Overheating Issue

[jsdieter]

My 78 spider was running great last summer, fall, and early into winter. In the colder months I had to block part of the grill with cardboard so the engine could reach full operating temperature. It sat for 2-3 months during the snow storms in the Washington DC area and while the salt was on the roads. I drove it a few times when it warmed up then my radiator neck got a crack. I took it to my radiator guy and he soldered a new one on. I reinstalled the radiator and it was cooling ok. Then the top tank started leaking so I took it back out and had it repaired. Since reinstalling two months ago I have not been able to get it to run at normal operating temperature. I have been through hours of running and over a tank of gas trying to bleed out the system. There always seem to be bubbles even after hours of bleeding. I have a T fitting installed at the highest point in the system, and I use a bleed funnel. Normally these do the trick, but not this time. With the cap off the T fitting I can see the water flowing, so I know the water pump is good. I have tried filling every way I have heard to help air escape. I’ve used an airlift to pull a vacuum on the cooling system, which it held for over fifteen. Still ran hot. I put the bleed funnel on and still small bubbles come up from the funnel. I had been thinking head gasket, but other than a few small bubbles that come it in a pretty steady stream there is no evidence to support this—no oil in water/water in oil, no white smoke, and tonight it passed a combustion leak test (I hoped it would fail this to give me something to fix). The thermostat was opening when it should have, but I put a new on just in case it wasn’t flowing right (I hate just throwing parts at something). The new thermostat also works as it should, and has a small hole drilled at the top. I trust my temperature gauge because when I hold an infrared thermometer next to the sensor the readings are the same. I am completely out of ideas. I work at an auto repair shop and have spoken with over half a dozen mechanics and they are stumped. I’m still leaning towards head gasket because I don’t know where the air could be coming from, but maybe it’s just not enough for the combustion leak test to detect. The bubbles do come at a higher rate with higher RPMs. Anyone out there have any ideas?

[So Cal Mark]

sounds like a head gasket issue to me

[jsdieter]

I finally got everything together do this job. I torqued the head down last night. This morning I was putting the exhaust manifold on and one of the studs snapped. Can I reuse the head gasket since it has never been started? Thanks.

[So Cal Mark]

I would, unless you applied sealer to it that causes it to peel when you remove the head