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Valve cover leak (common?)

Aeroelastic

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Oct 13, 2018
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Hi all,

I have identified an oil leak at the back of my valve cover at the back of the engine near the firewall. This has slowly drip to the top of the gearbox bellhousing etc, making a mess. Is this quite common in the KZTE?

I know there is a half moon plug there, it seems like its leaking from there. I cant find the exact picture of the half moon for my Prado but found some from another cruiser - This is not my car.

half moon 2.gif
half moon 3.png


I have a few questions:
  • Has anyone replaced the valve gasket before, does the rubber gasket go around the semi circular section of the half moon or across the top? i.e. do I need additional FIPG (form in Place Gasket) around the half moon?
  • Is the rubber gasket sufficient around the rest of the cover or do I need to use more FIPG around the multiple 10mm bolt holes?
  • The torque setting of the 10mm bolt has been discussed a lot online but cant find a confirmed value, some says finger tight. Too tight you might bend the plastic, too loose it will leak again. Anyone has any experience?
  • Mine has an intercooler (not the D4D), as its a Prado. I need to remove this hence likely need to change the intake flange gasket (I believe is a steel gasket). I cant find the gasket (part number 17116-67021), seems to be rare in the UK. any suggestion? see picture below
  • Lastly, never done this before, is it tricky? any tips?
1566159079488_big.jpg
 

Shayne

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Feb 2, 2013
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I have never removed my cover but i did tighten the bolts down at motorway service station once .

I only opened the bonnet to check on something unimportant that i'd been messing with recently so to see oil had been weeping out was a worry but i had a couple of hundred miles to do before i could give it any proper attention .

It never leaked again and i'd forgotten about it until your thread reminded me .
 

Aeroelastic

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I might try tightening first, I remember the seller told me he changed the cover gasket just before I got it 18 month ago. maybe it wasn't installed properly.

I take it that its just small wrench and force that you would use for tightening interior fixings, like the 10mm bolt for the panel below the steering wheel? not sure if this is the best description but not properly tight tight.
 

Beastrider

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Hi - I don’t have the intercooler but I have changed the cam cover gasket - it was straightforward. You only need small amount of sealant.

Remove all traces of the previous sealant around the half moon plug and from the timing cover - both sides and de-grease the surfaces. Address any burrs or nicks on the sealing surface. Clean the cover and fit the new cover gasket (£10 from Roughtrax). Apply sealant to the curved part of the half moon plug and in the area of the timing belt cover (two places) but not a lot. You don’t want excess chunks of sealant falling off later and getting in the oil galleries.
Make sure the plug is installed level with the gasket surface, wipe away excess and apply a bit more sealant to the flat upper surface of the plug and across the joints either side of the plug. No sealant required elsewhere.
Both Haynes and Max Elbert manuals say 9Nm for the camcover bolts/nuts. Best of luck.
 

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Shayne

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9Nm when your on the road is a long socket on a 1/4" rachet your thumb on top and as tight as you dare with 2 fingers :lol:
 

Aeroelastic

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Thanks, very detailed write up, give me confidence. What is the attached picture showing? The bit that needs sealant?
 
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Beastrider

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Hi - sealant is required in two areas
1. On the half moon plug, as described in the text
2. At the joint between the cylinder head and the timing belt cover (either side of the front camshaft bearing). Without the sealant, oil can weep there. The picture shows one of these joints.
Just go sparingly with the sealant.
 
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