1998 GMC 4.3L Head Gasket

[Ray Parker]

Can anyone tell me how hard it is to change the head gaskets on my 4.3L. the reason I am asking is my radiator is loosing coolant, I replaced the water pump, I have replaced the heater core . I've checked for leaks everywhere and cannot find any but when I crank the truck up and it runs for a couple of minutes and cut it off I can smell coolant. The engine runs good no smoking at all . I also checked the oil no coolant there that I can see. I need help with solving the mystery of the missing coolant.
TYIA.
Ray

 

[east302]

Have you done a pressure test on the system? Most parts stores will rent the test kit, it could just be a leak that you aren’t seeing (bottom of radiator) or one that is drying up with engine heat.

 

[stutaeng]

Yeah, you have to run additional diagnostics before condemning the head gasket. These engines are not known to blow head gaskets being all iron, but anything is possible.

You most likely have an intake manifold gasket that's leaking. Now, THAT is a very common problem on the Vortec engines.

I did mine last year at 245k miles on my '99 4.3 Silverado (NBS.) I had the same symptoms. Very slow coolant disappearing, maybe a quart every 2-3 months, then one day I started seeing coolant between the valve cover and intake on the driver side. No codes and engine ran fine. Seems daunting, but not too bad of a job. Hardest part is marking and reinstalling the distributer and the loosening the fuel lines.

Trust me a blown head gasket will make the engine run like crap and you would get all sorts of misfires.

 

[Schurkey]

Yank the spark plugs, look for evidence of steam-cleaning.

Yes, an intake-gasket leak is fairly common.

 

[Ray Parker]

Have you done a pressure test on the system? Most parts stores will rent the test kit, it could just be a leak that you aren’t seeing (bottom of radiator) or one that is drying up with engine heat.

Thank you for your help

 

[Ray Parker]

Yank the spark plugs, look for evidence of steam-cleaning.

Yes, an intake-gasket leak is fairly common.

Thank you for your help

 

[Ray Parker]

Yeah, you have to run additional diagnostics before condemning the head gasket. These engines are not known to blow head gaskets being all iron, but anything is possible.

You most likely have an intake manifold gasket that's leaking. Now, THAT is a very common problem on the Vortec engines.

I did mine last year at 245k miles on my '99 4.3 Silverado (NBS.) I had the same symptoms. Very slow coolant disappearing, maybe a quart every 2-3 months, then one day I started seeing coolant between the valve cover and intake on the driver side. No codes and engine ran fine. Seems daunting, but not too bad of a job. Hardest part is marking and reinstalling the distributer and the loosening the fuel lines.

Trust me a blown head gasket will make the engine run like crap and you would get all sorts of misfires.

Thank you for your help

 

[Ray Parker]

Have you done a pressure test on the system? Most parts stores will rent the test kit, it could just be a leak that you aren’t seeing (bottom of radiator) or one that is drying up with engine heat.

Thank you for your help

 

[Ray Parker]

Yeah, you have to run additional diagnostics before condemning the head gasket. These engines are not known to blow head gaskets being all iron, but anything is possible.

You most likely have an intake manifold gasket that's leaking. Now, THAT is a very common problem on the Vortec engines.

I did mine last year at 245k miles on my '99 4.3 Silverado (NBS.) I had the same symptoms. Very slow coolant disappearing, maybe a quart every 2-3 months, then one day I started seeing coolant between the valve cover and intake on the driver side. No codes and engine ran fine. Seems daunting, but not too bad of a job. Hardest part is marking and reinstalling the distributer and the loosening the fuel lines.

Trust me a blown head gasket will make the engine run like crap and you would get all sorts of misfires.

Thank you for your help

 

[Ray Parker]

Have you done a pressure test on the system? Most parts stores will rent the test kit, it could just be a leak that you aren’t seeing (bottom of radiator) or one that is drying up with engine heat.

I replaced the radiator and both hoses