Oil Leakage from Head (near distributer)

[chenfon]

My AE70 completed convert 1 year+, now the engine start leak motor oil.
first start from the Motor oil lever gage, where found the housing oil ring wearoff. replace and add in silicone gasket then no more leak, but nightmare arrive where found the engine oil pressure increase where cause the oil lever gage "POP-up" when in high RPM. my mech. advise me to tight the gage to prevent pop-up. this really help for few day.
after enjoy the leak free day, suddently found leak more serious at distributer side. after use the talcum power check method, found the oil leak from HEAD part (as per photo circle). currently still uable do any thing on it, wonder what the function of this hole? and another question is when i done repair this leak, what about the high pressure? please do help. thank you

[jondee86]

If the oil level gauge (= dipstick) is being forced out of its holder, it is
usually because there is excessive crankcase pressure inside the engine.
The pressure is caused by "blowby" of combustion gases past the piston
rings. The amount of blowby increases at high rpm's.

Check that your cam cover vent is not blocked. You may need to fit an
extra vent (two intake side cam covers) and run the tubes to a "catchcan".

Cheers... jondee86

[fax0815]

As above, you seem to have a lot of crank case pressure, from my expirience a 4AGE can produce a lot of blowby.

I did this and had no problems afterwards


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[jondee86]

Regarding the plug arrowed in the pictures... I believe it is a threaded
plug used to close a drilled oil gallery. It appears to to be connected to
the gallery that carries oil to the camshafts.

Perhaps someone can confirm ??

Cheers... jondee86

[fax0815]

Yeap it´s an unused oil gallery, take the headles allen key bolt out and seal it with teflon tape.

[chenfon]

thanks guys, i have take out the "NUT" and again add in silicone gasket to total seal the hole. it did work, now again leakage. this time is behind the timing gear cover. i think i hav to open the whole "head" for inspection.
hopefully not the head "crack".

[jondee86]

Oil leaks at the front of the head can come about in three ways...

1. Camshaft seals leaking. Take the top timing belt cover off (5 small
bolts) and look.

2. Cam covers loose, and leaking thru the gasket. The rubber gasket gets
compressed over time, and loses its seal. You need to check the 8 small
nuts are firm. They can be finger tight if they haven't been snugged down
for 25 years Use the smallest spanner you can find.

3. Joint at front of cam cover not sealed with a dab of silicone when the
covers were put on last. This is the corner where flat surface of the head
meets the half circle over the cam seal housing. Needs a small dab either
side to seal the corner against leakage.

Personally, I would bet on the cam seals if they have not been replaced
in a long time. Easy job to replace the seals. You don't have to take the
cams out, but you will need to take the cam pulleys off.

Cheers... jondee86

[fax0815]

+1 for Cam seals, common problem.
Easy to change, but be carefull not to tilt it inside the seat. I wasn´t and hat to change it again.

[chenfon]

THANKS GUY
WILL AGAIN TRY THIS COMING WEEKEND AND UPDATE WITH PHOT LATER.

[ash16valve]

While you at it rather change both Cam seals and crank seal :wink:

That's the 1st thing I did when I bought both my TC's