Replacing the head gasket

[Storm]

I have to replace the head gasket on my moke as there is brown gunk in the coolant. I have a new gasket but it has no markings. Do I put the copper side up or the, what looks like, aluminium side up?? I would of thought the copper side??

[Storm]

I had to fit a new unleaded head to my moke so I bought a 1100cc head to fit on my 998cc block.
I replaced the head gasket, cleaned everything within an inch of its life, put the copper side up ( as recommended by the manufacturer ). I ran the engine for a while and all seemed okay. Ran it into town today and lost a bit of power on the way home. Removed the radiator cap and once again there is brown sludge in under the cap. So it looks as if there is a leak between the water galleries and the pistons.
I checked the head and the block for flatness and they both look okay.
 I cannot understand what I am doing wrong. The only thing I can think of is the fact that I put a smear of Loctite ( MR5923 ) on both sides of the gasket. Could this stop the gasket from sitting down flat?? but if not what should be done to stop this happening again.

[Terry]

Hi,

as far as I am aware you shouldn't use any type of sealant/glue between the gasket and block or head so it could be an issue but couldn't say for certain. Copper gaskets also have some sort of issue with using coolant in them first time up until they have had a chance to settle in and be pretension.

If you have brown sludge that is a sign you have oil getting into the water rather than "So it looks as if there is a leak between the water galleries and the pistons." When the piston gets access to the water way you tend to find a lot of pressure build up and bubbles in the water.

If brown sludge is a symptom of why you replaced the head gasket in the first place then it could just be residue of the previous issue just circulation in the system and coming back to the cap again if you hadn't flushed the block.

The loss of power suggests a leak in the pistons so if you haven't already done so, do a compression test on each cylinder and look for a cylinder that is down on compression or two next to one another showing the same numbers or takes more revolutions to build up to a reasonable number.

Terry

[Drakman]

Assuming you put the head back correctly and tensioned it down properly, i would be looking for a cracked head or maybe a slip cast block.  Has the block been bored or sleeved?  Look for stained areas on the cylinder walls sometimes when blocks have been bored there can be tiny pin holes through to the water jacket.  Is there water in the oil?  looks milky white after running if there is.

With the radiator cap off and the thermostat open are there bubbles in the radiator?

And no sealant on a head gasket, you could use "copper coat" on  solid copper gasket though.

How did you check the for flatness, with a straight edge and feeler gauges?

All of the above are probably worse case things, it could be as simple as there is still some crap in the radiator that you didn't clean out.

Just my 2 cents worth.

As Terry said, a compression test is the first place to start and look at the plugs if there is any thing wrong you might see some thing on the plugs.

Cheers
Dave

[Storm]

So I have just removed the head from the block and the head gasket shows no sign of a leak. All holes line up and all have solid imprint rings around them. I have put a straight edge across the head and the block and there are no gaps on either. Plugs are all similar in colour, so I think I will get the head tested as this is the only thing that is new and this will rule out any problems with that.

[Halfpint]

Hi,
Did you do a compression test before removing the head?
This may have given you a clue to the power loss.
HP

[Storm]

I did not want to run the engine again until I have an idea of where the problem is. I will check when I replace the head. Pistons look good with no slop. I have an idea that the power loss was due to the fact that the coolant temp went up over 240 degrees and the oil was probably very thin due to the temp yesterday. It was not really a power loss as the car was still cruising at 80.

[yellaterra]

Hi Storm.   If the temp went up to 240 then you probably have a radiator full of that previous engine gunk probably pay you to get it cleaned out before you attempt another run with the new head gasket. Don’t know if you have a std rad or a extra core one but on the safe side get it cleaned and checked before running it again. We certainly had a hot experience this week and radiator cooling problems are a known problem with our mokes if their not up to scratch

[Storm]

I think the main problem, on that day was the fact that it was over 40 degrees and the radiator could not get cold air to cool it. I will clean out the cooling system though.

[Storm]

To flush the radiator I understand to be a bit of a pain but it will have to be done. I have been told you can use baking soda, water and white vinegar to flush the internals as the vinegar reacts with the soda.

[yellaterra]

Hi storm. Again i stress cooling off moke radiators is important. You have already investedmoney and your time into your moke. Take it out and get it done once and checked that its right to go. There are a couple of good radiator shops withold school knowledge of mini radiators. Get it done by them properly to protect your engine investment you can use your garden hose to reverse flush the engine block but i. Feel most of the engine crap is already in your radiator. Happy mokin YT

[FNQ]

hi Storm


As per a number of above comments, i would check for leaks in the radiator side and or sludge.  You mentioned you had to replace the head- is it because the first one warped or cracked  due to overheating?  You get my drift,,,,, seek the cause don't just treat the symptom. It sounds as if your head gasket replacement went fine and the head sealed around the pistons. Again as per above, i would suggest getting the cooling side of things spot on. Get the cap pressure tested, get the radiator pressure tested ( include the hoses)  see if there is brown boil stain on bonnet above the cap area, your brown sludge is a classic sign of dirty cooling passages and boiled dry.


Vinegar and soda basically neutralise each other, - either can be effective used alone - but a rad shop full clean out is better .  Just note ask for a guesttimate, as there are many alloy radiators available for under 100 AUssie dollars. ( I have spent closer to 350 getting one refurbed - rodded, resoldered etc, but i also have used the chinese alloy ones with good effect.


Also to try and not sound all doom and gloom - 40 degree heat tested out lots of motors lately and i saw plenty of all types of cars sitting on the side of the road trying to cool off - hopefully the fix is not problematic.


While your head is off - check it for straightness also.  Cheer Darryl

[Storm]

Had the head tested and all okay. Checked both for flatness and both seemed flat. Cleaned the head and the block, fitted a new head gasket ( No sealant ) and slowly re-torqued the head down. 30 then 40 then 45lbs ft. Replaced all gaskets and left to dry overnight. Flushed out the radiator with water, added some cleaner and ran the engine for around 10 mins. Let it cool down and again flushed the system with water and then replaced the coolant. Noticed a small couple of beads of water where the new head gasket is. Borrowed a coolant pressure tester and pressurised the coolant to 13 psi. The needle very slowly dropped. I decided to torque the head down to 50lbs ft. and retest. Gauge needle very very slowly dropped but hardly noticeable. Decided to take the car for a run, temp went up to 180 degrees ( Just over 200 when doing 100 Kph ) and the oil pressure was good, ran well and on return checked the coolant and a few very small bits of brown gunk, rechecked the head and set the tappets again. Checked the compression on each cylinder and 1 was 130, 2 was 135, 3 was 130 and 4 was 135, so the compression looks okay. Each cylinder took 10 turns of the engine before the gauge stopped going up. Re pressurised the coolant and it is stable but I still think I might torque the head down another 5lbf ft.

[Terry]

Hi,

I would just drive it for awhile and not going for anymore torque on the head. 45 is with nuts/stud is normally fine, less if you have bolts, but I would think if you over do the torque you could have problems if things get overly hot again.

From what you have described it sound pretty normal to me.

Terry