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Engine tapping when hot.

4K views 15 replies 6 participants last post by  atec77 
#1 ·
Hi Guys, I have a au fairlane 4.0l vct + tickford, 120,000ks. Bought 2nd hand 5000k ago. I have what sounded like a stuck lifter noise and replaced all lifters. noise remains!! only hearing it at normal temp. never when cold or on startup like lifters or bigends. Particularly loud around flexplate/ bell housing area, t/conv bolts are tight. Ford dealer says "they all make that noise, just yours is a bit worse" load of bull I say, there is a problem but they want a blank cheque to look for the noise. Please help if you have any ideas I would be very gratefull.
Davsmit.
 
#2 ·
Davs,
not sure on such a late model. But on the earlier ones, its a sign of poor servicing, and/or poor lubricant quality.
On the earlier models i have found the oil galleries on th eoverhead gear block easilyl with crap oil, and hence need removing and cleaning to provide proper oil flow.

Can't suggest a start point as i don't know your expertise level.

Jas
 
#3 ·
Thanks Jas,
Ive been thinking same thing. I am a diesel fitter since 1979, and am struggling with this one now for 5 months. I had a set of lifters fitted when I first bought it as that was the obvious possibility. Mechanic told me the donk was spotless inside and assured me he cleaned oil galleries and found nothing. The car has been serviced exclusively by Frost Ford in Darwin since new, and always on time. (I rang the original & only owner prior to purchase, he adored the car and regretted its sale forced apon him because it had lost its business tax advantages, my gain though).
Having said that, I tend to agree with you on a blocked oil supply to one lifter. Is it likely to be evident if I run it w/out valve cover and see oil discharge from rockers?? Never been inside one of these engines but this would be my course of action. Tried engine on 10w30, 15w40 and now 20w50 oil, no difference, worse now if anything.
Your thoughts??
Rgds Davs.
 
#5 ·
It's a long shot but it could also be a loose control valve (the ones that vary the runner length) butterfly in the intake runner flapping (held shut when cold). Remove the vacuum hose from the diaphragm (engine off) and see if you can get the same noise if you manually lift the control rod and turn the lever back and forth to open and close the 6 valves.
 
#6 ·
Davs,
not sure on the VCT's (am a panel beater, not mechanic (but nothing scares me)
On the EA-ED's the lash adjusters are non adjustable, and i would dare say the VCT ones are the same. They can be tested, but finding someone outside ford with the gear could be hard. When i rebuilt the motor in my EB i looked at replacing these as a matter of course. I bauted at $28 to me for each....there are 24 of em. I was lucky being in trade that i was able to get them tested, and only replaced two.
I did however replace the oil pump in the process.

Since the rebuild, i have stuck with mobil 1 oil...sparodically (too busy to service it) and the falcon tap hasn't resurfaced.

Cheers
Jas
 
#8 ·
Thanks Guys,
Further investigation has narrowed it down to bottom end/flywheel front of trans/t.conv area. Using stethascope against trans front & sump rear seems loudest. top end sounds like a different car by comparison. Being OHC I doubt lash adjusters as this would surely eminate from above.
- No noise on cold start-up,
- No noise on start-up after oil & filter change ie 0 oil press.
- Noise disappears above 1800 rpm
- Noise is same in neutral, rev. drive, and T/C stall
- Noise is relative to engine RPM
- Oil pressure is above gage centrepoint at idle and rises only slightly at revs.
- Ford techs in Darwin and Melb. are trying to tell me all au have same noise. (no way)
- Has anyone had a recall/warranty like this, maybe a coverup by the dealer I bought from??
A carton of best beer to he who can solve this one...
Rgds. Davs
 
#9 ·
Well I'll ask the basics:

does noise go away on the uphill and come back on the downhill?
have you carried out a compression test?
have you carried out a vacuum diagnostic test (eg sticky valve)?
is there a clutch thrust bearing that could be playing up?
are the engine and tranny mounts in good condition?
does the spark plug show over fueling?
 
#10 ·
All the above been done, all good, engine is running perfect, just a blessed knock in it. I suspect the noise is CAUSED by oil pressure, rather than as a result of lack of oil.Sounds a bit like clapping with wet hands (if that helps) seems worse since changing to 20w50 last week, next move is to empty filter when hot (& noisy) and restart donk to see if noise is delayed while pressure rises.
Stay Tuned!!!
davsmit.
 
#13 ·
Thanks for the wonderful suggestions,
Try this one. Ford tech today told me of a AUII taxi problem where #6 piston gets carbon deposits causing a "hot knock". He is getting (at no charge to me) a supply of what he called 'Carbon Buster' which he will injest into my engine via PCV hose. I googled 'decarbonise, engine,ford' and found the exact simptoms reported in USA on 4.0l ohc 1999-2000+ ford explorer, same donk I suspect. They recomend a controlled stream of carby cleaner ,1/2 a can into hot engine via same hose, shut off engine 1hour, add rest of can then go hard on the freeway until smoke clears. Yes that is a Ford bulleten!!
I will let you know what happens.
Tks Davsmit
 
#16 ·
davsmit said:
Hi Guys,
I tried the Subaru cleaner last week. no different!!!

Has anyone heard of trans lock-up clutch problems with AU??? noise could well be coming from T/ converter and I believe some dramas here in AU...
Get the motor hot , park and pull the air cleaner , dribble a flow of water into the running motor , dont stall it , and keep revs around 2>3k , now does it spit and smoke heavily ?
usually a couple of minutes will offers a short term solution being in the water "blasts" a lot of cylinder carbon away ( very old fix) if the knock improves then you have heavy carbon in a rear cylinder and the head might need cleaning if all else fails .
good luck
 
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