head gasket question

[mrsmothers]

I have a sbc in my 1950 I had a coolant leak on top of the motor and coolant sat there for a few days. Strange part about the leak my thermostat housing was leaking which put coolant down the front of the motor. For some reason I had coolant all down the side and back of the intake as well.

Any way I drove the truck about a mile ran fine the next day I went to take it out it back fired twice so I came home now my oil is milky. Truck dosent smoke cant tell if I am loosing coolant the oil level is not going up its just milky.


So million dollar question blown head gasket? coolant leaked past valve cover gaskets or blown intake gasket.

[mr48chev]

The first thing I would do is to get my hands on a pump up cooling system pressure tester and see if the cooling system will hold pressure. If you don't have one or one of your buddies doesn't have one you can do the pay for it use it and take it back and get a full refund "tool borrow" from Autozone. They are about 85 bucks most of the time so a guy can't be expected to just run out and buy one.

If it holds pressure I'd drain the oil and change the filter and go again. If the level comes up on the dipstick while the pressure on the cooling system drops it's time to take the intake and heads off the engine and see what is going on.

[spinned]

Unless it is leaking from the thermostat and just blowing back on the engine, you may have a more serious problem. This recently happened to me... I think my block cracked and now I am installing a new 383 stroker.

My truck started to smoke white fumes, and when I changed the oil it looked like a mocha latte! When I opened the radiator cap, I couldnt see any radiator fluid. I first tried installing a new intake manifold thinking I might cure the problem by installing the intake manifold gasket, but nope no go.

If it is not the intake manifold, it could be a head gasket. My repair guy said if that is the case the heads need to come off and they should be inspected and likely resurfaced. Probably more work would be necessary if ward parts or valves are noticed.

The other likely possibility is a cracked block.

[Speedbumpauto]

Even though I don't suscribe to the tool procurememt method, the advice is reasonable. When the T stat housing leaks, coolant goes everywhere, that's no mystery. You didn't say anything about temperature. Head gaskets don't usually let go unless things get pretty hot. How hot did it get in that mile? and how far did you go the next day before it "backfired twice."? If you went far enough that the heat in the heads fired the mixture instead of the spark plug, it could easily be the head gasket(s).

[OrrieG]

I'm not a big fan of running engines that have gotten water in the oil. You may have already compromised some rings and bearings. Do a leak down on the cylinders to see if its a head gasket or cracked cylinder wall or head. Cracked T stat housing usually can't get water into an oil passage without other problems. Might be an intake gasket if the leakdown does not show anything. Once you find and fix the problem, put in new oil and cross your fingers. If it starts and doesn't make any racket or blow oil smoke you may have gotten lucky.

[Nordic]

Blown head gasket generally runs hot and pushes coolant out the overflow, if you are getting water in the oil it is probably a bad intake gasket. You did not say if it was running well for a while and then just happened , or if it was a fresh rebuild,

[mrsmothers]

Well I rented a cooling tester, I pressured the system and it did not leak.
I gave it about ten min, my oil level hasn't changed. The first time it back fired the motor was still cold ran less then 2 min . The second time it did it I had gone .3 miles so it didn't make it far.

The time I went about a mile in it was the first time it had been on the street. I found no gauges worked well nothing worked. So I don't know how hot it got but it ran well.


When I picked up this 50 it wasn't running had been sitting for about 3 years. I rebuilt the carb the timing was a mess. gave it new plugs wires oil ext..

[mrsmothers]

its kind of hard to see but every dark spot on the intake had standing antifreeze on it.

[spinned]

I think the hose leaked and the fan just blew it all over your engine