Hey everyone!

I just bought the other day a 96 thunderbird and I have an issue and think I may need a new head.

After I bought it, from private party, I noticed it was 3 qts low on oil. First bad sign of trying to hide something. So I topped it up with the proper level and drove it, and everything seemed ok.

the engine is smooth, sounds great, but while accelerating on a bridge with concrete walls I heard it, sounds like a knock. Puzzled, I went home popped the hood and rev'd it at the TB. sounds good. no noises at all. Up and down, sounded good. So, went for another drive. I still heard it, now that I was payin attention I heard it, consistent knock above 2500 rpms. But could not replicate the noise parked.

So today after driving it home from work, about 20 miles, I can hear it faintly on the highway at 22rpm sometimes. And it does come and go.

So I had the ac on and this time I could replicate it parked. And it is tough, I have to float the rpm's at about 3000 and let it drop and I can pick up on it. Its coming from the back driver side. I think thats #8 cylinder. It is noticeable, and it sounds like it is coming from the upper end of the engine. I have tried to research but have been left with no conclusion. Its the 96 4.6 with exactly 200,000 mi on it.

With how it sounds I do almost feel if is valve train noise and is only on one valve. Like maybe I have a weak valve spring, or a bad HLA. But i don't want to drop a valve and destroy my head or worse.

So I was hoping to find a 4.6 guru that can drop some knowledge upon me. I am really fond of these ford mod motors but this is actually my first. Typically I only buy probes, but I couldn't find one. lol. And I know the HLA on the probes always made noise, but this one is a little more metalic and does get a little loud at upper rpms. But only under a load. You can barely hear it and HAVE to have the AC on to reproduce it in park, and it is only about 2500 rpm or higher do I hear it.

I work all week, but I plan to grandma it all week and keep the rpms low. So the noise doesn't happen, and wanted to dig into it this weekend. I would appreciate some input, its hard to search for, "4.6 2v upper end engine knock under load" and come back with anything useful.

Thanks in advance!!!

 

I started a thread in this forum, please add here: https://www.fordforum.com/forum/gene...r-noise-27820/