1989 Chevy 350 bad intake or head gasket?

stewart14 · February 7, 2016

I have a 1989 chevy 4x4 with a 350 TBI.Recently, it started running rough & blew white smoke out the exhaust.There is no antifreeze in the oil, I pulled all the plugs & #7 cylinder blows antifreeze out when cranking.The compression is good on all cylinders but #7 compression leaks down.I am thinking it would be more likely to be the intake gasket than head as there is no oil contamination.Any thoughts on this would be appreciated before I start tearing it down. Thanks!

LeoS41280 · February 7, 2016

Has the engine been overheated?

stewart14 · February 8, 2016

no, it hasn't overheated-temp. always stays normal.It has been losing some antifreeze for awhile but no signs of a leak or exhaust smoke until now.

diyer2 · February 8, 2016

IMO

No oil contamination could mean no. 7 is burning the anti freeze thus the white smoke. Not leaking bad enough to contaminate the oil. What does the plug out of 7 look like?

No. 7 bad valve or valves, valve seat, rings?

Badass69 · February 8, 2016

I have a 1989 chevy 4x4 with a 350 TBI.Recently, it started running rough & blew white smoke out the exhaust.There is no antifreeze in the oil, I pulled all the plugs & #7 cylinder blows antifreeze out when cranking.The compression is good on all cylinders but #7 compression leaks down.I am thinking it would be more likely to be the intake gasket than head as there is no oil contamination.Any thoughts on this would be appreciated before I start tearing it down. Thanks!

Considering 7 leaks that pressure is going somewhere which is likely into the cooling system thus head gasket or cracked head. TBI heads like to crack as well. The oil will stay clean if the head gasket is pushing coolant into the cylinder.

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