up as coolant in the oil or white smoke coming out of a tail pipe.
Jeff-
Current project
1979 Firebird Formula / in the family since new
Previous projects
68 Chevelle
72 GTO
78 DKM Trans Am #127