the-jag-guy

iTrader: (11)

I have 2 different 98 LS1/automatic engines from Camaros in a couple of project cars I'm building. The engines and all the pieces on them look identical. The first car is running now and I had it out for a drive- runs great, and kept pretty cool the whole way. But on last mile or so of a 20 mile drive, the engine started to overheat. No coolant was lost and the fans were running. What's interesting is the radiator itself felt cool, the upper hose was hot, and the lower hose was cool, almost cold. I'm thinking- thermostat died. Took it out and was going to replace it with one from the other engine. The the second thermostat won't fit in the water pump- the hole is too small. The second thermostat is the outlet/thermostat assembly, while the first one has 2 separate pieces (outlet and thermostat with a rubber ring between them).

I checked a new water pump at the parts store and it has the bigger hole. Is anyone aware of running changes in LS1 water pumps???

Engine #1 ( the running one) came from a car with last 7 digits of the VIN 2142887, and engine number 2 came from VIN 2151465

I still think my overheating may be the thermostat, but I'll need a new water pump to try it out....

2001NBMZ28

One of the pumps has probably been replaced, the old style tstat won't fit the newer replacement pumps.