I bought a used set of stock 5.3 heads that were disassembled. Took them in to a shop to have them cleaned up, and they recommended a valve job for $200. I declined, and took them home and tested the valve sealing by spraying brake cleaner down into the ports. After sitting for a minute or so I could see the bottom of the valves starting to get wet from brake cleaner soaking through. After letting them sit for a couple minutes there was brake cleaner that had soaked all the way through and dripped on the counter. Is this normal or do I need to have the valve job done?

 

They will probable be ok. I would have probably sprung for the valve job, just so you would have a known "good" set of heads on the motor, since the rest of the motor is fairly new. If you would have "lapped" the valves when it was assembled, there probable wouldn't be any brake clean seeping though. How many miles were these supposed to have on them?

 

If your only concerned about the valves sealing, the small amount of leakage your seeing isn't necessarily going to show up as a power loss. More than likely after a some mileage is put on them they will seal up water tight. A performance valve job can offer some flow advantages and maybe that's why the machine shop recommended it? What ever the case, a very slow fluid leak is not going to cause a problem with the engine's ability to make adequate cylinder pressure. A little lapping compound on the valves and seats as kb mentioned above will help stop any leakage. Just be sure to clean up any left over compound from the head and valves when you're done.

Good luck.

Richard

 

OK sounds good, thanks guys. I'll get some lapping compound for them, and otherwise I won't worry about it.

I think they were supposed to have about 10k miles.