Truck still runs hot. idles in shop at about 205. climbs to 220 driving. Stop before it gets any hotter. Only about 90deg. outside. So here is what I know."all temps taken with laser heat gun"
Radiator has 20-25deg. drop from top tank to bottom tank. that is with the electric fan on.
A 25deg drop would take 205 to 180, so the radiator doesn't appear to be the problem.
water pump flows what i would consider a normal amount of coolant when t-stat is open
tried 180, 160, 180 drilled, and no t-stat. all like results
added 1200cfm fan to front of radiator, same results
removed lower half of fan shroud to force more air through top, same results
This again says the radiator is not the problem. The water is being heated too much for the cooling system to maintain the correct temp.
tested coolant with block leak tester for leaking head gasket or head, so sign of hc in coolant.
I still think the head is the source of the problem. Heat comes from the engine. If the water flow through the block and the heads is unrestricted but temp is still too high, the head gasket is the only thing I can think of that could cause the problem.
Exhaust gases are @ 500deg, so it wouldn't take much exposure to superheat the water to the point that the cooling system cannot cope.
big red flags are jumping at me in a couple areas.
* engine heats real fast. about 2min from cold to 190
* temp sender at back of head reads 205 when front thermostat housing reads 180, but block reads 205 from front to back
is it possible that the head gasket is blocking some water ports? can they be installed backwards, or upside down? Could it be the wrong head? been years and years since i had one apart.
That's certainly a possibility. If the gasket isn't a 235 gasket, and water ports are blocked, that would account for the excessive heat.
In either case, I think the culprit is the head gasket or head.
