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Should I do anything about a minor oil leak?

S

settimo velo

Contributing Member
My engines underwent an initial test run yesterday, out of the boat. They both started first time and seem to run well!

I have just uploaded a short video of one engine running, on the Facebook link given below. After a 15 minute run the only issue I have found is a thin trace of oil along the lower edge of the right hand head gasket. I guess the oil channels are close to the edge of the head and the water channels nearest the cylinder bore. There is no sign of any water getting in the oil.

Is this kind of oil leak a characteristic of these engines?
Oil line along edge of head gasket.jpg
Vintage British automotive engines usually leak oil like a sieve, so my instinct is not to worry about this for now. Ultimately the engines will be tested under load in the boat, so I expect that I'm not really going to know what they're like until then?

If the cylinder head does need to come off to have a new gasket fitted when the engine is in the boat then I do not suppose that it is going to be significantly more difficult to do that with the engine in the boat than out.

What would you do?
 
settimo velo said:
I guess the oil channels are close to the edge of the head and the water channels nearest the cylinder bore.
Click to expand...
they're "miles" away.
probably running down from the valve cover gasket and settling there.

in finding oil leaks - always look higher up
 
Normally marine engines have NO leaks.....My 1987 bildge is clean.........no oil ever.....

Is it above the fill hole on the vavle cover?

Try to find source......
 
Wouldn't put them back in until completely satisfied all is well. Take advantage of them being out of the boat. A lot easier to correct issues before reinstalling. Will probably get worse under load.
 
And the torque of the head bolts are what?

Who did the torquing down ?

What gasket was used.

Was the surfaces clean and true ?

Me i would torque the bolts on a warm motor. Center out.

No cracks, i shouldn't have to ask.
 
It could be running down from higher up. I will take a closer look. There is also a minor leak from the back edge of one of the rocker covers on the other engine. If it is not coming down from higher up I think I will try a torque when everything is warm and hope that makes a difference ... Getting the head off looks like quite a big job, with the need to remove the distributor and the inlet manifold with carb. Good to know these engines are not particularly prone to oil leaks.
 
Most cases it is spilled oil from valve (rocker) cover when adding/changing oil or loose valve covers/bad valve cover gaskets. Of course you will do a oil change before installing, CORRECT??

One idea for you would be to add remote oil filters for both engines. It will put the oil filter on the exhaust manifold attached to a bracket. It makes changing oil filters a breeze!!! I did this with mine and NO MORE standing upside down to change the oil filter. Below is a link to what it is. It is not necessary to purchase the whole unit from merc. All you need is the adapter for the oil filter location now and the adapter for the new location. You can make a mounting bracket and get the high temp oil lines from a local automotive supply. This adds ~ 1/2 quart (16 oz) of oil to system

I purchased my whole set up from a local automotive parts store. One of the best mods I did!!
Below is a link to this websites parts available for your motor for a remote oil filter. It should give you an idea of what you may need.

http://www.marineengine.com/parts/m...&componentId=2822&component=REMOTE+OIL+FILTER
 
I cleaned off the oil run this afternoon and ran the engine again. Result = no oil leaking from either the head gasket or anywhere else! As this is on the oil fill side I think it must be spillage from when I put oil in the engine.

I was looking at the oil filter and wondering if I would be able to reach it when the engines are installed. I think the remote filter is probably going to be the best solution. Another thing also occured to me ... Is there any other way to drain oil from these engines apart from removing the sump drain plug? I'm used to sucking it out of small diesel engines with a hand held pump connected to a tube through the dip stick hole, but I cannot see that working here and that drain plug is going to be long reach under the engine - just as far as the oil filter.
 
View attachment 1814
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The oil dip stick tube end should be a garden hose threaded fiiting.

Merc sells or any marine supply (here anyway in the USA) a hand pump that screws to the fitting.

Get an old 2 gallon plastic jug with a screw on cap and drill a hole thru it for the output tube on the hand pump. Also poke a few small holes for venting somewhere like the handle.

See pic attached.....

Also I reccomend putting some kind of hose clamp on the hose where it is attached to the pump and on the orange rubber of the pump on the brass body to keep it from comming apart Mine is done this way. I use this exact set up. does a real nice job and NO mess!!
 
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Ah, I see, I was wondering what that fitting was on the end of the dipstick tube. I already have one of those hand pumps. However, my other engine does not have the fitting on the end of the dipstick tube for some reason. Anyway, I guess the idea is to suck the oil out of the dipstick tube so I will try to find a pipe that I can clamp onto the end of the dipstick and connect to my hand pump.

This must leave some oil in the bottom of the sump, but I suppose that can be drained off now again by reaching the sump drain plug.... I shall take advantage of that opportuniity now whilst the engines are out of the boat. I can see why Merc changed to the Quick Engine Oil Drain, to drain right down to the bottom of the sump. However, that's only usable if the boat is out of the water.

