I have a 98 Disco...I successfully performed the head gasket (rebuilt heads/guides, etc.) job six months ago. The oil is clean. Noticed that the exhaust is white Smokey, oil is clean so far..confused...should I do the chem test for blown HG?

 

Uh oh, sounds like something may have been missed

Definitely test it to be sure, and how have your oil levels been?

I had a similar experience after my HG rebuild, and it turned out that the viscous fan clutch was failing and causing heat spikes and made the coolant leak out from under the cap.

The way to test the viscous fan clutch is to park the vehicle, turn off the engine, and try to spin the fan in front of your radiator by hand (let me stress, TURN OFF THE ENGINE BEFORE STICKING YOUR HAND THERE)... should barely spin or move like it has peanut butter inside (that's a good sign).

If it feels really easy to spin by hand or there is no resistance, then it might be time to replace the viscous fan clutch

Had my viscous fan replaced, and no more issues with the cooling system, no more bubbling from the reservoir cap. Learned this from all the great people on this forum!

 

Okay, will check. I did replace with the Chevy fan clutch. I have the black coolant reservoir, but a newer cap...should replace both? I'm getting white exhaust...the oil is clear, not muddy, as was previous...Do you know the name of the HG test kit that test radiator fluid? Yes, all the expertise in this forum has saved me. thanks to ALL...

 

I am afraid if you have white smoke in the exhaust there is a problem. It is called an exhaust gas in coolant block test kit, a liquid that changes color when it "smells" exhaust gas in the coolant. Were heads machined? Or tested for flatness?