MikeAK Posted March 1, 2022 Share Posted March 1, 2022 A few weeks ago I overheated my P38 4.6 on a play day. Got a radiator full of mud and didn't notice the temperature gauge hard over until steam came from under the bonnet! what a muppet I am! Since then it's been using water, about 1/2 an expansion tank over about 10 miles. Doesn't overheat as long as it's kept topped up, temp gauge sits bang in the middle. Put some UV dye in a couple of weeks ago but so signs of external leaks. Cooling system holds pressure on a pressure test at 1 bar when cold. Radiator hoses get very hard when hot so I assume combustion gas getting in the cooling system when the engine is hot. So yesterday I decided to investigate properly and did a compression test when hot. All cylinders around 175 to 180 psi apart from number 3 which is 145 psi. Followed that by a leak down test but was surprised to see no significant difference on number 3 and no bubbling in the expansion tank which I was expecting, but engine had cooled down somewhat by then. However obviously something wrong with number 3 so today I took off the left hand head and found this. Looks to me like a crack in the cylinder wall, but would like the opinions of people with experience of these things. The crack (if it is) is adjacent to one of the head bolt holes, which I supposed is the more stressed area of the bore. I presume the block must also be cracked behind the liner to allow passage of water/combustion gasses? Does this mean it's beyond top hatting? Thanks Mike Quote Link to comment Share on other sites More sharing options...
elbekko Posted March 2, 2022 Share Posted March 2, 2022 That does look awfully like a crack. Top hatting might still work, I'd check with an engine rebuilder. Quote Link to comment Share on other sites More sharing options...
SteveG Posted March 2, 2022 Share Posted March 2, 2022 As above talk to someone like Ray at V8 developments or Turner Engineering, but I suspect they’d both say don’t bother. When I spoke to them, they both test your block before carrying the liner treatment and if they find any damage/cracks on the block they recommend not using it. Sending pics to them should get you a definitive answer. I have a complete gems 4.6 engine here that I don’t plan to use, but probably no use to you as you’ll only need the block. cheers Steve Quote Link to comment Share on other sites More sharing options...
MikeAK Posted March 3, 2022 Author Share Posted March 3, 2022 Hi, thanks for the replies. Emailed Turners with the pictures, but got an automated message back saying office closed this week. Will ring next week and see what they have to say. Mike Quote Link to comment Share on other sites More sharing options...
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