Also, I've noticed that one of my sumps is approx. 1" deeper than the other. It has a flat bottom, rather than the angled bottom of the other sump, which has the same profile as current production. The engines are 93 - 95. Does anyone know if Merc changed the sump profile at this time?
 
For what this is worth......, I've been around, seen, used, experimented with, and have criticized some of these oil extractor kits. The best that I have found, is the Tempo Oil Boy.
Simple.... non-electric, no spills, no mess. Simply connect to your style remote drain system......, pump up and walk away, and let it do it's job.
These come with an array of tubes and connections, including the one needed for the threaded dip stick tube. Plus an array of plastic straws for normal/small dip stick tubes.

Warm your engine up prior to your oil change.
This makes evacuation faster and easier, and oil filter removal easier.

140805.jpeg


These can also be used to start a siphon, suck water from a bilge, purge/prime a closed cooling system (when adding cabin heat or a WH), etc.
Great tool, IMO.
These are also now being sold under a few other brand names.

.
 
settimo velo said:
Ah, I see, I was wondering what that fitting was on the end of the dipstick tube. I already have one of those hand pumps. However, my other engine does not have the fitting on the end of the dipstick tube for some reason. Anyway, I guess the idea is to suck the oil out of the dipstick tube so I will try to find a pipe that I can clamp onto the end of the dipstick and connect to my hand pump.

This must leave some oil in the bottom of the sump, but I suppose that can be drained off now again by reaching the sump drain plug.... I shall take advantage of that opportuniity now whilst the engines are out of the boat. I can see why Merc changed to the Quick Engine Oil Drain, to drain right down to the bottom of the sump. However, that's only usable if the boat is out of the water.

Also, I've noticed that one of my sumps is approx. 1" deeper than the other. It has a flat bottom, rather than the angled bottom of the other sump, which has the same profile as current production. The engines are 93 - 95. Does anyone know if Merc changed the sump profile at this time?
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I cant speek to the difference in oil pan difference. WHat I can speak to is the dip stick tubes with the threaded fitting on the end. The dip stick tube goes to about 1/8" to 1/4 inch from the bottom of the oil pan so what ever is left over is of NO consequence!! If the dip stick tube with NO threaded fitting does go to the same depth as the other one with the fitting then yes some kind of adaptor will work. The only way to tell would be to try and try before installing into the boat!!!!

If it works then all you need is the threaded fitting that fits over the tube. They are just pressed on.

Post the serial numbers of Both motors and we can pin point what is what.

Of course if you install a oil drain set up to the bottom of each oil pan and make sure you have a propper fitting that will attach to your hand pump then you can just suck out the oil that way and GET IT ALL!!
 
The dipstick with the thread is on the engine with the deeper oil pan, which is S/No OF068418. The other engine with the oil pan with the angled bottom and no thread on the dipstick is S/No OF070624. These are both in the 93 - 95 range of 4.3LXV6 having the 4bbl carb. However, it is possible that various parts including oil pans and dipsticks have been changed over the years, but any light that you can shed on the changes that Mercruiser made would be interesting and appreciated. I imagine the bottom of these oil pans - and maybe the dipstick tubes as well - are vulnerable to dents in transport, installation and removal ... I have a few dents in the bottom of the deeper oil pan, but no leaks!

I didn't realise that the dipstick tube went that deep. Extracting the last 1/4" is not really worth the bother. I'm going to change oil and filters before installing the engines in the boat so I'll see how much I can suck out and take it from there.
 
It would drive me nuts if each engine were that different from one another. I made a deliberate point of having mine being identical when I built them.
Call me anal, if you wish! :D

Both engines are out, correct?
If so, why not match one oil pan to the other, add a remote oil drain hose to each of them (doing away with the dip stick tube idea), then convert both dip sticks to the same (which ever that may be), and end up with both engines being configured the same way?

A remote oil drain hose system is typically much faster at allowing oil to be pulled from the pan.

Just a thought.
Besides, it's so much easier asking you to do this, right? LOL
 
I do not reconize the deep one..Never seen one before. Not to say it is not available. I just have never seen one.

On my merc parts CD when I looked at each of the engine serial numbers they both had the same exact oil pan, The shorter on with the white oil filter.


I agree make BOTH THE SAME. Go with the shorter oil pan as that is the merc stock oil pan. if you get the pan also get the propper dip stick tube and dip stick.

Just make sure the oil pump pick up is the same between both motors. If the deeper one has a deeper pick up tube then maybe just leave it alone...

V6 motor oil capacity is ~ 4.5 quarts WITH filter.
 
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