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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22899
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Just started up my 1970 MGB engine after full rebuild of the

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Just started up my 1970 MGB engine after full rebuild of the engine and head. A lot of smoke to begin of course but now much less...I haven't driven it yet but I suppose this might disappear. But then suddenly I noticed smoke coming out of the radiator overflow pipe, and the radiator is empty of coolant, so all has been burnt off... The head gasket I used wasn't new...but it had only been used in a previous failed start-up when a small hole blew out in the head which also caused water into the fuel system. Of course, I cleaned it but perhaps it was not able to seal again? So it can only be the head gasket?
Thanks, Nick

Hello Nick

head gaskets generally shouldn't be re-used so yes I'd agree thats likely to be the fault

Once you've got the head off again I'd also use a straight edge to check the block and head faces for flatness and checking the edges of the casting for any burrs or raised edges that could hold the head and block apart


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Customer: replied 1 year ago.
Matt, engine is reconditioned, head is reconditioned, gasket new one installed (torque wrench new)...after start-up no smoke for a short while then it started smoking again. Temperature starting to go above "Normal" and I can see the level in the radiator is again water is escaping. How to get the good seal...something must be wrong I assume with the head?Nick

Hello Nick

that may well be the case

The other thing to try is a head gasket / block test kit as these take a coolant sample and analyse it for any signs of combustion gas - if present this would indicate a possible crack in the head thats leaking into the water jacket

now if it is cracked what would be worth trying is a bottle of this sealent

I've used it myself and its quite remarkable stuff - an engine that had water jetting out of the head joint stopped leaking and went on to do 20K miles before my wife then crashed the car

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