Ideas on my leak?

[Lobo'74]

Truck has been sitting for about a month or so. I started it up , let it idle for a couple of minutes moving another car off the driveway, then drove about a mile to the gas station. Found fresh engine coolant in the "dimple" in the left front of my intake manifold, and a small line of fluid all down the left engine/intake manifold/valve cover area. No visible leak. I dried it all off and ran it for another 5 - 7 miles or so and checked it again... Still no more leak.

The engine is a '79 350 so it has the thermostat cover on top of the engine in this same area. Any chance that after sitting in the garage for a month that the gasket around the thermostat dried out and allowed the leak until it swelled up again?

No fluid in the oil so i don't think its a cracked block, but is is weird.

Any ideas?

[JimKshortstep4x4]

My first thought would be the t-stat housing but it is possible to get a leak from the manifold bolts. If you can get one, put a pressure tester on the radiator and pump it up to 10 PSI and let it set. Your leak should show up.

Jim

[Lippyp]

T-stat housing, mine does exactly the same, I've got an aftermarket cover with the O ring seal and nogasket, but the intake manifold is a little corroded underneath it and it just won't seal. I've tried everything, gasket with sealnt, gasket without, O ring type, just sealant. I'm getting a nerw intake manifold soon so that should sort the problem, but I bet that's where your water is coming from.

[Lobo'74]

I appreciate the assistance. Drove it for 30 -45 minutes... No leak.

Don't you just hate to troubleshoot intermittent faults?

Thanks again.

[1-PU70]

Check the bolts on the t-stat housing and the intake to make shure they are tight. Check the hose clamp too.