Seeking advice -Thermostat housing intake plenum
I recently began noticing a coolant smell in my 99 GM 4.6 and after some investigation found a hairline crack in my thermostat housing. I haven’t had time to look real close, but it appears to fix this I’ll need to replace the entire intake manifold / plenum. Is this correct? Are all of these made out of plastic? What’s the deal with that??
Can an aftermarket ALUMINUM plenum by purchased? If so, where is the best place to buy.
Also, is there any online instructions available for removing the intake plenum?
Thanks for any advice.