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Hello,
At the request of Eric over on Facebook. I’m going to throw my hat into the ring with this very oddball noise.
Minor backround: Truck purchased several years ago with two blown heads. (common fail as they crack if the engine overheats) We replaced the heads with new design ones from “World Products”. We did have to recycle the valve train parts due to running out of money. It’s been flawless and running decent for the last 3 years or so until recently.
Recently it started running very rough. It had the same issue when we purchased it and it turned out to be clogged up injectors. So naturally we redid the process. During all of this I noticed a very bad sound. Now in the interest of full information, I do a lot of work on a Ranger forum. I posted the video over there and had limited responses. But they ranged from exhaust leak to bad rod.
I removed the heat riser that surrounds the exhaust manifold. I can not find any source of exhaust leaking. There is a minor exhaust leak at the flange to the Y pipe. But it is a very minor leak. Plus that wouldn’t explain the next part.
If I remove the spark from the passenger side rear plug–The noise all but vanishes. This noise happens under “Load” very loud–when done with the oil filler cap removed–The “Blow By” gasses seem to get worse and it seems to surge (engine does not surge–the visual gasses appear to surge) and become more visual. eg: Hear the noise–see an increase in the gasses– Remove the spark–Limited noise and no real change in seeing the blow by gasses under load.
Ran a compression test at the start of all this: All cylinders floating in the 170 to 180 range. This engine has very decent compression considering the age and mileage.
There is the video of the noise. (My thanks to my better half for doing the video)
Any ideas and/or feedback would be welcome. This is normally my daily driver–Even though it’s broken down 3 times in the past with transmission issues? It has never left me stranded. (Yeah the A4LD has a bad rap….It’s not the strongest transmission made) The truck is fully paid for and I can’t afford a car payment–so what ever it takes I have to repair this. I just hope it won’t take to much $$, as it’s in short supply.
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At the beginning of the video, I’m thinking at idle, it sounds like about 5 clicks per second. Five clicks per second x 60 seconds x 2 = 600 rpm. Is that about where your idle is? And it sounds like valve noise too. However, it fires at the same rate that it clicks and removing the spark plug mitigates the problem. So, must be down below.
I’d suggest pulling the oil filter and cutting it open, looking for metal.
Idle was at about 850, maybe slightly higher. (Engine was still fairly cold. I had my hand around the exhaust pipes trying to feel for a leak–that gets wicked hot and quick!)
The noise itself seems to be isolated to the upper region of that head. One of the guys in the Ranger forum suggested doing the trick using a wooden stick or a long probe. Running the piston up to TDC and turning it slightly so the crank is pulling down on the piston. Then giving the piston a shove to see if I hear a ‘clunk’. I’ll give both suggestions a shot on Sunday (my next day off). Yeah I hear a lot of rattles and noises from under the truck when I put the ear next to the oil pan. But the noise isn’t that loud under at the pan. It honestly seems like it’s coming from the valve cover?
This is why I’m so cornfused about it. It sounds like an exhaust leak…but it might be transmitting from anywhere on that side? And under sounds actually as noisy as it’s always been. Granted an exhaust leak from that cylinder would of course ‘vanish’ when spark is removed….just like a rod knock or piston skirt slap would. Thankfully the better half’s Beetle is doing well, as I’m driving that bubblemobile until this gets worked out.
I thank everyone for the advice! But I get the feeling I’m going to have to pull that cylinder head off–either to search deeper—or to pull the piston and connecting rod out.
S-
To me it sounds like an exhaust leak. Since Fords are famous for exhaust manifolds cracking, you might check there. This video might also be helpful.
Good luck and keep us posted on what you find.
Will do! I had the heat riser shield pulled off that “Log” of a manifold already to check for any broken bolts. There is only one area I could not get my hand around to inspect, and that was the area just above the oil filter extended mount (The nice part that flips the filter 90 deg’s so we can get to the stinker)
The riser may be back on now, but I can still see and inspect the area around that rear cylinder’s exhaust port. I’m hopeful that maybe the gasket blew out, or the crack might be in that area. I couldn’t wrap my hand around there due to the tight space. But a car ramp and a little time…. I’ll report back on what we find.
Thanks again!!
S-
(By the way…That was one of the first videos I checked out LOL.)
You have an exhaust leak between the exhaust manifold and the cylinder head most likely at the cylinder that the noise goes away on when you remove the spark.
Another helpful tip might be to use an inspection mirror to help you get eyes on it. These can be very handy in tight places.
http://www.jbtoolsales.com/performance-tool-1125-telescoping-inspection-mirror/#oid=1002_1
Keep us posted.
Both Eric and wysetech nailed it.
However it wasn’t quite a cracked manifold. Someone will have to explain to my why in the world “Murphy” spends so much time with me. The gasket physically blew out just under the corner edge/front of that cylinder. So there was no way to see, or feel any leak using conventional means. (can’t get fingers there) So I pulled it apart, purchased new bolts–and thank God each bolt came out with no snapping (Love anti-seize) About 1″ of gasket was missing?!?!
I’ll post a “Vent-a-Thread” about another annoying topic that just cropped up on this truck.
Many thanks again!!
S-
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