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5.0 whistling noise

fastpakr

Well-Known Member
Joined
February 18, 2005
Messages
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City, State
Roanoke, VA
Year, Model & Trim Level
99 4wd - 5.0/4R70W/BW4406
I'm nearing completion on a 5.0 Explorer -> '99 Ranger swap. Got to the point of cranking it up on Saturday and it fired instantly. However, there's an odd whistling noise coming from the right rear of the engine (general vicinity of EGR and the A/C evaporator housing).

Here's a quick clip of it running:


I've tried temporarily removing the vacuum lines from each port on the intake and plugging them with my finger. There was a slight change in pitch when doing so, but it definitely didn't eliminate the noise. The engine seems to idle pretty smoothly at 900ish RPM. No fluctuations, and no codes in the first couple of minutes I had it running. Any thoughts on what might be creating the noise? A couple of other people have suggested an intake gasket leak or something in the EGR itself. I'm trying to assemble a list of things to check when I can get back to it sometime this week.
 



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Take the oil cap off with it running and see if the noise changes.
 












I'll check both. For that matter, I have the IAC from the 3.0, but it's spent some time out in the rain during the swap. Worth a shot...
 






Tried swapping the IAC and pulling the oil cap with no effect. Also pulled the fan to hopefully make it easier to hear and control spraying carb cleaner to locate a vacuum leak. Checked through Torque app with engine running and saw only 8-10 psi of manifold vacuum at idle. No codes, but the idle was rougher than I remembered when writing the original post. Here's a video that hopefully clarifies the location of the noise:


At this point I'm assuming it's a major vacuum leak in that area. Either a gasket mating surface or a connection that I just missed in my search. Going back through photos to see if there's something attached to the bottom of the upper intake that I'm forgetting.
 






There are hard plastic vacuum lines that run under and around the upper and become very brittle with age.

Does the sound go away when you rev it a bit?
 






It does go away, or so I was told by the guy giving me a hand with it on Sunday.

I did have to make some repairs to broken lines and move a few things around to match better on the Ranger. Maybe something is hooked up wrong and /or broken. Going in for a better look again this evening.
 


















I had a bad IAC valve on our 2000 Mountaineer 5.0L. It made kind of a howl, or humming noise, at idle (not a whistle). Cleaning it (and its filter) didn't help. I replaced it with a new Chinese made one off eBay for around $22. That was about 3-4 year ago. Still quiet.
 






The IAC's on the 5.0 donor and the original 3.0 in the truck were both working fine when they were pulled, and I've now tried both so I think it's not that.

The noise is definitely loudest towards the passenger rear of the engine. I'll start there with carb cleaner to locate the source. Thanks again for all the suggestions.
 






I had a bad IAC valve on our 2000 Mountaineer 5.0L. It made kind of a howl, or humming noise, at idle (not a whistle). Cleaning it (and its filter) didn't help. I replaced it with a new Chinese made one off eBay for around $22. That was about 3-4 year ago. Still quiet.

We just went to the scrap yard and got it but it sounded just like that and your correct no matter how much it is cleaned won't help still don't make us try tho lol
 






Got a better look this evening. Found one of the egr to intake bolts was loose. Tightening that helped quite a bit but left the whistle at about half volume. Shooting carb cleaner at the base of the intake to egr connection still causes a stumble. Unbolted egr from intake hoping I'd just forgotten the gasket but it was there. Started to remove the egr tube to check for leaks but accidentally bent it beyond repair so I cut it to speed removing the remains.

I'll wait for the egr spacer to come in next week, then pull the upper intake and check thoroughly for leaks as well as re torque the lower intake bolts. While it's off I'll add in the phenolic spacer. Hopefully it will be resolved when I'm done
 






I'm sorry; I don't have anything to offer to help you with the noise. But I'm jealous of how clean that engine bay is ALMOST looking. That intake manifold looks like it's in pretty good shape!
 






20171208_103705.jpg


It definitely needed a bit of cleanup from the original donor pictured above. Started as a quick swap project but ended up rebuilding the engine and throwing in a higher lift cam with matching springs. I really hope this is the last big detail to fight because it's about time to start driving this thing!
I'm sorry; I don't have anything to offer to help you with the noise. But I'm jealous of how clean that engine bay is ALMOST looking. That intake manifold looks like it's in pretty good shape!
 






View attachment 160932

It definitely needed a bit of cleanup from the original donor pictured above. Started as a quick swap project but ended up rebuilding the engine and throwing in a higher lift cam with matching springs. I really hope this is the last big detail to fight because it's about time to start driving this thing!
Wow! Big improvement! Once you're all buttoned up and done I'm sure it'll look damn near perfect. I'm jealous. I spent some time on mine using S100 Total Cycle Cleaner (motorcycle cleaner) but it was HOT and I was starting to be frustrated with the lack of progress so mine is looking LAME!
Before:
36856975_10160830385820107_6523468690220908544_o.jpg


After :( :
36755319_10160830386060107_1582895267634479104_o.jpg
 






CHECK THE PCV VALVE make sure its seated
Real PITA to get to but can be done

Sounds exactly like a 5.0 where the PCV valve has not been seated fully. I like to actually silicoln the rubber surround gasket in place
 






Do you mean put RTV around the plastic insert into the lower intake? If so, I did do that. Will definitely give it another close look however. Thanks for the tip.
 






yes
that stupid rubber adapter likes to dry up and come loose too easily making it difficult to seat the pcv. So over the years I just started to RTV it in place.
As you know there is a bunch of plumbing on the underside and back of the upper plenum...it all must be in place.
The PCV is so hard to seat when installing the upper intake I have done a few 5.0 start it up and hissing noise...I know exactly where to look first, usually find the pcv valve hanging about 1" above its hole :)
It IS possible to reach around back there from the passenger side of things, maybe have to loose the DPFE sensor from the intake bracket to make room for your arm/hand
 



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Thanks for the clarification. Gives me some things to focus on when I pull the upper next week. The EGR spacer I need (hope it's the right part) will be here on Wednesday, allowing me to use the phenolic spacer. Everything else is on the shelf at the local Advance Auto.
 






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