External coolant leak at head?
Thread Starter
Teching In
Joined: Nov 2013
Posts: 13
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From: CT
External coolant leak at head? while working on my 5.3 swap project the other day, I noticed coolant had been dripping off my cross member. I looked up the passenger side of the engine and found it's leaking coolant from what looks like the corner of the head by the casting number where it meets the block. When I picked up this engine I noticed traces of coolant in the same spot but thought nothing of it. I put in new head gaskets and bolts and dropped it in the car.
Being this is happening again, is it safe to assume I have a bad head? These are the famous 706 Castech heads, but don't show cracks internally, and my motor oil is free of coolant. Anyone ever hear of these failing externally?
Being this is happening again, is it safe to assume I have a bad head? These are the famous 706 Castech heads, but don't show cracks internally, and my motor oil is free of coolant. Anyone ever hear of these failing externally?
Thread Starter
Teching In
Joined: Nov 2013
Posts: 13
Likes: 0
From: CT
I added some of those GM coolant tabs to it, seems to have slowed the leak down a lot, but it's still there. Now I can see where it's coming from and it's not good. There's a 1" crack in the head right above one of the bolts. I don't see any coolant in the oil, so it's just a nuisance (for now).
I found a couple pairs of heads in the yard, both are 5.3s, one has 706s without the castech logo and the others are 862s. Any difference or advantage of one over the other?
I found a couple pairs of heads in the yard, both are 5.3s, one has 706s without the castech logo and the others are 862s. Any difference or advantage of one over the other?
I got bit by that on my 04 suburban, except it was going out the exhaust. I grabbed used 706 heads from a 07, and havent' had issue since. Verify the year is not 04-06 before putting them on. FWIW, I don't think thers is much diference between 862 and 706.
