A customer has discovered the dangers of K-Seal in a 1.8 petrol engine. As we always say NEVER use such things in your Freelander. Here’s what happened to him after using K-Seal and another sealing product:

“I notice that the engine block coolant passages on the inlet side are not connected to the coolant passages on the exhaust side. Thus, without the cylinder head, coolant wouldn’t be able to make it from the inlet side coolant passages to the exhaust side coolant passages of the cylinder block.. Unless the cylinder head is connected.
I cleaned it today.. The tiny holes, 8 of them, about the diameter size of a pencil, 2 of them completely blocked with leak sealer K-Seal gunk! I knew as i put the hose through there and water wont run it just turns back. So i poked a tiny screwdriver in there, it wont budge. Then i hit it again with high pressure hose spray, water simply returns back! I tried poking about with a screwdriver,still no luck. Then, i flooded the hole with WD40 then poked around with a screwdriver and viola, it’s finally freed the K-Seal gunk.
I didn’t know K-Seal could do so much damage to the cylinder head.. So what’s happened for me is that the K-Seal has stopped the leak from the cylinder head due to lost torque of the bolts, so i thought sweet, no more cylinder head coolant weepage, well done K-Seal… but what it’s actually done is blocked those tiny coolant passages in the cylinder head, and then the overheating started… Now I knew why.

And all those leak sealers boast “wont clog your cooling system”… yeah right!”