18mm or 20mm head gasket??

[tiny_J]

I got an 06 6.0, I have read that engines built 03-05 have 18mm and engines built 06-07 have 20mm. Where can I find a build date of the engine, or is it just a best guess thing?

With my truck being an 06 i just thought that the engine might of been build in 05 and sat around or something. I just want to make sure I buy the right ones the first time.

[Fred@PMM]

Check the build date in your door, if it is Pre-January 06 Build its for sure 18mm. Anywhere after that you would need an oasis ran to find exact build date. Also, if the truck has had heads replaced under warranty it can still be a 20mm and require the use of a step dowel.

[06StrokeWagon]

if your truck is pre jan 06 do you have to run 18's or can you run 20's

[Fred@PMM]

Originally Posted by 06StrokeWagon

if your truck is pre jan 06 do you have to run 18's or can you run 20's

If your heads are 18mm you will have to use 18mm gaskets, if your heads are 20mm you have to use 20mm gaskets.

[tiny_J]

ok thanks guys for the quick response!

[Dave]

Or if you can still read the sticker on the valve cover the engine build date is noted on it.