Oil leak on a 350 chev

[leeogrady]

Hi,

I am new to the world of chev350's but have one in my recently purchased truck.
I have a leak that appears to be coming from the right hand head in right at the back lower corner. The leak is only minor but i think is getting worse. It only leaks under pressure (engine running). Oil pressure when i was slowly cruising down thompsons track the other day was aprx 35psi, on way up around 40psi, is this relativly normal?
I am planning to strip the top down and replace gaskets/check heads dont need skimming. Is there anythin else that would be recomended to check/replace while i am in there?

Cheers
Lee

[mudlva]

hi there welcome aboard

check the tapped cover gasket as weel as the gasket under the dissy and the thread around the oil preasure sender as all those areas tend to give a bit of sepage .

why are you pulling the motor apart for? if its not broke leave well alone as they are good reilable power plants untill peolpe start mucking around with them ( i found this out )

oil preasure is fine for a standard oil pump at idle and hot the preasure will drop to next to nothing thats fine, BUTas soon as for foot goes down the oil preasure should pick up as well thats what to look for
the gauge will move around a bit thats normal expecially when hot

what wagon have you got and where abouts in nz are ya?

[sig]

sounds like valve cover gasket .buy some new cork ones and silicon them on .problem solved

[sibainmud]

Could be the valley cover/intake manifold. There is a spot that needs silicone between the head gasket, block and manifold.
These leaks can get worse over time when using an alloy intake as the rate of expansion of the different metals causes distortion.

[mudlva]

Could be the valley cover/intake manifold. There is a spot that needs silicone between the head gasket, block and manifold.
These leaks can get worse over time when using an alloy intake as the rate of expansion of the different metals causes distortion.

hay i dont want to get into a slinging match here but every steel tappat cover that ive had has always leaked over time and when i installed a set of "cheap" alloy covers with a cork gasket it has fixed the problem, same thing with the other lads who have run sbc's as well shit design on the holding down of the covers when it only relies on 4 bolts to hold it all in place

just my experiance

[Fakey]

As said above itll be your tin rocker covers not holding the corners of the gaskets down. Get some strong alloy ones an silicon them on. Thats what I did with mine then the cast iron inlet manifold started leaking so redid that aswell

[muddyhilux]

as above and sepage is common,ive been chasing my tail on a number of top end gaskets for a while now then i gave up cos its not causing issues anyway

[Fakey]

Its not sepage, its just sweat from all the horse power Small leaks you can live with but my ones were leaking straight onto my exhaust so it smoked quite a bit

[sibainmud]

Perhaps I didn't type that well
Defiantly no slingin' match
I could of sworn I didn't mention rocker covers
I was talking about the joint of the head, head gasket and intake manifold.
I know about the rocker cover issues, steel ones are more like tin.
Over torquing the R/covers will cause leaks due to distortion.
All good, just some suggestions for him to look at.
Cheers,

[mudlva]

ah yes the intake manufold

it could of been more me thinking rocker covers as i was continuely fighting those things for so long before i moved to alloy

strangly tho ive not had a problem with the intake, i know of a mate that did but he bought a alloy cheinse one so we put it down to that more then a design fault

cheers

and the rteason i mentioned the dissy is that ive that the little gasket in there break and seep oil out
oddly enough whenever i have bought a water pump gasket set it had a thermostate and dissy gasket with it must be saying something there ah

[sig]

if you are resealing your intake manifold ,throw the rubber end gaskets away and use a thick bead of silicon .dont even know why they supply them, fcukin useless things .as soon as i started doing that hey presto no more leaks

[leeogrady]

Thats awesome guys, just what i was after. Looks like the old DIY gaskets is mostly the way to go, and a few good points of what else to check while i am in there! Thanks!
I will try keeping the old rocker covers for now, but will keep my eye open for a new set for a later date!

mudlva: The reason i am pulling the top apart is to fix the leak, its annoying me now whenever i stop and leave it running theres a large puddle of oil after i pull off and i dont like leaving trails through the bush!

The truck it is in is http://www.offroadexpress.co.nz/4wds/57 ... club-truck and i am up in Tauranga.

I will have to check the oil pressure when i put the pedal to the metal as I dont recall the pressure increasing, but to be honest i dont really look at gauges when i floor it

[mudlva]

yeah sweet my bad

you did mention about a possible skim of the head i couldnt work that one out but im guessing you were talking about the intake manufold

ive had 5 sbc now and only 1 that didnt leak got the impression they were built that way means you can extend the oil changes by lots as im always adding oil

[leeogrady]

ive had 5 sbc now and only 1 that didnt leak got the impression they were built that way means you can extend the oil changes by lots as im always adding oil

Now that is actually not a bad point!! Maybe i should leave it as is!