[P38] Exhaust gases in coolant

blue_cheese said:

I've only had it a month, got it cheap from a no-reserve auction so I knew the risks.
Has about 85k miles

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Thats why I asked.
Its likely had a HG problem they did it and punted it on.

Cant really see in the pics. Heads need checking for flatness, block needs checking for liner (Ht, movment for want of a better discription)

The last pic and the first pic look a bit "more looking at needed"
J

My engine (4.0 GEMS) was rebuilt by V8 Developments.
Top hats, and kept same capacity as before.
All major components reused - engine had done about 90k miles.
Superb job and runs like a Swiss watch.
Total cost about £6k.

I like the way they answered my questions:
Run in the camshaft? No need.
Tighten the head bolts? No need.
Just come back in 500 miles for an oil change and check-over.

blue_cheese said:

Morning,

Good news is that the heads are off.

Bad news - the gaskets look like they're in pretty good nick to me. I was praying for an obvious blown gasket, but it seems that's not the case.
View attachment 336625

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Bottom of both those gaskets look pretty bad to me.

Grrrrrr said:

Bottom of both those gaskets look pretty bad to me.

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pwood999 said:

Bottom right in that picture looks questionable to me ?

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Thanks for your opinions, I'm relieved to hear that.

If there's any additional photos I can provide, please let me know.

At this point, I have to reassemble either way. I'll take the heads to the machine shop on Monday and see what the tech says.

There might still be hope!

blue_cheese said:

Thanks for your opinions, I'm relieved to hear that.

If there's any additional photos I can provide, please let me know.

At this point, I have to reassemble either way. I'll take the heads to the machine shop on Monday and see what the tech says.

There might still be hope!

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Straight edge and feeler gauges should be enough. Make sure surfaces are clean using plastic edge or something softer than the metal so it doesn't scratch the surface. Clean with soft rag and solvent like diesel or petrol.

blue_cheese said:

Morning,

Good news is that the heads are off.

Bad news - the gaskets look like they're in pretty good nick to me. I was praying for an obvious blown gasket, but it seems that's not the case.
View attachment 336625

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Both the top left and bottom right do not look great at all.
Wipe all the oil off but not the carbon buildup, then its usually quite easy to see where its been leaking. Then us some new pics of the top and bottom.

blue_cheese said:

Pictures attached below.
I've only had it a month, got it cheap from a no-reserve auction so I knew the risks.
Has about 85k miles

View attachment 336626View attachment 336627View attachment 336628View attachment 336629

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Cylinder 2, 3, 8 all have ring wash. Its where oil gets past your piston rings and then washes the outer edge of the piston clean as you can see thers no carbon buildup on those edges. The top edge of cylinder 8 seems particulary bad.

Also wipe down the oil on the block, but not the carbon buildup so we can have a nice look at the surface. Do the same to your heads and send some pics of those too.

The oil coming out of the oil feed to the heads seems extremely dirty and gummy.

The cross hatching on your bores still look pretty good though.

Cylinder 8 looks very funky, something is not right there. The whole bore is very black with lots of carbon buildup. What ive circled in green kindof looks like a hotspot. What ive circled in blue looks like a crack in the liner to me.
Send some better pictures of that cylinder.

Thanks again all, your input is greatly appreciated.

I'll get some better pictures in the morning, and I'll have a close look at no 8 to see if it's a crack.

+1 on steel rule & feeler gauge for flatness. You can also shine a torch from behind the rule, and easily see any gaps due to warp. Why pay a workshop to do something so simple !!

If they do need a skim, I can recommend Classic Modern Engine Services in Bracknell. They did an excellent job on mine, plus replaced all the old rusty core plugs & helicoiled the block where prev owner had over tightened the head bolts.

Thanks for your recommendations. I live in South Wales, so I fear all of the well-known shops on this forum will be out of my reach!

I've been out this morning to take some close up pictures.
Got both sides of each gasket, a closer look at each cylinder, and one of the heads.

FEI said:

Cylinder 8 looks very funky, something is not right there. The whole bore is very black with lots of carbon buildup. What ive circled in green kindof looks like a hotspot. What ive circled in blue looks like a crack in the liner to me.
Send some better pictures of that cylinder.
View attachment 336695

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I couldn't see the crack on closer inspection, I've taken a picture with a light shining on it.

Please can you give the photos a skim and let me know your thoughts.



Many thanks

blue_cheese said:

Thanks for your recommendations. I live in South Wales, so I fear all of the well-known shops on this forum will be out of my reach!

I've been out this morning to take some close up pictures.
Got both sides of each gasket, a closer look at each cylinder, and one of the heads.




I couldn't see the crack on closer inspection, I've taken a picture with a light shining on it.

Please can you give the photos a skim and let me know your thoughts.

View attachment 336719View attachment 336722View attachment 336723View attachment 336724View attachment 336725View attachment 336726View attachment 336727View attachment 336728View attachment 336729View attachment 336730View attachment 336731View attachment 336732View attachment 336733

Many thanks

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I'm no V8 expert but both the first and last photo's appear to show leaks, bottom right to the water gallery in the first photo and top right in the last photo.

Yeah cylinder 8 bore actually looks fine form those new pictures.
From the pictures it does not look like any of your liners have slipped either.

You might have a coolant leak past the hg into your cylinders but its kinda hard to tell that from pictures, the hg doesn't look good around the coolant passages though.

You definitely have ring wash though. So you might(leaning more towards probaly) have to replace piston rings.
A note on this though. When i first got my p38 i was burning oil, i suspected piston rings and after doing about 2 oil changes and about 10 000km the engine kinda stopped burning oil. The same thing happened with another p38 my brother bought. So we suspect if the engines stand for long, oil changes neglected and dont get driven often the oil in the rings gets gummed up and the rings aren't able to move freely causing them to leak. So it seems after a few oil changes with some high quality oil it seems to fix itself.
But when i did my HG on my car though which was after it had stopped burning oil i did not see any ring wash on my pistons.
So in your case it might go away it might not, thats a gamble you will have to take if you are willing.

Clean off the block and heads really well. Some scotch bright and q20 works quite well, a plastic scraper works well for the tougher spots, a carpet knife for even tougher spots but be very careful not to stracth anything with this. Even with the plastic scraper id be careful to not scratch the aluminium. Put the piston about halway down the bore where you are working with a rag in the bottom and then remove the rag to get most of the dirt out and then while vacuuming out the bore slowly move the piston down to get all the dirt.

Also make sure you clean out the threads for the headbolts in the block. If you take a old headbolt and cut a slot along its threads length wise it makes for a semi decent thread chaser.

Id get myself a straight edge and check the flatness of the block and heads after a thourough cleaning. Just to see if its necessary to send off to a machine shop. Its quite easy to do.

If you not sending anything to a machine shop id also strip the heads down and clean all the carbon off the valves and valve seats, then reassemble them and check for leaking valves, position the heads upside down fill the area above the valves with water(i cant seem to think of the name for it now) then blow some compressed air in through the port and see if you get any bubbles past the valves. If they are leaking youll just have to lap them. While doing this it wont hurt to replace the valve stem seals, they quite cheap and easy to replace. For cleaning valves, put the valve in a drill and some scotch brite and q20 works very well.

I would aslo highly recommend arp headstuds.