Please don't tell me blown head gasket

[grantgsr]

I have a 1971 Fiat spider with a 1608 engine and I converted to an 1800 intake manifold several years ago so I could put on a weber 34 ADF carburetor. I haven't run it very much the last few years while I was waiting to get some body work done. Now that that is done I'm trying to get all mechanical issue squared away and while letting it run to check my fan and thermostat, I noticed coolant leaking from the bottom. I eventually traced it to a leak from the very back port on the intake manifold and, closest to the firewall. I had this capped off with a rubber cap and a hose clamp. So, is this a dried a blown head gasket or some other kind of gasket failure? Any suggestions or condolences appreciated.

Grant

[kmoses]

If it is a 5/16" (8mm) fitting you have capped then it is the coolant feed for the carburetor water choke. If you are not using it, run a hose from the fitting to the pipe that runs under the exhaust manifold and attaches to the water pump. There should be a connection branch that is angled toward the back of the engine. This will keep coolant moving at the back of the head.

[grantgsr]

Thanks! That sounds like good news. The fitting is approximately 5/16 (8mm). But I cannot find any connnection on the metal pipe from the water pump to the heater that runs under the exhaust manifold. Any ideas?

[phaetn]

Some heater pipes have an extraneous nipple near the firewall. Mine doesn't. It attaches on one end with a flange to the water pump, the other end is just mated to a rubber hose that leads to the interior heater.

I, too, have an 1800 head and have the port that you are talking about blocked. It's just a piece of hose with a bolt in it, clamped. I guess the system never builds over 18-20 PSI, though I have tested it at more than that with a coolant pressure tester when I was chasing down a coolant leak into the combustion chamber. Turns out it was from the intake gasket at the rear. The intake manifolds were sand cast and I guess aren't always perfect. Some copper spray-gasket on both sides of the proper paper gasket helped seal it.

Cheers,
phaetn

[kmoses]

I don't know how Fiat hooked up the water choke return on the 1600cc engine, or if they even used a water choke. That being said, you could add the newer style heater pipe that has the nipple on the side like the one shown in this link. https://autoricambi.us/collections/cool ... 124-1975on
or you could just block off the port again.

[grantgsr]

That heater pipe with the nipple would be just the thing. For now I'll just do a better job of plugging the nipple on the manifold. Thanks all for putting my mind to rest -- I was worried that was supposed to be a vacuum port and coolant was coming out.