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Coolant loss

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aroostok

Jedi Hopeful
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I've been checking some past topics but don't seem to find this one.
I have a coolant loss problem. After drive for about an hour I will lose about half a normal container of antifreeze. The engine was rebuilt about 3,000 miles ago and I just recently replaced the radiator with a NEW one (not rebuilt). Hoses are all good. Fan works fine (this is a 76 B by the way converted to 2 HS4's). It almost seems as if I'm down to 2 possiblities - thermostat or (please don't say this) head gasket. Thermostat is same age as engine rebuild. I have been watching the coolant situation since I noticed the temperature increasing and then decreasing almost at will (it's will - not mine). Any thoughts?
 
Have you pulled your oil dipstick and looked at the condition of the oil?
If the oil looks kind of milky gray, like a milkshake, then you have found where the coolant is going ... into the sump.
The unstable engine temp is the tipoff.
I won't mention the "h..d g....t", but that's a good place to start.
 
Yes I have and the oil looks fine. Don't see any evidence of leaks around freeze plugs or anything.
If I do replace the head gasket I shouldn't have to do a valve job, should I, since the engine only has 3000 miles on it?
 
Run engine from cold with radiator cap off. If coolant foams or has lots of small bubbles while it warms up you have a head gasket problem. Check exhaust for excess moisture. You can buy one of those little lights from Sears that looks like a wire with bulb on end and pressurize coolant and check for antifreeze in cylinders. Any one of these can help before tear down. ALSO: check heater core for leaks, car is 31 years old and probably original core. Also, check heater hoses for leaks. If youhave a valve to turn water on and off to core can leak too. Most of these will leak slowly and sometimes take a while to see. But, they can move your temp up and down. There is a black light kit with dye you can run in coolant and check for leaks, works very well.
 
/bcforum/images/%%GRAEMLIN_URL%%/iagree.gif Yep...if its not leaking out somewhere, its burning/blowing out somewhere...head gasket leak into exhaust is a possibility.
 
Noticed a few weeks ago when I was doing plug replacements that I had quite a few black spots (like a spray pattern) back at the exhaust. Could this be an indication of water in the exhaust like Tony mentions?
 
Yep, just could be. chances are you need to have the head leveled and a new gasket.

While it is out have a machine shop do the guides and valves if it has been awile.
 
Okay, now that I'm totally befuddled, what about a replacement head gasket. This is a 76 engine converted to dual carbs. Both Moss and Victoria British list different headgaskets for 72-74 and 75-80. It seems that the difference according to Victoria British is that one is composit (75-80) and the other copper. What about going to the copper head gasket they also advertise that fits all years? By the way, Victoria British's is 30 bucks and Moss's is 93 bucks. Why such a big difference?
 
Sorry to belabor this topic but could the fact that the head was not retorqued after 500 miles after rebuild have any effect that retorquing might fix?
 
Too late now to retorque. But it could have.

Copper gasket by all means.
 
Not too late to retorque. What have you to loose by trying. Engine was rebuilt 3000 miles ago, should not need guides or valve work unless not included in rebuild. Would try retorque. Spray pattern is normal on start with a cold engine, is the after puddle any bigger or does the exhaust smell like anitfreeze ( yep smell it a little dose won't kill ya, didn't really say that!) Look in cylinders for water, look at radiator for bubbles, before tearing down. Might save some$ and time.
 
Everything done in rebuild including complete valve job, bearings, camshaft, whole nine yards.
Think I'll try the retorque for a day, take it for a run and see what happens. If not, head comes off and new gasket goes on. Thanks guys. You've been really helpful - as always. Greatest forum on the net, bar none.
 
Oh, thought the head was off, sorry. Yep torque it down and see what happens.
 
Here's where we'll all go our separate ways...I say Felpro gasket & nothing else!
 
Payen or Felpro. Retorque any time, as Larry said. Nothing to lose. Just do it in sequence, break 'em loose first, then re-torque. The 45~50 ft/lb sounds correct to me for MGB head torque.
 
coolant going down. No obvious external leaks. No coolant in the oil and no oil in the coolant..then it is most likely a headgasket. It has to go somewhere!
 
Did the re-torque and filled the radiator. Ran it for about 20 minutes (with cap off and heater on). Didn't notice any bubbles. Oil looks good. Did have some pushing out the overflow tube. Could I have filled the radiator too full or do I have to suspect something worse?
 
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