Coolant leak

88_AHB

88_AHB

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Hey guys,

I have a small coolant leak when the 318 is running, at back of the rear passenger cylinder head. It don't seem like its coming from the freeze plug, or the intake above, what other possibilities could it be, a small plug? Anyone else have a leak in this similar area? Hard to see back there since its so close to the firewall. I plan to look further into it this weekend with daylight and more patience.

Thanks
 
Could be weeping out of the head gasket. The head gasket doesn't need to fail dramatically.

Have you done any work, like replaced an intake?

If it's not the heater core leaking onto the engine, I'd lean towards head gasket
 
AMC Diplomat said:
Could be weeping out of the head gasket. The head gasket doesn't need to fail dramatically.

Have you done any work, like replaced an intake?

If it's not the heater core leaking onto the engine, I'd lean towards head gasket
Click to expand...
No, in fact I had the motor completely rebuilt about 7 years ago and I put around 15k miles or so on it?
 
Interesting enough, it was leaking through the rear intake manifold bolt. Whats even more interesting is as I just put a socket on the bolt, the head came off and I saw this...
I didn't even try to loosen it yet, it was just sitting there lol! All the other bolts are tight.
Anyone ever see this happen with a motor that was rebuilt recently with around 15k miles and all new hardware,intake manifold etc?

347f10da-9d31-4b20-ac2f-58ce469e612e.jpg


8136bf02-7a29-45ed-bbd8-05e824033fe5.jpg
 
88_AHB said:
Interesting enough, it was leaking through the rear intake manifold bolt. Whats even more interesting is as I just put a socket on the bolt, the head came off and I saw this..
Click to expand...
Can't say I have...but I will say this: a picture is worth a thousand words...right? See that coolant pooling on top of the intake manifold and head mating space? Yup, you can tell it's weeping it's way into that area.

Alright...so that's an interesting situation.

I assume you torqued the bolts correctly, both pattern (start and center and fan out) and final torque (what fastener brand, what's their torque?), yes?

Did you use bolt under-head fastener lube? ...or what did you use?

I'm thinking this bolt head must have pretty much cracked off way back when and was basically just holding on somehow...

Ohh, and I've got to ask: what's all that wavy stuff in that corner of the intake???
 
M_Body_Coupe said:
Can't say I have...but I will say this: a picture is worth a thousand words...right? See that coolant pooling on top of the intake manifold and head mating space? Yup, you can tell it's weeping it's way into that area.

Alright...so that's an interesting situation.

I assume you torqued the bolts correctly, both pattern (start and center and fan out) and final torque (what fastener brand, what's their torque?), yes?

Did you use bolt under-head fastener lube? ...or what did you use?

I'm thinking this bolt head must have pretty much cracked off way back when and was basically just holding on somehow...

Ohh, and I've got to ask: what's all that wavy stuff in that corner of the intake???
Click to expand...
The intake was installed by my engine builder (who built multiple engines in the past for me) and unsure on the brand of bolts, I ordered everything off of summit racing back then, either holley or ARP if I recall. I'm assuming they used under head fastener lube during the installation? I remember re-torquing them to 25lbs not much after installing the motor into the car but not since then and all the other bolts seemed tight today at 25lbs. The wavy stuff on the corner of the intake is the automotive clear coat, I was trying to keep the intake as clean as possible, its since yellowed/cracked.
 
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